MC9S12E256 Data Sheet
MC9S12E256
Rev. 1.08
01/2006
MC9S12E256 Data Sheet, Rev. 1.08
4Freescale Semiconductor
To provide the most up-to-date information, the revision of our documents on the World Wide Web will be
the most current. Your printed copy may be an earlier revision. To verify you have the latest information
available, refer to:
http://freescale.com/
The following revision history table summarizes changes contained in this document.
Revision History
Date Revision
Level Description
November 10, 2005 1.07 New Data Sheet
January 18, 2005 1.08
Table A-4. Operating Conditions — Updated minimum value for I/O, Regulator and
Analog Supply Voltage
Table A-9. Voltage Regulator Electrical Parameters — Updated minimum value for Low
Voltage Interrupt for both Assert Level and Deassrt Level.
Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.
This product incorporates SuperFlash® technology licensed from SST.
© Freescale Semiconductor, Inc., 2006. All rights reserved.
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 5
List of Chapters
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1) . . . . . . . 21
Chapter 2 256 Kbyte Flash Module (FTS256K2V1) . . . . . . . . . . . . . . . . . . 81
Chapter 3 Port Integration Module (PIM9E256V1). . . . . . . . . . . . . . . . . . 119
Chapter 4 Clocks and Reset Generator (CRGV4) . . . . . . . . . . . . . . . . . . 165
Chapter 5 Oscillator (OSCV2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4) . . . . . . . . . . . .205
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1) . . . . . . . . . . . . . . 235
Chapter 8 Serial Communication Interface (SCIV4) . . . . . . . . . . . . . . . .243
Chapter 9 Serial Peripheral Interface (SPIV3) . . . . . . . . . . . . . . . . . . . . . 275
Chapter 10 Inter-Integrated Circuit (IICV2) . . . . . . . . . . . . . . . . . . . . . . . . 297
Chapter 11 Pulse Width Modulator with Fault Protection
(PMF15B6CV2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
Chapter 12 Pulse-Width Modulator (PWM8B6CV1). . . . . . . . . . . . . . . . . . 377
Chapter 13 Timer Module (TIM16B4CV1). . . . . . . . . . . . . . . . . . . . . . . . . .411
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2). . . . . . . . . . . .437
Chapter 15 Background Debug Module (BDMV4). . . . . . . . . . . . . . . . . . . 445
Chapter 16 Debug Module (DBGV1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .469
Chapter 17 Interrupt (INTV1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .501
Chapter 18 Multiplexed External Bus Interface (MEBIV3) . . . . . . . . . . . .509
Chapter 19 Module Mapping Control (MMCV4) . . . . . . . . . . . . . . . . . . . . . 541
Appendix A Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . .559
Appendix B Ordering Information and Mechanical Drawings. . . . . . . . . . 594
List of Chapters
MC9S12E256 Data Sheet, Rev. 1.08
6Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 7
Contents
Section Number Title Page
Chapter 1
MC9S12E256 Device Overview (MC9S12E256DGV1)
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.2 Device Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.2.1 Detailed Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.2.2 Part ID Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
1.3 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
1.3.1 Device Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
1.3.2 Signal Properties Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
1.4 Detailed Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.1 EXTAL, XTAL — Oscillator Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.2 RESET — External Reset Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.3 TEST — Test Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.4 XFC — PLL Loop Filter Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.5 BKGD / TAGHI / MODC — Background Debug, Tag High & Mode Pin . . . . . . . . . . . 61
1.4.6 PA[7:0] / ADDR[15:8] / DATA[15:8] — Port A I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.7 PB[7:0] / ADDR[7:0] / DATA[7:0] — Port B I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . 61
1.4.8 PE7 / NOACC / XCLKS — Port E I/O Pin 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
1.4.9 PE6 / MODB / IPIPE1 — Port E I/O Pin 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
1.4.10 PE5 / MODA / IPIPE0 — Port E I/O Pin 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
1.4.11 PE4 / ECLK— Port E I/O Pin 4 / E-Clock Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
1.4.12 PE3 / LSTRB / TAGLO — Port E I/O Pin 3 / Low-Byte Strobe (LSTRB) . . . . . . . . . . 63
1.4.13 PE2 / R/W — Port E I/O Pin 2 / Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
1.4.14 PE1 / IRQ — Port E input Pin 1 / Maskable Interrupt Pin . . . . . . . . . . . . . . . . . . . . . . . 63
1.4.15 PE0 / XIRQ — Port E input Pin 0 / Non Maskable Interrupt Pin . . . . . . . . . . . . . . . . . . 64
1.4.16 PK7 / ECS / ROMCTL — Port K I/O Pin 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
1.4.17 PK6 / XCS — Port K I/O Pin 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
1.4.18 PK[5:0] / XADDR[19:14] — Port K I/O Pins [5:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
1.4.19 PAD[15:0] / AN[15:0] / KWAD[15:0] — Port AD I/O Pins [15:0] . . . . . . . . . . . . . . . . 65
1.4.20 PM7 / SCL — Port M I/O Pin 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
1.4.21 PM6 / SDA — Port M I/O Pin 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
1.4.22 PM5 / TXD2 — Port M I/O Pin 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
1.4.23 PM4 / RXD2 — Port M I/O Pin 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
1.4.24 PM3 — Port M I/O Pin 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
1.4.25 PM1 / DAO1 — Port M I/O Pin 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Contents
MC9S12E256 Data Sheet, Rev. 1.08
8Freescale Semiconductor
Section Number Title Page
1.4.26 PM0 / DAO2 — Port M I/O Pin 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
1.4.27 PP[5:0] / PW0[5:0] — Port P I/O Pins [5:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
1.4.28 PQ[6:4] / IS[2:0] — Port Q I/O Pins [6:4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
1.4.29 PQ[3:0] / FAULT[3:0] — Port Q I/O Pins [3:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
1.4.30 PS7 / SS — Port S I/O Pin 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
1.4.31 PS6 / SCK — Port S I/O Pin 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
1.4.32 PS5 / MOSI — Port S I/O Pin 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
1.4.33 PS4 / MISO — Port S I/O Pin 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
1.4.34 PS3 / TXD1 — Port S I/O Pin 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
1.4.35 PS2 / RXD1 — Port S I/O Pin 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
1.4.36 PS1 / TXD0 — Port S I/O Pin 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
1.4.37 PS0 / RXD0 — Port S I/O Pin 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
1.4.38 PT[7:4] / IOC1[7:4]— Port T I/O Pins [7:4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
1.4.39 PT[3:0] / IOC0[7:4]— Port T I/O Pins [3:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
1.4.40 PU[7:6] — Port U I/O Pins [7:6] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
1.4.41 PU[5:4] / PW1[5:4] — Port U I/O Pins [5:4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
1.4.42 PU[3:0] / IOC2[7:4]/PW1[3:0] — Port U I/O Pins [3:0] . . . . . . . . . . . . . . . . . . . . . . . . 68
1.4.43 VDDX,VSSX — Power & Ground Pins for I/O Drivers . . . . . . . . . . . . . . . . . . . . . . . . 69
1.4.44 VDDR, VSSR — Power Supply Pins for I/O Drivers & for Internal Voltage Regulator 69
1.4.45 VDD1, VDD2, VSS1, VSS2 — Power Supply Pins for Internal Logic . . . . . . . . . . . . . 69
1.4.46 VDDA, VSSA — Power Supply Pins for ATD and VREG . . . . . . . . . . . . . . . . . . . . . . 69
1.4.47 VRH, VRL — ATD Reference Voltage Input Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
1.4.48 VDDPLL, VSSPLL — Power Supply Pins for PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
1.5 System Clock Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
1.6 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
1.6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
1.6.2 Chip Configuration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
1.7 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
1.7.1 Securing the Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
1.7.2 Operation of the Secured Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
1.7.3 Unsecuring the Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
1.8 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.8.1 Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.8.2 Pseudo Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.8.3 Wait . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.8.4 Run . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.9 Resets and Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.9.1 Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
1.9.2 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
1.10 Recommended Printed Circuit Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Contents
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 9
Section Number Title Page
Chapter 2
256 Kbyte Flash Module (FTS256K2V1)
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
2.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
2.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
2.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
2.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
2.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
2.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
2.4.1 Flash Command Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
2.5 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.5.3 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.6 Flash Module Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
2.6.1 Unsecuring the MCU using Backdoor Key Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
2.6.2 Unsecuring the Flash Module in Special Single-Chip Mode using BDM . . . . . . . . . . . 117
2.7 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
2.7.1 Flash Reset Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
2.7.2 Reset While Flash Command Active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
2.8 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
2.8.1 Description of Flash Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Chapter 3
Port Integration Module (PIM9E256V1)
3.1 lntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.1.2 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
3.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
3.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
3.3.1 Port AD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
3.3.2 Port M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
3.3.3 Port P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
3.3.4 Port Q . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
3.3.5 Port S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
3.3.6 Port T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
3.3.7 Port U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
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3.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
3.4.1 I/O Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
3.4.2 Input Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
3.4.3 Data Direction Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
3.4.4 Reduced Drive Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
3.4.5 Pull Device Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
3.4.6 Polarity Select Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
3.4.7 Pin Configuration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
3.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
3.5.1 Reset Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
3.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
3.6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
3.6.2 Interrupt Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
3.6.3 Operation in Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Chapter 4
Clocks and Reset Generator (CRGV4)
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
4.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
4.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
4.2.1 VDDPLL, VSSPLL — PLL Operating Voltage, PLL Ground . . . . . . . . . . . . . . . . . . . . . . 167
4.2.2 XFC — PLL Loop Filter Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
4.2.3 RESET — Reset Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
4.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
4.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
4.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
4.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
4.4.1 Phase Locked Loop (PLL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
4.4.2 System Clocks Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
4.4.3 Clock Monitor (CM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
4.4.4 Clock Quality Checker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
4.4.5 Computer Operating Properly Watchdog (COP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
4.4.6 Real-Time Interrupt (RTI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
4.4.7 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
4.4.8 Low-Power Operation in Run Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
4.4.9 Low-Power Operation in Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
4.4.10 Low-Power Operation in Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
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4.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
4.5.1 Clock Monitor Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
4.5.2 Computer Operating Properly Watchdog (COP) Reset . . . . . . . . . . . . . . . . . . . . . . . . . 198
4.5.3 Power-On Reset, Low Voltage Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
4.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
4.6.1 Real-Time Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
4.6.2 PLL Lock Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
4.6.3 Self-Clock Mode Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Chapter 5
Oscillator (OSCV2)
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
5.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
5.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
5.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
5.2.1 VDDPLL and VSSPLL — PLL Operating Voltage, PLL Ground . . . . . . . . . . . . . . . . . . . 202
5.2.2 EXTAL and XTAL — Clock/Crystal Source Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
5.2.3 XCLKS — Colpitts/Pierce Oscillator Selection Signal . . . . . . . . . . . . . . . . . . . . . . . . . 203
5.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
5.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
5.4.1 Amplitude Limitation Control (ALC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
5.4.2 Clock Monitor (CM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
5.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Chapter 6
Analog-to-Digital Converter (ATD10B16CV4)
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
6.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
6.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
6.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
6.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
6.2.1 ANx (x = 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) — Analog Input
Channel x Pins 207
6.2.2 ETRIG3, ETRIG2, ETRIG1, ETRIG0 — External Trigger Pins . . . . . . . . . . . . . . . . . 207
6.2.3 VRH, VRL — High Reference Voltage Pin, Low Reference Voltage Pin . . . . . . . . . . . 207
6.2.4 VDDA, VSSA — Analog Circuitry Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . 207
6.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
6.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
6.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
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6.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
6.4.1 Analog Sub-block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
6.4.2 Digital Sub-Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
6.4.3 Operation in Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
6.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
6.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Chapter 7
Digital-to-Analog Converter (DAC8B1CV1)
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
7.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
7.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
7.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
7.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
7.2.1 DAO — DAC Channel Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.2.2 VDDA — DAC Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.2.3 VSSA — DAC Ground Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.2.4 VREF — DAC Reference Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.2.5 VRL — DAC Reference Ground Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
7.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
7.4.1 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
7.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
7.5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Chapter 8
Serial Communication Interface (SCIV4)
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
8.1.1 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
8.1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
8.1.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
8.1.4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
8.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
8.2.1 TXD — SCI Transmit Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
8.2.2 RXD — SCI Receive Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
8.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
8.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
8.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
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8.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
8.4.1 Infrared Interface Submodule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
8.4.2 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
8.4.3 Baud Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
8.4.4 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
8.4.5 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
8.4.6 Single-Wire Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
8.4.7 Loop Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
8.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
8.5.1 Description of Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
8.5.2 Recovery from Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Chapter 9
Serial Peripheral Interface (SPIV3)
9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
9.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
9.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
9.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
9.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
9.2.1 MOSI — Master Out/Slave In Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
9.2.2 MISO — Master In/Slave Out Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
9.2.3 SS — Slave Select Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
9.2.4 SCK — Serial Clock Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
9.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
9.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
9.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
9.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
9.4.1 Master Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
9.4.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
9.4.3 Transmission Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
9.4.4 SPI Baud Rate Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
9.4.5 Special Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
9.4.6 Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
9.4.7 Operation in Run Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
9.4.8 Operation in Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
9.4.9 Operation in Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
9.5 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
9.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
9.6.1 MODF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
9.6.2 SPIF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
9.6.3 SPTEF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
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Chapter 10
Inter-Integrated Circuit (IICV2)
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
10.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
10.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
10.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
10.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
10.2.1 IIC_SCL — Serial Clock Line Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
10.2.2 IIC_SDA — Serial Data Line Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
10.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
10.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
10.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
10.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
10.4.1 I-Bus Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
10.4.2 Operation in Run Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
10.4.3 Operation in Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
10.4.4 Operation in Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
10.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
10.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
10.7 Initialization/Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
10.7.1 IIC Programming Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Chapter 11
Pulse Width Modulator with Fault Protection (PMF15B6CV2)
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
11.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
11.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
11.1.3 Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
11.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
11.2.1 PWM0–PWM5 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
11.2.2 FAULT0–FAULT3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
11.2.3 IS0–IS2 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
11.3 Memory Map and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
11.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
11.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
11.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
11.4.1 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
11.4.2 Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
11.4.3 PWM Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
11.4.4 Independent or Complementary Channel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
11.4.5 Deadtime Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
11.4.6 Software Output Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
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11.4.7 PWM Generator Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
11.4.8 Fault Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
11.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
11.6 Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
11.7 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
Chapter 12
Pulse-Width Modulator (PWM8B6CV1)
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
12.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
12.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
12.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
12.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
12.2.1 PWM5 — Pulse Width Modulator Channel 5 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
12.2.2 PWM4 — Pulse Width Modulator Channel 4 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
12.2.3 PWM3 — Pulse Width Modulator Channel 3 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
12.2.4 PWM2 — Pulse Width Modulator Channel 2 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
12.2.5 PWM1 — Pulse Width Modulator Channel 1 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
12.2.6 PWM0 — Pulse Width Modulator Channel 0 Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
12.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
12.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
12.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
12.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
12.4.1 PWM Clock Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
12.4.2 PWM Channel Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
12.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
12.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
Chapter 13
Timer Module (TIM16B4CV1)
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
13.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
13.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
13.1.3 Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
13.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
13.2.1 IOC7 — Input Capture and Output Compare Channel 7 Pin . . . . . . . . . . . . . . . . . . . . 414
13.2.2 IOC6 — Input Capture and Output Compare Channel 6 Pin . . . . . . . . . . . . . . . . . . . . 414
13.2.3 IOC5 — Input Capture and Output Compare Channel 5 Pin . . . . . . . . . . . . . . . . . . . . 414
13.2.4 IOC4 — Input Capture and Output Compare Channel 4 Pin . . . . . . . . . . . . . . . . . . . . 414
13.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
13.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
13.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
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13.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
13.4.1 Prescaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
13.4.2 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
13.4.3 Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
13.4.4 Pulse Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
13.4.5 Event Counter Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
13.4.6 Gated Time Accumulation Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
13.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
13.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
13.6.1 Channel [7:4] Interrupt (C[7:4]F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
13.6.2 Pulse Accumulator Input Interrupt (PAOVI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
13.6.3 Pulse Accumulator Overflow Interrupt (PAOVF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
13.6.4 Timer Overflow Interrupt (TOF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
Chapter 14
Dual Output Voltage Regulator (VREG3V3V2)
14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
14.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
14.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
14.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
14.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
14.2.1 VDDR — Regulator Power Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
14.2.2 VDDA, VSSA — Regulator Reference Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
14.2.3 VDD, VSS — Regulator Output1 (Core Logic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
14.2.4 VDDPLL, VSSPLL — Regulator Output2 (PLL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
14.2.5 VREGEN — Optional Regulator Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
14.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
14.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
14.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
14.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
14.4.1 REG — Regulator Core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
14.4.2 Full-Performance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
14.4.3 Reduced-Power Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
14.4.4 LVD — Low-Voltage Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
14.4.5 POR — Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
14.4.6 LVR — Low-Voltage Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
14.4.7 CTRL — Regulator Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
14.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
14.5.1 Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
14.5.2 Low-Voltage Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
14.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
14.6.1 LVI — Low-Voltage Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
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Chapter 15
Background Debug Module (BDMV4)
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
15.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
15.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
15.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
15.2.1 BKGD — Background Interface Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
15.2.2 TAGHI — High Byte Instruction Tagging Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
15.2.3 TAGLO — Low Byte Instruction Tagging Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
15.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
15.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
15.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
15.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
15.4.1 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
15.4.2 Enabling and Activating BDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
15.4.3 BDM Hardware Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454
15.4.4 Standard BDM Firmware Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
15.4.5 BDM Command Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
15.4.6 BDM Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
15.4.7 Serial Interface Hardware Handshake Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
15.4.8 Hardware Handshake Abort Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
15.4.9 SYNC — Request Timed Reference Pulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
15.4.10Instruction Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
15.4.11Instruction Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
15.4.12Serial Communication Time-Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
15.4.13Operation in Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
15.4.14Operation in Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
Chapter 16
Debug Module (DBGV1)
16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
16.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
16.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
16.1.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
16.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473
16.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
16.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
16.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
16.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
16.4.1 DBG Operating in BKP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
16.4.2 DBG Operating in DBG Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
16.4.3 Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498
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16.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 499
16.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 499
Chapter 17
Interrupt (INTV1)
17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
17.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
17.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
17.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
17.4.1 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
17.5 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
17.6 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
17.6.1 Interrupt Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
17.6.2 Highest Priority I-Bit Maskable Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
17.6.3 Interrupt Priority Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
17.7 Exception Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
Chapter 18
Multiplexed External Bus Interface (MEBIV3)
18.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
18.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
18.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
18.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
18.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
18.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
18.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
18.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
18.4.1 Detecting Access Type from External Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
18.4.2 Stretched Bus Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
18.4.3 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
18.4.4 Internal Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
18.4.5 Low-Power Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
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Chapter 19
Module Mapping Control (MMCV4)
19.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
19.1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
19.1.2 Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
19.2 External Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
19.3 Memory Map and Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
19.3.1 Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
19.3.2 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544
19.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
19.4.1 Bus Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
19.4.2 Address Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
19.4.3 Memory Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554
Appendix A
Electrical Characteristics
A.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
A.1.1 Parameter Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
A.1.2 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560
A.1.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561
A.1.4 Current Injection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561
A.1.5 Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562
A.1.6 ESD Protection and Latch-up Immunity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563
A.1.7 Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
A.1.8 Power Dissipation and Thermal Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
A.1.9 I/O Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
A.1.10 Supply Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567
A.2 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569
A.2.1 Chip Power-up and LVI/LVR Graphical Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . 570
A.2.2 Output Loads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571
A.3 Startup, Oscillator, and PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571
A.3.1 Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571
A.3.2 Oscillator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573
A.3.3 Phase Locked Loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574
A.4 Flash NVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
A.4.1 NVM Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
A.4.2 NVM Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
A.5 SPI Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
A.5.1 Master Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
A.5.2 Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 583
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A.6 ATD Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
A.6.1 ATD Operating Characteristics — 5V Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
A.6.2 ATD Operating Characteristics — 3.3V Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
A.6.3 Factors Influencing Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586
A.6.4 ATD Accuracy — 5V Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587
A.6.5 ATD Accuracy — 3.3V Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
A.7 DAC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
A.7.1 DAC Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
A.8 External Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590
Appendix B
Ordering Information and Mechanical Drawings
MC9S12E256 Data Sheet, Rev. 1.08
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Chapter 1
MC9S12E256 Device Overview (MC9S12E256DGV1)
1.1 Introduction
The MC9S12E256 is a 112/80 pin low cost general purpose MCU comprised of standard on-chip
peripherals including a 16-bit central processing unit (HCS12 CPU), 256K bytes of Flash EEPROM, 16K
bytes of RAM, three asynchronous serial communications interface modules (SCI), a serial peripheral
interface (SPI), an Inter-IC Bus (IIC), three 4-channel 16-bit timer modules (TIM), a 6-channel 15-bit
Pulse Modulator with Fault protection module (PMF), a 6-channel 8-bit Pulse Width Modulator (PWM),
a 16-channel 10-bit analog-to-digital converter (ADC), and two 1-channel 8-bit digital-to-analog
converters (DAC). The MC9S12E256 has full 16-bit data paths throughout. The inclusion of a PLL circuit
allows power consumption and performance to be adjusted to suit operational requirements. In addition to
the I/O ports available on each module, 16 dedicated I/O port bits are available with Wake-Up capability
from STOP or WAIT mode. Furthermore, an on chip bandgap based voltage regulator (VREG) generates
the internal digital supply voltage of 2.5V (VDD) from a 2.97V to 5.5V external supply range.
1.1.1 Features
• 16-bit HCS12 CORE
— HCS12 CPU
– Upward compatible with M68HC11 instruction set
– Interrupt stacking and programmer’s model identical to M68HC11
– Instruction queue
– Enhanced indexed addressing
— Module Mapping Control (MMC)
— Interrupt control (INT)
— Background Debug Module (BDM)
— Debugger (DBG12) including breakpoints and change-of-flow trace buffer
— Multiplexed External Bus Interface (MEBI)
• Wake-Up interrupt inputs
— Up to 16 port bits available for wake up interrupt function with digital filtering
• Memory
— 256K Byte Flash EEPROM
— 16K Byte RAM
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
22 Freescale Semiconductor
• Two 1-channel Digital-to-Analog Converters (DAC)
— 8-bit resolution
• Analog-to-Digital Converter (ADC)
— 16-channel module with 10-bit resolution
— External conversion trigger capability
• Three 4-channel Timers (TIM)
— Programmable input capture or output compare channels
— Simple PWM mode
— Counter modulo reset
— External event counting
— Gated time accumulation
• 6 PWM channels (PWM)
— Programmable period and duty cycle
— 8-bit 6-channel or 16-bit 3-channel
— Separate control for each pulse width and duty cycle
— Center-aligned or left-aligned outputs
— Programmable clock select logic with a wide range of frequencies
— Fast emergency shutdown input
• 6-channel Pulse width Modulator with Fault protection (PMF)
— Three independent 15-bit counters with synchronous mode
— Complementary channel operation
— Edge and center aligned PWM signals
— Programmable dead time insertion
— Integral reload rates from 1 to 16
— Four fault protection shut down input pins
— Three current sense input pins
• Serial interfaces
— Three asynchronous serial communication interfaces (SCI)
— Synchronous serial peripheral interface (SPI)
— Inter-IC Bus (IIC)
• Clock and Reset Generator (CRG)
— Windowed COP watchdog
— Real Time interrupt
— Clock Monitor
— Pierce or low current Colpitts oscillator
— Phase-locked loop clock frequency multiplier
— Self Clock mode in absence of external clock
— Low power 0.5 to 16Mhz crystal oscillator reference clock
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 23
• Operating frequency
— 50MHz equivalent to 25MHz Bus Speed
• Internal 2.5V Regulator
— Input voltage range from 2.97V to 5.5V
— Low power mode capability
— Includes low voltage reset (LVR) circuitry
— Includes low voltage interrupt (LVI) circuitry
• 112-Pin LQFP or 80-Pin QFP package
— Up to 90 I/O lines with 5V input and drive capability (112 pin package)
— Up to two dedicated 5V input only lines (IRQ and XIRQ)
— Sixteen 3.3V/5V A/D converter inputs
• Development Support.
— Single-wire background debugTM mode
— On-chip hardware breakpoints
— Enhanced debug features
1.1.2 Modes of Operation
User modes (Expanded modes are only available in the 112-pin package version)
• Normal modes
— Normal Single-Chip Mode
— Normal Expanded Wide Mode
— Normal Expanded Narrow Mode
— Emulation Expanded Wide Mode
— Emulation Expanded Narrow Mode
• Special Operating Modes
— Special Single-Chip Mode with active Background Debug Mode
— Special Test Mode (Freescale use only)
— Special Peripheral Mode (Freescale use only)
• Low power modes
— Stop Mode
— Pseudo Stop Mode
— Wait Mode
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
24 Freescale Semiconductor
1.1.3 Block Diagram
Figure 1-1. MC9S12E256 Block Diagram
256K Byte Flash EEPROM
16K Byte RAM
RESET
EXTAL
XTAL
SCI0
BKGD
R/W
MODB/IPIPE1
XIRQ
NOACC/XCLKS
System
Integration
Module
(SIM)
VDDR
CPU12
Periodic Interrupt
COP Watchdog
Clock Monitor
Single-wire Background
Debugger(DBG12)
CRG
XFC
Multiplexed Address/Data Bus
VRH
VRL
Multiplexed
Wide Bus
Multiplexed
VDDX
VSSX
Narrow Bus
IRQ
LSTRB/TAGLO
ECLK
MODA/IPIPE0
PA4
PA3
PA2
PA1
PA0
PA7
PA6
PA5
TEST
ADDR12
ADDR11
ADDR10
ADDR9
ADDR8
ADDR15
ADDR14
ADDR13
DATA12
DATA11
DATA10
DATA9
DATA8
DATA15
DATA14
DATA13
PB4
PB3
PB2
PB1
PB0
PB7
PB6
PB5
ADDR4
ADDR3
ADDR2
ADDR1
ADDR0
ADDR7
ADDR6
ADDR5
DATA4
DATA3
DATA2
DATA1
DATA0
DATA7
DATA6
DATA5
DATA4
DATA3
DATA2
DATA1
DATA0
DATA7
DATA6
DATA5
PE3
PE4
PE5
PE6
PE7
PE0
PE1
PE2
IOC06
IOC16
IOC04
IOC17
IOC05
IOC07
IOC14
IOC15
PT3
PT4
PT5
PT6
PT7
PT0
PT1
PT2
ADC
AN2
AN6
AN0
AN7
AN1
AN3
AN4
AN5
PAD3
PAD4
PAD5
PAD6
PAD7
PAD0
PAD1
PAD2
RXD0
TXD0
PS3
PS4
PS5
PS0
PS1
PS2
SCI1 RXD1
TXD1
PQ3
PQ4
PQ5
PQ6
PQ0
PQ1
PQ2
PS6
PS7
I/O Driver 3.3V/5V VDDA
VSSA
DDRA DDRB
PTA PTB
DDRE
PTE
PTT
DDRT
PTQ
PTS
Clock and
Reset
Generation
Voltage Regulator
VSSR
Debug Module
VDDR
VSSR
Voltage Regulator 3.3V/5V
TIM0
PW01
PW00
PAD
DAO0
DAO1
PP3
PP4
PP5
PP2
PTP
DDRP
AN10
AN11
AN8
AN9
PAD8
PAD9
PAD10
PAD11
PAD12
PAD13
KWAD3
KWAD4
KWAD5
KWAD6
KWAD7
KWAD0
KWAD1
KWAD2
KWAD8
KWAD9
KWAD10
KWAD11
KWAD12
KWAD13
TIM1
SPI
MISO
MOSI
SCK
RXD2
TXD2
PM7
PM4
PM5
PM6
SDA
SCL
PTM
SS
DDRM DDRS
AN12
AN13
AN14
AN15
KWAD14
KWAD15
PAD14
PAD15
Signals shown in Bold are not available on the 80 Pin Package
PM0
PM1
PK3
PK4
PK5
PK6
PK0
PK1
PK2
DDRK
PTK
XADDR14
XADDR15
XADDR16
XADDR17
XADDR18
XADDR19
XCS
VDDPLL
VSSPLL
PLL 2.5V
VDD1,2
VSS1,2
Internal Logic 2.5V
IIC
SCI2
PP0
PP1
PU3
PU4
PU5
PU6
PU7
PU0
PU1
PU2
PTU
DDRU
PM3
PMF
PW03
PW02
PW05
PW04
FAULT1
FAULT0
FAULT3
FAULT2
IS1
IS0
IS2
PK7 ECS
ADC/DAC 3.3V/5V
Voltage Reference
Breakpoints
DAC0
DAC1
DDRQ
MODC/TAGHI
IOC24
IOC25
IOC26
IOC27
TIM2
PW12
PW13
PW14
PW15
PWM
PW10
PW11 MUX
DDRAD
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 25
1.2 Device Memory Map
Table 1-1 shows the device register map of the MC9S12E256 after reset. Figure 1-2 illustrates the device
memory map with Flash and RAM.
Table 1-1. Device Register Map Overview
Address Module Size
0x0000–0x0017 CORE (Ports A, B, E, Modes, Inits, Test) 24
0x0018 Reserved 1
0x0019 Voltage Regulator (VREG) 1
0x001A–0x001B Device ID register (PARTID) 2
0x001C–0x001F CORE (MEMSIZ, IRQ, HPRIO) 4
0x0020–0x002F CORE (DBG) 16
0x0030–0x0033 CORE (PPAGE, Port K) 4
0x0034–0x003F Clock and Reset Generator (PLL, RTI, COP) 12
0x0040–0x006F Standard Timer 16-bit 4 channels (TIM0) 48
0x0070–0x007F Reserved 16
0x0080–0x00AF Analog to Digital Converter 10-bit 16 channels (ATD) 48
0x00B0–0x00C7 Reserved 24
0x00C8–0x00CF Serial Communications Interface 0 (SCI0) 8
0x00D0–0x00D7 Serial Communications Interface 1 (SCI1) 8
0x00D8–0x00DF Serial Peripheral Interface (SPI) 8
0x00E0–0x00E7 Inter IC Bus 8
0x00E8–0x00EF Serial Communications Interface 2 (SCI2) 8
0x00F0–0x00F3 Digital to Analog Converter 8-bit 1-channel (DAC0) 4
0x00F4–0x00F7 Digital to Analog Converter 8-bit 1-channel (DAC1) 4
0x00F8–0x00FF Reserved 8
0x0100- 0x010F Flash Control Register 16
0x0110–0x013F Reserved 48
0x0140–0x016F Standard Timer 16-bit 4 channels (TIM1) 48
0x0170–0x017F Reserved 16
0x0180–0x01AF Standard Timer 16-bit 4 channels (TIM2) 48
0x01B0–0x01DF Reserved 48
0x01E0–0x01FF Pulse Width Modulator 8-bit 6 channels (PWM) 32
0x0200–0x023F Pulse Width Modulator with Fault 15-bit 6 channels (PMF) 64
0x0240–0x027F Port Integration Module (PIM) 64
0x0280–0x03FF Reserved 384
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
26 Freescale Semiconductor
Figure 1-2. MC9S12E256 User Configurable Memory Map
VECTORS
0x0000
0xFFFF
0xC000
0x8000
0x4000
0x0400
0xFF00
EXT
NORMAL
SINGLE CHIP EXPANDED SPECIAL
SINGLE CHIP
0xFF00
0xFFFF
BDM
(If Active)
0xC000
0xFFFF
16K Fixed Flash EEPROM
2K, 4K, 8K or 16K Protected Boot Sector
0x8000
0xBFFF
16K Page Window
sixteen * 16K Flash EEPROM Pages
0x4000
0x7FFF
16K Bytes RAM
Mappable to any 16K Boundary
0x0000
0x03FF
1K Register Space
Mappable to any 2K Boundary
The figure shows a useful map, which is not the map out of reset. After reset the map is:
0x0000–0x03FF: Register Space
0x0000–0x3FFF: 16K RAM (only 15K RAM visible 0x0400–0x3FFF)
VECTORS
VECTORS
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 27
1.2.1 Detailed Register Map
0x0000 – 0x000F MEBI Map 1 of 3 (HCS12 Multiplexed External Bus Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0000 PORTA RBit 7654321Bit 0
W
0x0001 PORTB RBit 7654321Bit 0
W
0x0002 DDRA RBit 7654321Bit 0
W
0x0003 DDRB RBit 7654321Bit 0
W
0x0004 Reserved R00000000
W
0x0005 Reserved R00000000
W
0x0006 Reserved R00000000
W
0x0007 Reserved R00000000
W
0x0008 PORTE RBit 765432
Bit 1 Bit 0
W
0x0009 DDRE RBit 76543Bit 2
00
W
0x000A PEAR RNOACCE 0PIPOE NECLK LSTRE RDWE 00
W
0x000B MODE RMODC MODB MODA 0IVIS 0EMK EME
W
0x000C PUCR RPUPKE 00
PUPEE 00
PUPBE PUPAE
W
0x000D RDRIV RRDPK 00
RDPE 00
RDPB RDPA
W
0x000E EBICTL R0000000
ESTR
W
0x000F Reserved R00000000
W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
28 Freescale Semiconductor
0x0010 – 0x0014 MMC Map 1 of 4 (HCS12 Module Mapping Control)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0010 INITRM RRAM15 RAM14 RAM13 RAM12 RAM11 00
RAMHAL
W
0x0011 INITRG R0 REG14 REG13 REG12 REG11 000
W
0x0012 INITEE REE15 EE14 EE13 EE12 EE11 00
EEON
W
0x0013 MISC R0000
EXSTR1 EXSTR0 ROMHM ROMON
W
0x0014 MTST0 RBit 7654321Bit 0
W
0x0015 – 0x0016 INT Map 1 of 2 (HCS12 Interrupt)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0015 ITCR R0 0 0 WRINT ADR3 ADR2 ADR1 ADR0
W
0x0016 ITEST RINTE INTC INTA INT8 INT6 INT4 INT2 INT0
W
0x0017 – 0x0017MMC Map 2 of 4 (HCS12 Module Mapping Control)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0017 MTST1 RBit 7654321Bit 0
W
0x0018 – 0x0018 Miscellaneous Peripherals (Device User Guide)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0018 Reserved R00000000
W
0x0019 – 0x0019 VREG3V3 (Voltage Regulator)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0019 VREGCTRL R00000LVDS
LVIE LV IF
W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 29
0x001A – 0x001B Miscellaneous Peripherals (Device User Guide)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x001A PARTIDH R ID15 ID14 ID13 ID12 ID11 ID10 ID9 ID8
W
0x001B PARTIDL R ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0
W
0x001C – 0x001D MMC Map 3 of 4 (HCS12 Module Mapping Control, Device User Guide)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x001C MEMSIZ0 R reg_sw0 0 eep_sw1 eep_sw0 0 ram_sw2 ram_sw1 ram_sw0
W
0x001D MEMSIZ1 Rrom_sw1rom_sw00000pag_sw1pag_sw0
W
0x001E – 0x001E MEBI Map 2 of 3 (HCS12 Multiplexed External Bus Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x001E INTCR RIRQE IRQEN 000000
W
0x001F – 0x001F INT Map 2 of 2 (HCS12 Interrupt)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x001F HPRIO RPSEL7 PSEL6 PSEL5 PSEL4 PSEL3 PSEL2 PSEL1 0
W
0x0020 – 0x002F DBG (Including BKP) Map 1 of 1 (HCS12 Debug)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0020 DBGC1 R DBGEN ARM TRGSEL BEGIN DBGBRK 0CAPMOD
—W
0x0021 DBGSC R AF BF CF 0 TRG
—W
0x0022 DBGTBH R Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
—W
0x0023 DBGTBL R Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
—W
0x0024 DBGCNT R TBF 0 CNT
—W
0x0025 DBGCCX R PAGSEL EXTCMP
—W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
30 Freescale Semiconductor
0x0026 DBGCCH R Bit 15 14 13 12 11 10 9 Bit 8
—W
0x0027 DBGCCL R Bit 7654321Bit 0
—W
0x0028 DBGC2 R BKABEN FULL BDM TAGAB BKCEN TAGC RWCEN RWC
BKPCT0 W
0x0029 DBGC3 R BKAMBH BKAMBL BKBMBH BKBMBL RWAEN RWA RWBEN RWB
BKPCT1 W
0x002A DBGCAX R PAGSEL EXTCMP
BKP0X W
0x002B DBGCAH R Bit 15 14 13 12 11 10 9 Bit 8
BKP0H W
0x002C DBGCAL R Bit 7654321Bit 0
BKP0L W
0x002D DBGCBX R PAGSEL EXTCMP
BKP1X W
0x002E DBGCBH R Bit 15 14 13 12 11 10 9 Bit 8
BKP1H W
0x002F DBGCBL R Bit 7654321Bit 0
BKP1L W
0x0030 – 0x0031 MMC Map 4 of 4 (HCS12 Module Mapping Control)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0030 PPAGE R0 0 PIX5 PIX4 PIX3 PIX2 PIX1 PIX0
W
0x0031 Reserved R00000000
W
0x0032 – 0x0033 MEBI Map 3 of 3 (HCS12 Multiplexed External Bus Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0032 PORTK RECS XCS XAB19 XAB18 XAB17 XAB16 XAB15 XAB14
W
0x0033 DDRK RBit 7654321Bit 0
W
0x0020 – 0x002F DBG (Including BKP) Map 1 of 1 (HCS12 Debug) (continued)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 31
0x0034 – 0x003F CRG (Clock and Reset Generator)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0034 SYNR R0 0 SYN5 SYN4 SYN3 SYN2 SYN1 SYN0
W
0x0035 REFDV R0000
REFDV3 REFDV2 REFDV1 REFDV0
W
0x0036 CTFLG
TEST ONLY
R TOUT7 TOUT6 TOUT5 TOUT4 TOUT3 TOUT2 TOUT1 TOUT0
W
0x0037 CRGFLG RRTIF PROF 0LOCKIF LOCK TRACK SCMIF SCM
W
0x0038 CRGINT RRTIE 00
LOCKIE 00
SCMIE 0
W
0x0039 CLKSEL RPLLSEL PSTP SYSWAI ROAWAI PLLWAI CWAI RTIWAI COPWAI
W
0x003A PLLCTL RCME PLLON AUTO ACQ 0PRE PCE SCME
W
0x003B RTICTL R0 RTR6 RTR5 RTR4 RTR3 RTR2 RTR1 RTR0
W
0x003C COPCTL RWCOP RSBCK 000
CR2 CR1 CR0
W
0x003D FORBYP
TEST ONLY
RRTIBYP COPBYP 0PLLBYP 00
FCM 0
W
0x003E CTCTL
TEST ONLY
R TCTL7 TCTL6 TCTL5 TCTL4 TCLT3 TCTL2 TCTL1 TCTL0
W
0x003F ARMCOP R00000000
WBit 7654321Bit 0
0x0040 – 0x006F TIM0 (Timer 16 Bit 4 Channels) (Sheet 1 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0040 TIOS RIOS7 IOS6 IOS5 IOS4 0000
W
0x0041 CFORC R00000000
WFOC7FOC6FOC5FOC4
0x0042 OC7M ROC7M7 OC7M6 OC7M5 OC7M4 0000
W
0x0043 OC7D ROC7D7 OC7D6 OC7D5 OC7D4 0000
W
0x0044 TCNT (hi) R Bit 15 14 13 12 11 10 9 Bit 8
W
0x0045 TCNT (lo) RBit 7654321Bit 0
W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
32 Freescale Semiconductor
0x0046 TSCR1 RTEN TSWAI TSFRZ TFFCA 0000
W
0x0047 TTOV RTOV7 TOV6 TOV5 TOV4 0000
W
0x0048 TCTL1 ROM7OL7OM6OL6OM5OL5OM4OL4
W
0x0049 Reserved R00000000
W
0x004A TCTL3 REDG7B EDG7A EDG6B EDG6A EDG5B EDG5A EDG4B EDG4A
W
0x004B Reserved R00000000
W
0x004C TIE RC7I C6I C5I C4I 0000
W
0x004D TSCR2 RTOI 000
TCRE PR2 PR1 PR0
W
0x004E TFLG1 RC7F C6F C5F C4F 0000
W
0x004F TFLG2 RTOF 0000000
W
0x0050 Reserved R00000000
W
0x0051 Reserved R00000000
W
0x0052 Reserved R00000000
W
0x0053 Reserved R00000000
W
0x0054 Reserved R00000000
W
0x0055 Reserved R00000000
W
0x0056 Reserved R00000000
W
0x0057 Reserved R00000000
W
0x0058 TC4 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x0040 – 0x006F TIM0 (Timer 16 Bit 4 Channels) (Sheet 2 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 33
0x0059 TC4 (lo) RBit 7654321Bit 0
W
0x005A TC5 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x005B TC5 (lo) RBit 7654321Bit 0
W
0x005C TC6 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x005D TC6 (lo) RBit 7654321Bit 0
W
0x005E TC7 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x005F TC7 (lo) RBit 7654321Bit 0
W
0x0060 PACTL R0 PAEN PAMOD PEDGE CLK1 CLK0 PAOVI PAI
W
0x0061 PAFLG R000000
PAOV F PA I F
W
0x0062 PACNT (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x0063 PACNT (lo) RBit 7654321Bit 0
W
0x0064 Reserved R00000000
W
0x0065 Reserved R00000000
W
0x0066 Reserved R00000000
W
0x0067 Reserved R00000000
W
0x0068 Reserved R00000000
W
0x0069 Reserved R00000000
W
0x006A Reserved R00000000
W
0x006B Reserved R00000000
W
0x0040 – 0x006F TIM0 (Timer 16 Bit 4 Channels) (Sheet 3 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
34 Freescale Semiconductor
0x006C Reserved R00000000
W
0x006D Reserved R00000000
W
0x006E Reserved R00000000
W
0x006F Reserved R00000000
W
0x0070 – 0x007F Reserved
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0070–
0x007F Reserved R00000000
W
0x0080 – 0x00AF ATD (Analog to Digital Converter 10 Bit 16 Channel) (Sheet 1 of 3)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0080 ATDCTL0 R0000
WRAP31WRAP21WRAP11WRAP01
W
0x0081 ATDCTL1 R
ETRIGSEL2000
ETRIGCH32ETRIGCH22ETRIGCH12ETRIGCH02
W
0x0082 ATDCTL2 RADPU AFFC AWAI ETRIGLE ETRIGP ETRIG ASCIE ASCIF
W
0x0083 ATDCTL3 R0 S8C S4C S2C S1C FIFO FRZ1 FRZ0
W
0x0084 ATDCTL4 RSRES8 SMP1 SMP0 PRS4 PRS3 PRS2 PRS1 PRS0
W
0x0085 ATDCTL5 RDJM DSGN SCAN MULT 0CC CB CA
W
0x0086 ATDSTAT0 RSCF 0ETORF FIFOR 0 CC2 CC1 CC0
W
0x0087 Reserved R00000000
W
0x0088 ATDTEST0 R00000000
W
0x0089 ATDTEST1 R0000000
SC
W
0x008A ATDSTAT0 R CCF15 CCF14 CCF13 CCF12 CCF11 CCF10 CCF9 CCF8
W
0x0040 – 0x006F TIM0 (Timer 16 Bit 4 Channels) (Sheet 4 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 35
0x008B ATDSTAT1 R CCF7 CCF6 CCF5 CCF4 CCF3 CCF2 CCF1 CCF0
W
0x008C ATDDIEN0 RIEN15 IEN14 IEN13 IEN12 IEN11 IEN10 IEN9 IEN8
W
0x008D ATDDIEN1 RIEN7 IEN6 IEN5 IEN4 IEN3 IEN2 IEN1 IEN0
W
0x008E PORTAD0 R PTAD15 PTAD14 PTAD13 PTAD12 PTAD11 PTAD10 PTAD9 PTAD8
W
0x008F PORTAD1 R PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
W
0x0090 ATDDR0H R Bit15 14 13 12 11 10 9 Bit8
W
0x0091 ATDDR0L RBit7Bit6000000
W
0x0092 ATDDR1H R Bit15 14 13 12 11 10 9 Bit8
W
0x0093 ATDDR1L RBit7Bit6000000
W
0x0094 ATDDR2H R Bit15 14 13 12 11 10 9 Bit8
W
0x0095 ATDDR2L RBit7Bit6000000
W
0x0096 ATDDR3H R Bit15 14 13 12 11 10 9 Bit8
W
0x0097 ATDDR3L RBit7Bit6000000
W
0x0098 ATDDR4H R Bit15 14 13 12 11 10 9 Bit8
W
0x0099 ATDDR4L RBit7Bit6000000
W
0x009A ATDDR5H R Bit15 14 13 12 11 10 9 Bit8
W
0x009B ATDDR5L RBit7Bit6000000
W
0x009C ATDDR6H R Bit15 14 13 12 11 10 9 Bit8
W
0x009D ATDDR6L RBit7Bit6000000
W
0x0080 – 0x00AF ATD (Analog to Digital Converter 10 Bit 16 Channel) (Sheet 2 of 3)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
36 Freescale Semiconductor
0x009E ATDDR7H R Bit15 14 13 12 11 10 9 Bit8
W
0x009F ATDDR7L RBit7Bit6000000
W
0x00A0 ATDDR8H R Bit15 14 13 12 11 10 9 Bit8
W
0x00A1 ATDDR8L RBit7Bit6000000
W
0x00A2 ATDDR9H R Bit15 14 13 12 11 10 9 Bit8
W
0x00A3 ATDDR9L RBit7Bit6000000
W
0x00A4 ATDDR10H R Bit15 14 13 12 11 10 9 Bit8
W
0x00A5 ATDDR10L RBit7Bit6000000
W
0x00A6 ATDDR11H R Bit15 14 13 12 11 10 9 Bit8
W
0x00A7 ATDDR11L RBit7Bit6000000
W
0x00A8 ATDDR12H R Bit15 14 13 12 11 10 9 Bit8
W
0x00A9 ATDDR12L RBit7Bit6000000
W
0x00AA ATDDR13H R Bit15 14 13 12 11 10 9 Bit8
W
0x00AB ATDDR13L RBit7Bit6000000
W
0x00AC ATDDR14H R Bit15 14 13 12 11 10 9 Bit8
W
0x00AD ATDDR14L RBit7Bit6000000
W
0x00AE ATDDR15H R Bit15 14 13 12 11 10 9 Bit8
W
0x00AF ATDDR15L RBit7Bit6000000
W
1WRAP0–3 bits are available in version V04 of ATD10B16C
2ETRIGSEL and ETRIGCH0–3 bits are available in version V04 of ATD10B16C
0x0080 – 0x00AF ATD (Analog to Digital Converter 10 Bit 16 Channel) (Sheet 3 of 3)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 37
0x00B0 – 0x00C7 Reserved
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00B0–
0x00C7 Reserved R00000000
W
0x00C8 – 0x00CF SCI0 (Asynchronous Serial Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00C8 SCIBDH RIREN TNP1 TNP0 SBR12 SBR11 SBR10 SBR9 SBR8
W
0x00C9 SCIBDL RSBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
W
0x00CA SCICR1 RLOOPS SCISWAI RSRC M WAKE ILT PE PT
W
0x00CB SCICR2 RTIE TCIE RIE ILIE TE RE RWU SBK
W
0x00CC SCISR1 R TDRE TC RDRF IDLE OR NF FE PF
W
0x00CD SCISR2 R0 0 0 TXPOL1
1TXPOL and RXPOL bits are available in version V04 of SCI
RXPOL1BRK13 TXDIR RAF
W
0x00CE SCIDRH RR8 T8 000000
W
0x00CF SCIDRL RR7R6R5R4R3R2R1R0
WT7T6T5T4T3T2T1T0
0x00D0 – 0x00D7 SCI1 (Asynchronous Serial Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00D0 SCIBDH RIREN TNP1 TNP0 SBR12 SBR11 SBR10 SBR9 SBR8
W
0x00D1 SCIBDL RSBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
W
0x00D2 SCICR1 RLOOPS SCISWAI RSRC M WAKE ILT PE PT
W
0x00D3 SCICR2 RTIE TCIE RIE ILIE TE RE RWU SBK
W
0x00D4 SCISR1 R TDRE TC RDRF IDLE OR NF FE PF
W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
38 Freescale Semiconductor
0x00D5 SCISR2 R0 0 0 TXPOL1RXPOL1BRK13 TXDIR RAF
W
0x00D6 SCIDRH RR8 T8 000000
W
0x00D7 SCIDRL RR7R6R5R4R3R2R1R0
WT7T6T5T4T3T2T1T0
1TXPOL and RXPOL are available in version V04 of SCI
0x00D8 – 0x00DF SPI (Serial Peripheral Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00D8 SPICR1 RSPIE SPE SPTIE MSTR CPOL CPHA SSOE LSBFE
W
0x00D9 SPICR2 R0 0 0 MODFEN BIDIROE 0SPISWAI SPC0
W
0x00DA SPIBR R0 SPPR2 SPPR1 SPPR0 0SPR2 SPR1 SPR0
W
0x00DB SPISR RSPIF0SPTEFMODF0000
W
0x00DC Reserved R00000000
W
0x00DD SPIDR RBit7654321Bit0
W
0x00DE Reserved R00000000
W
0x00DF Reserved R00000000
W
0x00E0 – 0x00E7 IIC (Inter-IC Bus)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00E0 IBAD RADR7 ADR6 ADR5 ADR4 ADR3 ADR2 ADR1 0
W
0x00E1 IBFD RIBC7 IBC6 IBC5 IBC4 IBC3 IBC2 IBC1 IBC0
W
0x00E2 IBCR RIBEN IBIE MS/SL Tx/Rx TXAK 00
IBSWAI
WRSTA
0x00E3 IBSR R TCF IAAS IBB IBAL 0SRW
IBIF RXAK
W
0x00D0 – 0x00D7 SCI1 (Asynchronous Serial Interface) (continued)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 39
0x00E4 IBDR RD7 D6 D5 D4 D3 D2 D1 D0
W
0x00E5 Reserved R00000000
W
0x00E6 Reserved R00000000
W
0x00E7 Reserved R00000000
W
0x00E8 – 0x00EF SCI2 (Asynchronous Serial Interface)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00E8 SCIBDH RIREN TNP1 TNP0 SBR12 SBR11 SBR10 SBR9 SBR8
W
0x00E9 SCIBDL RSBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
W
0x00EA SCICR1 RLOOPS SCISWAI RSRC M WAKE ILT PE PT
W
0x00EB SCICR2 RTIE TCIE RIE ILIE TE RE RWU SBK
W
0x00EC SCISR1 R TDRE TC RDRF IDLE OR NF FE PF
W
0x00ED SCISR2 R0 0 0 TXPOL1
1TXPOL and RXPOL are available in version V04 of SCI
RXPOL1BRK13 TXDIR RAF
W
0x00EE SCIDRH RR8 T8 000000
W
0x00EF SCIDRL RR7R6R5R4R3R2R1R0
WT7T6T5T4T3T2T1T0
0x00E0 – 0x00E7 IIC (Inter-IC Bus) (continued)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
40 Freescale Semiconductor
0x00F0 – 0x00F3 DAC0 (Digital-to-Analog Converter)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00F0 DACC0 RDACE DACTE 0 0 DJM DSGN DACWAI DACOE
W
0x00F1 DACC1 R00000000
W
0x00F2 DACD RBIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
W
0x00F3 DACD RBIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
W
0x00F4 – 0x00F7 DAC1 (Digital-to-Analog Converter)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00F4 DACC0 RDACE DACTE 0 0 DJM DSGN DACWAI DACOE
W
0x00F5 DACC1 R00000000
W
0x00F6 DACD RBIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
W
0x00F7 DACD RBIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
W
0x00F8 – 0x00FF Reserved
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00F8–
0x00FF Reserved R00000000
W
0x0100 – 0x010F Flash Control Register
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0100 FCLKDIV RFDIVLD PRDIV8 FDIV5 FDIV4 FDIV3 FDIV2 FDIV1 FDIV0
W
0x0101 FSEC R KEYEN1 NV6 NV5 NV4 NV3 NV2 SEC1 SEC0
W
0x0102 Reserved for
Factory Test
R00000000
W
0x0103 FCNFG RCBEIE CCIE KEYACC 00000
W
0x0104 FPROT RFPOPEN NV6 FPHDIS FPHS1 FPHS0 FPLDIS FPLS1 FPLS0
W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 41
0x0105 FSTAT RCBEIF CCIF PVIOL ACCERR 0BLANK 00
W
0x0106 FCMD R0 CMDB6 CMDB5 00
CMDB2 0CMDB0
W
0x0107 Reserved for
Factory Test
R00000000
W
0x0108 Reserved for
Factory Test
R00000000
W
0x0109 Reserved for
Factory Test
R00000000
W
0x010A Reserved for
Factory Test
R00000000
W
0x010B Reserved for
Factory Test
R00000000
W
0x010C Reserved R00000000
W
0x010D Reserved R00000000
W
0x010E Reserved R00000000
W
0x010F Reserved R00000000
W
0x0110 – 0x013F Reserved
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0110–
0x013F Reserved R00000000
W
0x0140 – 0x016F TIM1 (Timer 16 Bit 4 Channels) (Sheet 1 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0140 TIOS RIOS7 IOS6 IOS5 IOS4 0000
W
0x0141 CFORC R00000000
WFOC7FOC6FOC5FOC4
0x0142 OC7M ROC7M7 OC7M6 OC7M5 OC7M4 0000
W
0x0143 OC7D ROC7D7 OC7D6 OC7D5 OC7D4 0000
W
0x0100 – 0x010F Flash Control Register (continued)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
42 Freescale Semiconductor
0x0144 TCNT (hi) R Bit 15 14 13 12 11 10 9 Bit 8
W
0x0145 TCNT (lo) RBit 7654321Bit 0
W
0x0146 TSCR1 RTEN TSWAI TSFRZ TFFCA 0000
W
0x0147 TTOV RTOV7 TOV6 TOV5 TOV4 0000
W
0x0148 TCTL1 ROM7OL7OM6OL6OM5OL5OM4OL4
W
0x0149 Reserved R00000000
W
0x014A TCTL3 REDG7B EDG7A EDG6B EDG6A EDG5B EDG5A EDG4B EDG4A
W
0x014B Reserved R00000000
W
0x014C TIE RC7I C6I C5I C4I 0000
W
0x014D TSCR2 RTOI 000
TCRE PR2 PR1 PR0
W
0x014E TFLG1 RC7F C6F C5F C4F 0000
W
0x014F TFLG2 RTOF 0000000
W
0x0150 Reserved R00000000
W
0x0151 Reserved R00000000
W
0x0152 Reserved R00000000
W
0x0153 Reserved R00000000
W
0x0154 Reserved R00000000
W
0x0155 Reserved R00000000
W
0x0156 Reserved R00000000
W
0x0140 – 0x016F TIM1 (Timer 16 Bit 4 Channels) (Sheet 2 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 43
0x0157 Reserved R00000000
W
0x0158 TC4 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x0159 TC4 (lo) RBit 7654321Bit 0
W
0x015A TC5 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x015B TC5 (lo) RBit 7654321Bit 0
W
0x015C TC6 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x015D TC6 (lo) RBit 7654321Bit 0
W
0x015E TC7 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x015F TC7 (lo) RBit 7654321Bit 0
W
0x0160 PACTL R0 PAEN PAMOD PEDGE CLK1 CLK0 PAOVI PAI
W
0x0161 PAFLG R000000
PAOV F PA I F
W
0x0162 PACNT (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x0163 PACNT (lo) RBit 7654321Bit 0
W
0x0164 Reserved R00000000
W
0x0165 Reserved R00000000
W
0x0166 Reserved R00000000
W
0x0167 Reserved R00000000
W
0x0168 Reserved R00000000
W
0x0169 Reserved R00000000
W
0x0140 – 0x016F TIM1 (Timer 16 Bit 4 Channels) (Sheet 3 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
44 Freescale Semiconductor
0x016A Reserved R00000000
W
0x016B Reserved R00000000
W
0x016C Reserved R00000000
W
0x016D Reserved R00000000
W
0x016E Reserved R00000000
W
0x016F Reserved R00000000
W
0x0170 – 0x017F Reserved
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0110–
0x013F Reserved R00000000
W
0x0180 – 0x01AF TIM2 (Timer 16 Bit 4 Channels) (Sheet 1 of 3)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0180 TIOS RIOS7 IOS6 IOS5 IOS4 0000
W
0x0181 CFORC R00000000
WFOC7FOC6FOC5FOC4
0x0182 OC7M ROC7M7 OC7M6 OC7M5 OC7M4 0000
W
0x0183 OC7D ROC7D7 OC7D6 OC7D5 OC7D4 0000
W
0x0184 TCNT (hi) R Bit 15 14 13 12 11 10 9 Bit 8
W
0x0185 TCNT (lo) RBit 7654321Bit 0
W
0x0186 TSCR1 RTEN TSWAI TSFRZ TFFCA 0000
W
0x0187 TTOV RTOV7 TOV6 TOV5 TOV4 0000
W
0x0188 TCTL1 ROM7OL7OM6OL6OM5OL5OM4OL4
W
0x0140 – 0x016F TIM1 (Timer 16 Bit 4 Channels) (Sheet 4 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 45
0x0189 Reserved R00000000
W
0x018A TCTL3 REDG7B EDG7A EDG6B EDG6A EDG5B EDG5A EDG4B EDG4A
W
0x018B Reserved R00000000
W
0x018C TIE RC7I C6I C5I C4I 0000
W
0x018D TSCR2 RTOI 000
TCRE PR2 PR1 PR0
W
0x018E TFLG1 RC7F C6F C5F C4F 0000
W
0x018F TFLG2 RTOF 0000000
W
0x0190 Reserved R00000000
W
0x0191 Reserved R00000000
W
0x0192 Reserved R00000000
W
0x0193 Reserved R00000000
W
0x0194 Reserved R00000000
W
0x0195 Reserved R00000000
W
0x0196 Reserved R00000000
W
0x0197 Reserved R00000000
W
0x0198 TC4 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x0199 TC4 (lo) RBit 7654321Bit 0
W
0x015A TC5 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x019B TC5 (lo) RBit 7654321Bit 0
W
0x019C TC6 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x0180 – 0x01AF TIM2 (Timer 16 Bit 4 Channels) (Sheet 2 of 3)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
46 Freescale Semiconductor
0x019D TC6 (lo) RBit 7654321Bit 0
W
0x019E TC7 (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x019F TC7 (lo) RBit 7654321Bit 0
W
0x01A0 PACTL R0 PAEN PAMOD PEDGE CLK1 CLK0 PAOVI PAI
W
0x01A1 PAFLG R000000
PAOV F PA I F
W
0x01A2 PACNT (hi) RBit 15 14 13 12 11 10 9 Bit 8
W
0x01A3 PACNT (lo) RBit 7654321Bit 0
W
0x01A4 Reserved R00000000
W
0x01A5 Reserved R00000000
W
0x01A6 Reserved R00000000
W
0x01A7 Reserved R00000000
W
0x01A8 Reserved R00000000
W
0x01A9 Reserved R00000000
W
0x01AA Reserved R00000000
W
0x01AB Reserved R00000000
W
0x01AC Reserved R00000000
W
0x01AD Reserved R00000000
W
0x01AE Reserved R00000000
W
0x01AF Reserved R00000000
W
0x0180 – 0x01AF TIM2 (Timer 16 Bit 4 Channels) (Sheet 3 of 3)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 47
0x01B0 – 0x01DF Reserved
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x01B0–
0x01DF Reserved R00000000
W
0x01E0 – 0x01FF PWM (Pulse Width Modulator)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x01E0 PWME R0 0 PWME5 PWME4 PWME3 PWME2 PWME1 PWME0
W
0x01E1 PWMPOL R0 0 PPOL5 PPOL4 PPOL3 PPOL2 PPOL1 PPOL0
W
0x01E2 PWMCLK R0 0 PCLK5 PCLK4 PCLK3 PCLK2 PCLK1 PCLK0
W
0x01E3 PWMPRCLK R0 PCKB2 PCKB1 PCKB0 0PCKA2 PCKA1 PCKA0
W
0x01E4 PWMCAE R0 0 CAE5 CAE4 CAE3 CAE2 CAE1 CAE0
W
0x01E5 PWMCTL R0 CON45 CON23 CON01 PSWAI PFRZ 00
W
0x01E6 PWMTST
Te s t O n ly
R00000000
W
0x01E7 PWMPRSC R00000000
W
0x01E8 PWMSCLA RBit 7 6 5 4 3 2 1 Bit 0
W
0x01E9 PWMSCLB RBit 7 6 5 4 3 2 1 Bit 0
W
0x01EA PWMSCNTA R00000000
W
0x01EB PWMSCNTB R00000000
W
0x01EC PWMCNT0 R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
0x01ED PWMCNT1 R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
0x01EE PWMCNT2 R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
0x01EF PWMCNT3 R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
48 Freescale Semiconductor
0x01F0 PWMCNT4 R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
0x01F1 PWMCNT5 R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
0x01F2 PWMPER0 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F3 PWMPER1 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F4 PWMPER2 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F5 PWMPER3 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F6 PWMPER4 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F7 PWMPER5 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F8 PWMDTY0 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01F9 PWMDTY1 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01FA PWMDTY2 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01FB PWMDTY3 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01FC PWMDTY4 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01FD PWMDTY5 RBit 7 6 5 4 3 2 1 Bit 0
W
0x01FE PWMSDN RPWMIF PWMIE 0 PWMLVL 0PWM5IN
PWM5INL PWM5ENA
WPWMRSTRT
0x01FF Reserved R00000000
W
0x01E0 – 0x01FF PWM (Pulse Width Modulator) (continued)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 49
0x0200 – 0x023F PMF (Pulse width Modulator with Fault protection) (Sheet 1 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0200 PMFCFG0 RWP MTG EDGEC EDGEB EDGEA INDEPC INDEPB INDEPA
W
0x0201 PMFCFG1 RENHA 0
BOTNEGC TOPNEGC BOTNEGB TOPNEGB BOTNEGA TOPNEGA
W
0x0202 PMFCFG2 R0 0 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0
W
0x0203 PMFCFG3 RPMFWAI PMFFRZ 0VLMODE SWAPC SWAPB SWAPA
W
0x0204 PMFFCTL RFMODE3 FIE3 FMODE2 FIE2 FMODE1 FIE1 FMODE0 FIE0
W
0x0205 PMFFPIN R0 FPINE3 0FPINE2 0FPINE1 0FPINE0
W
0x0206 PMFFSTA R0 FFLAG3 0FFLAG2 0FFLAG1 0FFLAG0
W
0x0207 PMFQSMP RQSMP3 QSMP2 QSMP1 QSMP0
W
0x0208 PMFDMPA RDMP13 DMP12 DMP11 DMP10 DMP03 DMP02 DMP01 DMP00
W
0x0209 PMFDMPB RDMP33 DMP32 DMP31 DMP30 DMP23 DMP22 DMP21 DMP20
W
0x020A PMFDMPC RDMP53 DMP52 DMP51 DMP50 DMP43 DMP42 DMP41 DMP40
W
0x020B Reserved R00000000
W
0x020C PMFOUTC R0 0OUTCTL5 OUTCTL4 OUTCTL3 OUTCTL2 OUTCTL1 OUTCTL0
W
0x020D PMFOUTB R0 0 OUT5 OUT4 OUT3 OUT2 OUT1 OUT0
W
0x020E PMFDTMS R 0 0 DT5 DT4 DT3 DT2 DT1 DT0
W
0x020F PMFCCTL R0 0 ISENS 0IPOLC IPOLB IPOLA
W
0x0210 PMFVAL0 RBit 15 14 13 12 11 10 9 Bit 8
W
0x0211 PMFVAL0 RBit 7654321Bit 0
W
0x0212 PMFVAL1 RBit 15 14 13 12 11 10 9 Bit 8
W
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
50 Freescale Semiconductor
0x0213 PMFVAL1 RBit 7654321Bit 0
W
0x0214 PMFVAL2 RBit 15 14 13 12 11 10 9 Bit 8
W
0x0215 PMFVAL2 RBit 7654321Bit 0
W
0x0216 PMFVAL3 RBit 15 14 13 12 11 10 9 Bit 8
W
0x0217 PMFVAL3 RBit 7654321Bit 0
W
0x0218 PMFVAL4 RBit 15 14 13 12 11 10 9 Bit 8
W
0x0219 PMFVAL4 RBit 7654321Bit 0
W
0x021A PMFVAL5 RBit 15 14 13 12 11 10 9 Bit 8
W
0x021B PMFVAL5 RBit 7654321Bit 0
W
0x021C Reserved R00000000
W
0x021D Reserved R00000000
W
0x021E Reserved R00000000
W
0x021F Reserved R00000000
W
0x0220 PMFENCA RPWMENA 00000
LDOKA PWMRIEA
W
0x0221 PMFFQCA RLDFQA HALFA PRSCA PWMRFA
W
0x0222 PMFCNTA R0 Bit 14 13 12 11 10 9 Bit 8
W
0x0223 PMFCNTA RBit 7654321Bit 0
W
0x0224 PMFMODA R0 Bit 14 13 12 11 10 9 Bit 8
W
0x0225 PMFMODA RBit 7654321Bit 0
W
0x0200 – 0x023F PMF (Pulse width Modulator with Fault protection) (Sheet 2 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 51
0x0226 PMFDTMA R0000
Bit 11 10 9 Bit 8
W
0x0227 PMFDTMA RBit 7654321Bit 0
W
0x0228 PMFENCB RPWMENB 00000
LDOKB PWMRIEB
W
0x0229 PMFFQCB RLDFQB HALFB PRSCB PWMRFB
W
0x022A PMFCNTB R0 Bit 14 13 12 11 10 9 Bit 8
W
0x022B PMFCNTB RBit 7654321Bit 0
W
0x022C PMFMODB R0 Bit 14 13 12 11 10 9 Bit 8
W
0x022D PMFMODB RBit 7654321Bit 0
W
0x022E PMFDTMB R0000
Bit 11 10 9 Bit 8
W
0x022F PMFDTMB RBit 7654321Bit 0
W
0x0230 PMFENCC RPWMENC 00000
LDOKC PWMRIEC
W
0x0231 PMFFQCC RLDFQC HALFC PRSCC PWMRFC
W
0x0232 PMFCNTC R0 Bit 14 13 12 11 10 9 Bit 8
W
0x0233 PMFCNTC RBit 7654321Bit 0
W
0x0234 PMFMODC R0 Bit 14 13 12 11 10 9 Bit 8
W
0x0235 PMFMODC RBit 7654321Bit 0
W
0x0236 PMFDTMC R0000
Bit 11 10 9 Bit 8
W
0x0237 PMFDTMC RBit 7654321Bit 0
W
0x0238 Reserved R00000000
W
0x0200 – 0x023F PMF (Pulse width Modulator with Fault protection) (Sheet 3 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
52 Freescale Semiconductor
0x0239 Reserved R00000000
W
0x023A Reserved R00000000
W
0x023B Reserved R00000000
W
0x023C Reserved R00000000
W
0x023D Reserved R00000000
W
0x023E Reserved R00000000
W
0x023F Reserved R00000000
W
0x0240 – 0x027F PIM (Port Interface Module) (Sheet 1 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0240 PTT RPTT7 PTT6 PTT5 PTT4 PTT3 PTT2 PTT1 PTT0
W
0x0241 PTIT R PTIT7 PTIT6 PTIT5 PTIT4 PTIT3 PTIT2 PTIT1 PTIT0
W
0x0242 DDRT RDDRT7 DDRT7 DDRT5 DDRT4 DDRT3 DDRT2 DDRT1 DDRT0
W
0x0243 RDRT RRDRT7 RDRT6 RDRT5 RDRT4 RDRT3 RDRT2 RDRT1 RDRT0
W
0x0244 PERT RPERT7 PERT6 PERT5 PERT4 PERT3 PERT2 PERT1 PERT0
W
0x0245 PPST RPPST7 PPST6 PPST5 PPST4 PPST3 PPST2 PPST1 PPST0
W
0x0246 Reserved R00000000
W
0x0247 Reserved R00000000
W
0x0248 PTS RPTS7 PTS6 PTS5 PTS4 PTS3 PTS2 PTS1 PTS0
W
0x0249 PTIS R PTIS7 PTIS6 PTIS5 PTIS4 PTIS3 PTIS2 PTIS1 PTIS0
W
0x0200 – 0x023F PMF (Pulse width Modulator with Fault protection) (Sheet 4 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 53
0x024A DDRS RDDRS7 DDRS6 DDRS5 DDRS4 DDRS3 DDRS2 DDRS1 DDRS0
W
0x024B RDRS RRDRS7 RDRS6 RDRS5 RDRS4 RDRS3 RDRS2 RDRS1 RDRS0
W
0x024C PERS RPERS7 PERS6 PERS5 PERS4 PERS3 PERS2 PERS1 PERS0
W
0x024D PPSS RPPSS7 PPSS6 PPSS5 PPSS4 PPSS3 PPSS2 PPSS1 PPSS0
W
0x024E WOMS RWOMS7 WOMS6 WOMS5 WOMS4 WOMS3 WOMS2 WOMS1 WOMS0
W
0x024F Reserved R00000000
W
0x0250 PTM RPTM7 PTM6 PTM5 PTM4 PTM3 0PTM1 PTM0
W
0x0251 PTIM R PTIM7 PTIM6 PTIM5 PTIM4 PTIM3 0 PTIM1 PTIM0
W
0x0252 DDRM RDDRM7 DDRM6 DDRM5 DDRM4 DDRM3 0DDRM1 DDRM0
W
0x0253 RDRM RRDRM7 RDRM6 RDRM5 RDRM4 RDRM3 0RDRM1 RDRM0
W
0x0254 PERM RPERM7 PERM6 PERM5 PERM4 PERM3 0PERM1 PERM0
W
0x0255 PPSM RPPSM7 PPSM6 PPSM5 PPSM4 PPSM3 0PPSM1 PPSM0
W
0x0256 WOMM RWOMM7 WOMM6 WOMM5 WOMM4 0000
W
0x0257 Reserved R00000000
W
0x0258 PTP R0 0 PTP5 PTP4 PTP3 PTP2 PTP1 PTP0
W
0x0259 PTIP R 0 0 PTIP5 PTIP4 PTIP3 PTIP2 PTIP1 PTIP0
W
0x025A DDRP R0 0 DDRP5 DDRP4 DDRP3 DDRP2 DDRP1 DDRP0
W
0x025B RDRP R0 0 RDRP5 RDRP4 RDRP3 RDRP2 RDRP1 RDRP0
W
0x025C PERP R0 0 PERP5 PERP4 PERP3 PERP2 PERP1 PERP0
W
0x0240 – 0x027F PIM (Port Interface Module) (Sheet 2 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
54 Freescale Semiconductor
0x025D PPSP R0 0 PPSP5 PPSP4 PPSP3 PPSP2 PPSP1 PPSP0
W
0x025E Reserved R00000000
W
0x025F Reserved R00000000
W
0x0260 PTQ R0 PTQ6 PTQ5 PTQ4 PTQ3 PTQ2 PTQ1 PTQ0
W
0x0261 PTIQ R 0 PTIQ6 PTIQ5 PTIQ4 PTIQ3 PTIQ2 PTIQ1 PTIQ0
W
0x0262 DDRQ R0 DDRQ6 DDRQ5 DDRQ4 DDRQ3 DDRQ2 DDRQ1 DDRQ0
W
0x0263 RDRQ R0 RDRQ6 RDRQ5 RDRQ4 RDRQ3 RDRQ2 RDRQ1 RDRQ0
W
0x0264 PERQ R0 PERQ6 PERQ5 PERQ4 PERQ3 PERQ2 PERQ1 PERQ0
W
0x0265 PPSQ R0 PPSQ6 PPSQ5 PPSQ4 PPSQ3 PPSQ2 PPSQ1 PPSQ0
W
0x0266 Reserved R00000000
W
0x0267 Reserved R00000000
W
0x0268 PTU RPTU7 PTU6 PTU5 PTU4 PTU3 PTU2 PTU1 PTU0
W
0x0269 PTIU R PTIU7 PTIU6 PTIU5 PTIU4 PTIU3 PTIU2 PTIU1 PTIU0
W
0x026A DDRU RDDRU7 DDRU6 DDRU5 DDRU4 DDRU3 DDRU2 DDRU1 DDRU0
W
0x026B RDRU RRDRU7 RDRU6 RDRU5 RDRU4 RDRU3 RDRU2 RDRU1 RDRU0
W
0x026C PERU RPERU7 PERU6 PERU5 PERU4 PERU3 PERU2 PERU1 PERU0
W
0x026D PPSU RPPSU7 PPSU6 PPSU5 PPSU4 PPSU3 PPSU2 PPSU1 PPSU0
W
0x026E MODRR R0000
MODRR3 MODRR2 MODRR1 MODRR0
W
0x026F Reserved R00000000
W
0x0240 – 0x027F PIM (Port Interface Module) (Sheet 3 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 55
0x0270 PTAD(H) RPTAD15 PTAD14 PTAD13 PTAD12 PTAD11 PTAD10 PTAD9 PTAD8
W
0x0271 PTAD(L) RPTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
W
0x0272 PTIAD(H) R PTIAD15 PTIAD14 PTIAD13 PTIAD12 PTIAD11 PTIAD10 PTIAD9 PTIAD8
W
0x0273 PTIAD(L) R PTIAD7 PTIAD6 PTIAD5 PTIAD4 PTIAD3 PTIAD2 PTIAD1 PTIAD0
W
0x0274 DDRAD(H) RDDRAD15 DDRAD14 DDRAD13 DDRAD12 DDRAD11 DDRAD10 DDRAD9 DDRAD8
W
0x0275 DDRAD(L) RDDRAD7 DDRAD6 DDRAD5 DDRAD4 DDRAD3 DDRAD2 DDRAD1 DDRAD0
W
0x0276 RDRAD(H) R
RDRAD15 RDRAD14 RDRAD13 RDRAD12 RDRAD11 RDRAD10 RDRAD9 RDRAD8
W
0x0277 RDRAD(L) RRDRAD7 RDRAD6 RDRAD5 RDRAD4 RDRAD3 RDRAD2 RDRAD1 RDRAD0
W
0x0278 PERAD(H) RPERAD15 PERAD14 PERAD13 PERAD12 PERAD11 PERAD10 PERAD9 PERAD8
W
0x0279 PERAD(L) RPERAD7 PERAD6 PERAD5 PERAD4 PERAD3 PERAD2 PERAD1 PERAD0
W
0x027A PPSAD(H) RPPSAD15 PPSAD14 PPSAD13 PPSAD12 PPSAD11 PPSAD10 PPSAD9 PPSAD8
W
0x027B PPSAD(L) RPPSAD7 PPSAD6 PPSAD5 PPSAD4 PPSAD3 PPSAD2 PPSAD1 PPSAD0
W
0x027C PIEAD(H) RPIEAD15 PIEAD14 PIEAD13 PIEAD12 PIEAD11 PIEAD10 PIEAD9 PIEAD8
W
0x027D PIEAD(L) RPIEAD7 PIEAD6 PIEAD5 PIEAD4 PIEAD3 PIEAD2 PIEAD1 PIEAD0
W
0x027E PIFAD(H) RPIFAD15 PIFAD14 PIFAD13 PIFAD12 PIFAD11 PIFAD10 PIFAD9 PIFAD8
W
0x027F PIFAD(L) RPIFAD7 PIFAD6 PIFAD5 PIFAD4 PIFAD3 PIFAD2 PIFAD1 PIFAD0
W
0x0280 – 0x03FF Reserved Space
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0280–
0x2FF Reserved R00000000
W
0x0300–
0x03FF Unimplemented
R00000000
W
0x0240 – 0x027F PIM (Port Interface Module) (Sheet 4 of 4)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
56 Freescale Semiconductor
1.2.2 Part ID Assignments
The part ID is located in two 8-bit registers PAR TIDH and P AR TIDL (addresses 0x001A and 0x001B after
reset. The read-only value is a unique part ID for each revision of the chip. Table 1-2 shows the assigned
part ID numbers.
The device memory sizes are located in two 8-bit registers MEMSIZ0 and MEMSIZ1 (addresses 0x001C
and 0x001D after reset). Table 1-3 shows the read-only values of these registers. Refer to Chapter 19,
“Module Mapping Control (MMCV4)” for further details.
Table 1-2. Assigned Part ID Numbers
Device Mask Set Number Part ID1
1The coding is as follows:
Bit 15–12: Major family identifier
Bit 11–8: Minor family identifier
Bit 7–4: Major mask set revision number including FAB transfers
Bit 3–0: Minor — non full — mask set revision
MC9S12E256 0L43X 0x5000
Table 1-3. Memory Size Registers
Device Register name Value
MC9S12E256 MEMSIZ0 0x07
MC9S12E256 MEMSIZ1 0x81
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 57
1.3 Signal Description
1.3.1 Device Pinout
Figure 1-3. Pin Assignments for 112-LQFP
VRH
VDDA
PAD07/AN07/KWAD07
PAD06/AN06/KWAD06
PAD05/AN05/KWAD05
PAD04/AN04/KWAD04
PAD03/AN03/KWAD03
PAD02/AN02/KWAD02
PAD01/AN01/KWAD01
PAD00/AN00/KWAD00
PA7/ADDR15/DATA15
PA6/ADDR14/DATA14
PA5/ADDR13/DATA13
PA4/ADDR12/DATA12
VSS2
VDD2
PA3/ADDR11/DATA11
PA2/ADDR10/DATA10
PA1/ADDR9/DATA9
PA0/ADDR8/DATA8
PS7/SS
PS6/SCK
PS5/MOSI
PS4/MISO
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
PP0/PW00
PP1/PW01
PP2/PW02
PP3/PW03
PP4/PW04
PP5/PW05
PK7/ECS/ROMCTL
PK6/XCS
PK5/XADDR19
PK4/XADDR18
VDD1
VSS1
PK3/XADDR17
PK2/XADDR16
PK1/XADDR15
PK0/XADDR14
PM1/DA1
PM0/DA0
PAD15/AN15/KWAD15
PAD14/AN14/KWAD14
PAD13/AN13/KWAD13
PAD12/AN12/KWAD12
PAD11/AN11/KWAD11
PAD10/AN10/KWAD10
PAD09/AN09/KWAD09
PAD08/AN08/KWAD08
VSSA
VRL
PM3
RXD2/PM4
TXD2/PM5
SDA/PM6
SCL/PM7
FAULT0/PQ0
FAULT1/PQ1
FAULT2/PQ2
FAULT3/PQ3
ADDR0/DATA0/PB0
ADDR1/DATA1/PB1
ADDR2/DATA2/PB2
ADDR3/DATA3/PB3
VDDX
VSSX
ADDR4/DATA4/PB4
ADDR5/DATA5/PB5
ADDR6/DATA6/PB6
ADDR7/DATA7/PB7
IS0/PQ4
IS1/PQ5
IS2/PQ6
MODC/TAGHI/BKGD
IOC04/PT0
IOC05/PT1
IOC06/PT2
IOC07/PT3
IOC14/PT4
IOC15/PT5
IOC16/PT6
IOC17/PT7
PW10/IOC24/PU0
PW11/IOC25/PU1
PW14/PU4
PW15/PU5
XCLKS/NOACC/PE7
MODB/IPIPE1/PE6
MODA/IPIPE0/PE5
ECLK/PE4
VSSR
VDDR
RESET
VDDPLL
XFC
VSSPLL
EXTAL
XTAL
TEST
PU6
PU7
PW12/IOC26/PU2
PW13/IOC27PU3
LSTRB/TAGLO/PE3
R/W/PE2
IRQ/PE1
XIRQ/PE0
Signals shown in Bold are not available on the 80-pin package
MC9S12E256
112 LQFP
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
58 Freescale Semiconductor
Figure 1-4. Pin Assignments for 80-QFP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
MC9S12E256
80 QFP
VRH
VDDA
PAD07/AN07/KWAD07
PAD06/AN06/KWAD06
PAD05/AN05/KWAD05
PAD04/AN04/KWAD04
PAD03/AN03/KWAD03
PAD02/AN02/KWAD02
PAD01/AN01/KWAD01
PAD00/AN00/KWAD00
VSS2
VDD2
PS7/SS
PS6/SCK
PS5/MOSI
PS4/MISO
PS3/TXD1
PS2/RXD1
PS1/TXD0
PS0/RXD0
PP0/PW00
PP1/PW01
PP2/PW02
PP3/PW03
PP4/PW04
PP5/PW05
VDD1
VSS1
PM1/DA1
PM0/DA0
PAD15/AN15/KWAD15
PAD14/AN14/KWAD14
PAD13/AN13/KWAD13
PAD12/AN12/KWAD12
PAD11/AN11/KWAD11
PAD10/AN10/KWAD10
PAD09/AN09/KWAD09
PAD08/AN08/KWAD08
VSSA
VRL
PM3
RXD2/PM4
TXD2/PM5
SDA/PM6
SCL/PM7
FAULT0/PQ0
FAULT1/PQ1
FAULT2/PQ2
FAULT3/PQ3
VDDX
VSSX
IS0/PQ4
IS1/PQ5
IS2/PQ6
MODC/TAGHI/BKGD
IOC04/PT0
IOC05/PT1
IOC06/PT2
IOC07/PT3
IOC14/PT4
IOC15/PT5
IOC16/PT6
IOC17/PT7
PW10/IOC24/PU0
PW11/IOC25/PU1
XCLKS/NOACC/PE7
ECLK/PE4
VSSR
VDDR
RESET
VDDPLL
XFC
VSSPLL
EXTAL
XTAL
TEST
PW12/IOC26/PU2
PW13/IOC27/PU3
IRQ/PE1
XIRQ/PE0
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 59
1.3.2 Signal Properties Summary
Table 1-4. Signal Properties
Pin Name
Function 1
Pin Name
Function 2
Pin Name
Function 3
Power
Domain
Internal Pull Resistor
Description
CTRL Reset State
EXTAL — — VDDPLL NA NA Oscillator pins
XTAL — — VDDPLL NA NA
XFC — — VDDPLL NA NA PLL loop filter pin
RESET — — VDDX None None External reset pin
BKGD MODC TAGHI VDDX Up Up Background debug, mode pin, tag signal
high
TEST VPP — NA NA NA Test pin only
PAD[15,13,
12,8,6,4,2,0]
AN[15,13,
12,8,6,4,2,0]
KWAD[15,13,
12,8,6,4,2,0]
VDDX PERAD/
PPSAD
Disabled Port AD I/O Pins, ATD inputs, keypad
Wake-up
PAD[14,11,
10,9,7,5,3,1]
AN[14,11,
10,9,7,5,3,1]
KWAD[14,11,
10,9,7,5,3,1]
VDDX PERAD/
PPSAD
Disabled Port AD I/O Pins, ATD inputs, keypad
Wake-up
PA[7:0] ADDR[15:8]/
DATA[15:8]
— VDDX PUCR Disabled Port A I/O pin, multiplexed
address/data
PB[7:0] ADDR[7:0]/
DATA[7:0]
— VDDX PUCR Disabled Port B I/O pin, multiplexed
address/data
PE7 NOACC XCLKS VDDX Input Input Port E I/O pin, access, clock select
PE6 IPIPE1 MODB VDDX While RESET is low:
Down
Port E I/O pin, pipe status, mode
selection
PE5 IPIPE0 MODA VDDX While RESET is low:
Down
Port E I/O pin, pipe status, mode
selection
PE4 ECLK — VDDX PUCR Mode Dep1Port E I/O pin, bus clock output
PE3 LSTRB TAGLO VDDX PUCR Mode Dep1Port E I/O pin, low strobe, tag signal
low
PE2 R/W — VDDX PUCR Mode Dep1Port E I/O pin, R/W in expanded modes
PE1 IRQ — VDDX PUCR Up Port E input, external interrupt pin
PE0 XIRQ — VDDX PUCR Up Port E input, non-maskable interrupt pin
PK[7] ECS ROMCTL VDDX PUCR Up Port K I/O Pin, Emulation Chip Select
PK[6] XCS — VDDX PUCR Up Port K I/O Pin, External Chip Select
PK[5:0] XADDR[19:14] — VDDX PUCR Up Port K I/O Pins, Extended Addresses
PM7 SCL — VDDX PERM/
PPSM
Up Port M I/O Pin, IIC SCL signal
PM6 SDA — VDDX PERM/
PPSM
Up Port M I/O Pin, IIC SDA signal
PM5 TXD2 — VDDX PERM/
PPSM
Up Port M I/O Pin, SCI2 transmit signal
PM4 RXD2 — VDDX PERM/
PPSM
Up Port M I/O Pin, SCI2 receive signal
PM3 — — VDDX PERM/
PPSM
Disabled Port M I/O Pin
PM1 DAO1 — VDDX PERM/
PPSM
Disabled Port M I/O Pin, DAC1 output
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
60 Freescale Semiconductor
NOTE
Signals shown in bold are not available in the 112-pin package.
Signals shown in italic are not available in the 80-pin package.
If the port pins are not bonded out in the chosen package the user should initialize the registers to be inputs
with enabled pull resistance to avoid excess current consumption. This applies to the following pins:
(80QFP): Port A[7:0], Port B[7:0], Port E[6,5,3,2], Port K[7:0], Port U[7:4]
(64QFN): Port U[3:0], Port Q[6:4], Port M[3], Port AD[14,11,10,9,7,5,3,1]
PM0 DAO0 — VDDX PERM/
PPSM
Disabled Port M I/O Pin, DAC0 output
PP[5:0] PW0[5:0] — VDDX PERP/
PPSP
Disabled Port P I/O Pins, PWM output
PQ[6:4] IS[6:4] — VDDX PERQ/
PPSQ
Disabled Port Q I/O Pins, IS[6:4] input
PQ[3:0] FAULT[3:0] — VDDX PERQ/
PPSQ
Disabled Port Q I/O Pins, Fault[3:0] input
PS7 SS — VDDX PERS/
PPSS
Up Port S I/O Pin, SPI SS signal
PS6 SCK — VDDX PERS/
PPSS
Up Port S I/O Pin, SPI SCK signal
PS5 MOSI — VDDX PERS/
PPSS
Up Port S I/O Pin, SPI MOSI signal
PS4 MISO — VDDX PERS/
PPSS
Up Port S I/O Pin, SPI MISO signal
PS3 TXD1 — VDDX PERS/
PPSS
Up Port S I/O Pin, SCI1 transmit signal
PS2 RXD1 — VDDX PERS/
PPSS
Up Port S I/O Pin, SCI1 receive signal
PS1 TXD0 — VDDX PERS/
PPSS
Up Port S I/O Pin, SCI0 transmit signal
PS0 RXD0 — VDDX PERS/
PPSS
Up Port S I/O Pin, SCI0 receive signal
PT[7:4] IOC1[7:4] — VDDX PERT/
PPST
Disabled Port T I/O Pins, timer (TIM1)
PT[3:0] IOC0[7:4] — VDDX PERT/
PPST
Disabled Port T I/O Pins, timer (TIM0)
PU[7:6] — — VDDX PERU/
PPSU
Disabled Port U I/O Pins
PU[5:4] PW1[5:4] — VDDX PERU/
PPSU
Disabled Port U I/O Pins, PWM outputs
PU[3:0] IOC2[7:4] PW1[3:0] VDDX PERU/
PPSU
Disabled Port U I/O Pins, timer (TIM2), PWM
outputs
1The Port E output buffer enable signal control at reset is determined by the PEAR register and is mode dependent. For
example, in special test mode RDWE = LSTRE = 1 which enables the PE[3:2] output buffers and disables the pull-ups. Refer
to Chapter 18, “Multiplexed External Bus Interface (MEBIV3)” for PEAR register details.
Table 1-4. Signal Properties
Pin Name
Function 1
Pin Name
Function 2
Pin Name
Function 3
Power
Domain
Internal Pull Resistor
Description
CTRL Reset State
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 61
1.4 Detailed Signal Descriptions
1.4.1 EXTAL, XTAL — Oscillator Pins
EXTAL and XTAL are the external clock and crystal driver pins. On reset all the device clocks are derived
from the EXTAL input frequency. XTAL is the crystal output.
1.4.2 RESET — External Reset Pin
RESET is an active low bidirectional control signal that acts as an input to initialize the MCU to a known
start-up state. It also acts as an open-drain output to indicate that an internal failure has been detected in
either the clock monitor or COP watchdog circuit. External circuitry connected to the RESET pin should
not include a large capacitance that would interfere with the ability of this signal to rise to a valid logic one
within 32 ECLK cycles after the low drive is released. Upon detection of any reset, an internal circuit
drives the RESET pin low and a clocked reset sequence controls when the MCU can begin normal
processing.
1.4.3 TEST — Test Pin
The TEST pin is reserved for test and must be tied to VSS in all applications.
1.4.4 XFC — PLL Loop Filter Pin
Dedicated pin used to create the PLL loop filter. See Chapter 4, “Clocks and Reset Generator (CRGV4)”
for more detailed information.
1.4.5 BKGD / TAGHI / MODC — Background Debug, Tag High & Mode Pin
The BKGD / TAGHI / MODC pin is used as a pseudo-open-drain pin for the background debug
communication. It is used as a MCU operating mode select pin during reset. The state of this pin is latched
to the MODC bit at the rising edge of RESET. In MCU expanded modes of operation, when instruction
tagging is on, an input low on this pin during the falling edge of E-clock tags the high half of the instruction
word being read into the instruction queue. This pin always has an internal pull up.
1.4.6 PA[7:0] / ADDR[15:8] / DATA[15:8] — Port A I/O Pins
PA[7:0] are general purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the multiplexed external address and data bus. PA[7:0] pins are not available in the 80 pin package
version.
1.4.7 PB[7:0] / ADDR[7:0] / DATA[7:0] — Port B I/O Pins
PB[7:0] are general purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the multiplexed external address and data bus. PB[7:0] pins are not available in the 80 pin package
version.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
62 Freescale Semiconductor
1.4.8 PE7 / NOACC / XCLKS — Port E I/O Pin 7
PE7 is a general purpose input or output pin. During MCU expanded modes of operation, the NOACC
signal, when enabled, is used to ind icate that the current bus cycle is an unused or “free cycle”. This signal
will assert when the CPU is not using the bus. The XCLKS is an input signal which controls whether a
crystal in combination with the internal Colpitts (low power) oscillator is used or whether Pierce
oscillator/external clock circuitry is used. The state of this pin is latched at the rising edge of RESET. If
the input is a logic low the EXTAL pin is configured for an external clock drive or a Pierce Oscillator. If
the input is a logic high a Colpitts oscillator circuit is configured on EXTAL and XTAL. Since this pin is
an input with a pull-up device during reset, if the pin is left floating, the default configuration is a Colpitts
oscillator circuit on EXTAL and XTAL.
Figure 1-5. Colpitts Oscillator Connections (PE7 = 1)
Figure 1-6. Pierce Oscillator Connections (PE7 = 0)
1.4.9 PE6 / MODB / IPIPE1 — Port E I/O Pin 6
PE6 is a general purpose input or output pin. It is used as a MCU operating mode select pin during reset.
The state of this pin is latched to the MODB bit at the rising edge of RESET. This pin is shared with the
instruction queue tracking signal IPIPE1. This pin is an input with a pull-down device which is only active
when RESET is low. PE6 is not available in the 80 pin package version.
MCU
C2
EXTAL
XTAL
Crystal or
VSSPLL
ceramic resonator
C1
CDC1
1. Due to the nature of a translated ground Colpitts oscillator a DC voltage bias is
applied to the crystal. Please contact the crystal manufacturer for crystal DC
MCU
EXTAL
XTAL
RS1
RB
VSSPLL
Crystal or
ceramic resonator
C2
C1
1. Rs can be zero (shorted) when use with higher frequency crystals.
Refer to manufacturer’s data.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 63
1.4.10 PE5 / MODA / IPIPE0 — Port E I/O Pin 5
PE5 is a general purpose input or output pin. It is used as a MCU operating mode select pin during reset.
The state of this pin is latched to the MODA bit at the rising edge of RESET. This pin is shared with the
instruction queue tracking signal IPIPE0. This pin is an input with a pull-down device which is only active
when RESET is low. PE5 is not available in the 80-pin package version.
1.4.11 PE4 / ECLK— Port E I/O Pin 4 / E-Clock Output
PE4 is a general purpose input or output pin. In Normal Single Chip mode PE4 is configured with an active
pull-up while in reset and immediately out of reset. The pullup can be turned off by clearing PUPEE in the
PUCR register. In all modes except Normal Single Chip Mode, the PE4 pin is initially configured as the
output connection for the internal bus clock (ECLK). ECLK is used as a timing reference and to
demultiplex the address and data in expanded modes. The ECLK frequency is equal to 1/2 the crystal
frequency out of reset. The ECLK output function depends upon the settings of the NECLK bit in the
PEAR register, the IVIS bit in the MODE register and the ESTR bit in the EBICTL register. All clocks,
including the ECLK, are halted when the MCU is in STOP mode. It is possible to configure the MCU to
interface to slow external memory. ECLK can be stretched for such accesses. The PE4 pin is initially
configured as ECLK output with stretch in all expanded modes. Reference the MISC register
(EXSTR[1:0] bits) for more information. In normal expanded narrow mode, the ECLK is available for use
in external select decode logic or as a constant speed clock for use in the external application system.
1.4.12 PE3 / LSTRB / TAGLO — Port E I/O Pin 3 / Low-Byte Strobe (LSTRB)
PE3 can be used as a general-purpose I/O in all modes and is an input with an active pull-up out of reset.
The pullup can be turned off by clearing PUPEE in the PUCR register. PE3 can also be configured as a
Low-Byte Strobe (LSTRB). The LSTRB signal is used in write operations, so external low byte writes will
not be possible until this function is enabled. LSTRB can be enabled by setting the LSTRE bit in the PEAR
register. In Expanded Wide and Emulation Narrow modes, and when BDM tagging is enabled, the LSTRB
function is multiplexed with the TAGLO function. When enabled a logic zero on the TAGLO pin at the
falling edge of ECLK will tag the low byte of an instruction word being read into the instruction queue.
PE3 is not available in the 80 pin package version.
1.4.13 PE2 / R/W — Port E I/O Pin 2 / Read/Write
PE2 can be used as a general-purpose I/O in all modes and is configured an input with an active pull-up
out of reset. The pullup can be turned off by clearing PUPEE in the PUCR register. If the read/write
function is required it should be enabled by setting the RDWE bit in the PEAR register. External writes
will not be possible until the read/write function is enabled. The PE2 pin is not available in the 80 pin
package version.
1.4.14 PE1 / IRQ — Port E input Pin 1 / Maskable Interrupt Pin
PE1 is always an input and can always be read. The PE1 pin is also the IRQ input used for requesting an
asynchronous interrupt to the MCU. During reset, the I bit in the condition code register (CCR) is set and
any IRQ interrupt is masked until software enables it by clearing the I bit. The IRQ is software
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
64 Freescale Semiconductor
programmable to either fa lli ng edge-sensitive triggering or level-sensitive triggering based on the setting
of the IRQE bit in the IRQCR register. The IRQ is always enabled and configured to level-sensitive
triggering out of reset. It can be disabled by clearing IRQEN bit in the IRQCR register. There is an active
pull-up on this pin while in reset and immediately out of reset. The pullup can be turned off by clearing
PUPEE in the PUCR register.
1.4.15 PE0 / XIRQ — Port E input Pin 0 / Non Maskable Interrupt Pin
PE0 is always an input and can always be read. The PE0 pin is also the XIRQ input for requesting a
nonmaskable asynchronous interrupt to the MCU. During reset, the X bit in the condition code register
(CCR) is set and any XIRQ interrupt is masked until MCU software enables it by clearing the X bit.
Because the XIRQ input is level sensitive triggered, it can be connected to a multiple-source wired-OR
network. There is an active pull-up on this pin while in reset a nd immediately out of reset. The pullup can
be turned off by clearing PUPEE in the PUCR register.
1.4.16 PK7 / ECS / ROMCTL — Port K I/O Pin 7
PK7 is a general purpose input or output pin. During MCU expanded modes of operation, when the EMK
bit in the MODE register is set to 1, this pin is used as the emulation chip select output (ECS). In expanded
modes the PK7 pin can be used to determine the reset state of the ROMON bit in the MISC register. At
the rising edge of RESET, the state of the PK7 pin is latched to the ROMON bit. There is an active pull-up
on this pin while in reset and immediately out of reset. The pullup can be turned off by clearing PUPKE
in the PUCR register. Refer to Chapter 18, “Multiplexed External Bus Interface (MEBIV3)” for further
details. PK7 is not available in the 80 pin package version.
1.4.17 PK6 / XCS — Port K I/O Pin 6
PK6 is a general purpose input or output pin. During MCU expanded modes of operation, when the EMK
bit in the MODE register is set to 1, this pin is used as an external chip select signal for most external
accesses that are not selected by ECS. There is an active pull-up on this pin while in reset and immediately
out of reset. The pullup can be turned of f by clearing PUPKE in the PUCR register. Refer to Chapter 18,
“Multiplexed External Bus Interface (MEBIV3)” for further details. PK6 is not available in the 80 pin
package version.
1.4.18 PK[5:0] / XADDR[19:14] — Port K I/O Pins [5:0]
PK[5:0] are general purpose input or output pins. In MCU expanded modes of operation, when the EMK
bit in the MODE register is set to 1, PK[5:0] provide the expanded address XADDR[19:14] for the external
bus. There are active pull-ups on PK[5:0] pins while in reset and immediately out of reset. The pullup can
be turned off by clearing PUPKE in the PUCR register. Refer to Chapter 18, “Multiplexed External Bus
Interface (MEBIV3)” for further details. PK[5:0] are not available in the 80 pin package version.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 65
1.4.19 PAD[15:0] / AN[15:0] / KWAD[15:0] — Port AD I/O Pins [15:0]
PAD[15:0] are the analog inputs for the analog to digital converter (ADC). They can also be configured as
general purpose digital input or output pin. When enabled as digital inputs or outputs, the PAD[15:0] can
also be configured as Keypad Wake-up pins (KWU) and generate interrupts causing the MCU to exit
STOP or WAIT mode. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and the Chapter 6,
“Analog-to-Digital Converter (ATD10B16CV4)” for information about pin configurations.
1.4.20 PM7 / SCL — Port M I/O Pin 7
PM7 is a general purpose input or output pin. When the IIC module is enabled it becomes the serial clock
line (SCL) for the IIC module (IIC). While in reset and immediately out of reset the PM7 pin is configured
as a high impedance input pin. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and
Chapter 10, “Inter-Integrated Circuit (IICV2)” for information about pin configurations.
1.4.21 PM6 / SDA — Port M I/O Pin 6
PM6 is a general purpose input or output pin. When the IIC module is enabled it becomes the Serial Data
Line (SDL) for the IIC module (IIC). While in reset and immediately out of reset the PM6 pin is configured
as a high impedance input pin. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and
Chapter 10, “Inter-Integrated Circuit (IICV2)” for information about pin configurations.
1.4.22 PM5 / TXD2 — Port M I/O Pin 5
PM5 is a general purpose input or output. When the Serial Communications Interface 2 (SCI2) transmitter
is enabled the PM5 pin is configured as the transmit pin TXD2 of SCI2. While in reset and immediately
out of reset the PM5 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 8, “Serial Communication Interface (SCIV4)” for information
about pin configurations.
1.4.23 PM4 / RXD2 — Port M I/O Pin 4
PM4 is a general purpose input or output. When the Serial Communications Interface 2 (SCI2) receiver is
enabled the PM4 pin is configured as the receive pin RXD2 of SCI2. While in reset and immediately out
of reset the PM4 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 8, “Serial Communication Interface (SCIV4)” for information
about pin configurations.
1.4.24 PM3 — Port M I/O Pin 3
PM3 is a general purpose input or output pin. While in reset and immediately out of reset the PM3 pin is
configured as a high impedance input pin. Consult Chapter 3, “Port Integration Module (PIM9E256V1)”
for information about pin configurations.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
66 Freescale Semiconductor
1.4.25 PM1 / DAO1 — Port M I/O Pin 1
PM1 is a general purpose input or output pin. When the Digital to Analog module 1 (DAC1) is enabled
the PM1 pin is configured as the analog output DA01 of DAC1. While in reset and immediately out of
reset the PM1 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 7, “Digital-to-Analog Converter (DAC8B1CV1)” for information
about pin configurations.
1.4.26 PM0 / DAO2 — Port M I/O Pin 0
PM0 is a general purpose input or output pin. When the Digital to Analog module 2 (DAC2) is enabled
the PM0 pin is configured as the analog output DA02 of DAC2. While in reset and immediately out of
reset the PM0 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 7, “Digital-to-Analog Converter (DAC8B1CV1)” for information
about pin configurations.
1.4.27 PP[5:0] / PW0[5:0] — Port P I/O Pins [5:0]
PP[5:0] are general purpose input or output pins. When the Pulse width Modulator with Fault protection
(PMF) is enabled the PP[5:0] output pins, as a whole or as pairs, can be configured as PW0[5:0] outputs.
While in reset and immediately out of reset the PP[5:0] pins are configured as a high impedance input pins.
Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and Chapter 11, “Pulse Width Modulator
with Fault Protection (PMF15B6CV2)” for information about pin configurations.
1.4.28 PQ[6:4] / IS[2:0] — Port Q I/O Pins [6:4]
PQ[6:4] are general purpose input or output pins. When enabled in the Pulse width Modulator with Fault
protection module (PMF), the PQ[6:4] pins become the current status input pins, IS[2:0], for top/bottom
pulse width correction. While in reset and immediately out of reset PP[5:0] pins are configured as a high
impedance input pins. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and Chapter 11,
“Pulse W idth Modulator with Fault Protection (PMF15B6CV2)” for information about pin configurations.
1.4.29 PQ[3:0] / FAULT[3:0] — Port Q I/O Pins [3:0]
PQ[3:0] are general purpose input or output pins. When enabled in the Pulse width Modulator with Fault
protection module (PMF), the PQ[3:0] pins become the Fault protection inputs pins, FAULT[3:0], of the
PMF. While in reset and immediately out of reset the PQ[3:0] pins are configured as a high impedance
input pins. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and the Chapter 11, “Pulse
Width Modulator with Fault Protection (PMF15B6CV2)” for information about pin configurations.
1.4.30 PS7 / SS — Port S I/O Pin 7
PS7 is a general purpose input or output. When the Serial Peripheral Interface (SPI) is enabled PS7
becomes the slave select pin SS. While in reset and immediately out of reset the PS7 pin is configured as
a high impedance input pin. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and Chapter 9,
“Serial Peripheral Interface (SPIV3)” for information about pin configurations.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 67
1.4.31 PS6 / SCK — Port S I/O Pin 6
PS6 is a general purpose input or output pin. When the Serial Peripheral Interface (SPI) is enabled PS6
becomes the serial clock pin, SCK. While in reset and immedi ately out of reset the PS6 pin is configured
as a high impedance input pin. Consult Chapter 3, “Port Integration Module (PIM9E256V1)” and
Chapter 9, “Serial Peripheral Interface (SPIV3)” for information about pin configurations.
1.4.32 PS5 / MOSI — Port S I/O Pin 5
PS5 is a general purpose input or output pin. When the Serial Peripheral Interface (SPI) is enabled PS5 is
the master output (during master mode) or slave input (during slave mode) pin. While in reset and
immediately out of reset the PS5 pin is configured as a high impedance input pin Consult Chapter 3, “Port
Integration Module (PIM9E256V1)” and Chapter 9, “Serial Peripheral Interface (SPIV3)” for information
about pin configurations.
1.4.33 PS4 / MISO — Port S I/O Pin 4
PS4 is a general purpose input or output pin. When the Serial Peripheral Interface (SPI) is enabled PS4 is
the master input (during master mode) or slave output (during slave mode) pin. While in reset and
immediately out of reset the PS4 pin is configured as a high impedance input pin. Consult Chapter 3, “Port
Integration Module (PIM9E256V1)” and Chapter 9, “Serial Peripheral Interface (SPIV3)” for information
about pin configurations.
1.4.34 PS3 / TXD1 — Port S I/O Pin 3
PS3 is a general purpose input or output. When the Serial Communications Interface 1 (SCI1) transmitter
is enabled the PS3 pin is configured as the transmit pin, TXD1, of SCI1. While in reset and immediately
out of reset the PS3 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 8, “Serial Communication Interface (SCIV4)” for information
about pin configurations.
1.4.35 PS2 / RXD1 — Port S I/O Pin 2
PS2 is a general purpose input or output. When the Serial Communications Interface 1 (SCI1) receiver is
enabled the PS2 pin is configured as the receive pin RXD1 of SCI1. While in reset and immediately out
of reset the PS2 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 8, “Serial Communication Interface (SCIV4)” for information
about pin configurations.
1.4.36 PS1 / TXD0 — Port S I/O Pin 1
PS1 is a general purpose input or output. When the Serial Communications Interface 0 (SCI0) transmitter
is enabled the PS1 pin is configured as the transmit pin, TXD0, of SCI0. While in reset and immediately
out of reset the PS1 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 8, “Serial Communication Interface (SCIV4)” for information
about pin configurations.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
68 Freescale Semiconductor
1.4.37 PS0 / RXD0 — Port S I/O Pin 0
PS0 is a general purpose input or output. When the Serial Communications Interface 0 (SCI0) receiver is
enabled the PS0 pin is configured as the receive pin RXD0 of SCI0. While in reset and immediately out
of reset the PS0 pin is configured as a high impedance input pin. Consult Chapter 3, “Port Integration
Module (PIM9E256V1)” and Chapter 8, “Serial Communication Interface (SCIV4)” for information
about pin configurations.
1.4.38 PT[7:4] / IOC1[7:4]— Port T I/O Pins [7:4]
PT[7:4] are general purpose input or output pins. When the Timer system 1 (TIM1) is enabled they can
also be configured as the TIM1 input capture or output compare pins IOC1[7-4]. While in reset and
immediately out of reset the PT[7:4] pins are configured as a high impedance input pins. Consult
Chapter 3, “Port Integration Module (PIM9E256V1)” and Chapter 13, “Timer Module (TIM16B4CV1)”
for information about pin configurations.
1.4.39 PT[3:0] / IOC0[7:4]— Port T I/O Pins [3:0]
PT[3:0] are general purpose input or output pins. When the Timer system 0 (TIM0) is enabled they can
also be configured as the TIM0 input capture or output compare pins IOC0[7-4]. While in reset and
immediately out of reset the PT[3:0] pins are configured as a high impedance input pins. Consult
Chapter 3, “Port Integration Module (PIM9E256V1)” and Chapter 13, “Timer Module (TIM16B4CV1)”
for information about pin configurations.
1.4.40 PU[7:6] — Port U I/O Pins [7:6]
PU[7:6] are general purpose input or output pins. While in reset and immediately out of reset the PU[7:6]
pins are configured as a high impedance input pins. Consult Chapter 3, “Port Integration Module
(PIM9E256V1)” for information about pin configurations. PU[7:6] are not available in the 80 pin package
version.
1.4.41 PU[5:4] / PW1[5:4] — Port U I/O Pins [5:4]
PU[5:4] are general purpose input or output pins. When the Pulse W idth Modulator (PWM) is enabled the
PU[5:4] output pins, individually or as a pair, can be configured as PW1[5:4] outputs. While in reset and
immediately out of reset the PU[5:4] pins are configured as a high impedance input pins. Consult
Chapter 3, “Port Integration Module (PIM9E256V1)” and Chapter 12, “Pulse-Width Modulator
(PWM8B6CV1)” for information about pin configurations. PU[5:4] are not available in the 80 pin package
version.
1.4.42 PU[3:0] / IOC2[7:4]/PW1[3:0] — Port U I/O Pins [3:0]
PU[3:0] are general purpose input or output pins. When the Timer system 2 (TIM2) is enabled they can
also be configured as the TIM2 input capture or output compare pins IOC2[7-4]. When the Pulse Width
Modulator (PWM) is enabled the PU[3:0] output pins, individually or as a pair, can be configured as
PW1[3:0] outputs. The MODRR register in the Port Integration Module determines if the TIM2 or PWM
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 69
function is selected. While in rese t and immediately out of reset the PU[3:0] pins are configured as a high
impedance input pins. Consult Chapter 3, “Port Integration Module (PIM9E256V1)”, Chapter 13, “T imer
Module (TIM16B4CV1)”, and Chapter 12, “Pulse-Width Modulator (PWM8B6CV1)” for information
about pin configurations.
1.4.43 VDDX,VSSX — Power & Ground Pins for I/O Drivers
External power and ground for I/O drivers. Bypass requirements depend on how heavily the MCU pins are
loaded.
1.4.44 VDDR, VSSR — Power Supply Pins for I/O Drivers & for Internal
Voltage Regulator
External power and ground for I/O drivers and input to the internal voltage regulator . Bypass requirements
depend on how heavily the MCU pins are loaded.
1.4.45 VDD1, VDD2, VSS1, VSS2 — Power Supply Pins for Internal Logic
Power is supplied to the MCU through VDD and VSS. This 2.5V supply is derived from the internal
voltage regulator . There is no static load on those pins allowed. The internal voltage regulator is turned off,
if VDDR is tied to ground.
1.4.46 VDDA, VSSA — Power Supply Pins for ATD and VREG
VDDA, VSSA are the power supply and ground input pins for the voltage regulator and the analog to
digital converter.
1.4.47 VRH, VRL — ATD Reference Voltage Input Pins
VRH and VRL are the reference voltage input pins for the analog to digital converter.
1.4.48 VDDPLL, VSSPLL — Power Supply Pins for PLL
Provides operating voltage and ground for the Oscillator and the Phased-Locked Loop. This allows the
supply voltage to the Oscillator and PLL to be bypassed independently. This 2.5V voltage is generated by
the internal voltage regulator.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
70 Freescale Semiconductor
NOTE
All VSS pins must be connected together in the application. Because fast
signal transitions place high, short-duration current demands on the power
supply, use bypass capacitors with high-frequency characteristics and place
them as close to the MCU as possible. Bypass requirements depend on
MCU pin load.
Table 1-5. MC9S12E256 Power and Ground Connection Summary
Mnemonic Nominal
Voltage Description
VDD1, VDD2 2.5 V Internal power and ground generated by internal regulator. These also allow an external
source to supply the core VDD/VSS voltages and bypass the internal voltage regulator.
VSS1, VSS2 0V
VDDR 3.3/5.0 V External power and ground, supply to internal voltage regulator.
To disable voltage regulator attach VDDR to VSSR.
VSSR 0 V
VDDX 3.3/5.0 V External power and ground, supply to pin drivers.
VSSX 0 V
VDDA 3.3/5.0 V Operating voltage and ground for the analog-to-digital converter, the reference for the
internal voltage regulator and the digital-to-analog converters, allows the supply voltage to
the A/D to be bypassed independently.
VSSA 0 V
VRH 3.3/5.0 V Reference voltage high for the ATD converter, and DAC.
VRL 0 V Reference voltage low for the ATD converter.
VDDPLL 2.5 V Provides operating voltage and ground for the Phased-Locked Loop. This allows the supply
voltage to the PLL to be bypassed independently. Internal power and ground generated by
internal regulator.
VSSPLL 0 V
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 71
1.5 System Clock Description
The Clock and Reset Generator provides the internal clock signals for the core and all peripheral modules.
Figure 1-7 shows the clock connections from the CRG to all modules. Consult Chapter 4, “Clocks and
Reset Generator (CRGV4)” for details on clock generation.
Figure 1-7. Clock Connections
Table 1-6. Clock Selection Based on PE7
PE7 = XCLKS Description
1 Colpitts Oscillator selected
0 Pierce Oscillator/external clock selected
CRG Bus Clock
Core Clock
EXTAL
XTAL
Oscillator Clock
HCS12 CORE
PWM
RAM
PIM
IIC
DAC
Flash
ATD
SCI0, SCI1, SCI2
PMF
SPI
BDM
OSC
CPU
MEBI MMC
INT DBG
TIM0, TIM1, TIM2
VREG
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
72 Freescale Semiconductor
1.6 Modes of Operation
1.6.1 Overview
Eight possible modes determine the operating configuration of the MC9S12E256. Each mode has an
associated default memory map and external bus configuration controlled by a further pin.
Three low power modes exist for the device.
1.6.2 Chip Configuration Summary
The operating mode out of reset is determined by the states of the MODC, MODB, and MODA pins during
reset. The MODC, MODB, and MODA bits in the MODE register show the current operating mode and
provide limited mode switching during operation. The states of the MODC, MODB, and MODA pins are
latched into these bits on the rising edge of the reset signal. The ROMCTL signal allows the setting o f the
ROMON bit in the MISC register thus controlling whether the internal Flash is visible in the memory map.
ROMON = 1 mean the Flash is visible in the memory map. The state of the ROMCTL pin is latched into
the ROMON bit in the MISC register on the rising edge of the reset signal.
For further explanation on the modes refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”.
Table 1-7. Mode Selection
BKGD =
MODC
PE6 =
MODB
PE5 =
MODA
PK7 =
ROMCTL
ROMON
Bit Mode Description
0 0 0 X 1 Special Single Chip, BDM allowed and ACTIVE. BDM is
allowed in all other modes but a serial command is
required to make BDM active.
00101Emulation Expanded Narrow, BDM allowed
10
0 1 0 X 0 Special Test (Expanded Wide), BDM allowed
01101Emulation Expanded Wide, BDM allowed
10
1 0 0 X 1 Normal Single Chip, BDM allowed
10100Normal Expanded Narrow, BDM allowed
11
1 1 0 X 1 Peripheral; BDM allowed but bus operations would cause
bus conflicts (must not be used)
11100Normal Expanded Wide, BDM allowed
11
Table 1-8. Clock Selection Based on PE7
PE7 = XCLKS Description
1 Colpitts Oscillator selected
0 Pierce Oscillator/external clock selected
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 73
1.7 Security
The device will make available a security feature preventing the unauthorized read and write of the
memory contents. This feature allows:
• Protection of the contents of FLASH,
• Operation in single-chip mode,
• Operation from external memory with internal FLASH disabled.
The user must be reminded that part of the security must lie with the user’s code. An extreme example
would be user’ s code that dumps the contents of the internal program. This code would defeat the purpose
of security. At the same time the user may also wish to put a back door in the user’ s program. An example
of this is the user downloads a key through the SCI which allows access to a programming routine that
updates parameters.
1.7.1 Securing the Microcontroller
Once the user has programmed the FLASH, the part can be secured by programming the security bits
located in the FLASH module. These non-volatile bits will keep the part secured through resetting the part
and through powering down the part.
The security byte resides in a portion of the Flash array.
Check Chapter 2, “256 Kbyte Flash Module (FTS256K2V1)” for more details on the security
configuration.
1.7.2 Operation of the Secured Microcontroller
1.7.2.1 Normal Single Chip Mode
This will be the most common usage of the secured part. Everything will appear the same as if the part was
not secured with the exception of BDM operation. The BDM operation will be blocked.
1.7.2.2 Executing from External Memory
The user may wish to execute from external space with a secured microcontroller. This is accomplished
by resetting directly into expanded mode. The internal FLASH will be disabled. BDM operations will be
blocked.
1.7.3 Unsecuring the Microcontroller
In order to unsecure the microcontroller , the internal FLASH must be erased. This can be done through an
external program in expanded mode.
Once the user has erased the FLASH, the part can be reset into special single chip mode. This invokes a
program that verifies the erasure of the internal FLASH. Once this program completes, the user can erase
and program the FLASH security bits to the unsecured state. This is generally done through the BDM, but
the user could also change to expanded mode (by writing the mode bits through the BDM) and jumping to
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
74 Freescale Semiconductor
an external program (again through BDM commands). Note that if the part goes through a reset before the
security bits are reprogrammed to the unsecure state, the part will be secured again.
1.8 Low Power Modes
The microcontroller features three main low power modes. Consult the respective block description
chapter for information on the module behavior in Stop, Pseudo Stop, and W ait Mode. An important source
of information about the clock system is Chapter 4, “Clocks and Reset Generator (CRGV4)”.
1.8.1 Stop
Executing the CPU STOP instruction st ops all clocks and the oscillator thus putting the chip in fully static
mode. Wake up from this mode can be done via reset or external interrupts.
1.8.2 Pseudo Stop
This mode is entered by executing the CPU STOP instruction. In this mode the oscillator is still running
and the Real Time Interrupt (RTI) or Watchdog (COP) sub module can stay active. Other peripherals are
turned off. This mode consumes more current than the full STOP mode, but the wake up time from this
mode is significantly shorter.
1.8.3 Wait
This mode is entered by executing the CPU WAI instruction. In this mode the CPU will not execute
instructions. The internal CPU signals (address and data bus) will be fully static. All peripherals stay
active. For further power consumption the peripherals can individually turn off their local clocks.
1.8.4 Run
Although this is not a low power mode, unused peripheral modules should not be enabled in order to save
power.
1.9 Resets and Interrupts
Consult the Exception Processing section of the CPU12 Reference Manual for information on resets and
interrupts. System resets can be generated through external control of the RESET pin, through the clock
and reset generator module CRG or through the low voltage reset (LVR) generator of the voltage regulator
module. Refer to Chapter 4, “Clocks and Reset Generator (CRGV4)” and Chapter 14, “Dual Output
Voltage Regulator (VREG3V3V2)” for detailed information on reset generation.
1.9.1 Vectors
Table 1-9 lists interrupt sources and vectors in default order of priority.
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 75
Table 1-9. Interrupt Vector Locations
Vector Address Interrupt Source CCR
Mask Local Enable HPRIO Value
to Elevate
0xFFFE, 0xFFFF External Reset, Power On Reset or Low
Voltage Reset (see Section 4.3.2.4, “CRG
Flags Register (CRGFLG)” to determine
reset source)
None None –
0xFFFC, 0xFFFD Clock Monitor fail reset None COPCTL (CME, FCME) –
0xFFFA, 0xFFFB COP failure reset None COP rate select –
0xFFF8, 0xFFF9 Unimplemented instruction trap None None –
0xFFF6, 0xFFF7 SWI None None –
0xFFF4, 0xFFF5 XIRQ X-Bit None –
0xFFF2, 0xFFF3 IRQ I-Bit INTCR (IRQEN) 0xF2
0xFFF0, 0xFFF1 Real Time Interrupt I-Bit CRGINT (RTIE) 0xF0
0xFFE8 to 0xFFEF Reserved
0xFFE6, 0xFFE7 Standard Timer 0 channel 4 I-Bit TIE (C4I) 0xE6
0xFFE4, 0xFFE5 Standard Timer 0 channel 5 I-Bit TIE (C5I) 0xE4
0xFFE2, 0xFFE3 Standard Timer 0 channel 6 I-Bit TIE (C6I) 0xE2
0xFFE0, 0xFFE1 Standard Timer 0 channel 7 I-Bit TIE (C7I) 0xE0
0xFFDE, 0xFFDF Standard Timer overflow I-Bit TSCR2 (TOI) 0xDE
0xFFDC, 0xFFDD Pulse accumulator overflow I-Bit PACTL(PAOVI) 0xDC
0xFFDA, 0xFFDB Pulse accumulator input edge I-Bit PACTL (PAI) 0xDA
0xFFD8, 0xFFD9 SPI I-Bit SPICR1 (SPIE, SPTIE) 0xD8
0xFFD6, 0xFFD7 SCI0 I-Bit SCICR2
(TIE, TCIE, RIE, ILIE)
0xD6
0xFFD4, 0xFFD5 SCI1 I-Bit SCICR2
(TIE, TCIE, RIE, ILIE)
0xD4
0xFFD2, 0xFFD3 SCI2 I-Bit SCICR2
(TIE, TCIE, RIE, ILIE)
0xD2
0xFFD0, 0xFFD1 ATD I-Bit ATDCTL2 (ASCIE) 0xD0
0xFFCE, 0xFFCF Port AD (KWU) I-Bit PTADIF (PTADIE) 0xCE
0xFFC8 to 0xFFCD Reserved
0xFFC6, 0xFFC7 CRG PLL lock I-Bit PLLCR (LOCKIE) 0xC6
0xFFC4, 0xFFC5 CRG Self Clock Mode I-Bit PLLCR (SCMIE) 0xC4
0xFFC2, 0xFFC3 Reserved
0xFFC0, 0xFFC1 IIC Bus I-Bit IBCR (IBIE) 0xC0
0xFFBA to 0xFFBF Reserved
0xFFB8, 0xFFB9 FLASH I-Bit FCNFG (CCIE, CBEIE) 0xB8
0xFFB6, 0xFFB7 Standard Timer 1 channel 4 I-Bit TIE (C4I) 0xB6
0xFFB4, 0xFFB5 Standard Timer 1 channel 5 I-Bit TIE (C5I) 0xB4
0xFFB2, 0xFFB3 Standard Timer 1 channel 6 I-Bit TIE (C6I) 0xB2
0xFFB0, 0xFFB1 Standard Timer 1 channel 7 I-Bit TIE (C7I) 0xB0
0xFFAE, 0xFFAF Standard Timer 1 overflow I-Bit TSCR2 (TOI) 0xAE
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
76 Freescale Semiconductor
1.9.2 Resets
Resets are a subset of the interrupts featured in Table 1-9. The different sources capable of generating a
system reset are summarized in Table 1-10.
1.9.2.1 Reset Summary Table
0xFFAC, 0xFFAD Standard Timer 1 Pulse accumulator
overflow
I-Bit PACTL (PAOVI) 0xAC
0xFFAA, 0xFFAB Standard Timer 1 Pulse accumulator input
edge
I-Bit PACTL (PAI) 0xAA
0xFFA8, 0xFFA9 Reserved
0xFFA6, 0xFFA7 Standard Timer 2 channel 4 I-Bit TIE (C4I) 0xA6
0xFFA4, 0xFFA5 Standard Timer 2 channel 5 I-Bit TIE (C5I) 0xA4
0xFFA2, 0xFFA3 Standard Timer 2 channel 6 I-Bit TIE (C6I) 0xA2
0xFFA0, 0xFFA1 Standard Timer 2 channel 7 I-Bit TIE (C7I) 0xA0
0xFF9E, 0xFF9F Standard Timer overflow I-Bit TSCR2 (TOI) 0x9E
0xFF9C, 0xFF9D Standard Timer 2 Pulse accumulator
overflow
I-Bit PACTL (PAOVI) 0x9C
0xFF9A, 0xFF9B Standard Timer 2 Pulse accumulator input
edge
I-Bit PACTL (PAI) 0x9A
0xFF98, 0xFF99 PMF Generator A Reload I-Bit PMFENCA (PWMRIEA) 0x98
0xFF96, 0xFF97 PMF Generator B Reload I-Bit PMFENCB (PWMRIEB) 0x96
0xFF94, 0xFF95 PMF Generator C Reload I-Bit PMFENCC (PWMRIEC) 0x94
0xFF92, 0xFF93 PMF Fault 0 I-Bit PMFFCTL (FIE0) 0x92
0xFF90, 0xFF91 PMF Fault 1 I-Bit PMFFCTL (FIE1) 0x90
0xFF8E, 0xFF8F PMF Fault 2 I-Bit PMFFCTL (FIE2) 0x8E
0xFF8C, 0xFF8D PMF Fault 3 I-Bit PMFFCTL (FIE3) 0x8C
0xFF8A, 0xFF8B VREG LVI I-Bit CTRL0 (LVIE) 0x8A
0xFF88, 0xFF89 PWM Emergency Shutdown I-Bit PWMSDN(PWMIE) 0x88
0xFF80 to 0xFF87 Reserved
Table 1-10. Reset Summary
Reset Priority Source Vector
Power-on Reset 1 CRG Module 0xFFFE, 0xFFFF
External Reset 1 RESET pin 0xFFFE, 0xFFFF
Low Voltage Reset 1 VREG Module 0xFFFE, 0xFFFF
Clock Monitor Reset 2 CRG Module 0xFFFC, 0xFFFD
COP Watchdog Reset 3 CRG Module 0xFFFA, 0xFFFB
Table 1-9. Interrupt Vector Locations (continued)
Vector Address Interrupt Source CCR
Mask Local Enable HPRIO Value
to Elevate
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 77
1.9.2.2 Effects of Reset
When a reset occurs, MCU registers and control bits are changed to known start-up states. Refer to the
respective module block description chapters for register reset states. Refer to Chapter 18, “Multiplexed
External Bus Interface (MEBIV3)” for mode dependent pin configuration of port A, B and E out of reset.
Refer to Chapter 3, “Port Integration Module (PIM9E256V1)” for reset configurations of all peripheral
module ports.
Refer to Table 1-1 for locations of the memories depending on the operating mode after reset.
The RAM array is not automatically initialized out of reset.
1.10 Recommended Printed Circuit Board Layout
The Printed Circuit Board (PCB) must be carefully laid out to ensure proper operation of the voltage
regulator as well as the MCU itself. The following rules must be observed:
• Every supply pair must be decoupled by a ceramic capacitor connected as near as possible to the
corresponding pins (C1–C6).
• Central point of the ground star should be the VSSR pin.
• Use low ohmic low inductance connections between VSS1, VSS2 and VSSR.
• VSSPLL must be directly connected to VSSR.
• Keep traces of VSSPLL, EXTAL and XTAL as short as possible and occupied board area for C7,
C8, C11 and Q1 as small as possible.
• Do not place other signals or supplies underneath area occupied by C7, C8, C10 and Q1 and the
connection area to the MCU.
• Central power input should be fed in at the VDDA/VSSA pins.
Table 1-11. Recommended Decoupling Capacitor Choice
Component Purpose Type Value
C1 VDD1 filter cap Ceramic X7R 100–220nF
C2 VDD2 filter cap (80 QFP only) Ceramic X7R 100–220nF
C3 VDDA filter cap Ceramic X7R 100nF
C4 VDDR filter cap X7R/tantalum >=100nF
C5 VDDPLL filter cap Ceramic X7R 100nF
C6 VDDX filter cap X7R/tantalum >=100nF
C7 OSC load cap
See PLL specification chapter
C8 OSC load cap
C9 PLL loop filter cap
C10 PLL loop filter cap
C11 DC cutoff cap
R1 PLL loop filter res
Q1 Quartz
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
78 Freescale Semiconductor
Figure 1-8. Recommended PCB Layout (112-LQFP)
NOTE: Oscillator in Colpitts mode.
C5
C4
C6
C1
C3
C2
C8
C7
Q1
C10
C9
R1
VDD1
VSS1
VDDR
VSSR
VDDX
VSSX VDD2
VSS2
VDDPLL
VSSPLL
VDDA
VSSA
C11
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 79
Figure 1-9. Recommended PCB Layout (80-QFP)
NOTE: Oscillator in Colpitts mode.
VDDA
C5
C4
C8
C7
Q1
C10
C9
R1
VDDR
VSSR
VDDPLL
VSSPLL
C11
C1
C3
VDD1
VSS1
VSSA
C6
VDDX
VSSX
C2
VDD2
VSS2
Chapter 1 MC9S12E256 Device Overview (MC9S12E256DGV1)
MC9S12E256 Data Sheet, Rev. 1.08
80 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 81
Chapter 2
256 Kbyte Flash Module (FTS256K2V1)
2.1 Introduction
This document describes the FTS256K2 module that includes a 256 Kbyte Flash (nonvolatile) memory.
The Flash memory may be read as either bytes, aligned words, or misaligned words. Read access time is
one bus cycle for bytes and aligned words, and two bus cycles for misaligned words.
The Flash memory is ideal for program and data storage for single-supply applications allowing for field
reprogramming without requiring external voltage sources for program or erase. Program and erase
functions are controlled by a command driven interface. The Flash module supports both block erase and
sector erase. An erased bit reads 1 and a programmed bit reads 0. The high voltage required to program
and erase the Flash memor y is generated internally. It is not possible to read from a Flash block while it is
being erased or programmed.
CAUTION
A Flash word must be in the erased state before being programmed.
Cumulative programming of bits within a Flash word is not allowed.
2.1.1 Glossary
Banked Register — A memory-mapped register operating on one Flash block which shares the same
register address as the equivalent registers for the other Flash blocks. The active register bank is selected
by the BKSEL bit in the FCNFG register.
Command Write Sequence — A three-step MCU instruction sequence to execute built-in algorithms
(including program and erase) on the Flash memory.
Common Register — A memory-mapped register which operates on all Flash blocks.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
82 Freescale Semiconductor
2.1.2 Features
• 256 Kbytes of Flash memory comprised of two 128 Kbyte blocks with each block divided into
128 sectors of 1024 bytes
• Automated program and erase algorithm
• Interrupts on Flash command completion, command buffer empty
• Fast sector erase and word program operation
• 2-stage command pipeline for faster multi-word program times
• Sector erase abort feature for critical interrupt response
• Flexible protection scheme to prevent accidental program or erase
• Single power supply for all Flash operations including program and erase
• Security feature to prevent unauthorized access to the Flash memory
• Code integrity check using built-in data compression
2.1.3 Modes of Operation
Program, erase, erase verify , and data compress operations (please refer to Section 2.4.1, “Flash Command
Operations” for details).
2.1.4 Block Diagram
A block diagram of the Flash module is shown in Figure 2-1.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 83
Figure 2-1. FTS256K2 Block Diagram
FTS256K2
Oscillator
Clock
Divider
Clock
Command
Interface
Command Pipelines
comm2
Command
Interrupt
Request
Common
FCLK
addr2
data2
comm1
addr1
data1
Flash Block 0
64K * 16 Bits
Flash Block 1
64K * 16 Bits
Registers
Banked
Registers
Protection
Security
sector 0
sector 1
sector 127
sector 0
sector 1
sector 127
Flash Block 0-1
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
84 Freescale Semiconductor
2.2 External Signal Description
The Flash module contains no signals that connect off-chip.
2.3 Memory Map and Register Definition
This subsection describes the memory map and registers for the Flash module.
2.3.1 Module Memory Map
The Flash memory map is shown in Figure 2-2. The HCS12 architecture places the Flash memory
addresses between 0x4000 and 0xFFFF which corresponds to three 16-Kbyte pages. The content of the
HCS12 core PPAGE register is used to map the logical middle page ranging from address 0x8000 to
0xBFFF to any physical 16 Kbyte page in the Flash memory. By placing 0x3E or 0x3F in the HCS12 Core
PPAGE register, the associated 16 Kbyte pages appear twice in the MCU memory map.
The FPROT register, described in Section 2.3.2.5, “Flash Protection Register (FPROT)”, can be set to
globally protect a Flash block. However, three separate memory regions, one growing upward from the
first address in the next-to-last page in the Flash block (called the lower region), one growing downward
from the last address in the last page in the Flash block (called the higher region), and the remaining
addresses in the Flash block, can be activated for protection. The Flash locations of these protectable
regions are shown in Table 2-2. The higher address region of Flash block 0 is mainly targeted to hold the
boot loader code because it covers the vector space. The lower address region of any Flash block can be
used for EEPROM emulation in an MCU without an EEPROM module because it can remain unprotected
while the remaining addresses are protected from program or erase.
Security information that allows the MCU to restrict access to the Flash module is stored in the Flash
configuration field found in Flash block 0, described in Table 2-1.
Table 2-1. Flash Configuration Field
Unpaged
Flash Address
Paged Flash
Address
(PPAGE 0x3F)
Size
(Bytes) Description
0xFF00 – 0xFF07 0xBF00 – 0xBF07 8 Backdoor Comparison Key
Refer to Section 2.6.1, “Unsecuring the MCU using Backdoor Key
Access”
0xFF08 – 0xFF0B 0xBF08 – 0xBF0B 4 Reserved
0xFF0C 0xBF0C 1 Block 1 Flash Protection Byte
Refer to Section 2.3.2.7, “Flash Status Register (FSTAT)”
0xFF0D 0xBF0D 1 Block 0 Flash Protection Byte
Refer toSection 2.3.2.7, “Flash Status Register (FSTAT)”
0xFF0E 0xBF0E 1 Flash Nonvolatile Byte
Refer to Section 2.3.2.9, “Flash Control Register (FCTL)”
0xFF0F 0xBF0F 1 Flash Security Byte
Refer to Section 2.3.2.2, “Flash Security Register (FSEC)”
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 85
Figure 2-2. Flash Memory Map
0x30 0x31 0x32 0x33 0x34 0x35 0x36 0x37
Block 1
Flash Registers
MODULE BASE + 0x0000
0xFF00 – 0xFF0F, Flash Configuration Field
MODULE BASE + 0x000F
0x8000
(16 bytes)
Flash Protected Low Sectors
1, 2, 4, 8 Kbytes
FLASH_START = 0x4000
0x5000
0x4400
0x6000
16K PAGED
MEMORY
0x38 0x39 0x3A 0x3B
0x3E
0x3C 0x3D 0x3E 0x3F
Note: 0x30–0x3F correspond to the PPAGE register content
FLASH_END = 0xFFFF
0xF800
0xF000
0xC000
0xE000 Flash Protected High Sectors
2, 4, 8, 16 Kbytes
0x3F
Block 0
0x4800
Flash Blocks
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
86 Freescale Semiconductor
Table 2-2. Detailed Flash Memory Map
MCU Address
Range PPAGE Protectable Lower
Range
Protectable Higher
Range
Flash
Block
Block Relative
Address1
1Block relative address for each 128 Kbyte Flash block consists of 17 address bits.
0x4000–0x7FFF Unpaged
(0x3E)
0x4000–0x43FF N.A. 0 0x018000–0x01BFFF
0x4000–0x47FF
0x4000–0x4FFF
0x4000–0x5FFF
0x8000–0xBFFF 0x30 N.A. N.A. 1 0x000000–0x003FFF
0x31 N.A. N.A. 0x004000–0x007FFF
0x32 N.A. N.A. 0x008000–0x00BFFF
0x33 N.A. N.A. 0x00C000–0x00FFFF
0x34 N.A. N.A. 0x010000–0x013FFF
0x35 N.A. N.A. 0x014000–0x017FFF
0x36 0x8000–0x83FF N.A. 0x018000–0x01BFFF
0x8000–0x87FF
0x8000–0x8FFF
0x8000–0x9FFF
0x37 N.A. 0xB800–0xBFFF 0x01C000–0x01FFFF
0xB000–0xBFFF
0xA000–0xBFFF
0x8000–0xBFFF
0x8000–0xBFFF 0x38 N.A. N.A. 0 0x000000–0x003FFF
0x39 N.A. N.A. 0x004000–0x007FFF
0x3A N.A. N.A. 0x008000–0x00BFFF
0x3B N.A. N.A. 0x00C000–0x00FFFF
0x3C N.A. N.A. 0x010000–0x013FFF
0x3D N.A. N.A. 0x014000–0x017FFF
0x3E 0x8000–0x83FF N.A. 0x018000–0x01BFFF
0x8000–0x87FF
0x8000–0x8FFF
0x8000–0x9FFF
0x3F N.A. 0xB800–0xBFFF 0x01C000–0x01FFFF
0xB000–0xBFFF
0xA000–0xBFFF
0x8000–0xBFFF
0xC000–0xFFFF Unpaged
(0x3F)
N.A. 0xF800–0xFFFF 0 0x01C000–0x01FFFF
0xF000–0xFFFF
0xE000–0xFFFF
0xC000–0xFFFF
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 87
The Flash module also contains a set of 16 control and status registers located in address space module
base + 0x0000 to module base + 0x000F. In order to accommodate more than one Flash block with a
minimum register address space, a set of registers located from module base + 0x0004 to module
base + 0x000B are repeated in all banks. The active register bank is selected by the BKSEL bits in the
unbanked Flash configuration register (FCNFG). A summary of these registers is given in Table 2-3 while
their accessibility in normal and special modes is detailed in Section 2.3.2, “Register Descriptions”.
Table 2-3. Flash Register Map
Module
Base + Register Name Normal Mode
Access
0x0000 Flash Clock Divider Register (FCLKDIV) R/W
0x0001 Flash Security Register (FSEC) R
0x0002 Flash Test Mode Register (FTSTMOD)1
1Intended for factory test purposes only.
R
0x0003 Flash Configuration Register (FCNFG) R/W
0x0004 Flash Protection Register (FPROT) R/W
0x0005 Flash Status Register (FSTAT) R/W
0x0006 Flash Command Register (FCMD) R/W
0x0007 Flash Control Register (FCTL) R
0x0008 Flash High Address Register (FADDRHI)1R
0x0009 Flash Low Address Register (FADDRLO)1R
0x000A Flash High Data Register (FDATAHI) R
0x000B Flash Low Data Register (FDATALO) R
0x000C RESERVED11R
0x000D RESERVED21R
0x000E RESERVED31R
0x000F RESERVED41R
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
88 Freescale Semiconductor
2.3.2 Register Descriptions
Register
Name Bit 7654321Bit 0
FCLKDIV R FDIVLD PRDIV8 FDIV5 FDIV4 FDIV3 FDIV2 FDIV1 FDIV0
W
FSEC R KEYEN RNV5 RNV4 RNV3 RNV2 SEC
W
FTSTMOD R 0 0 0 WRALL 0000
W
FCNFG R CBEIE CCIE KEYACC 0000
BKSEL
W
FPROT R FPOPEN RNV6 FPHDIS FPHS FPLDIS FPLS
W
FSTAT R CBEIF CCIF PVIOL ACCERR 0BLANK0 0
W
FCMD R 0 CMDB
W
FCTL R NV7 NV6 NV5 NV4 NV3 NV2 NV1 NV0
W
FADDRHI R FADDRHI
W
FADDRLO R FADDRLO
W
FDATAHI R FDATAHI
W
FDATALO R FDATALO
W
RESERVED1 R 0 0000000
W
= Unimplemented or Reserved
Figure 2-3. FTS256K2 Register Summary
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 89
2.3.2.1 Flash Clock Divider Register (FCLKDIV)
The unbanked FCLKDIV register is used to control timed events in program and erase algorithms.
All bits in the FCLKDIV register are readable, bits 6-0 are write once and bit 7 is not writable.
RESERVED2 R 0 0000000
W
RESERVED3 R 0 0000000
W
RESERVED4 R 0 0000000
W
76543210
RFDIVLD
PRDIV8 FDIV5 FDIV4 FDIV3 FDIV2 FDIV1 FDIV0
W
Reset00000000
= Unimplemented or Reserved
Figure 2-4. Flash Clock Divider Register (FCLKDIV)
Table 2-4. FCLKDIV Field Descriptions
Field Description
7
FDIVLD
Clock Divider Loaded.
0 Register has not been written.
1 Register has been written to since the last reset.
6
PRDIV8
Enable Prescalar by 8.
0 The oscillator clock is directly fed into the clock divider.
1 The oscillator clock is divided by 8 before feeding into the clock divider.
5-0
FDIV[5:0]
Clock Divider Bits — The combination of PRDIV8 and FDIV[5:0] must divide the oscillator clock down to a
frequency of 150 kHz–200 kHz. The maximum divide ratio is 512. Please refer to Section 2.4.1.1, “Writing the
FCLKDIV Register” for more information.
Register
Name Bit 7654321Bit 0
= Unimplemented or Reserved
Figure 2-3. FTS256K2 Register Summary (continued)
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
90 Freescale Semiconductor
2.3.2.2 Flash Security Register (FSEC)
The unbanked FSEC register holds all bits associated with the security of the MCU and Flash module.
All bits in the FSEC register are readable but are not writable.
The FSEC register is loaded from the Flash Configuration Field at address $FF0F during the reset
sequence, indicated by F in Figure 2-5.
The security function in the Flash module is described in Section 2.6, “Flash Module Security”.
76543210
RKEYEN RNV5 RNV4 RNV3 RNV2 SEC
W
ResetFFFFFFFF
= Unimplemented or Reserved
Figure 2-5. Flash Security Register (FSEC)
Table 2-5. FSEC Field Descriptions
Field Description
1-0
KEYEN[1:0]
Backdoor Key Security Enable Bits —The KEYEN[1:0] bits define the enabling of backdoor key access to the
Flash module as shown in Ta b l e 2 - 6 .
5-2
RNV[5:2]
Reserved Nonvolatile Bits — The RNV[5:2] bits must remain in the erased 1 state for future enhancements.
1-0
SEC[1:0]
Flash Security Bits — The SEC[1:0] bits define the security state of the MCU as shown in Ta b l e 2 - 7 . If the Flash
module is unsecured using backdoor key access, the SEC bits are forced to 10.
Table 2-6. Flash KEYEN States
KEYEN[1:0] Status of Backdoor Key Access
00 DISABLED
011
1Preferred KEYEN state to disable Backdoor Key Access.
DISABLED
10 ENABLED
11 DISABLED
Table 2-7. Flash Security States
SEC[1:0] Status of Security
00 SECURED
011
1Preferred SEC state to set MCU to secured state.
SECURED
10 UNSECURED
11 SECURED
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 91
2.3.2.3 Flash Test Mode Register (FTSTMOD)
The unbanked FTSTMOD register is used to control Flash test features.
All bits read 0 and are not writable in normal mode. The WRALL bit is writable only in special mode to
simplify mass erase and erase verify operations. When writing to the FTSTMOD regis ter in special mode,
all unimplemented/reserved bits must be written to 0.
76543210
R0 0 0
WRALL
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 2-6. Flash Test Mode Register (FTSTMOD)
Table 2-8. FTSTMOD Field Descriptions
Field Description
4
WRALL
Write to All Register Banks — If the WRALL bit is set, all banked registers sharing the same register address
will be written simultaneously during a register write.
0 Write only to the bank selected via BKSEL.
1 Write to all register banks.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
92 Freescale Semiconductor
2.3.2.4 Flash Configuration Register (FCNFG)
The unbanked FCNFG register enables the Flash interrupts and gates the security backdoor writes.
CBEIE, CCIE, KEYACC and BKSEL bits are readable and writable while all remaining bits read 0 and
are not writable. KEYACC is only writable if KEYEN (see Section 2.3.2.2, “Flash Security Register
(FSEC)”) is set to the enabled state.
76543210
R
CBEIE CCIE KEYACC
0000
BKSEL
W
Reset00000000
= Unimplemented or Reserved
Figure 2-7. Flash Configuration Register (FCNFG)
Table 2-9. FCNFG Field Descriptions
Field Description
7
CBEIE
Command Buffer Empty Interrupt Enable — The CBEIE bit enables an interrupt in case of an empty command
buffer in the Flash module.
0 Command buffer empty interrupt disabled.
1 An interrupt will be requested whenever the CBEIF flag (see Section 2.3.2.7, “Flash Status Register (FSTAT)”)
is set.
6
CCIE
Command Complete Interrupt Enable — The CCIE bit enables an interrupt in case all commands have been
completed in the Flash module.
0 Command complete interrupt disabled.
1 An interrupt will be requested whenever the CCIF flag (see Section 2.3.2.7, “Flash Status Register (FSTAT)”)
is set.
5
KEYACC
Enable Security Key Writing
0 Flash writes are interpreted as the start of a command write sequence.
1 Writes to Flash array are interpreted as keys to open the backdoor. Reads of the Flash array return invalid
data.
0
BKSEL
Block Select — The BKSEL bit indicates which register bank is active.
0 Select register bank associated with Flash block 0.
1 Select register bank associated with Flash block 1.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 93
2.3.2.5 Flash Protection Register (FPROT)
The banked FPROT register defines which Flash sectors are protected against program or erase operations.
All bits in the FPROT register are readable and writable with restrictions except for RNV[6] which is only
readable (see Section 2.3.2.6, “Flash Protection Restrictions”).
During reset, the banked FPROT registers are loaded from the Flash Configuration Field at the address
shown in Table 2-10. To change the Flash protection that will be loaded during the reset sequence, the
upper sector of the Flash memory must be unprotected, then the Flash Protect/Security byte located as
described in Table 2-1 must be reprogrammed.
Trying to alter data in any of the protected areas in the Flash block will result in a protection violation error
and the PVIOL flag will be set in the FSTAT register. A mass erase of the Flash block is not possible if
any of the contained Flash sectors are protected.
76543210
R
FPOPEN
RNV6
FPHDIS FPHS FPLDIS FPLS
W
ResetFFFFFFFF
= Unimplemented or Reserved
Figure 2-8. Flash Protection Register (FPROT)
Table 2-10. Reset Loading of FPROT
Flash Address Protection Byte for
0xFF0D Flash Block 0
0xFF0C Flash Block 1
Table 2-11. FPROT Field Descriptions
Field Description
7
FPOPEN
Protection Function Bit — The FPOPEN bit determines the protection function for program or erase as shown
in Tabl e 2 -12.
0 FPHDIS and FPLDIS bits define unprotected address ranges as specified by the corresponding FPHS[1:0]
and FPLS[1:0] bits. For an MCU without an EEPROM module, the FPOPEN clear state allows the main part
of the Flash block to be protected while a small address range can remain unprotected for EEPROM
emulation.
1 FPHDIS and FPLDIS bits enable protection for the address range specified by the corresponding FPHS[1:0]
and FPLS[1:0] bits.
6
RNV[6]
Reserved Nonvolatile Bit — The RNV[6] bit must remain in the erased state 1 for future enhancements.
5
FPHDIS
Flash Protection Higher Address Range Disable — The FPHDIS bit determines whether there is a
protected/unprotected area in the higher address space of the Flash block.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
4:3
FPHS[1:0]
Flash Protection Higher Address Size — The FPHS[1:0] bits determine the size of the protected/unprotected
area as shown in Ta b l e 2 - 1 3 . The FPHS[1:0] bits can only be written to while the FPHDIS bit is set.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
94 Freescale Semiconductor
All possible Flash protection scenarios are illustrated in Figure 2-9. Although the protection scheme is
loaded from the Flash array after reset, it can be changed by the user. This protection scheme can be used
by applications requiring re-programming in single-chip mode while providing as much protection as
possible if re-programming is not required.
2
FPLDIS
Flash Protection Lower address range Disable — The FPLDIS bit determines whether there is a
protected/unprotected area in the lower address space of the Flash block.
0 Protection/Unprotection enabled
1 Protection/Unprotection disabled
1:0
FPLS[1:0]
Flash Protection Lower Address Size — The FPLS[1:0] bits determine the size of the protected/unprotected
area as shown in Ta b l e 2 - 1 4 . The FPLS[1:0] bits can only be written to while the FPLDIS bit is set.
Table 2-12. Flash Protection Function
FPOPEN FPHDIS FPLDIS Function1
1For range sizes, refer to Ta b l e 2- 1 3 and Ta b l e 2 - 1 4 .
1 1 1 No Protection
1 1 0 Protected Low Range
1 0 1 Protected High Range
1 0 0 Protected High and Low Ranges
0 1 1 Full Block Protected
0 1 0 Unprotected Low Range
0 0 1 Unprotected High Range
0 0 0 Unprotected High and Low Ranges
Table 2-13. Flash Protection Higher Address Range
FPHS[1:0] Unpaged
Address Range
Paged
Address Range Protected Size
00 0xF800–0xFFFF 0x0037/0x003F: 0xC800–0xCFFF 2 Kbytes
01 0xF000–0xFFFF 0x0037/0x003F: 0xC000–0xCFFF 4 Kbytes
10 0xE000–0xFFFF 0x0037/0x003F: 0xB000–0xCFFF 8 Kbytes
11 0xC000–0xFFFF 0x0037/0x003F: 0x8000–0xCFFF 16 Kbytes
Table 2-14. Flash Protection Lower Address Range
FPLS[1:0] Unpaged
Address Range
Paged
Address Range Protected Size
00 0x4000–0x43FF 0x0036/0x003E: 0x8000–0x83FF 1 Kbyte
01 0x4000–0x47FF 0x0036/0x003E: 0x8000–0x87FF 2 Kbytes
10 0x4000–0x4FFF 0x0036/0x003E: 0x8000–0x8FFF 4 Kbytes
11 0x4000–0x5FFF 0x0036/0x003E: 0x8000–0x9FFF 8 Kbytes
Table 2-11. FPROT Field Descriptions (continued)
Field Description
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 95
Figure 2-9. Flash Protection Scenarios
7 6 5 4
FPHS[1:0] FPLS[1:0]
3210
FPHS[1:0] FPLS[1:0]
FPHDIS = 1
FPLDIS = 1
FPHDIS = 1
FPLDIS = 0
FPHDIS = 0
FPLDIS = 1
FPHDIS = 0
FPLDIS = 0
Scenario
Scenario
Unprotected region Protected region with size
Protected region Protected region with size
defined by FPLS
defined by FPHSnot defined by FPLS, FPHS
FPOPEN = 1FPOPEN = 0
PPAGE 0x0036–0x0037
0x003E–0x003F
PPAGE 0x0030–0x0035
0x0038–0x003D
PPAGE 0x0036–0x0037
0x003E–0x003F
PPAGE 0x0030–0x0035
0x0038–0x003D
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
96 Freescale Semiconductor
2.3.2.6 Flash Protection Restrictions
The general guideline is that Flash protection can only be added and not removed. Table 2-15 specifies all
valid transitions between Flash protection scenarios. Any attempt to write an invalid scenario to the
FPROT register will be ignored and the FPROT register will remain unchanged. The contents of the
FPROT register reflect the activ e protection scenario. See the FPHS and FPLS descriptions for additional
restrictions.
2.3.2.7 Flash Status Register (FSTAT)
The banked FSTAT register defines the operational status of the module.
Table 2-15. Flash Protection Scenario Transitions
From
Protection
Scenario
To Protection Scenario1
1Allowed transitions marked with X.
01234567
0 XXXX
1XX
2XX
3X
4XX
5 XXXX
6XXXX
7 XXXXXXXX
76543210
R
CBEIF
CCIF
PVIOL ACCERR
0BLANK0 0
W
Reset11000000
= Unimplemented or Reserved
Figure 2-10. Flash Status Register (FSTAT — Normal Mode)
76543210
R
CBEIF
CCIF
PVIOL ACCERR
0BLANK
FAIL
0
W
Reset11000000
= Unimplemented or Reserved
Figure 2-11. Flash Status Register (FSTAT — Special Mode)
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 97
CBEIF , PVIOL, and ACCERR are readable and writable, CCIF and BLANK are readable and not writable,
remaining bits read 0and are not writable in norma l mode. FAIL is readable and wr itable in special mode.
FAIL must be clear when starting a command write sequence.
Table 2-16. FSTAT Field Descriptions
Field Description
7
CBEIF
Command Buffer Empty Interrupt Flag — The CBEIF flag indicates that the address, data and command
buffers are empty so that a new command write sequence can be started. The CBEIF flag is cleared by writing
a 1 to CBEIF. Writing a 0 to the CBEIF flag has no effect on CBEIF. Writing a 0 to CBEIF after writing an aligned
word to the Flash address space but before CBEIF is cleared will abort a command write sequence and cause
the ACCERR flag to be set. Writing a 0 to CBEIF outside of a command write sequence will not set the ACCERR
flag. The CBEIF flag is used together with the CBEIE bit in the FCNFG register to generate an interrupt request
(see Figure 2-29).
0 Buffers are full.
1 Buffers are ready to accept a new command.
6
CCIF
Command Complete Interrupt Flag — The CCIF flag indicates that there are no more commands pending. The
CCIF flag is cleared when CBEIF is clear and sets automatically upon completion of all active and pending
commands. The CCIF flag does not set when an active commands completes and a pending command is fetched
from the command buffer. Writing to the CCIF flag has no effect on CCIF. The CCIF flag is used together with
the CCIE bit in the FCNFG register to generate an interrupt request (see Figure 2-29).
0 Command in progress.
1 All commands are completed.
5
PVIOL
Protection Violation Flag — The PVIOL flag indicates an attempt was made to program or erase an address in
a protected area of the Flash block during a command write sequence. The PVIOL flag is cleared by writing a 1
to PVIOL. Writing a 0 to the PVIOL flag has no effect on PVIOL. While PVIOL is set, it is not possible to launch
a command or start a command write sequence.
0 No failure.
1 A protection violation has occurred.
4
ACCERR
Access Error Flag — The ACCERR flag indicates an illegal access to the Flash array caused by either a
violation of the command write sequence, issuing an illegal command (illegal combination of the CMDBx bits in
the FCMD register), launching the sector erase abort command terminating a sector erase operation early or the
execution of a CPU STOP instruction while a command is executing (CCIF = 0). The ACCERR flag is cleared by
writing a 1 to ACCERR. Writing a 0 to the ACCERR flag has no effect on ACCERR. While ACCERR is set in any
of the banked FTSAT registers, it is not possible to launch a command or start a command write sequence in any
of the Flash blocks. If ACCERR is set by an erase verify operation or a data compress operation, any buffered
command will not launch.
0 No access error detected.
1 Access error has occurred.
2
BLANK
Erase Verify Operation Status Flag — When the CCIF flag is set after completion of an erase verify command,
the BLANK flag indicates the result of the erase verify operation. The BLANK flag is cleared by the Flash module
when CBEIF is cleared as part of a new valid command write sequence. Writing to the BLANK flag has no effect
on BLANK.
0 Flash block verified as not erased.
1 Flash block verified as erased.
1
FAIL
Flag Indicating a Failed Flash Operation — The FAIL flag will set if the erase verify operation fails (selected
Flash block verified as not erased). The FAIL flag is cleared by writing a 1 to FAIL. Writing a 0 to the FAIL flag
has no effect on FAIL.
0 Flash operation completed without error.
1 Flash operation failed.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
98 Freescale Semiconductor
2.3.2.8 Flash Command Register (FCMD)
The banked FCMD register is the Flash command register.
All CMDB bits are readable and writable during a command write sequence while bit 7 reads 0 and is not
writable.
76543210
R0
CMDB
W
Reset00000000
= Unimplemented or Reserved
Figure 2-12. Flash Command Register (FCMD - NVM User Mode)
Table 2-17. FCMD Field Descriptions
Field Description
6-0
CMDB[6:0]
Flash Command — Valid Flash commands are shown in Tabl e 2 - 1 8 . Writing any command other than those
listed in Tabl e 2 - 1 8 sets the ACCERR flag in the FSTAT register.
Table 2-18. Valid Flash Command List
CMDB[6:0] NVM Command
0x05 Erase Verify
0x06 Data Compress
0x20 Word Program
0x40 Sector Erase
0x41 Mass Erase
0x47 Sector Erase Abort
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 99
2.3.2.9 Flash Control Register (FCTL)
The banked FCTL register is the Flash control register.
All bits in the FCTL register are readable but are not writable.
The FCTL register is loaded from the Flash Configuration Field byte at $FF0E during the reset sequence,
indicated by F in Figure 2-13.
2.3.2.10 Flash Address Registers (FADDR)
The banked FADDRHI and FADDRLO registers are the Flash address registers.
All FADDRHI and FADDRLO bits are readable but are not writable. After an array write as part of a
command write sequence, the FADDR registers will contain the mapped MCU address written.
76543210
R NV7 NV6 NV5 NV4 NV3 NV2 NV1 NV0
W
ResetFFFFFFFF
= Unimplemented or Reserved
Figure 2-13. Flash Control Register (FCTL)
Table 2-19. FCTL Field Descriptions
Field Description
7-0
NV[7:0]
Nonvolatile Bits — The NV[7:0] bits are available as nonvolatile bits. Refer to the Device User Guide for proper
use of the NV bits.
76543210
R FADDRHI
W
Reset00000000
= Unimplemented or Reserved
Figure 2-14. Flash Address High Register (FADDRHI)
76543210
R FADDRLO
W
Reset00000000
= Unimplemented or Reserved
Figure 2-15. Flash Address Low Register (FADDRLO)
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
100 Freescale Semiconductor
2.3.2.11 Flash Data Registers (FDATA)
The banked FDATAHI and FDATALO registers are the Flash data registers.
All FDATAHI and FDATALO bits are readable but are not writable. After an array write as part of a
command write sequence, the FDATA registers will contain the data written. At the completion of a data
compress operation , the resulting 16-bit signature is stored in the FDATA registers. The data compression
signature is readable in the FDATA registers until a new command write sequence is started.
2.3.2.12 RESERVED1
This register is reserved for factory testing and is not accessible.
All bits read 0 and are not writable.
2.3.2.13 RESERVED2
This register is reserved for factory testing and is not accessible.
All bits read 0 and are not writable.
76543210
RFDATAHI
W
Reset00000000
= Unimplemented or Reserved
Figure 2-16. Flash Data High Register (FDATAHI)
76543210
RFDATALO
W
Reset00000000
= Unimplemented or Reserved
Figure 2-17. Flash Data Low Register (FDATALO)
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 2-18. RESERVED1
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 2-19. RESERVED2
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 101
2.3.2.14 RESERVED3
This register is reserved for factory testing and is not accessible.
All bits read 0 and are not writable.
2.3.2.15 RESERVED4
This register is reserved for factory testing and is not accessible.
All bits read 0 and are not writable.
2.4 Functional Description
2.4.1 Flash Command Operations
W rite and read operations are both used for the program, erase, erase verify, and data compress algorithms
described in this subsection. The program and erase algorithms are time controlled by a state machine
whose timebase, FCLK, is derived from the oscillator clock via a programmable divider. The command
register as well as the associated address and data registers operate as a buffer and a register (2-stage FIFO)
so that a second command along with the necessary data and address can be stored to the buf fer while the
first command remains in progress. This pipelined operation allows a time optimization when
programming more than one word on a specific row in the Flash block as the high voltage generation can
be kept active in between two programming commands. The pipelined operation also allows a
simplification of command launching. Buffer empty as well as command completion are signalled by flags
in the Flash status register with interrupts generated, if enabled.
The next paragraphs describe:
1. How to write the FCLKDIV register.
2. Command write sequences used to program, erase, and verify the Flash memory.
3. Valid Flash commands.
4. Effects resulting from illegal Flash command write sequences or aborting Flash operations.
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 2-20. RESERVED3
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 2-21. RESERVED4
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
102 Freescale Semiconductor
2.4.1.1 Writing the FCLKDIV Register
Prior to issuing any program, erase, erase verify, or data compress command, it is first necessary to write
the FCLKDIV register to divide the oscillator clock down to within the 150 kHz to 200 kHz range. Because
the program and erase timings are also a function of the bus clock, the FCLKDIV determination must take
this information into account.
If we define:
• FCLK as the clock of the Flash timing control block,
• Tbus as the period of the bus clock, and
• INT(x) as taking the integer part of x (e.g. INT(4.323)=4).
Then, FCLKDIV register bits PRDIV8 and FDIV[5:0] are to be set as described in Figure 2-22.
For example, if the oscillator clock frequency is 950 kHz and the bus clock frequency is 10 MHz,
FCLKDIV bits FDIV[5:0] must be set to 4 (000100) and bit PRDIV8 set to 0. The resulting FCLK
frequency is then 190 kHz. As a result, the Flash program and erase algorithm timings are increased over
the optimum target by:
CAUTION
Program and erase command execution time will increase proportionally
with the period of FCLK. Because of the impact of clock synchronization
on the accuracy of the functional timings, programming or erasing the Flash
memory cannot be performed if the bus clock runs at less than 1 MHz.
Programming or erasing the Flash memory with FCLK < 150 kHz must be
avoided. Setting FCLKDIV to a value such that FCLK < 150 kHz can
destroy the Flash memory due to overstress. Setting FCLKDIV to a value
such that (1/FCLK + Tbus) < 5µs can result in incomplete programming or
erasure of the Flash memory cells.
If the FCLKDIV register is written, the FDIVLD bit is set automatically. If the FDIVLD bit is 0, the
FCLKDIV register has not been written since the last reset. Flash commands will not be executed if the
FCLKDIV register has not been written to.
200 190–()200⁄100×5%=
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 103
Figure 2-22. Determination Procedure for PRDIV8 and FDIV Bits
PRDIV8=1
YES
NO
PRDIV8=0 (reset)
FCLK=(PRDCLK)/(1+FDIV[5:0])
PRDCLK=oscillator_clock
PRDCLK=oscillator_clock/8
PRDCLK[MHz]*(5+Tbus[µs]) NO
FDIV[5:0]=PRDCLK[MHz]*(5+Tbus[µs])-1
YES
START
Tbus < 1µs?
an integer?
FDIV[5:0]=INT(PRDCLK[MHz]*(5+Tbus[µs]))
1/FCLK[MHz] + Tbus[µs] > 5
AND
FCLK > 0.15 MHz
?
END
YES
NO
FDIV[5:0] > 4?
ALL COMMANDS IMPOSSIBLE
YES
NO
ALL COMMANDS IMPOSSIBLE
NO
TRY TO DECREASE Tbus
YES
OSCILLATOR
CLOCK
> 12.8 MHZ?
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
104 Freescale Semiconductor
2.4.1.2 Command Write Sequence
The Flash command controller is used to supervise the command write sequence to execute program,
erase, erase verify, and data compress algorithms.
Before starting a command write sequence, the ACCERR and PVIOL flags in the FSTAT register must be
clear (see Section 2.3.2.7, “Flash Status Register (FSTAT)”) and the CBEIF flag must be tested to
determine the state of the address, data, and command buffers. If the CBEIF flag is set, indicating the
buffers are empty, a new command write sequence can be started. If the CBEIF flag is clear, indicating the
buffers are not available, a new command write sequence will overwrite the contents of th e address, data,
and command buffers.
A command write sequence consists of three steps which must be strictly adhered to with writes to the
Flash module not permitted between the steps. However , Flash register and array reads are allowed during
a command write sequence. A command write sequence consists of the following steps:
1. Write an aligned data word to a valid Flash array address. The address and data will be stored in
the address and data buffers, respectively. If the CBEIF flag is clear when the Flash array write
occurs, the contents of the address and data buffers will be overwritten and the CBEIF flag will be
set.
2. Write a valid command to the FCMD register.
a) For the erase verify command (see Section 2.4.1.3.1, “Erase Verify Command”), the contents
of the data buffer are ignored and all address bits in the address buffer are ignored.
b) For the data compress command (see Section 2.4.1.3.2, “Data Compress Command”), the
contents of the data buffer represents the number of consecutive words to read for data
compression and the contents of the address buffer represents the starting address.
c) For the program command (see Section 2.4.1.3.3, “Program Command”), the contents of the
data buffer will be programmed to the address specified in the address buffer with all address
bits valid.
d) For the sector erase command (see Section 2.4.1.3.4, “Sector Erase Command”), the contents
of the data buffer are ignored and address bits [9:0] contained in the address buffer are ignored.
e) For the mass erase command (see Section 2.4.1.3.5, “Mass Erase Command”), the contents of
the data buffer and address buffer are ignored.
f) For the sector erase abort command (see Section 2.4.1.3.6, “Sector Erase Abort Command”),
the contents of the data buffer and address buffer are ignored.
3. Clear the CBEIF flag by writing a 1 to CBEIF to launch the command. When the CBEIF flag is
cleared, the CCIF flag is cleared on the same bus cycle by internal hardware indicating that the
command was successfully launched. For all command write sequences except data compress and
sector erase abort, the CBEIF flag will set four bus cycles after the CCIF flag is cleared indicating
that the address, data, and command buffers are ready for a new command write sequence to begin.
For data compress and sector erase abort operations, the CBEIF flag will remain clear until the
operation completes.
A command write sequence can be aborted prior to clearing the CBEIF flag by writing a 0 to the CBEIF
flag and will result in the ACCERR flag being set.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 105
Except for the sector erase abort command, a buffered command will wait for the active operation to be
completed before being launched. The sector erase abort command is launched when the CBEIF flag is
cleared as part of a sector erase abort command write sequence. After a command is launched, the
completion of the command operation is indicated by the setting of the CCIF flag. The CCIF flag only sets
when all active and buffered commands have been completed.
2.4.1.3 Valid Flash Commands
Table 2-20 summarizes the valid Flash commands along with the effects of the commands on the Flash
block.
CAUTION
A Flash word must be in the erased state before being programmed.
Cumulative programming of bits within a Flash word is not allowed.
Table 2-20. Valid Flash Command Description
FCMDB NVM
Command Function on Flash Memory
0x05 Erase Verify Verify all memory bytes in the Flash block are erased. If the Flash block is erased, the BLANK flag in
the FSTAT register will set upon command completion.
0x06 Data
Compress
Compress data from a selected portion of the Flash block. The resulting signature is stored in the
FDATA register.
0x20 Program Program a word (two bytes) in the Flash block.
0x40 Sector
Erase
Erase all memory bytes in a sector of the Flash block.
0x41 Mass Erase Erase all memory bytes in the Flash block. A mass erase of the full Flash block is only possible when
FPLDIS, FPHDIS, and FPOPEN bits in the FPROT register are set prior to launching the command.
0x47 Sector
Erase Abort
Abort the sector erase operation. The sector erase operation will terminate according to a set
procedure. The Flash sector must not be considered erased if the ACCERR flag is set upon command
completion.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
106 Freescale Semiconductor
2.4.1.3.1 Erase Verify Command
The erase verify operation is used to confirm that a Flash block is erased. After launching the erase verify
command, the CCIF flag in the FSTAT register will set after the operation has completed unless a second
command has been buffered. The number of bus cycles required to execute the erase verify operation is
equal to the number of addresses in the Flash block plus 12 bus cycles as measured from the time the
CBEIF flag is cleared until the CCIF flag is set. The result of the erase verify operation is ref lected in the
state of the BLANK flag in the FSTAT register. If the BLANK flag is set in the FSTAT register, the Flash
memory is erased.
Figure 2-23. Example Erase Verify Command Flow
Write: Register FCLKDIV
Read: Register FCLKDIV
Bit FDIVLD set?
Write: Flash Block Address
Write: Register FCMD
Erase Verify Command 0x05
Write: Register FSTAT
yes
no
Clear bit CBEIF 0x80
Clock Register
Loaded
Check
1.
2.
3.
Clear bit ACCERR 0x10
Write: Register FSTAT
yes
Access
Error Check
Read: Register FSTAT
no
no
and Dummy Data
Bit Polling for
Command
Completion Check
Read: Register FSTAT
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
CCIF
Set?
Bit
ACCERR
Set?
Bit
EXIT
yes
BLANK
Set?
Bit
yes
no Flash Block Not Erased;
Mass Erase Flash Block
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 107
2.4.1.3.2 Data Compress Command
The data compress command is used to check Flash code integrity by compressing data from a selected
portion of the Flash block into a signature analyzer. The starting address for the data compress operation
is defined by the address written during the command write sequence. The number of consecutive word
addresses compress ed is defined by the data written during the command write sequence. If the data value
written is 0x0000, 64K addresses or 128 Kbytes will be compressed. After launching the data compress
command, the CCIF flag in the FSTAT register will set after the data compress operation has completed.
The number of bus cycles required to execute the data compress operation is equal to two times the number
of addresses read plus 20 bus cycles as measured from the time the CBEIF flag is cleared until the CCIF
flag is set. After the CCIF flag is set, the signature generated by the data compress operation is available
in the FDATA register. The signature in the FDATA register can be compared to the expected signature
to determine the integrity of the selected data stored in the Flash block. If the last address of the Flash block
is reached during the data compress operation, data compression will continue with the starting address of
the Flash block.
NOTE
Since the FDATA register (or data buffer) is written to as part of the data
compress operation, a command write sequence is not allowed to be
buffered behind a data compress command write sequence. The CBEIF flag
will not set after launching the data compress command to indicate that a
command must not be buffered behind it. If an attempt is made to start a new
command write sequence with a data compress operation active, the
ACCERR flag in the FSTAT register will be set. A new command write
sequence must only be started after reading the signature stored in the
FDATA register.
In order to take corrective action, it is recommended that the data compress command be executed on a
Flash sector or subset of a Flash sector. If the data compress operation on a Flash sector returns an invalid
signature, the Flash sector must be erased using the sector erase command and then reprogrammed using
the program command.
The data compress command can be used to verify that a sector or sequential set of sectors are erased.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
108 Freescale Semiconductor
Figure 2-24. Example Data Compress Command Flow
Write: Register FCLKDIV
Read: Register FCLKDIV
Bit FDIVLD set?
Write: Flash address to start
Write: Register FCMD
Data Compress Command 0x06
Write: Register FSTAT
yes
no
Clear bit CBEIF 0x80
Clock Register
Loaded
Check
1.
2.
3.
Clear bit ACCERR 0x10
Write: Register FSTAT
yes
no
Access
Error Check
Read: Register FSTAT
no
EXIT
compression and number of
Bit Polling for
Command
Completion Check
Read: Register FSTAT
yes
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
CCIF
Set?
Bit
ACCERR
Set?
Bit
word addresses to compress
Read: Register FDATA
Data Compress Signature
no Erase and Reprogram
yes
Signature
Valid?
Signature
Flash Region Compressed
Compared to
Known Value
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 109
2.4.1.3.3 Program Command
The program command is used to program a previously erased word in the Flash memory using an
embedded algorithm. If the word to be programmed is in a protected area of the Flash block, the PVIOL
flag in the FSTAT register will set and the program command will not launch. After the program command
has successfully launched, the CCIF flag in the FSTAT register will set after the program operation has
completed unless a second command has been buffered.
A summary of the launching of a program operation is shown in Figure 2-25.
Figure 2-25. Example Program Command Flow
Write: Register FCLKDIV
Read: Register FCLKDIV
Bit FDIVLD set?
Write: Flash Address and
Write: Register FCMD
Program Command 0x20
Write: Register FSTAT
yes
no
Clear bit CBEIF 0x80
yes
Clock Register
Loaded
Check
1.
2.
3.
Clear bit ACCERR 0x10
Write: Register FSTAT
no
yes
no
Protection
Violation Check
Access
Error Check
Read: Register FSTAT
no
no
Address, Data,
Command
Buffer Empty Check
Next Write?
yes
EXIT
no
Program Data
Clear bit PVIOL 0x20
Write: Register FSTAT
yes
Bit Polling for
Command
Completion Check
Read: Register FSTAT
yes
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
CCIF
Set?
Bit
CBEIF
Set?
Bit
ACCERR
Set?
Bit
PVIOL
Set?
Bit
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
110 Freescale Semiconductor
2.4.1.3.4 Sector Erase Command
The sector erase command is used to erase the addressed sector in the Flash memory using an embedded
algorithm. If the Flash sector to be erased is in a protected area of the Flash block, the PVIOL flag in the
FSTAT register will set and the sector erase command will not launch. After the sector erase command
has successfully launched, the CCIF flag in the FSTAT register will set after the sector erase operation has
completed unless a second command has been buffered.
Figure 2-26. Example Sector Erase Command Flow
Write: Register FCLKDIV
Read: Register FCLKDIV
Bit FDIVLD set?
Write: Flash Sector Address
Write: Register FCMD
Sector Erase Command 0x40
Write: Register FSTAT
yes
no
Clear bit CBEIF 0x80
yes
Clock Register
Loaded
Check
1.
2.
3.
Clear bit ACCERR 0x10
Write: Register FSTAT
no
yes
no
Protection
Violation Check
Access
Error Check
Read: Register FSTAT
no
no
Address, Data,
Command
Buffer Empty Check
Next Write?
yes
EXIT
no
and Dummy Data
Clear bit PVIOL 0x20
Write: Register FSTAT
yes
Bit Polling for
Command
Completion Check
Read: Register FSTAT
yes
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
CCIF
Set?
Bit
PVIOL
Set?
Bit
ACCERR
Set?
Bit
CBEIF
Set?
Bit
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 111
2.4.1.3.5 Mass Erase Command
The mass erase command is used to erase a Flash memory block using an embedded algorithm. If the Flash
block to be erased contains any protected area, the PVIOL flag in the FSTAT register will set and the mass
erase command will not launch. After the mass erase command has successfully launched, the CCIF flag
in the FSTAT register will set after the mass erase operation has completed unless a second command has
been buffered.
Figure 2-27. Example Mass Erase Command Flow
Write: Register FCLKDIV
Read: Register FCLKDIV
Bit FDIVLD set?
Write: Flash Block Address
Write: Register FCMD
Mass Erase Command 0x41
Write: Register FSTAT
yes
no
Clear bit CBEIF 0x80
yes
Clock Register
Loaded
Check
1.
2.
3.
Clear bit ACCERR 0x10
Write: Register FSTAT
no
yes
no
Protection
Violation Check
Access
Error Check
Read: Register FSTAT
CCIF
Set?
Bit no
no
Address, Data,
Command
Buffer Empty Check
Next Write?
yes
EXIT
no
and Dummy Data
Clear bit PVIOL 0x20
Write: Register FSTAT
yes
Bit Polling for
Command
Completion Check
Read: Register FSTAT
yes
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
PVIOL
Set?
Bit
ACCERR
Set?
Bit
CBEIF
Set?
Bit
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
112 Freescale Semiconductor
2.4.1.3.6 Sector Erase Abort Command
The sector erase abort command is used to terminate the sector erase operation so that other sectors in the
Flash block are available for read and program operations without waiting for the sector erase operation
to complete. If the sector erase abort command is launched resulting in the early termination of an active
sector erase operation, the ACCERR flag will set after the operation completes as indicated by the CCIF
flag being set. The ACCERR flag sets to inform the user that the sector may not be fully erased and a new
sector erase command must be launched before programming any location in that specific sector. If the
sector erase abort command is launched but the active sector erase operation completes normally, the
ACCERR flag will not set upon completion of the operation as indicated by the CCIF flag being set.
Therefore, if the ACCERR flag is not set after the sector erase abort command has completed, the sector
being erased when the abort command was launched is fully erased. The maximum number of cycles
required to abort a sector erase operation is equal to four FCLK periods (see Section 2.4.1.1, “Writing the
FCLKDIV Register”) plus five bus cycles as measured from the time the CBEIF flag is cleared until the
CCIF flag is set.
NOTE
Since the ACCERR bit in the FSTAT register may be set at the completion
of the sector erase abort operation, a command write sequence is not
allowed to be buffered behind a sector erase abort command write sequence.
The CBEIF flag will not set after laun ching the sector erase abort command
to indicate that a command must not be buffered behind it. If an attempt is
made to start a new command write sequence with a sector erase abort
operation active, the ACCERR flag in the FSTAT register will be set. A new
command write sequence may be started after clearing the ACCERR flag, if
set.
NOTE
The sector erase abort command must be used sparingly because a sector
erase operation that is aborted counts as a complete program/erase cycle.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 113
Figure 2-28. Example Sector Erase Abort Command Flow
Write: Dummy Flash Address
Write: Register FCMD
Sector Erase Abort Cmd 0x47
Write: Register FSTAT
Clear bit CBEIF 0x80
1.
2.
3.
Read: Register FSTAT
no
EXIT
and Dummy Data
Bit Polling for
Command
Completion Check
Read: Register FSTAT
yes
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
NOTE: command write sequence
aborted by writing 0x00 to
FSTAT register.
CCIF
Set?
Bit
Execute Sector Erase Command Flow
no
Bit Polling for
Command
Completion Check
Read: Register FSTAT
yes
CCIF
Set?
Bit no
yes
Abort
Needed?
Erase
EXIT
Clear bit ACCERR 0x10
Write: Register FSTAT
yes
no
Access
Error Check ACCERR
Set?
Bit
EXIT
Sector Erase
Completed Sector Erase
Aborted
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
114 Freescale Semiconductor
2.4.1.4 Illegal Flash Operations
The ACCERR flag will be set during the command write sequence if any of the following illegal steps are
performed, causing the command write sequence to immediately abort:
1. Writing to a Flash address before initializing the FCLKDIV register.
2. W riting to a Flash address in the range 0x8000–0 xBFFF when the PPAGE register does not select
a 16 Kbyte page in the Flash block selected by the BKSEL bit in the FCNFG register.
3. Writing to a Flash address in the range 0x4000–0x7FFF or 0xC000–0xFFFF with the BKSEL bit
in the FCNFG register not selecting Flash block 0.
4. Writing a byte or misaligned word to a valid Flash address.
5. Starting a command write sequence while a data compress operation is active.
6. Starting a command write sequence while a sector erase abort operation is active.
7. Writing a second word to a Flash address in the same command write sequence.
8. Writing to any Flash register other than FCMD after writing a word to a Flash address.
9. Writing a second command to the FCMD register in the same command write sequence.
10. Writing an invalid command to the FCMD register.
11. When security is enabled, writing a command other than mass erase to the FCMD register when
the write originates from a non-secure memory location or from the Background Debug Mode.
12. Writing to any Flash register other than FSTAT (to clear CBEIF) after writing to the FCMD
register.
13. Writing a 0 to the CBEIF flag in the FSTAT register to abort a command write sequence.
The ACCERR flag will not be set if any Flash register is read during a valid command write sequence.
The ACCERR flag will also be set if any of the following events occur:
1. Launching the sector erase abort command while a sector erase operation is active which results in
the early termination of the sector erase operation (see Section 2.4.1.3.6, “Sector Erase Abort
Command”)
2. The MCU enters stop mode and a program or erase operation is in progress. The operation is
aborted immediately and any pending command is purged (see Section 2.5.2, “Stop Mode”).
If the Flash memory is read during execution of an algorithm (i.e., CCIF flag in the FSTAT register is low),
the read operation will return invalid data and the ACCERR flag will not be set.
If the ACCERR flag is set in the FSTAT register, the user must clear the ACCERR flag before starting
another command write sequence (see Section 2.3.2.7, “Flash Status Register (FSTAT)”).
The PVIOL flag will be set after the command is written to the FCMD register during a command write
sequence if any of the following illegal operations a re attempted, causing the command write sequence to
immediately abort:
1. Writing the program command if the address written in the command write sequence was in a
protected area of the Flash memory.
2. Writing the sector erase command if the address written in the command write sequence was in a
protected area of the Flash memory.
3. Writing the mass erase command while any Flash protection is enabled.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 115
If the PVIOL flag is set in the FSTAT register, the user must clear the PVIOL flag before starting another
command write sequence (see Section 2.3.2.7, “Flash Status Register (FSTAT)”).
2.5 Operating Modes
2.5.1 Wait Mode
If a command is active (CCIF = 0) when the MCU enters wait mode, the active command and any buffered
command will be completed.
The Flash module can recover the MCU from wait mode if the CBEIF and CCIF interrupts are enabled
(Section 2.8, “Interrupts”).
2.5.2 Stop Mode
If a command is active (CCIF = 0) when the MCU enters stop mode, the operation will be aborted and, if
the operation is program or erase, the Flash array data being programmed or erased may be corrupted and
the CCIF and ACCERR flags will be set. If active, the high voltage circuitry to the Flash memory will
immediately be switched off when entering stop mode. Upon exit from stop mode, the CBEIF flag is set
and any buffered command will not be launched. The ACCERR flag must be cleared before starting a
command write sequence (see Section 2.4.1.2, “Command Write Sequence”).
NOTE
As active commands are immediately aborted when the MCU enters stop
mode, it is strongly recommended that the user does not use the STOP
instruction during program or erase operations.
2.5.3 Background Debug Mode
In background debug mode (BDM), the FPROT register is writable. If the MCU is unsecured, then all
Flash commands listed in Table 2-20 can be executed.
2.6 Flash Module Security
The Flash module provides the necessary security information to the MCU. After each reset, the Flash
module determines the security state of the MCU as defined in Section 2.3.2.2, “Flash Security Register
(FSEC)”.
The contents of the Flash security byte at 0xFF0F in the Flash configuration field must be changed directly
by programming 0xFF0F when the MCU is unsecured and the higher address sector is unprotected. If the
Flash security byte remains in a secured state, any reset will cause the MCU to initialize to a secure
operating mode.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
116 Freescale Semiconductor
2.6.1 Unsecuring the MCU using Backdoor Key Access
The MCU may be unsecured by using the backdoor key access feature which requires knowledge of the
contents of the backdoor keys (four 16-bit words programmed at addresses 0xFF00–0xFF07). If the
KEYEN[1:0] bits are in the enabled state (see Section 2.3.2.2, “Flash Security Register (FSEC)”) and the
KEYACC bit is set, a write to a backdoor key address in the Flash memory triggers a compar ison between
the written data and the backdoor key data stored in the Flash memory. If all four words of data are written
to the correct addresses in the correct order and the data matches the backdoor keys stored in the Flash
memory, the MCU will be unsecured. The data must be written to the backdoor keys sequentially starting
with 0xFF00–0xFF01 and ending with 0xFF06–0xFF07. 0x0000 and 0xFFFF are not permitted as
backdoor keys. While the KEYACC bit is set, reads of the Flash memory will return invalid data.
The user code stored in the Flash memory must have a method of receiving the backdoor key from an
external stimulus. This external stimulus would typically be through one of the on-chip serial ports.
If the KEYEN[1:0] bits are in the enabled state (see Section 2.3.2.2, “Flash Security Register (FSEC)”),
the MCU can be unsecured by the backdoor access sequence described below:
1. Set the KEYACC bit in the Flash configuration register (FCNFG).
2. Write the correct four 16-bit words to Flash addresses 0xFF00–0xFF07 sequentially starting with
0xFF00.
3. Clear the KEYACC bit.
4. If all four 16-bit words match the backdoor keys stored in Flash addresses 0xFF00–0xFF07, the
MCU is unsecured and the SEC[1:0] bits in the FSEC register are forced to the unsecure state of
1:0.
The backdoor key access sequence is monitored by an internal security state machine. An illegal operation
during the backdoor key access sequence will cause the security state machine to lock, leaving the MCU
in the secured state. A reset of the MCU will cause the security state machine to exit the lock state and
allow a new backdoor key access sequence to be attempted. The following operations during the backdoor
key access sequence will lock the security state machine:
1. If any of the four 16-bit words does not match the backdoor keys programmed in the Flash array.
2. If the four 16-bit words are written in the wrong sequence.
3. If more than four 16-bit words are written.
4. If any of the four 16-bit words written are 0x0000 or 0xFFFF.
5. If the KEYACC bit does not remain set while the four 16-bit words are written.
6. If any two of the four 16-bit words are written on successive MCU clock cycles.
After the backdoor keys have been correctly matched, the MCU will be unsecured. After the MCU is
unsecured, the Flash security byte can be programmed to the unsecure state, if desired.
In the unsecure state, the user has full control of the contents of the backdoor keys by programming
addresses 0xFF00–0xFF07 in the Flash configuration field.
The security as defined in the Flash security byte (0xFF0F) is not changed by using the backdoor key
access sequence to unsecure. The backdoor keys stored in addresses 0xFF00–0xFF07 are unaffected by
the backdoor key access sequence. After the next reset of the MCU, the security state of the Flash module
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 117
is determined by the Flash security byte (0xFF0F). The backdoor key access sequence has no effect on the
program and erase protections defined in the Flash protection register.
It is not possible to unsecure the MCU in special single-chip mode by using the backdoor key access
sequence via the background debug mode (BDM).
2.6.2 Unsecuring the Flash Module in Special Single-Chip Mode using
BDM
The MCU can be unsecured in special single-chip mode by erasing the Flash module by the following
method :
• Reset the MCU into special single- chip mode, delay while the erase test is performed by the BDM
secure ROM, send BDM commands to disable protection in the Flash module, and execute a mass
erase command write sequence to erase the Flash memory.
After the CCIF flag sets to indicate that the mass operation has completed, reset the MCU into special
single-chip mode. The BDM secure ROM will verify that the Flash memory is erased and will assert the
UNSEC bit in the BDM status register. This BDM action will cause the MCU to override the Flash security
state and the MCU will be unsecured. All BDM commands will be enabled and the Flash security byte
may be programmed to the unsecure state by the following method:
• Send BDM commands to execute a word program sequence to program the Flash security byte to
the unsecured state and reset the MCU.
2.7 Resets
2.7.1 Flash Reset Sequence
On each reset, the Flash module executes a reset sequence to hold CPU activity while loading the
following registers from the Flash memory according to Table 2-1:
• FPROT — Flash Protection Register (see Section 2.3.2.5, “Flash Protection Register (FPROT)”).
• FCTL — Flash Control Register (see Section 2.3.2.9, “Flash Control Register (FCTL)”).
• FSEC — Flash Security Register (see Section 2.3.2.2, “Flash Security Register (FSEC)”).
2.7.2 Reset While Flash Command Active
If a reset occurs while any Flash command is in progress, that command will be immediately aborted. The
state of the word being programmed or the sector / block being erased is not guaranteed.
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
MC9S12E256 Data Sheet, Rev. 1.08
118 Freescale Semiconductor
2.8 Interrupts
The Flash module can generate an interrupt when all Flash command operations have completed, when
the Flash address, data, and command buffers are empty.
NOTE
Vector addresses and their relative interrupt priority are determined at the
MCU level.
2.8.1 Description of Flash Interrupt Operation
The logic used for generating interrupts is shown in Figure 2-29.
The Flash module uses the CBEIF and CCIF flags in combination with the CBIE and CCIE enable bits to
generate the Flash command interrupt request.
Figure 2-29. Flash Interrupt Implementation
For a detailed description of the register bits, refer to Section 2.3.2.4, “Flash Configuration Register
(FCNFG)” and Section 2.3.2.7, “Flash Status Register (FSTAT)”.
Table 2-21. Flash Interrupt Sources
Interrupt Source Interrupt Flag Local Enable Global (CCR) Mask
Flash address, data and command buffers empty CBEIF (FSTAT register) CBEIE (FCNFG register) I Bit
All Flash commands completed CCIF (FSTAT register) CCIE (FCNFG register) I Bit
Block 0 CBEIF
Flash Command
Block 0 Select
CBEIE
Block 1 CBEIF
Block 1 Select
Block 0 CCIF
Block 0 Select
CCIE
Block 1 CCIF
Block 1 Select
Interrupt Request
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 119
Chapter 3
Port Integration Module (PIM9E256V1)
3.1 lntroduction
The port integration module establishes the interface between the peripheral modules and the I/O pins for
for ports AD, M, P, Q, S, T and U.
This section covers:
• Port A, B, E, and K and the BKGD pin
• Port AD associated with ATD module (channels 15 through 0) and keyboard wake-up interrupts
• Port M connected to 2 DAC, 1 IIC and 1 SCI (SCI2) modules
• Port P and port Q connected to PMF module
• Port S connected to 2 SCI (SCI0 and SCI1) and 1 SPI modules
• Port T connected to 2 TIM (TIM0 and TIM1) modules
• Port U connected to 1 TIM (TIM2) and 1 PWM modules
Each I/O pin can be configured by several registers: input/output selection, drive strength reduction, enable
and select of pull resistors, wired-OR mode selection, interrupt enable, and/or status flags.
NOTE
Refer to Chapter 3, “Port Integration Module (PIM9E256V1)” for details on
ports A, B, E and K, and the BKGD pin.
3.1.1 Features
A standard port has the following minimum features:
• Input/output selection
• 5-V output drive with two selectable drive strength (or slew rates)
• 5-V digital and analog input
• Input with selectable pull-up or pull-down device
Optional features:
• Open drain for wired-OR connections
• Interrupt input with glitch filtering
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
120 Freescale Semiconductor
3.1.2 Block Diagram
Figure 3-1 is a block diagram of the PIM9E256V1.
Figure 3-1. PIM9E256V1 Block Diagram
Port T
PT0
PT1
PT2
PT3
PT4
PT5
PT6
PT7
TIM0/TIM1
IOC04
IOC05
IOC06
IOC07
IOC14
IOC15
IOC16
IOC17
Port P
PP0
PP1
PP2
PP3
PP4
PP5
Port S
PS0
PS1
PS2
PS3
PS4
PS5
PS6
PS7
RXD
TXD
RXD
TXD
SDI/MISO
SDO/MOSI
SCK
SS
SCI0
SCI1
SPI
Port Q Port M
SCI2
RXD2
TXD2
IIC
SDA
SCL
Port B
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
Port A
PA 0
PA 1
PA 2
PA 3
PA 4
PA 5
PA 6
PA 7
Port E
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
Port K
PK0
PK1
PK2
PK3
PK7
PK4
PK5
ADDR8/DATA8
ADDR9/DATA9
ADDR10/DATA10
ADDR11/DATA11
ADDR12/DATA12
ADDR13/DATA13
ADDR14/DATA14
ADDR15/DATA15
ADDR0/DATA0
ADDR1/DATA1
ADDR2/DATA2
ADDR3/DATA3
ADDR4/DATA4
ADDR5/DATA5
ADDR6/DATA6
ADDR7/DATA7
XIRQ
IRQ
R/W
LSTRB/TAGLO
ECLK
IPIPE0/MODA
NOACC/XCLKS
IPIPE1/MODB
XADDR15
XADDR16
XADDR17
ECS/ROMONE
XADRR18
XADDR19
CORE
XADDR14
CAN0 routing
BKGD/MODC/TAGHI BKGD
hhhkhkjsdhfshdfhskdf
FAULT0
FAULT1
FAULT2
FAULT3
IS0
PMF
PM7
DAO1
DAO0
PM6
PM5
PM4
PM3
PM1
PM0
Port U
IOC24
IOC25
IOC27
Port Integration Module
TIM2
PU0
PU1
PU2
PU3
PU4
PU5
PU6
PU7
ADC
PAD8
PAD9
PAD0
PAD1
PA D 2
PA D 3
PAD4
PA D 5
PAD6
PA D 7
Port AD
PA D 1 0
PAD1 1
PAD1 2
PAD1 3
PAD1 4
PA D 1 5
Interrupt Logic
PQ6
PQ5
PQ4
PQ3
PQ2
PQ1
PQ0
IOC26
PW15
PW14
PW13
PW12
PW11
PW04
PW03
PW02
PW01
PW00
PW10
PW05
MUX
PWM
PK6
XCS
AN0
AN1
AN2
AN3
AN4
AN5
AN6
AN7
AN8
AN9
AN10
AN11
AN12
AN13
AN14
AN15
DAC1
DAC0
IS2
IS1
KWAD0
KWAD1
KWAD2
KWAD3
KWAD4
KWAD5
KWAD6
KWAD7
KWAD8
KWAD9
KWAD10
KWAD11
KWAD12
KWAD13
KWAD14
KWAD15
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 121
3.2 External Signal Description
This section lists and describes the signals that connect off chip.
Table 3-1 shows all the pins and their functions that are controlled by the PIM9E256V1. The order in
which the pin functions are listed represents the functions priority (top – highest priority, bottom – lowest
priority).
Table 3-1. Detailed Signal Descriptions (Sheet 1 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
— BKGD MODC Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
Refer to Chapter 18,
“Multiplexed External Bus
Interface (MEBIV3)”
BKGD Refer to Chapter 15, “Background Debug Module
(BDMV4)”
TAGH I Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
Port A PA7 ADDR15/DATA15 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
Refer to Chapter 18,
“Multiplexed External Bus
Interface (MEBIV3)”
GPIO General-purpose I/O
PA6 ADDR14/DATA14 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PA5 ADDR13/DATA13 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PA4 ADDR12/DATA12 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PA3 ADDR11/DATA11 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PA2 ADDR10/DATA10 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PA1 ADDR9/DATA9 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PA0 ADDR8/DATA8 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
122 Freescale Semiconductor
Port B PB7 ADDR7/DATA7 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
Refer to Chapter 18,
“Multiplexed External Bus
Interface (MEBIV3)”
GPIO General-purpose I/O
PB6 ADDR6/DATA6 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PB5 ADDR5/DATA5 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PB4 ADDR4/DATA4 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PB3 ADDR3/DATA3 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PB2 ADDR2/DATA2 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PB1 ADDR1/DATA1 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PB0 ADDR0/DATA0 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
Port E PE7 XCLKS Refer to Chapter 5, “Oscillator (OSCV2)” Refer to Chapter 18,
“Multiplexed External Bus
Interface (MEBIV3)”
NOACC Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE6 IPIPE1/MODB Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE5 IPIPE0/MODA Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE4 ECLK Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE3 LSTRB/TAGLO Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE2 R/W Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE1 IRQ Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PE0 XIRQ Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
Table 3-1. Detailed Signal Descriptions (Sheet 2 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 123
Port K PK7 ECS/ROMONE Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
Refer to Chapter 18,
“Multiplexed External Bus
Interface (MEBIV3)”
GPIO General-purpose I/O
PK6 XCS Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PK5 XADDR19 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PK4 XADDR18 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PK3 XADDR17 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PK2 XADDR16 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PK1 XADDR15 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
PK0 XADDR14 Refer to Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”
GPIO General-purpose I/O
Table 3-1. Detailed Signal Descriptions (Sheet 3 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
124 Freescale Semiconductor
Port AD PAD15 AN15 Analog-to-digital converter input channel 15 GPIO
KWAD15 Keyboard wake-up interrupt 15
GPIO General-purpose I/O
PAD14 AN14 Analog-to-digital converter input channel 14
KWAD14 Keyboard wake-up interrupt 14
GPIO General-purpose I/O
PAD13 AN13 Analog-to-digital converter input channel 13
KWAD13 Keyboard wake-up interrupt 13
GPIO General-purpose I/O
PAD12 AN12 Analog-to-digital converter input channel 12
KWAD12 Keyboard wake-up interrupt 12
GPIO General-purpose I/O
PAD11 AN11 Analog-to-digital converter input channel 11
KWAD11 Keyboard wake-up interrupt 11
GPIO General-purpose I/O
PAD10 AN10 Analog-to-digital converter input channel 10
KWAD10 Keyboard wake-up interrupt 10
GPIO General-purpose I/O
PAD9 AN9 Analog-to-digital converter input channel 9
KWAD9 Keyboard wake-up interrupt 9
GPIO General-purpose I/O
PAD8 AN8 Analog-to-digital converter input channel 8
KWAD8 Keyboard wake-up interrupt 8
GPIO General-purpose I/O
PAD7 AN7 Analog-to-digital converter input channel 7
KWAD7 Keyboard wake-up interrupt 7
GPIO General-purpose I/O
PAD6 AN6 Analog-to-digital converter input channel 6
KWAD6 Keyboard wake-up interrupt 6
GPIO General-purpose I/O
PAD5 AN5 Analog-to-digital converter input channel 5
KWAD5 Keyboard wake-up interrupt 5
GPIO General-purpose I/O
PAD4 AN4 Analog-to-digital converter input channel 4
KWAD4 Keyboard wake-up interrupt 4
GPIO General-purpose I/O
PAD3 AN3 Analog-to-digital converter input channel 3
KWAD3 Keyboard wake-up interrupt 3
GPIO General-purpose I/O
PAD2 AN2 Analog-to-digital converter input channel 2
KWAD2 Keyboard wake-up interrupt 2
GPIO General-purpose I/O
PAD1 AN1 Analog-to-digital converter input channel 1
KWAD1 Keyboard wake-up interrupt 1
GPIO General-purpose I/O
PAD0 AN0 Analog-to-digital converter input channel 0
KWAD0 Keyboard wake-up interrupt 0
GPIO General-purpose I/O
Table 3-1. Detailed Signal Descriptions (Sheet 4 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 125
Port M PM7 SCL Inter-integrated circuit serial clock line GPIO
GPIO General-purpose I/O
PM6 SDA Inter-integrated circuit serial data line
GPIO General-purpose I/O
PM5 TXD2 Serial communication interface 2 transmit pin
GPIO General-purpose I/O
PM4 RXD2 Serial communication interface 2 receive pin
GPIO General-purpose I/O
PM3 GPIO General-purpose I/O
PM1 DAO1 Digital to analog convertor 1 output
GPIO General-purpose I/O
PM0 DAO0 Digital to analog convertor 0 output
GPIO General-purpose I/O
Port P PP5 PWM5 Pulse-width modulator 0 channel 5 GPIO
GPIO General-purpose I/O
PP4 PWM4 Pulse-width modulator 0 channel 4
GPIO General-purpose I/O
PP3 PWM3 Pulse-width modulator 0 channel 3
GPIO General-purpose I/O
PP2 PWM2 Pulse-width modulator 0 channel 2
GPIO General-purpose I/O
PP1 PWM1 Pulse-width modulator 0 channel 1
GPIO General-purpose I/O
PP0 PWM0 Pulse-width modulator 0 channel 0
GPIO General-purpose I/O
Port Q PQ6 IS2 PMF current status pin 2 GPIO
GPIO General-purpose I/O
PQ5 IS1 PMF current status pin 1
GPIO General-purpose I/O
PQ4 IS0 PMF current status pin 0
GPIO General-purpose I/O
PQ3 FAULT3 PMF fault pin3
GPIO General-purpose I/O
PQ2 FAULT2 PMF fault pin 2
GPIO General-purpose I/O
PQ1 FAULT11 PMF fault pin 1
GPIO General-purpose I/O
PQ0 FAULT0 PMF fault pin 0
GPIO General-purpose I/O
Table 3-1. Detailed Signal Descriptions (Sheet 5 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
126 Freescale Semiconductor
Port S PS7 SS Serial peripheral interface slave select input/output in
master mode, input in slave mode
GPIO
GPIO General-purpose I/O
PS6 SCK Serial peripheral interface serial clock pin
GPIO General-purpose I/O
PS5 MOSI Serial peripheral interface master out/slave in pin
GPIO General-purpose I/O
PS4 MISO Serial peripheral interface master in/slave out pin
GPIO General-purpose I/O
PS3 TXD0 Serial communication interface 1 transmit pin
GPIO General-purpose I/O
PS2 RXD0 Serial communication interface 1 receive pin
GPIO General-purpose I/O
PS1 TXD0 Serial communication interface 0 transmit pin
GPIO General-purpose I/O
PS0 RXD0 Serial communication interface 0 receive pin
GPIO General-purpose I/O
Port T PT7 IOC7 Timer 1 channel 7 GPIO
GPIO General-purpose I/O
PT6 IOC6 Timer 1 channel 6
GPIO General-purpose I/O
PT5 IOC5 Timer 1 channel 5
GPIO General-purpose I/O
PT4 IOC4 Timer 1 channel 4
GPIO General-purpose I/O
PT3 IOC3 Timer 0 channel 7
GPIO General-purpose I/O
PT2 IOC2 Timer 0 channel 6
GPIO General-purpose I/O
PT1 IOC1 Timer 0 channel 5
GPIO General-purpose I/O
PT0 IOC0 Timer 0 channel 4
GPIO General-purpose I/O
Table 3-1. Detailed Signal Descriptions (Sheet 6 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 127
Port U PU7 GPIO General-purpose I/O GPIO
PU6 GPIO General-purpose I/O
PU5 PW15 Pulse-width modulator 1 channel 5
GPIO General-purpose I/O
PU4 PW14 Pulse-width modulator 1 channel 4
GPIO General-purpose I/O
PU3 IOC3 Timer 2 channel 7
PW13 Pulse-width modulator 1 channel 3
GPIO General-purpose I/O
PU2 IOC2 Timer 2 channel 6
PW12 Pulse-width modulator 1 channel 2
GPIO General-purpose I/O
PU1 IOC1 Timer 2 channel 5
PW11 Pulse-width modulator 1 channel 1
GPIO General-purpose I/O
PU0 IOC0 Timer 2 channel 4
PW11 Pulse-width modulator 1 channel 0
GPIO General-purpose I/O
Table 3-1. Detailed Signal Descriptions (Sheet 7 of 7)
Port Pin
Name Pin Function Description Pin Function
after Reset
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
128 Freescale Semiconductor
3.3 Memory Map and Register Definition
This section provides a detailed description of all registers. Table 3-2 is a standard memory map of port
integration module.
Table 3-2. PIM9HZ256 Memory Map
Address Offset Use Access
0x0000 Port T I/O Register (PTT) R/W
0x0001 Port T Input Register (PTIT) R
0x0002 Port T Data Direction Register (DDRT) R/W
0x0003 Port T Reduced Drive Register (RDRT) R/W
0x0004 Port T Pull Device Enable Register (PERT) R/W
0x0005 Port T Polarity Select Register (PPST) R/W
0x0006 - 0x0007 Reserved —
0x0008 Port S I/O Register (PTS) R/W
0x0009 Port S Input Register (PTIS) R
0x000A Port S Data Direction Register (DDRS) R/W
0x000B Port S Reduced Drive Register (RDRS) R/W
0x000C Port S Pull Device Enable Register (PERS) R/W
0x000D Port S Polarity Select Register (PPSS) R/W
0x000E Port S Wired-OR Mode Register (WOMS) R/W
0x000F Reserved —
0x0010 Port M I/O Register (PTM) R/W
0x0011 Port M Input Register (PTIM) R
0x0012 Port M Data Direction Register (DDRM) R/W
0x0013 Port M Reduced Drive Register (RDRM) R/W
0x0014 Port M Pull Device Enable Register (PERM) R/W
0x0015 Port M Polarity Select Register (PPSM) R/W
0x0016 Port M Wired-OR Mode Register (WOMM) R/W
0x0017 Reserved —
0x0018 Port P I/O Register (PTP) R/W
0x0019 Port P Input Register (PTIP) R
0x001A Port P Data Direction Register (DDRP) R/W
0x001B Port P Reduced Drive Register (RDRP) R/W
0x001C Port P Pull Device Enable Register (PERP) R/W
0x001D Port P Polarity Select Register (PPSP) R/W
0x001E - 0x001F Reserved —
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 129
0x0020 Port Q I/O Register (PTQ) R/W
0x0021 Port Q Input Register (PTIQ) R
0x0022 Port Q Data Direction Register (DDRQ) R/W
0x0023 Port Q Reduced Drive Register (RDRQ) R/W
0x0024 Port Q Pull Device Enable Register (PERQ) R/W
0x0025 Port Q Polarity Select Register (PPSQ) R/W
0x0026 - 0x0027 Reserved —
0x0028 Port U I/O Register (PTU) R/W
0x0029 Port U Input Register (PTIU) R
0x002A Port U Data Direction Register (DDRU) R/W
0x002B Port U Reduced Drive Register (RDRU) R/W
0x002C Port U Pull Device Enable Register (PERU) R/W
0x002D Port U Polarity Select Register (PPSU) R/W
0x002E Port U Module Routing Register (MODRR) R/W
0x002F Reserved —
0x0030 Port AD I/O Register (PTAD) R/W
0x0031
0x0032 Port AD Input Register (PTIAD) R
0x0033
0x0034 Port AD Data Direction Register (DDRAD) R/W
0x0035
0x0036 Port AD Reduced Drive Register (RDRAD) R/W
0x0037
0x0038 Port AD Pull Device Enable Register (PERAD) R/W
0x0039
0x003A Port AD Polarity Select Register (PPSAD) R/W
0x003B
0x003D Port AD Interrupt Enable Register (PIEAD) R/W
0x003D
0x003E Port AD Interrupt Flag Register (PIFAD) R/W
0x003F
Table 3-2. PIM9HZ256 Memory Map (continued)
Address Offset Use Access
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
130 Freescale Semiconductor
3.3.1 Port AD
Port AD is associated with the analog-to-digital converter (ATD) and keyboard wake-up (KWU)
interrupts. Each pin is assigned to these modules according to the following priority: ATD > KWU >
general-purpose I/O.
For the pins of port AD to be used as inputs, the corresponding bits of the ATDDIEN0 and ATDDIEN1
registers in the ATD module must be set to 1 (digital input buffer is enabled). The ATDDIEN0 and
ATDDIEN1 registers do not affect the port AD pins when they are configured as outputs.
Refer to Chapter 6, “Analog-to-Digital Converter (ATD10B16CV4)” for information on the ATDDIEN0
and ATDDIEN1 registers.
During reset, port AD pins are configured as high-impedance analog inputs (digital input buffer is
disabled).
3.3.1.1 Port AD I/O Register (PTAD)
Read: Anytime. Write: Anytime.
If the data direction bit of the associated I/O pin (DDRADx) is set to 1 (output), a write to the
corresponding I/O Register bit sets the value to be driven to the Port AD pin. If the data direction bit of the
associated I/O pin (DDRADx) is set to 0 (input), a write to the corresponding I/O Register bit takes place
but has no effect on the Port AD pin.
If the associated data direction bit (DDRADx) is set to 1 (output), a read returns the value of the I/O register
bit.
If the associated data direction bit (DDRADx) is set to 0 (input) and the associated ATDDIEN0(1) bit is
set to 0 (digital input buffer is disabled), the associated I/O register bit (PTADx) reads “1”.
If the associated data direction bit (DDRADx) is set to 0 (input) and the associated ATDDIEN0(1) bit is
set to 1 (digital input buffer is enabled), a read returns the value of the pin.
76543210
RPTAD15 PTAD14 PTAD13 PTAD12 PTAD11 PTAD10 PTAD9 PTAD8
W
KWU: KWAD15 KWAD14 KWAD13 KWA12 KWAD11 KWAD10 KWAD9 KWAD8
ATD: AN15 AN14 AN13 AN12 AN11 AN10 AN9 AN8
Reset00000000
76543210
RPTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
W
KWU: KWAD7 KWAD6 KWAD5 KWAD4 KWAD3 KWAD2 KWAD1 KWAD0
ATD: AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
Reset00000000
Figure 3-2. Port AD I/O Register (PTAD)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 131
3.3.1.2 Port AD Input Register (PTIAD)
Read: Anytime. Write: Never; writes to these registers have no effect.
If the ATDDIEN0(1) bit of the associated I/O pin is set to 0 (digital input buffer is disabled), a read returns
a 1. If the ATDDIEN0(1) bit of the associated I/O pin is set to 1 (digital input buffer is enabled), a read
returns the status of the associated pin.
3.3.1.3 Port AD Data Direction Register (DDRAD)
Read: Anytime. Write: Anytime.
This register configures port pins PAD[15:0] as either input or output.
If a data direction bit is 0 (pin configured as input), then a read value on PTADx depends on the associated
ATDDIEN0(1) bit. If the associated ATDDIEN0(1) bit is set to 1 (digital input buffer is enabled), a read
on PTADx returns the value on port AD pin. If the associated ATDDIEN0(1) bit is set to 0 (digital input
buffer is disabled), a read on PTADx returns a 1.
76543210
R PTIAD15 PTIAD14 PTIAD13 PTIAD12 PTIAD11 PTIAD10 PTIAD9 PTIAD8
W
Reset11111111
76543210
R PTIAD7 PTIAD6 PTIAD5 PTIAD4 PTIAD3 PTIAD2 PTIAD1 PTIAD0
W
Reset11111111
= Reserved or Unimplemented
Figure 3-3. Port AD Input Register (PTIAD)
76543210
RDDRAD15 DDRAD14 DDRAD13 DDRAD12 DDRAD11 DDRAD10 DDRAD9 DDRAD8
W
Reset00000000
76543210
RDDRAD7 DDRAD6 DDRAD5 DDRAD4 DDRAD3 DDRAD2 DDRAD1 DDRAD0
W
Reset00000000
Figure 3-4. Port AD Data Direction Register (DDRAD)
Table 3-3. DDRAD Field Descriptions
Field Description
15:0
DDRAD[15:0]
Data Direction Port AD
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
132 Freescale Semiconductor
3.3.1.4 Port AD Reduced Drive Register (RDRAD)
Read: Anytime. Write: Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
3.3.1.5 Port AD Pull Device Enable Register (PERAD)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input pins. If
a pin is configured as output, the corresponding Pull Device Enable Register bit has no effect.
76543210
RRDRAD15 RDRAD14 RDRAD13 RDRAD12 RDRAD11 RDRAD10 RDRAD9 RDRAD8
W
Reset00000000
76543210
RRDRAD7 RDRAD6 RDRAD5 RDRAD4 RDRAD3 RDRAD2 RDRAD1 RDRAD0
W
Reset00000000
Figure 3-5. Port AD Reduced Drive Register (RDRAD)
Table 3-4. RDRAD Field Descriptions
Field Description
15:0
RDRAD[15:0]
Reduced Drive Port AD
0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
76543210
RPERAD15 PERAD14 PERAD13 PERAD12 PERAD11 PERAD10 PERAD9 PERAD8
W
Reset00000000
76543210
RPERAD7 PERAD6 PERAD5 PERAD4 PERAD3 PERAD2 PERAD1 PERAD0
W
Reset00000000
Figure 3-6. Port AD Pull Device Enable Register (PERAD)
Table 3-5. PERAD Field Descriptions
Field Description
15:0
PERAD[15:0]
Pull Device Enable Port AD
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 133
3.3.1.6 Port AD Polarity Select Register (PPSAD)
Read: Anytime. Write: Anytime.
The Port AD Polarity Select Register serves a dual purpose by selecting the polarity of the active interr upt
edge as well as selecting a pull-up or pull-down device if enabled (PERADx = 1). The Port AD Polarity
Select Register is effective only when the corresponding Data Direction Register bit is set to 0 (input).
In pull-down mode (PPSADx = 1), a rising edge on a port AD pin sets the corresponding PIFADx bit. In
pull-up mode (PPSADx = 0), a falling edge on a port AD pin sets the corresponding PIFADx bit.
76543210
RPPSAD15 PPSAD14 PPSAD13 PPSAD12 PPSAD11 PPSAD10 PPSAD9 PPSAD8
W
Reset00000000
76543210
RPPSAD7 PPSAD6 PPSAD5 PPSAD4 PPSAD3 PPSAD2 PPSAD1 PPSAD0
W
Reset00000000
Figure 3-7. Port AD Polarity Select Register (PPSAD)
Table 3-6. PPSAD Field Descriptions
Field Description
15:0
PPSAD[15:0]
Polarity Select Port AD
0 A pull-up device is connected to the associated port AD pin, and detects falling edge for interrupt generation.
1 A pull-down device is connected to the associated port AD pin, and detects rising edge for interrupt
generation.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
134 Freescale Semiconductor
3.3.1.7 Port AD Interrupt Enable Register (PIEAD)
Read: Anytime. Write: Anytime.
This register disables or enables on a per pin basis the edge sensitive external interrupt associated with
port AD.
76543210
RPIEAD15 PIEAD14 PIEAD13 PIEAD12 PIEAD11 PIEAD10 PIEAD9 PIEAD8
W
Reset00000000
76543210
RPIEAD7 PIEAD6 PIEAD5 PIEAD4 PIEAD3 PIEAD2 PIEAD1 PIEAD0
W
Reset00000000
Figure 3-8. Port AD Interrupt Enable Register (PIEAD)
Table 3-7. PIEAD Field Descriptions
Field Description
15:0
PIEAD[15:0]
Interrupt Enable Port AD
0 Interrupt is disabled (interrupt flag masked).
1 Interrupt is enabled.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 135
3.3.1.8 Port AD Interrupt Flag Register (PIFAD)
Read: Anytime. Write: Anytime.
Each flag is set by an active edge on the associated input pin. The active edge could be rising or falling
based on the state of the corresponding PPSADx bit. To clear each flag, write “1” to the corresponding
PIFADx bit. Writing a “0” has no effect.
NOTE
If the ATDDIEN0(1) bit of the associated pin is set to 0 (digital input buffer
is disabled), active edges can not be detected.
76543210
RPIFAD15 PIFAD14 PIFAD13 PIFAD12 PIFAD11 PIFAD10 PIFAD9 PIFAD8
W
Reset00000000
76543210
RPIFAD7 PIFAD6 PIFAD5 PIFAD4 PIFAD3 PIFAD2 PIFAD1 PIFAD0
W
Reset00000000
Figure 3-9. Port AD Interrupt Flag Register (PIFAD)
Table 3-8. PIFAD Field Descriptions
Field Description
15:0
PIFAD[15:0]
Interrupt Flags Port AD
0 No active edge pending. Writing a “0” has no effect.
1 Active edge on the associated bit has occurred (an interrupt will occur if the associated enable bit is set).
Writing a “1” clears the associated flag.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
136 Freescale Semiconductor
3.3.2 Port M
Port M is associated with the serial communication interface (SCI2) , Inter-IC bus (IIC) and the digital to
analog converter (DAC0 and DAC1) modules. Each pin is assigned to these modules according to the
following priority: IIC/SCI2/DAC1/DAC0 > general-purpose I/O.
When the IIC bus is enabled, the PM[7:6] pins become SCL and SDA respectively. Refer to Chapter 10,
“Inter-Integrated Circuit (IICV2)” for information on enabling and disabling the IIC bus.
When the SCI2 receiver and transmitter are enabled, the PM[5:4] become RXD2 and TXD2 respectively.
Refer to Chapter 8, “Serial Communication Interface (SCIV4)” for information on enabling and disabling
the SCI receiver and transmitter.
When the DAC1 and DAC0 outputs are enabled, the PM[1:0] become DAO1 and DAO0 respectively.
Refer to Chapter 7, “Digital-to-Analog Converter (DAC8B1CV1)” for information on enabling and
disabling the DAC output.
During reset, PM[3] and PM[1:0] pins are configured as high-impedance inputs and PM[7:4] pins are
configured as pull-up inputs.
3.3.2.1 Port M I/O Register (PTM)
Read: Anytime. Write: Anytime.
If the associated data direction bit (DDRMx) is set to 1 (output), a read returns the value of the I/O register
bit. If the associated data direction bit (DDRMx) is set to 0 (input), a read returns the value of the pin.
76543210
R
PTM7 PTM6 PTM5 PTM4 PTM3
0
PTM1 PTM0
W
IIC: SCL SDA
SCI2: TXD2 RXD2
DAC1/DAC0: DAO1 DAO0
Reset00000000
= Reserved or Unimplemented
Figure 3-10. Port M I/O Register (PTM)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 137
3.3.2.2 Port M Input Register (PTIM)
Read: Anytime. Write: Never, writes to this register have no effect.
This register always reads back the status of the associated pins.
3.3.2.3 Port M Data Direction Register (DDRM)
Read: Anytime. Write: Anytime.
This register configures port pins PM[7:3] and PM[1:0] as either input or output.
If the IIC is enabled, the IIC controls the SCL and SDA I/O direction, and the corresponding DDRM[7:6]
bits have no effect on their I/O direction. Refer to Chapter 10, “Inter-Integrated Circuit (IICV2)” for
details.
If the SCI2 transmitter is enabled, the I/O direction of the transmit pin TXD2 is controlled by SCI2, and
the DDRM5 bit has no effect. If the SCI2 receiver is enabled, the I/O direction of the rece ive pin RXD2 is
controlled by SCI2, and the DDRM4 bit has no effect. Refer to Chapter 8, “Serial Communication
Interface (SCIV4)” for further details.
If the DAC1 or DAC0 channel is enabled, the associated pin DAO1 or DAO0 is forced to be output, and
the associated DDRM1 or DDRM0 bit has no effect.
The DDRM bits do not change to reflect the pin I/O direction when not being used as GPIO. The
DDRM[7:3]; DDRM[1:0] bits revert to controlling the I/O direction of the pins when the associated IIC,
SCI, or DAC1/0 function are disabled.
76543210
R PTIM7 PTIM6 PTIM5 PTIM4 PTIM3 0 PTIM1 PTIM0
W
Resetuuuuu0uu
= Reserved or Unimplemented u = Unaffected by reset
Figure 3-11. Port M Input Register (PTIM)
76543210
RDDRM7 DDRM6 DDRM5 DDRM4 DDRM3 0DDRM1 DDRM0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-12. Port M Data Direction Register (DDRM)
Table 3-9. DDRM Field Descriptions
Field Description
7:3, 1:0
DDRM[7:3,
1:0]
Data Direction Port M
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
138 Freescale Semiconductor
3.3.2.4 Port M Reduced Drive Register (RDRM)
Read: Anytime. Write: Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
3.3.2.5 Port M Pull Device Enable Register (PERM)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input or
wired-OR output pins. If a pin is configured as push-pull output, the corresponding Pull Device Enable
Register bit has no effect.
76543210
R
RDRM7 RDRM6 RDRM5 RDRM4 RDRM3
0
RDRM1 RDRM0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-13. Port M Reduced Drive Register (RDRM)
Table 3-10. RDRM Field Descriptions
Field Description
7:3, 1:0
RDRM[7:3,
1:0]
Reduced Drive Port M
0 Full drive strength at output
1 Associated pin drives at about 1/3 of the full drive strength.
76543210
R
PERM7 PERM6 PERM5 PERM4 PERM3
0
PERM1 PERM0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-14. Port M Pull Device Enable Register (PERM)
Table 3-11. PERM Field Descriptions
Field Description
7:3, 1:0
PERM[7:3,
1:0]
Pull Device Enable Port M
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 139
3.3.2.6 Port M Polarity Select Register (PPSM)
Read: Anytime. Write: Anytime.
The Port M Polarity Select Register selects whether a pull-down or a pull-up device is connected to the
pin. The Port M Polarity Select Register is effective only when the corresponding Data Direction Register
bit is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
76543210
R
PPSM7 PPSM6 PPSM5 PPSM4 PPSM3
0
PPSM1 PPSM0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-15. Port M Polarity Select Register (PPSM)
Table 3-12. PPSM Field Descriptions
Field Description
7:3, 1:0
PPSM[7:3,
1:0]
Pull Select Port M
0 A pull-up device is connected to the associated port M pin.
1 A pull-down device is connected to the associated port M pin.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
140 Freescale Semiconductor
3.3.2.7 Port M Wired-OR Mode Register (WOMM)
Read: Anytime. Write: Anytime.
This register selects whether a port M output is configured as push-pull or wired-OR. When a Wired-OR
Mode Register bit is set to 1, the corresponding output pin is driven active low only (open drain) and a high
level is not driven. A Wired-OR Mode Register bit has no effect if the corresponding pin is configured as
an input.
These bits apply also to the SCI2 outputs and allow a multipoint connection of several serial modules.
If the IIC is enabled, the associated pins are always set to wired-OR mode, and the state of the
WOMM[7:6] bits have no effect. The WOMM[7:6] bits will not change to reflect their wired-OR mode
configuration when the IIC is enabled.
76543210
R
WOMM7 WOMM6 WOMM5 WOMM4
0000
W
Reset00000000
= Reserved or Unimplemented
Figure 3-16. Port M Wired-OR Mode Register (WOMM)
Table 3-13. WOMM Field Descriptions
Field Description
7:4
WOMM[7:4]
Wired-OR Mode Port M
0 Output buffers operate as push-pull outputs.
1 Output buffers operate as open-drain outputs.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 141
3.3.3 Port P
Port P is associated with the Pulse Width Modulator (PMF) modules. Each pin is assigned according to
the following priority: PMF > general-purpose I/O.
When a PMF channel is enabled, the corresponding pin becomes a PWM output. Refer to Chapter 11,
“Pulse Width Modulator with Fault Protection (PMF15B6CV2)” for information on enabling and
disabling the PWM channels.
During reset, port P pins are configured as high-impedance inputs.
3.3.3.1 Port P I/O Register (PTP)
Read: Anytime. Write: Anytime.
If the associated data direction bit (DDRPx) is set to 1 (output), a read returns the value of the I/O register
bit. If the associated data direction bit (DDRPx) is set to 0 (input), a read returns the value of the pin.
The PMF function takes precedence over the general-purpose I/O function if the associated PWM channel
is enabled. The PWM channels 5-0 are outputs if the respective channels are enabled.
3.3.3.2 Port P Input Register (PTIP)
Read: Anytime. Write: Never, writes to this register have no effect.
This register always reads back the status of the associated pins.
76543210
R0 0
PTP5 PTP4 PTP3 PTP2 PTP1 PTP0
W
PMF: PW05 PW04 PW03 PW02 PW01 PW00
Reset00000000
= Reserved or Unimplemented
Figure 3-17. Port P I/O Register (PTP)
76543210
R 0 0 PTIP5 PTIP4 PTIP3 PTIP2 PTIP1 PTIP0
W
Reset00uuuuuu
= Reserved or Unimplemented u = Unaffected by reset
Figure 3-18. Port P Input Register (PTIP)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
142 Freescale Semiconductor
3.3.3.3 Port P Data Direction Register (DDRP)
Read: Anytime. Write: Anytime.
This register configures port pins PP[5:0] as either input or output.
If a PMF channel is enabled, the corresponding pin is forced to be an output and the associated Data
Direction Register bit has no effect. If a PMF channel is disabled, the corresponding Data Direction
Register bit reverts to control the I/O direction of the associated pin.
3.3.3.4 Port P Reduced Drive Register (RDRP)
Read:Anytime. Write:Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
76543210
R0 0
DDRP5 DDRP4 DDRP3 DDRP2 DDRP1 DDRP0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-19. Port P Data Direction Register (DDRP)
Table 3-14. DDRP Field Descriptions
Field Description
5:0
DDRP[5:0]
Data Direction Port P
0 Associated pin is configured as input.
1 Associated pin is configured as output.
76543210
R0 0
RDRP5 RDRP4 RDRP3 RDRP2 RDRP1 RDRP0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-20. Port P Reduced Drive Register (RDRP)
Table 3-15. RDRP Field Descriptions
Field Description
5:0
RDRP[5:0]
Reduced Drive Port P
0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 143
3.3.3.5 Port P Pull Device Enable Register (PERP)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input pins. If
a pin is configured as output, the corresponding Pull Device Enable Register bit has no effect.
3.3.3.6 Port P Polarity Select Register (PPSP)
Read: Anytime. Write: Anytime.
The Port P Polarity Select Register selects whether a pull-down or a pull-up device is connected to the pin.
The Port P Polarity Select Register is effective only when the corresponding Data Direction Register bit
is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
76543210
R0 0
PERP5 PERP4 PERP3 PERP2 PERP1 PERP0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-21. Port P Pull Device Enable Register (PERP)
Table 3-16. PERP Field Descriptions
Field Description
5:0
PERP[5:0]
Pull Device Enable Port P
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
76543210
R0 0
PPSP5 PPSP4 PPSP3 PPSP2 PPSP1 PPSP0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-22. Port P Polarity Select Register (PPSP)
Table 3-17. PPSP Field Descriptions
Field Description
5:0
PPSP[5:0]
Polarity Select Port P
0 A pull-up device is connected to the associated port P pin.
1 A pull-down device is connected to the associated port P pin.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
144 Freescale Semiconductor
3.3.4 Port Q
Port Q is associated with the Pulse Width Modulator (PMF) modules. Each pin is assigned according to
the following priority: PMF > general-purpose I/O.
When a current status or fault function is enabled, the corresponding pin becomes an input. PQ[3:0] are
connected to FAULT[3:0] inputs and PQ[6:4] are connected to IS[2:0] inputs of the PMF module. Refer
to Chapter 11, “Pulse Width Modulator with Fault Protection (PMF15B6CV2)” for information on
enabling and disabling these PMF functions.
During reset, port Q pins are configured as high-impedance inputs.
3.3.4.1 Port Q I/O Register (PTQ)
Read: Anytime. Write: Anytime.
If the associated data direction bit (DDRQx) is set to 1 (output), a read returns th e value of the I/O register
bit. If the associated data direction bit (DDRQx) is set to 0 (input), a read returns the value of the pin.
3.3.4.2 Port Q Input Register (PTIQ)
Read: Anytime. Write: Never, writes to this register have no effect.
This register always reads back the status of the associated pins.
76543210
R0
PTQ5 PTQ5 PTQ4 PTQ3 PTQ2 PTQ1 PTQ0
W
PMF: IS2 IS1 IS0 FAULT3 FAULT2 FAULT1 FAULT0
Reset00000000
= Reserved or Unimplemented
Figure 3-23. Port Q I/O Register (PTQ)
76543210
R 0 PTIQ6 PTIQ5 PTIQ4 PTIQ3 PTIQ2 PTIQ1 PTIQ0
W
Reset0uuuuuuu
= Reserved or Unimplemented u = Unaffected by reset
Figure 3-24. Port Q Input Register (PTIQ)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 145
3.3.4.3 Port Q Data Direction Register (DDRQ)
Read: Anytime. Write: Anytime.
This register configures port pins PQ[6:0] as either input or output.
If a PMF function is enabled, the corresponding pin is forced to be an input and the associated Data
Direction Register bit has no effect. If a PMF channel is disabled, the corresponding Data Direction
Register bit reverts to control the I/O direction of the associated pin.
3.3.4.4 Port Q Reduced Drive Register (RDRQ)
Read:Anytime. Write:Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
76543210
R0
DDRQ6 DDRQ5 DDRQ4 DDRQ3 DDRQ2 DDRQ1 DDRQ0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-25. Port Q Data Direction Register (DDRQ)
Table 3-18. DDRQ Field Descriptions
Field Description
6:0
DDRQ[6:0]
Data Direction Port Q
0 Associated pin is configured as input.
1 Associated pin is configured as output.
76543210
R0
RDRQ6 RDRQ5 RDRQ4 RDRQ3 RDRQ2 RDRQ1 RDRQ0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-26. Port Q Reduced Drive Register (RDRQ)
Table 3-19. RDRQ Field Descriptions
Field Description
6:0
RDRQ[6:0]
Reduced Drive Port Q
0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
146 Freescale Semiconductor
3.3.4.5 Port Q Pull Device Enable Register (PERQ)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input pins. If
a pin is configured as output, the corresponding Pull Device Enable Register bit has no effect.
3.3.4.6 Port Q Polarity Select Register (PPSQ)
Read: Anytime. Write: Anytime.
The Port Q Polarity Select Register selects whether a pull-down or a pull-up device is connected to the pin.
The Port Q Polarity Select Register is effective only when the corresponding Data Direction Register bit
is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
76543210
R0
PERQ6 PERQ5 PERQ4 PERQ3 PERQ2 PERQ1 PERQ0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-27. Port Q Pull Device Enable Register (PERQ)
Table 3-20. PERQ Field Descriptions
Field Description
6:0
PERQ[6:0]
Pull Device Enable Port P
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
76543210
R0
PPSQ6 PPSQ5 PPSQ4 PPSQ3 PPSQ2 PPSQ1 PPSQ0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-28. Port Q Polarity Select Register (PPSQ)
Table 3-21. PPSQ Field Descriptions
Field Description
6:0
PPSQ[6:0]
Polarity Select Port Q
0 A pull-up device is connected to the associated port Q pin.
1 A pull-down device is connected to the associated port Q pin.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 147
3.3.5 Port S
Port S is associated with the serial peripheral interface (SPI) and serial communication interfaces (SCI0
and SCI1). Each pin is assigned to these modules according to the following priority: SPI/SCI1/SCI0 >
general-purpose I/O.
When the SPI is enabled, the PS[7:4] pins become SS, SCK, MOSI, and MISO respectively. Refer to
Chapter 9, “Serial Peripheral Interface (SPIV3)” for information on enabling and disabling the SPI.
When the SCI1 receiver and transmitter are enabled, the PS[3:2] pins become TXD1 and RXD1
respectively. When the SCI0 receiver and transmitter are enabled, the PS[1:0] pins become TXD0 and
RXD0 respectively. Refer to Chapter 8, “Serial Communication Interface (SCIV4)” for information on
enabling and disabling the SCI receiver and transmitter.
During reset, port S pins are configured as high-impedance inputs.
3.3.5.1 Port S I/O Register (PTS)
Read: Anytime. Write: Anytime.
If the associated data direction bit (DDRSx) is set to 1 (output), a read returns the value of the I/O register
bit. If the associated data direction bit (DDRSx) is set to 0 (input), a read returns the value of the pin.
3.3.5.2 Port S Input Register (PTIS)
Read: Anytime. Write: Never, writes to this register have no effect.
This register always reads back the status of the associated pins.
76543210
R
PTS7 PTS6 PTS5 PTS4 PTS3 PTS2 PTS1 PTS0
W
SPI: SS SCK MOSI MISO
SCI1/SCI0: TXD1 RXD1 TXD0 RXD0
Reset00000000
Figure 3-29. Port S I/O Register (PTS)
76543210
R PTIS7 PTIS6 PTIS5 PTIS4 PTIS3 PTIS2 PTIS1 PTIS0
W
Resetuuuuuuuu
= Reserved or Unimplemented u = Unaffected by reset
Figure 3-30. Port S Input Register (PTIS)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
148 Freescale Semiconductor
3.3.5.3 Port S Data Direction Register (DDRS)
Read: Anytime. Write: Anytime.
This register configures port pins PS[7:4] and PS[2:0] as either input or output.
When the SPI is enabled, the PS[7:4] pins become the SPI bidirectional pins. The associated Data
Direction Register bits have no effect.
When the SCI1 transmitter is enabled, the PS[3] pin becomes the TXD1 output pin and the associated Data
Direction Register bit has no effect. When the SCI1 receiver is enabled, the PS[2] pin becomes the RXD1
input pin and the associated Data Direction Register bit has no effect.
When the SCI0 transmitter is enabled, the PS[1] pin becomes the TXD0 output pin and the associated Data
Direction Register bit has no effect. When the SCI0 receiver is enabled, the PS[0] pin becomes the RXD0
input pin and the associated Data Direction Register bit has no effect.
If the SPI, SCI1 and SCI0 functions are disabled, the corresponding Data Direction Register bit reverts to
control the I/O direction of the associated pin.
76543210
R
DDRS7 DDRS6 DDRS5 DDRS4 DDRS3 DDRS2 DDRS1 DDRS0
W
Reset00000000
Figure 3-31. Port S Data Direction Register (DDRS)
Table 3-22. DDRS Field Descriptions
Field Description
7:0
DDRS[7:0]
Data Direction Port S
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 149
3.3.5.4 Port S Reduced Drive Register (RDRS)
Read: Anytime. Write: Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
3.3.5.5 Port S Pull Device Enable Register (PERS)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input or
wired-OR (open drain) output pins. If a pin is configured as push-pull output, the corresponding Pull
Device Enable Register bit has no effect.
76543210
R
RDRS7 RDRS6 RDRS5 RDRS4 RDRS3 RDRS2 RDRS1 RDRS0
W
Reset00000000
Figure 3-32. Port S Reduced Drive Register (RDRS)
Table 3-23. RDRS Field Descriptions
Field Description
7:0
RDRS[7:0]
Reduced Drive Port S
0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
76543210
R
PERS7 PERS6 PERS5 PERS4 PERS3 PERS2 PERS1 PERS0
W
Reset11111111
Figure 3-33. Port S Pull Device Enable Register (PERS)
Table 3-24. PERS Field Descriptions
Field Description
7:0
PERS[7:0]
Pull Device Enable Port S
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
150 Freescale Semiconductor
3.3.5.6 Port S Polarity Select Register (PPSS)
Read: Anytime. Write: Anytime.
The Port S Polarity Select Register selects whether a pull-down or a pull-up device is connected to the pin.
The Port S Polarity Select Register is effective only when the corresponding Data Direction Register bit
is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
3.3.5.7 Port S Wired-OR Mode Register (WOMS)
Read: Anytime. Write: Anytime.
This register selects whether a port S output is configured as push-pull or wired-OR. When a Wired-OR
Mode Register bit is set to 1, the corresponding output pin is driven active low only (open drain) and a high
level is not driven. A Wired-OR Mode Register bit has no effect if the corresponding pin is configured as
an input.
76543210
R
PPSS7 PPSS6 PPSS5 PPSS4 PPSS3 PPSS2 PPSS1 PPSS0
W
Reset00000000
Figure 3-34. Port S Polarity Select Register (PPSS)
Table 3-25. PPSS Field Descriptions
Field Description
7:0
PPSS[7:0]
Pull Select Port S
0 A pull-up device is connected to the associated port S pin.
1 A pull-down device is connected to the associated port S pin.
76543210
R
WOMS7 WOMS6 WOMS5 WOMS4 WOMS3 WOMS2 WOMS1 WOMS0
W
Reset00000000
Figure 3-35. Port S Wired-OR Mode Register (WOMS)
Table 3-26. WOMS Field Descriptions
Field Description
7:0
WOMS[7:0]
Wired-OR Mode Port S
0 Output buffers operate as push-pull outputs.
1 Output buffers operate as open-drain outputs.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 151
3.3.6 Port T
Port T is associated with two 4-channel timers (TIM0 and TIM1). Each pin is assigned to these modules
according to the following priority: TIM1/TIM0 > general-purpose I/O.
If the timer TIM0 is enabled, the channels configured for output compare are available on port T pins
PT[3:0]. If the timer TIM1 is enabled, the channels configured for output compare are available on port T
pins PT[7:4].
Refer to Chapter 13, “Timer Module (TIM16B4CV1)” for information on enabling and disabling the TIM
module.
During reset, port T pins are configured as high-impedance inputs.
3.3.6.1 Port T I/O Register (PTT)
Read: Anytime. Write: Anytime.
If the associated data direction bit (DDRTx) is set to 1 (output), a read returns the value of the I/O register
bit. If the associated data direction bit (DDRTx) is set to 0 (input), a read returns the value of the pin.
3.3.6.2 Port T Input Register (PTIT)
Read: Anytime. Write: Never, writes to this register have no effect.
This register always reads back the status of the associated pins.
76543210
R
PTT7 PTT6 PTT5 PTT4 PTT3 PTT2 PTT1 PTT0
W
TIM: OC17 OC16 OC15 OC14 OC07 OC06 OC05 OC04
Reset00000000
Figure 3-36. Port T I/O Register (PTT)
76543210
R PTIT7 PTIT6 PTIT5 PTIT4 PTIT3 PTIT2 PTIT1 PTIT0
W
Resetuuuuuuuu
= Reserved or Unimplemented u = Unaffected by reset
Figure 3-37. Port T Input Register (PTIT)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
152 Freescale Semiconductor
3.3.6.3 Port T Data Direction Register (DDRT)
Read: Anytime. Write: Anytime.
This register configures port pins PT[7:0] as either input or output.
If the TIM0(1) module is enabled, each port pin configured for output compare is forced to be an output
and the associated Data Direction Register bit has no effect. If the associated timer output compare is
disabled, the corresponding DDRTx bit reverts to control the I/O direction of the associated pin.
If the TIM0(1) module is enabled, each port pin configured as an input capture has the corresponding
DDRTx bit controlling the I/O direction of the associated pin.
3.3.6.4 Port T Reduced Drive Register (RDRT)
Read: Anytime. Write: Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
76543210
R
DDRT7 DDRT6 DDRT5 DDRT4 DDRT3 DDRT2 DDRT1 DDRT0
W
Reset00000000
Figure 3-38. Port T Data Direction Register (DDRT)
Table 3-27. DDRT Field Descriptions
Field Description
7:0
DDRT[7:0]
Data Direction Port T
0 Associated pin is configured as input.
1 Associated pin is configured as output.
76543210
R
RDRT7 RDRT6 RDRT5 RDRT4 RDRT3 RDRT2 RDRT1 RDRT0
W
Reset00000000
Figure 3-39. Port T Reduced Drive Register (RDRT)
Table 3-28. RDRT Field Descriptions
Field Description
7:0
RDRT[7:0]
Reduced Drive Port T
0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 153
3.3.6.5 Port T Pull Device Enable Register (PERT)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input pins. If
a pin is configured as output, the corresponding Pull Device Enable Register bit has no effect.
3.3.6.6 Port T Polarity Select Register (PPST)
Read: Anytime. Write: Anytime.
The Port T Polarity Select Register selects whether a pull-down or a pull-up device is connected to the pin.
The Port T Polarity Select Register is effective only when the corresponding Data Direction Register bit
is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
76543210
R
PERT7 PERT6 PERT5 PERT4 PERT3 PERT2 PERT1 PERT0
W
Reset00000000
Figure 3-40. Port T Pull Device Enable Register (PERT)
Table 3-29. PERT Field Descriptions
Field Description
7:0
PERT[7:0]
Pull Device Enable Port T
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
76543210
R
PPST7 PPST6 PPST5 PPST4 PPST3 PPST2 PPST1 PPST0
W
Reset00000000
Figure 3-41. Port T Polarity Select Register (PPST)
Table 3-30. PPST Field Descriptions
Field Description
7:0
PPST[7:0]
Pull Select Port T
0 A pull-up device is connected to the associated port T pin.
1 A pull-down device is connected to the associated port T pin.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
154 Freescale Semiconductor
3.3.7 Port U
Port U is associated with one 4-channel timer (TIM2) and the pulse width modulator (PWM) module. Each
pin is assigned to these modules according to the following priority: TIM2/PWM > general-purpose I/O.
If the timer TIM2 is enabled, the channels configured for output compare are available on port U pins
PU[3:0]. Refer to Chapter 13, “Timer Module (TIM16B4CV1)” for information on enabling and disabling
the TIM module.
When a PWM channel is enabled, the corresponding pin becomes a PWM output. Refer to Chapter 3, “Port
Integration Module (PIM9E256V1)” for information on enabling and disabling the PWM channels.
If both PWM and TIM2 are enabled simultaneously, the pin functionality is determined by the
configuration of the MODRR bits
During reset, port U pins are configured as high-impedance inputs.
3.3.7.1 Port U I/O Register (PTU)
Read: Anytime. Write: Anytime.
If the associated data direction bit (DDRUx) is set to 1 (output), a read returns th e value of the I/O register
bit. If the associated data direction bit (DDRUx) is set to 0 (input), a read returns the value of the pin.
3.3.7.2 Port U Input Register (PTIU)
Read: Anytime. Write: Never, writes to this register have no effect.
This register always reads back the status of the associated pins.
76543210
R
PTU7 PTU6 PTU5 PTU4 PTU3 PTU2 PTU1 PTU0
W
PWM: PW15 PW14 PW13 PW12 PW11 PW10
TIM2: OC27 OC26 OC25 OC24
Reset00000000
Figure 3-42. Port U I/O Register (PTU)
76543210
R PTIU7 PTIU6 PTIU5 PTIU4 PTIU3 PTIU2 PTIU1 PTIU0
W
Resetuuuuuuuu
= Reserved or Unimplemented u = Unaffected by reset
Figure 3-43. Port U Input Register (PTIU)
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 155
3.3.7.3 Port U Data Direction Register (DDRU)
Read: Anytime. Write: Anytime.
This register configures port pins PU[7:0] as either input or output.
If a pulse width modulator channel is enabled, the associated pin is forced to be an output and the
associated Data Direction Register bit has no effect. If the associated pulse width modulator channel is
disabled, the corresponding DDRUx bit reverts to control the I/O direction of the associated pin.
If the TIM2 module is enabled, each port pin configured for output compare is forced to be an output and
the associated Data Direction Register bit has no effect. If the associated timer output compare is disabled,
the corresponding DDRUx bit reverts to control the I/O direction of the associated pin.
If the TIM2 module is enabled, each port pin configured as an input capture has the corresponding DDRUx
bit controlling the I/O direction of the associated pin.
When both a timer function and a PWM function are enabled on the same pin, the MODRR register
determines which function has control of the pin
76543210
R
DDRU7 DDRU6 DDRU5 DDRU4 DDRU3 DDRU2 DDRU1 DDRU0
W
Reset00000000
Figure 3-44. Port U Data Direction Register (DDRU)
Table 3-31. DDRU Field Descriptions
Field Description
7:0
DDRU[7:0]
Data Direction Port U
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
156 Freescale Semiconductor
3.3.7.4 Port U Reduced Drive Register (RDRU)
Read: Anytime. Write: Anytime.
This register configures the drive strength of configured output pins as either full or reduced. If a pin is
configured as input, the corresponding Reduced Drive Register bit has no effect.
3.3.7.5 Port U Pull Device Enable Register (PERU)
Read: Anytime. Write: Anytime.
This register configures whether a pull-up or a pull-down device is activated on configured input pins. If
a pin is configured as output, the corresponding Pull Device Enable Register bit has no effect.
76543210
R
RDRU7 RDRU6 RDRU5 RDRU4 RDRU3 RDRU2 RDRU1 RDRU0
W
Reset00000000
Figure 3-45. Port U Reduced Drive Register (RDRU)
Table 3-32. RDRU Field Descriptions
Field Description
7:0
RDRU[7:0]
Reduced Drive Port U
0 Full drive strength at output.
1 Associated pin drives at about 1/3 of the full drive strength.
76543210
R
PERU7 PERU6 PERU5 PERU4 PERU3 PERU2 PERU1 PERU0
W
Reset00000000
Figure 3-46. Port U Pull Device Enable Register (PERU)
Table 3-33. PERU Field Descriptions
Field Description
7:0
PERU[7:0]
Pull Device Enable Port U
0 Pull-up or pull-down device is disabled.
1 Pull-up or pull-down device is enabled.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 157
3.3.7.6 Port U Polarity Select Register (PPSU)
Read: Anytime. Write: Anytime.
The Port U Polarity Select Register selects whether a pull-down or a pull-up device is connected to the pin.
The Port U Polarity Select Register is effective only when the corresponding Data Direction Register bit
is set to 0 (input) and the corresponding Pull Device Enable Register bit is set to 1.
3.3.7.7 Port U Module Routing Register (MODRR)
Read: Anytime. Write: Anytime.
This register selects the module connected to port U.
76543210
R
PPSU7 PPSU6 PPSU5 PPSU4 PPSU3 PPSU2 PPSU1 PPSU0
W
Reset00000000
Figure 3-47. Port U Polarity Select Register (PPSU)
Table 3-34. PPSU Field Descriptions
Field Description
7:0
PPSU[7:0]
Pull Select Port U
0 A pull-up device is connected to the associated port T pin.
1 A pull-down device is connected to the associated port T pin.
76543210
R0 0 0 0
MODRR3 MODRR2 MODRR1 MODRR0
W
Reset00000000
= Reserved or Unimplemented
Figure 3-48. Port U Module Routing Register (MODRR)
Table 3-35. MODRR Field Descriptions
Field Description
3:0
MODRR[3:0]
Pull Select Port U
0 If enabled, TIM2 channel is connected to the associated port U pin.
1 If enabled, PWM channel is connected to the associated port U pin.
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
158 Freescale Semiconductor
3.4 Functional Description
Each pin associated with ports AD, M, P, Q, S, T and U can act as general-purpose I/O. In addition the pin
can act as an output from a peripheral module or an input to a peripheral module.
A set of configuration registers is common to all ports. All registers can be written at any time, however a
specific configuration might not become active.
Example: Selecting a pull-up resistor. This resistor does not become active while the port is used
as a push-pull output.
3.4.1 I/O Register
The I/O Register holds the value driven out to the pin if the port is used as a general-purpose I/O. Writing
to the I/O Register only has an effect on the pin if the port is used as general-purpose output.
When reading the I/O Register, the value of each pin is returned if the corresponding Data Direction
Register bit is set to 0 (pin configured as input). If the data direction register bits is set to 1, the content of
the I/O Register bit is returned. This is independent of any other configuration (Figure 3-49).
Due to internal synchronization circuits, it can take up to 2 bus cycles until the correct value is read on the
I/O Register when changing the data direction register.
3.4.2 Input Register
The Input Register is a read-only register and generally returns the value of the pin (Figure 3-49). It can
be used to detect overload or short circuit conditions.
Due to internal synchronization circuits, it can take up to 2 bus cycles until the correct value is read on the
Input Register when changing the Data Direction Register.
3.4.3 Data Direction Register
The Data Direction Register defines whether the pin is used as an input or an output. A Data Direction
Register bit set to 0 configures the pin as an input. A Data Direction Register bit set to 0 configures the pin
as an output. If a peripheral module controls the pin the contents of the data direction register is ignored
(Figure 3-49).
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 159
Figure 3-49. Illustration of I/O Pin Functionality
Figure 3-50 shows the state of digital inputs and outputs when an analog module drives the port. When the
analog module is enabled all associated digital output ports are disabled and all associated digital input
ports read “1”.
Figure 3-50. Digital Ports and Analog Module
3.4.4 Reduced Drive Register
If the port is used as an output the Reduced Drive Register allows the configuration of the drive strength.
3.4.5 Pull Device Enable Register
The Pull Device Enable Register turns on a pull-up or pull-down device. The pull device becomes active
only if the pin is used as an input or as a wired-OR output.
PTx
DDRx
output enable
module enable
1
0
1
1
0
0
PAD
PTIx
data out
Digital
Module
Analog
Module
1
0
1
PAD
Digital
Input
Digital
Output
1
0
Analog
Module
Enable
Output
PIM Boundary
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
160 Freescale Semiconductor
3.4.6 Polarity Select Register
The Polarity Select Register selects either a pull-up or pull-down device if enabled. The pull device
becomes active only if the pin is used as an input or as a wired-OR output.
3.4.7 Pin Configuration Summary
The following table summarizes the effect of various configuration in the Data Direction (DDR),
Input/Output (I/O), reduced drive (RDR), Pull Enable (PE), Pull Select (PS) and Interrupt Enable (IE)
register bits. The PS configuration bit is used for two purposes:
1. Configure the sensitive interrupt edge (rising or falling), if interrupt is enabled.
2. Select either a pull-up or pull-down device if PE is set to “1”.
Table 3-36. Pin Configuration Summary
DDR IO RDR PE PS IE1
1Applicable only on Port AD.
Function2
2Digital outputs are disabled and digital input logic is forced to “1” when an analog module associated with the port is enabled.
Pull Device Interrupt
0 X X 0 X 0 Input Disabled Disabled
0 X X 1 0 0 Input Pull Up Disabled
0 X X 1 1 0 Input Pull Down Disabled
0 X X 0 0 1 Input Disabled Falling Edge
0 X X 0 1 1 Input Disabled Rising Edge
0 X X 1 0 1 Input Pull Up Falling Edge
0 X X 1 1 1 Input Pull Down Rising Edge
1 0 0 X X 0 Output to 0, Full Drive Disabled Disabled
1 1 0 X X 0 Output to 1, Full Drive Disabled Disabled
1 0 1 X X 0 Output to 0, Reduced Drive Disabled Disabled
1 1 1 X X 0 Output to 1, Reduced Drive Disabled Disabled
1 0 0 X 0 1 Output to 0, Full Drive Disabled Falling Edge
1 1 0 X 1 1 Output to 1, Full Drive Disabled Rising Edge
1 0 1 X 0 1 Output to 0, Reduced Drive Disabled Falling Edge
1 1 1 X 1 1 Output to 1, Reduced Drive Disabled Rising Edge
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 161
3.5 Resets
The reset values of all registers are given in the register description in Section 3.3, “Memory Map and
Register Definition”.
All ports start up as general-purpose inputs on reset.
3.5.1 Reset Initialization
All registers including the data registers get set/reset asynchronously. Table 3-37 summarizes the port
properties after reset initialization.
PTable 3-37. Port Reset State Summary
Port
Reset States
Data
Direction Pull Mode Red. Drive Wired-OR
Mode Interrupt
A Refer to
Chapter 18,
“Multiplexed
External Bus
Interface
(MEBIV3)”
Pull Up Refer to Chapter 18, “Multiplexed External Bus
Interface (MEBIV3)”
B
E
K
BKGD pin
AD Input Hi-z Disabled N/A Disabled
M[7:4] Input Pull Up Disabled Disabled N/A
M[3,1:0] Input Hi-z Disabled Disabled N/A
P Input Hi-z Disabled N/A N/A
Q Input Hi-z Disabled N/A N/A
S Input Pull Up Disabled Disabled N/A
T Input Hi-z Disabled N/A N/A
U Input Hi-z Disabled N/A N/A
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
162 Freescale Semiconductor
3.6 Interrupts
3.6.1 General
Port AD generates an edge sensitive interrupt if enabled. It offers sixteen I/O pins with edge triggered
interrupt capability in wired-OR fashion. The interrupt enable as well as the sensitivity to rising or falling
edges can be individually configured on per pin basis. All eight bits/pins share the same interrupt vector.
Interrupts can be used with the pins configured as inputs (with the corresponding ATDDIEN1 bit set to 1)
or outputs.
An interrupt is generated when a bit in the port interrupt flag register and its corresponding port interrupt
enable bit are both set. This external interrupt feature is ca pable to wake up the CPU when it is in stop or
wait mode.
A digital filter on each pin prevents pulses (Figure 3-52) shorter than a specified time from generating an
interrupt. The minimum time varies over process conditions, temperature and voltage (Figure 3-51 and
Table 3-38).
Figure 3-51. Interrupt Glitch Filter on Port AD (PPS = 0)
Table 3-38. Pulse Detection Criteria
Pulse
Mode
STOP STOP1
1These values include the spread of the oscillator frequency over temperature,
voltage and process.
Unit Unit
Ignored tpulse <= 3 Bus Clock tpulse <= 3.2 µs
Uncertain 3 < tpulse < 4 Bus Clock 3.2 < tpulse < 10 µs
Valid tpulse >= 4 Bus Clock tpulse >= 10 µs
Glitch, filtered out, no interrupt flag set
Valid pulse, interrupt flag set
tifmin
tifmax
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 163
Figure 3-52. Pulse Illustration
A valid edge on an input is detected if 4 consecutive samples of a passive level are followed by 4
consecutive samples of an active level directly or indirectly
The filters are continuously clocked by the bus clock in RUN and WAIT mode. In STOP mode the clock
is generated by a single RC oscillator in the port integration module. To maximize current saving the RC
oscillator runs only if the following condition is true on any pin:
Sample count <= 4 and port interrupt enabled (PIE=1) and port interrupt flag not set (PIF=0).
3.6.2 Interrupt Sources
NOTE
Vector addresses and their relative interrupt priority are determined at the
MCU level.
3.6.3 Operation in Stop Mode
All clocks are stopped in STOP mode. The port integration module has asynchronous paths on port AD to
generate wake-up interrupts from stop mode. For other sources of external interrupts refer to the respective
block description chapters.
Table 3-39. Port Integration Module Interrupt Sources
Interrupt
Source
Interrupt
Flag
Local
Enable
Global (CCR)
Mask
Port AD PIFAD[15:0] PIEAD[15:0] I Bit
tpulse
Chapter 3 Port Integration Module (PIM9E256V1)
MC9S12E256 Data Sheet, Rev. 1.08
164 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 165
Chapter 4
Clocks and Reset Generator (CRGV4)
4.1 Introduction
This specification describes the function of the clocks and reset generator (CRGV4).
4.1.1 Features
The main features of this block are:
• Phase-locked loop (PLL) frequency multiplier
— Reference divider
— Automatic bandwidth control mode for low-jitter operation
— Automatic frequency lock detector
— CPU interrupt on entry or exit from locked condition
— Self-clock mode in absence of reference clock
• System clock generator
— Clock quality check
— Clock switch for either oscillator- or PLL-based system clocks
— User selectable disabling of clocks during wait mode for reduced power consumption
• Computer operating properly (COP) watchdog timer with time-out clear window
• System reset generation from the following possible sources:
— Power-on reset
— Low voltage reset
Refer to the device overview section for availability of this feature.
—COP reset
— Loss of clock reset
— External pin reset
• Real-time interrupt (RTI)
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
166 Freescale Semiconductor
4.1.2 Modes of Operation
This subsection lists and briefly describes all operating modes supported by the CRG.
• Run mode
All functional parts of the CRG are running during normal run mode. If RTI or COP functionality
is required the individual bits of the associated rate select registers (COPCTL, RTICTL) have to be
set to a nonzero value.
• Wait mode
This mode allows to disable the system and core clocks depending on the configuration of the
individual bits in the CLKSEL register.
• Stop mode
Depending on the setting of the PSTP bit, stop mode can be dif ferentiated between full stop mode
(PSTP = 0) and pseudo-stop mode (PSTP = 1).
— Full stop mode
The oscillator is disabled and thus all system and core clocks are stopped. The COP and the
RTI remain frozen.
— Pseudo-stop mode
The oscillator continues to run and most of the system and core clocks are stopped. If the
respective enable bits are set the COP and RTI will continue to run, else they remain frozen.
• Self-clock mode
Self-clock mode will be entered if the clock monitor enable bit (CME) and the self-clock mode
enable bit (SCME) are both asserted and the clock monitor in the oscillator block detects a loss of
clock. As soon as self-clock mode is entered the CRGV4 starts to perform a clock quality check.
Self-clock mode remains active until the clock quality check indicates that the required quality of
the incoming clock signal is met (frequency and amplitude). Self-clock mode should be used for
safety purposes only. It provides reduced functionality to the MCU in case a loss of clock is causing
severe system conditions.
4.1.3 Block Diagram
Figure 4-1 shows a block diagram of the CRGV4.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 167
Figure 4-1. CRG Block Diagram
4.2 External Signal Description
This section lists and describes the signals that connect off chip.
4.2.1 VDDPLL, VSSPLL — PLL Operating Voltage, PLL Ground
These pins provides operating voltage (VDDPLL) and ground (VSSPLL) for the PLL circuitry. This allows
the supply voltage to the PLL to be independently bypassed. Even if PLL usage is not required VDDPLL
and VSSPLL must be connected properly.
4.2.2 XFC — PLL Loop Filter Pin
A passive external loop filter must be placed on the XFC pin. The filter is a second-order, low-pass filter
to eliminate the VCO input ripple. The value of the external filter network and the reference frequency
determines the speed of the corrections and the stability of the PLL. Refer to Chapter 1, “MC9S12E256
Device Overview (MC9S12E256DGV1)” for calculation of PLL loop filter (XFC) components. If PLL
usage is not required the XFC pin must be tied to VDDPLL.
CRG
Registers
Clock and Reset
COP
RESET
RTI
PLL
XFC
VDDPLL
VSSPLL
Oscil-
EXTAL
XTAL
Control
Bus Clock
System Reset
Oscillator Clock
PLLCLK
OSCCLK
Core Clock
Clock
Monitor
CM fail
Clock Quality
Checker
Reset
Generator
XCLKS
Power-on Reset
Low Voltage Reset 1
COP Timeout
Real-Time Interrupt
PLL Lock Interrupt
Self-Clock Mode
Interrupt
lator
Voltage
Regulator
1 Refer to the device overview section for availability of the low-voltage reset feature.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
168 Freescale Semiconductor
Figure 4-2. PLL Loop Filter Connections
4.2.3 RESET — Reset Pin
RESET is an active low bidirectional reset pin. As an input it initializes the MCU asynchronously to a
known start-up state. As an open-drain output it indicates that an system reset (internal to MCU) has been
triggered.
4.3 Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the CRGV4.
4.3.1 Module Memory Map
Table 4-1 gives an overview on all CRGV4 registers.
Table 4-1. CRGV4 Memory Map
Address
Offset Use Access
0x0000 CRG Synthesizer Register (SYNR) R/W
0x0001 CRG Reference Divider Register (REFDV) R/W
0x0002 CRG Test Flags Register (CTFLG)1
1CTFLG is intended for factory test purposes only.
R/W
0x0003 CRG Flags Register (CRGFLG) R/W
0x0004 CRG Interrupt Enable Register (CRGINT) R/W
0x0005 CRG Clock Select Register (CLKSEL) R/W
0x0006 CRG PLL Control Register (PLLCTL) R/W
0x0007 CRG RTI Control Register (RTICTL) R/W
0x0008 CRG COP Control Register (COPCTL) R/W
0x0009 CRG Force and Bypass Test Register (FORBYP)2
2FORBYP is intended for factory test purposes only.
R/W
0x000A CRG Test Control Register (CTCTL)3
3CTCTL is intended for factory test purposes only.
R/W
0x000B CRG COP Arm/Timer Reset (ARMCOP) R/W
MCU
XFC
RS
CS
VDDPLL
CP
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 169
NOTE
Register address = base address + address offset, where the base address is
defined at the MCU level and the address offset is defined at the module
level.
4.3.2 Register Descriptions
This section describes in address order all the CRGV4 registers and their individual bits.
Register
Name Bit 7654321Bit 0
SYNR R 0 0 SYN5 SYN4 SYN3 SYN2 SYN1 SYN0
W
REFDVR0000
REFDV3 REFDV2 REFDV1 REFDV0
W
CTFLGR00000000
W
CRGFLG R RTIF PORF LVRF LOCKIF LOCK TRACK SCMIF SCM
W
CRGINT R RTIE 00
LOCKIE 00
SCMIE 0
W
CLKSEL R PLLSEL PSTP SYSWAI ROAWAI PLLWAI CWAI RTIWAI COPWAI
W
PLLCTL R CME PLLON AUTO ACQ 0PRE PCE SCME
W
RTICTL R 0 RTR6 RTR5 RTR4 RTR3 RTR2 RTR1 RTR0
W
COPCTL R WCOP RSBCK 000
CR2 CR1 CR0
W
FORBYPR00000000
W
CTCTLR00000000
W
= Unimplemented or Reserved
Figure 4-3. CRG Register Summary
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
170 Freescale Semiconductor
4.3.2.1 CRG Synthesizer Register (SYNR)
The SYNR register controls the multiplication factor of the PLL. If the PLL is on, the count in the loop
divider (SYNR) register effectivel y multiplies up the PLL clock (PLLCLK) from the reference frequency
by 2 x (SYNR+1). PLLCLK will not be below the minimum VCO frequency (fSCM).
NOTE
If PLL is selected (PLLSEL=1), Bus Clock = PLLCLK / 2
Bus Clock must not exceed the maximum operating system frequency.
Read: anytime
Write: anytime except if PLLSEL = 1
NOTE
Write to this register initializes the lock detector bit and the track detector
bit.
ARMCOPR00000000
W Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
76543210
R0 0
SYN5 SYNR SYN3 SYN2 SYN1 SYN0
W
Reset00000000
= Unimplemented or Reserved
Figure 4-4. CRG Synthesizer Register (SYNR)
Register
Name Bit 7654321Bit 0
= Unimplemented or Reserved
Figure 4-3. CRG Register Summary (continued)
PLLCLK 2xOSCCLKx SYNR 1+()
REFDV 1+()
-----------------------------------
=
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 171
4.3.2.2 CRG Reference Divider Register (REFDV)
The REFDV register provides a finer granularity for the PLL multiplier steps. The count in the reference
divider divides OSCCLK frequency by REFDV + 1.
Read: anytime
Write: anytime except when PLLSEL = 1
NOTE
Write to this register initializes the lock detector bit and the track detector
bit.
4.3.2.3 Reserved Register (CTFLG)
This register is reserved for factory testing of the CRGV4 module and is not available in normal modes.
Read: always reads 0x0000 in normal modes
Write: unimplemented in normal modes
NOTE
Writing to this register when in special mode can alter the CRGV4
functionality.
76543210
R0 0 0 0
REFDV3 REFDV2 REFDV1 REFDV0
W
Reset00000000
= Unimplemented or Reserved
Figure 4-5. CRG Reference Divider Register (REFDV)
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 4-6. CRG Reserved Register (CTFLG)
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
172 Freescale Semiconductor
4.3.2.4 CRG Flags Register (CRGFLG)
This register provides CRG status bits and flags.
Read: anytime
Write: refer to each bit for individual write conditions
76543210
R
RTIF PORF LVRF LOCKIF
LOCK TRACK
SCMIF
SCM
W
Reset0Note 1Note 200000
1. PORF is set to 1 when a power-on reset occurs. Unaffected by system reset.
2. LVRF is set to 1 when a low-voltage reset occurs. Unaffected by system reset.
= Unimplemented or Reserved
Figure 4-7. CRG Flag Register (CRGFLG)
Table 4-2. CRGFLG Field Descriptions
Field Description
7
RTIF
Real-Time Interrupt Flag — RTIF is set to 1 at the end of the RTI period. This flag can only be cleared by writing
a 1. Writing a 0 has no effect. If enabled (RTIE = 1), RTIF causes an interrupt request.
0 RTI time-out has not yet occurred.
1 RTI time-out has occurred.
6
PORF
Power-on Reset Flag — PORF is set to 1 when a power-on reset occurs. This flag can only be cleared by writing
a 1. Writing a 0 has no effect.
0 Power-on reset has not occurred.
1 Power-on reset has occurred.
5
LVRF
Low-Voltage Reset Flag — If low voltage reset feature is not available (see Chapter 1, “MC9S12E256 Device
Overview (MC9S12E256DGV1)”), LVRF always reads 0. LVRF is set to 1 when a low voltage reset occurs. This
flag can only be cleared by writing a 1. Writing a 0 has no effect.
0 Low voltage reset has not occurred.
1 Low voltage reset has occurred.
4
LOCKIF
PLL Lock Interrupt Flag — LOCKIF is set to 1 when LOCK status bit changes. This flag can only be cleared by
writing a 1. Writing a 0 has no effect.If enabled (LOCKIE = 1), LOCKIF causes an interrupt request.
0 No change in LOCK bit.
1 LOCK bit has changed.
3
LOCK
Lock Status Bit — LOCK reflects the current state of PLL lock condition. This bit is cleared in self-clock mode.
Writes have no effect.
0 PLL VCO is not within the desired tolerance of the target frequency.
1 PLL VCO is within the desired tolerance of the target frequency.
2
TRACK
Track Status Bit — TRACK reflects the current state of PLL track condition. This bit is cleared in self-clock mode.
Writes have no effect.
0 Acquisition mode status.
1 Tracking mode status.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 173
4.3.2.5 CRG Interrupt Enable Register (CRGINT)
This register enables CRG interrupt requests.
Read: anytime
Write: anytime
1
SCMIF
Self-Clock Mode Interrupt Flag — SCMIF is set to 1 when SCM status bit changes. This flag can only be
cleared by writing a 1. Writing a 0 has no effect. If enabled (SCMIE=1), SCMIF causes an interrupt request.
0 No change in SCM bit.
1 SCM bit has changed.
0
SCM
Self-Clock Mode Status Bit — SCM reflects the current clocking mode. Writes have no effect.
0 MCU is operating normally with OSCCLK available.
1 MCU is operating in self-clock mode with OSCCLK in an unknown state. All clocks are derived from PLLCLK
running at its minimum frequency fSCM.
76543210
R
RTIE
00
LOCKIE
00
SCMIE
0
W
Reset00000000
= Unimplemented or Reserved
Figure 4-8. CRG Interrupt Enable Register (CRGINT)
Table 4-3. CRGINT Field Descriptions
Field Description
7
RTIE
Real-Time Interrupt Enable Bit
0 Interrupt requests from RTI are disabled.
1 Interrupt will be requested whenever RTIF is set.
4
LOCKIE
Lock Interrupt Enable Bit
0 LOCK interrupt requests are disabled.
1 Interrupt will be requested whenever LOCKIF is set.
1
SCMIE
Self-Clock Mode Interrupt Enable Bit
0 SCM interrupt requests are disabled.
1 Interrupt will be requested whenever SCMIF is set.
Table 4-2. CRGFLG Field Descriptions (continued)
Field Description
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
174 Freescale Semiconductor
4.3.2.6 CRG Clock Select Register (CLKSEL)
This register controls CRG clock selection. Refer to Figure 4-17 for details on the effect of each bit.
Read: anytime
Write: refer to each bit for individual write conditions
76543210
R
PLLSEL PSTP SYSWAI ROAWAI PLLWAI CWAI RTIWAI COPWAI
W
Reset00000000
Figure 4-9. CRG Clock Select Register (CLKSEL)
Table 4-4. CLKSEL Field Descriptions
Field Description
7
PLLSEL
PLL Select Bit — Write anytime. Writing a 1 when LOCK = 0 and AUTO = 1, or TRACK = 0 and AUTO = 0 has
no effect. This prevents the selection of an unstable PLLCLK as SYSCLK. PLLSEL bit is cleared when the MCU
enters self-clock mode, stop mode or wait mode with PLLWAI bit set.
0 System clocks are derived from OSCCLK (Bus Clock = OSCCLK / 2).
1 System clocks are derived from PLLCLK (Bus Clock = PLLCLK / 2).
6
PSTP
Pseudo-Stop Bit — Write: anytime — This bit controls the functionality of the oscillator during stop mode.
0 Oscillator is disabled in stop mode.
1 Oscillator continues to run in stop mode (pseudo-stop). The oscillator amplitude is reduced. Refer to oscillator
block description for availability of a reduced oscillator amplitude.
Note: Pseudo-stop allows for faster stop recovery and reduces the mechanical stress and aging of the resonator
in case of frequent stop conditions at the expense of a slightly increased power consumption.
Note: Lower oscillator amplitude exhibits lower power consumption but could have adverse effects during any
electro-magnetic susceptibility (EMS) tests.
5
SYSWAI
System Clocks Stop in Wait Mode Bit — Write: anytime
0 In wait mode, the system clocks continue to run.
1 In wait mode, the system clocks stop.
Note: RTI and COP are not affected by SYSWAI bit.
4
ROAWAI
Reduced Oscillator Amplitude in Wait Mode Bit — Write: anytime — Refer to Chapter 5, “Oscillator (OSCV2)”
for availability of a reduced oscillator amplitude. If no such feature exists in the oscillator block then setting this
bit to 1 will not have any effect on power consumption.
0 Normal oscillator amplitude in wait mode.
1 Reduced oscillator amplitude in wait mode.
Note: Lower oscillator amplitude exhibits lower power consumption but could have adverse effects during any
electro-magnetic susceptibility (EMS) tests.
3
PLLWAI
PLL Stops in Wait Mode Bit — Write: anytime — If PLLWAI is set, the CRGV4 will clear the PLLSEL bit before
entering wait mode. The PLLON bit remains set during wait mode but the PLL is powered down. Upon exiting
wait mode, the PLLSEL bit has to be set manually if PLL clock is required.
While the PLLWAI bit is set the AUTO bit is set to 1 in order to allow the PLL to automatically lock on the selected
target frequency after exiting wait mode.
0 PLL keeps running in wait mode.
1 PLL stops in wait mode.
2
CWAI
Core Stops in Wait Mode Bit — Write: anytime
0 Core clock keeps running in wait mode.
1 Core clock stops in wait mode.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 175
4.3.2.7 CRG PLL Control Register (PLLCTL)
This register controls the PLL functionality.
Read: anytime
Write: refer to each bit for individual write conditions
1
RTIWAI
RTI Stops in Wait Mode Bit — Write: anytime
0 RTI keeps running in wait mode.
1 RTI stops and initializes the RTI dividers whenever the part goes into wait mode.
0
COPWAI
COP Stops in Wait Mode Bit — Normal modes: Write once —Special modes: Write anytime
0 COP keeps running in wait mode.
1 COP stops and initializes the COP dividers whenever the part goes into wait mode.
76543210
R
CME PLLON AUTO ACQ
0
PRE PCE SCME
W
Reset11110001
= Unimplemented or Reserved
Figure 4-10. CRG PLL Control Register (PLLCTL)
Table 4-5. PLLCTL Field Descriptions
Field Description
7
CME
Clock Monitor Enable Bit — CME enables the clock monitor. Write anytime except when SCM = 1.
0 Clock monitor is disabled.
1 Clock monitor is enabled. Slow or stopped clocks will cause a clock monitor reset sequence or self-clock
mode.
Note: Operating with CME = 0 will not detect any loss of clock. In case of poor clock quality this could cause
unpredictable operation of the MCU.
Note: In Stop Mode (PSTP = 0) the clock monitor is disabled independently of the CME bit setting and any loss
of clock will not be detected.
6
PLLON
Phase Lock Loop On Bit — PLLON turns on the PLL circuitry. In self-clock mode, the PLL is turned on, but the
PLLON bit reads the last latched value. Write anytime except when PLLSEL = 1.
0 PLL is turned off.
1 PLL is turned on. If AUTO bit is set, the PLL will lock automatically.
5
AUTO
Automatic Bandwidth Control Bit — AUTO selects either the high bandwidth (acquisition) mode or the low
bandwidth (tracking) mode depending on how close to the desired frequency the VCO is running. Write anytime
except when PLLWAI=1, because PLLWAI sets the AUTO bit to 1.
0 Automatic mode control is disabled and the PLL is under software control, using ACQ bit.
1 Automatic mode control is enabled and ACQ bit has no effect.
4
ACQ
Acquisition Bit — Write anytime. If AUTO=1 this bit has no effect.
0 Low bandwidth filter is selected.
1 High bandwidth filter is selected.
Table 4-4. CLKSEL Field Descriptions (continued)
Field Description
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
176 Freescale Semiconductor
4.3.2.8 CRG RTI Control Register (RTICTL)
This register selects the timeout period for the real-time interrupt.
Read: anytime
Write: anytime
NOTE
A write to this register initializes the RTI counter.
2
PRE
RTI Enable during Pseudo-Stop Bit — PRE enables the RTI during pseudo-stop mode. Write anytime.
0 RTI stops running during pseudo-stop mode.
1 RTI continues running during pseudo-stop mode.
Note: If the PRE bit is cleared the RTI dividers will go static while pseudo-stop mode is active. The RTI dividers
will not initialize like in wait mode with RTIWAI bit set.
1
PCE
COP Enable during Pseudo-Stop Bit — PCE enables the COP during pseudo-stop mode. Write anytime.
0 COP stops running during pseudo-stop mode
1 COP continues running during pseudo-stop mode
Note: If the PCE bit is cleared the COP dividers will go static while pseudo-stop mode is active. The COP dividers
will not initialize like in wait mode with COPWAI bit set.
0
SCME
Self-Clock Mode Enable Bit — Normal modes: Write once —Special modes: Write anytime — SCME can not
be cleared while operating in self-clock mode (SCM=1).
0 Detection of crystal clock failure causes clock monitor reset (see Section 4.5.1, “Clock Monitor Reset”).
1 Detection of crystal clock failure forces the MCU in self-clock mode (see Section 4.4.7.2, “Self-Clock Mode”).
76543210
R0
RTR6 RTR5 RTR4 RTR3 RTR2 RTR1 RTR0
W
Reset00000000
= Unimplemented or Reserved
Figure 4-11. CRG RTI Control Register (RTICTL)
Table 4-6. RTICTL Field Descriptions
Field Description
6:4
RTR[6:4]
Real-Time Interrupt Prescale Rate Select Bits — These bits select the prescale rate for the RTI. See Ta b le 4 - 7 .
3:0
RTR[3:0]
Real-Time Interrupt Modulus Counter Select Bits — These bits select the modulus counter target value to
provide additional granularity. Ta ble 4-7 shows all possible divide values selectable by the RTICTL register. The
source clock for the RTI is OSCCLK.
Table 4-5. PLLCTL Field Descriptions (continued)
Field Description
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 177
Table 4-7. RTI Frequency Divide Rates
RTR[3:0]
RTR[6:4] =
000
(OFF)
001
(210)
010
(211)
011
(212)
100
(213)
101
(214)
110
(215)
111
(216)
0000 (÷1) OFF*210 211 212 213 214 215 216
0001 (÷2) OFF*2x210 2x211 2x212 2x213 2x214 2x215 2x216
0010 (÷3) OFF*3x210 3x211 3x212 3x213 3x214 3x215 3x216
0011 (÷4) OFF*4x210 4x211 4x212 4x213 4x214 4x215 4x216
0100 (÷5) OFF*5x210 5x211 5x212 5x213 5x214 5x215 5x216
0101 (÷6) OFF*6x210 6x211 6x212 6x213 6x214 6x215 6x216
0110 (÷7) OFF*7x210 7x211 7x212 7x213 7x214 7x215 7x216
0111 (÷8) OFF*8x210 8x211 8x212 8x213 8x214 8x215 8x216
1000 (÷9) OFF*9x210 9x211 9x212 9x213 9x214 9x215 9x216
1001 (÷10) OFF*10x210 10x211 10x212 10x213 10x214 10x215 10x216
1010 (³÷11) OFF*11x210 11x211 11x212 11x213 11x214 11x215 11x216
1011 (³÷12) OFF*12x210 12x211 12x212 12x213 12x214 12x215 12x216
1100 (÷³13) OFF*13x210 13x211 13x212 13x213 13x214 13x215 13x216
1101 (÷14) OFF*14x210 14x211 14x212 14x213 14x214 14x215 14x216
1110 (³÷15) OFF*15x210 15x211 15x212 15x213 15x214 15x215 15x216
1111 (÷³16) OFF*16x210 16x211 16x212 16x213 16x214 16x215 16x216
* Denotes the default value out of reset.This value should be used to disable the RTI to ensure future backwards compatibility.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
178 Freescale Semiconductor
4.3.2.9 CRG COP Control Register (COPCTL)
This register controls the COP (computer operating properly) watchdog.
Read: anytime
Write: WCOP, CR2, CR1, CR0: once in user mode, anytime in special mode
Write: RSBCK: once
76543210
RWCOP RSBCK 000
CR2 CR1 CR0
W
Reset00000000
= Unimplemented or Reserved
Figure 4-12. CRG COP Control Register (COPCTL)
Table 4-8. COPCTL Field Descriptions
Field Description
7
WCOP
Window COP Mode Bit — When set, a write to the ARMCOP register must occur in the last 25% of the selected
period. A write during the first 75% of the selected period will reset the part. As long as all writes occur during
this window, 0x0055 can be written as often as desired. As soon as 0x00AA is written after the 0x0055, the
time-out logic restarts and the user must wait until the next window before writing to ARMCOP. Ta b l e 4 - 9 shows
the exact duration of this window for the seven available COP rates.
0 Normal COP operation
1 Window COP operation
6
RSBCK
COP and RTI Stop in Active BDM Mode Bit
0 Allows the COP and RTI to keep running in active BDM mode.
1 Stops the COP and RTI counters whenever the part is in active BDM mode.
2:0
CR[2:0]
COP Watchdog Timer Rate Select — These bits select the COP time-out rate (see Tabl e 4 -9). The COP
time-out period is OSCCLK period divided by CR[2:0] value. Writing a nonzero value to CR[2:0] enables the COP
counter and starts the time-out period. A COP counter time-out causes a system reset. This can be avoided by
periodically (before time-out) reinitializing the COP counter via the ARMCOP register.
Table 4-9. COP Watchdog Rates1
1OSCCLK cycles are referenced from the previous COP time-out reset
(writing 0x0055/0x00AA to the ARMCOP register)
CR2 CR1 CR0 OSCCLK
Cycles to Time Out
0 0 0 COP disabled
001 2
14
010 2
16
011 2
18
100 2
20
101 2
22
110 2
23
111 2
24
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 179
4.3.2.10 Reserved Register (FORBYP)
NOTE
This reserved register is designed for factory test purposes only, and is not
intended for general user access. Writing to this register when in special
modes can alter the CRG’s functionality.
Read: always read 0x0000 except in special modes
Write: only in special modes
4.3.2.11 Reserved Register (CTCTL)
NOTE
This reserved register is designed for factory test purposes only, and is not
intended for general user access. W riting to this register when in special test
modes can alter the CRG’s functionality.
Read: always read 0x0080 except in special modes
Write: only in special modes
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 4-13. Reserved Register (FORBYP)
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 4-14. Reserved Register (CTCTL)
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
180 Freescale Semiconductor
4.3.2.12 CRG COP Timer Arm/Reset Register (ARMCOP)
This register is used to restart the COP time-out period.
Read: always reads 0x0000
Write: anytime
When the COP is disabled (CR[2:0] = “000”) writing to this register has no effect.
When the COP is enabled by setting CR[2:0] nonzero, the following applies:
Writing any value other than 0x0055 or 0x00AA causes a COP reset. To restart the COP time-out
period you must write 0x0055 followed by a write of 0x00AA. Other instructions may be executed
between these writes but the sequence (0x0055, 0x00AA) must be completed prior to COP end of
time-out period to avoid a COP reset. Sequences of 0x0055 writes or sequences of 0x00AA writes
are allowed. When the WCOP bit is set, 0x0055 and 0x00AA writes must be done in the last 25%
of the selected time-out period; writing any value in the first 75% of the selected period will cause
a COP reset.
4.4 Functional Description
This section gives detailed informations on the internal operation of the design.
4.4.1 Phase Locked Loop (PLL)
The PLL is used to run the MCU from a different time base than the incoming OSCCLK. For increased
flexibility, OSCCLK can be divided in a range of 1 to 16 to generate the reference frequency. This of fers
a finer multiplication granularity. The PLL can multiply this reference clock by a multiple of 2, 4, 6,...
126,128 based on the SYNR register.
CAUTION
Although it is possible to set the two dividers to command a very high clock
frequency, do not exceed the specified bus frequency limit for the MCU.
If (PLLSEL = 1), Bus Clock = PLLCLK / 2
The PLL is a frequency generator that operates in either acquisition mode or tracking mode, depending on
the difference between the output frequency and the target frequency. The PLL can change between
acquisition and tracking modes either automatically or manually.
76543210
R00000000
WBit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
Reset00000000
Figure 4-15. ARMCOP Register Diagram
PLLCLK 2 OSCCLK SYNR 1+[]
REFDV 1+[]
-----------------------------------
××=
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 181
The VCO has a minimum operating frequency, which corresponds to the self-clock mode frequency fSCM.
Figure 4-16. PLL Functional Diagram
4.4.1.1 PLL Operation
The oscillator output clock signal (OSCCLK) is fed through the reference programmable divider and is
divided in a range of 1 to 16 (REFDV+1) to output the reference clock. The VCO output clock, (PLLCLK)
is fed back through the programmable loop divider and is divided in a range of 2 to 128 in increments of
[2 x (SYNR +1)] to output the feedback clock. See Figure 4-16.
The phase detector then compares the feedback clock, with the reference clock. Correction pulses are
generated based on the phase difference between the two signals. The loop filter then slightly alters the DC
voltage on the external filter capacitor connected to XFC pin, based on the width and direction of the
correction pulse. The filter can make fast or slow corrections depending on its mode, as described in the
next subsection. The values of the external filter network and the reference frequency determine the speed
of the corrections and the stability of the PLL.
4.4.1.2 Acquisition and Tracking Modes
The lock detector compares the frequencies of the feedback clock, and the reference clock. Therefore, the
speed of the lock detector is directly proportional to the final reference frequency. The circuit determines
the mode of the PLL and the lock condition based on this comparison.
REDUCED
CONSUMPTION
OSCILLATOR
EXTAL
XTAL
OSCCLK
PLLCLK
REFERENCE
PROGRAMMABLE
DIVIDER PDET
PHASE
DETECTOR
REFDV <3:0>
LOOP
PROGRAMMABLE
DIVIDER
SYN <5:0>
CPUMP VCO
LOCK
LOOP
FILTER
XFC
PIN
UP
DOWN
LOCK
DETECTOR
REFERENCE
FEEDBACK
VDDPLL
VDDPLL/VSSPLL
CRYSTAL
MONITOR
VDDPLL/VSSPLL
VDD/VSS
supplied by:
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
182 Freescale Semiconductor
The PLL filter can be manually or automatically configured into one of two possible operating modes:
• Acquisition mode
In acquisition mode, the filter can make large frequency corrections to the VCO. This mode is used
at PLL start-up or when the PLL has suffered a severe noise hit and the VCO frequency is far off
the desired frequency. When in acquisition mode, the TRACK status bit is cleared in the CRGFLG
register.
• Tracking mode
In tracking mode, the filter makes only small corrections to the frequency of the VCO. PLL jitter
is much lower in tracking mode, but the response to noise is also slower. The PLL enters tracking
mode when the VCO frequency is nearly correct and the TRACK bit is set in the CRGFLG register.
The PLL can change the bandwidth or operational mode of the loop filter manually or automatically.
In automatic bandwidth control mode (AUTO = 1), the lock detector automatically switches between
acquisition and tracking modes. Automatic bandwidth control mode also is used to determine when the
PLL clock (PLLCLK) is safe to use as the source for the system and core clocks. If PLL LOCK interrupt
requests are enabled, the software can wait for an interrupt request and then check the LOCK bit. If CPU
interrupts are disabled, software can poll the LOCK bit continuously (during PLL start-up, usually) or at
periodic intervals. In either case, only when the LOCK bit is set, is the PLLCLK clock safe to use as the
source for the system and core clocks. If the PLL is selected as the source for the system and core clocks
and the LOCK bit is clear, the PLL has suf fered a severe no ise hit and the s oftware must tak e appropriate
action, depending on the application.
The following conditions apply when the PLL is in automatic bandwidth control mode (AUTO = 1):
• The TRACK bit is a read-only indicator of the mode of the filter.
• The TRACK bit is set when the VCO frequency is within a certain tolerance, ∆trk, and is clear when
the VCO frequency is out of a certain tolerance, ∆unt.
• The LOCK bit is a read-only indicator of the locked state of the PLL.
• The LOCK bit is set when the VCO frequency is within a certain tolerance, ∆Lock, and is cleared
when the VCO frequency is out of a certain tolerance, ∆unl.
• CPU interrupts can occur if enabled (LOCKIE = 1) when the lock condition changes, toggling the
LOCK bit.
The PLL can also operate in manual mode (AUTO = 0). Manual mode is used by systems that do not
require an indicator of the lock condition for proper operation. Such systems typicall y operate well below
the maximum system frequency (fsys) and require fast start-up. The following conditions apply when in
manual mode:
• ACQ is a writable control bit that controls the mode of the filter. Before turning on the PLL in
manual mode, the ACQ bit should be asserted to configure the filter in acquisition mode.
• After turning on the PLL by setting the PLLON bit software must wait a given time (tacq) before
entering tracking mode (ACQ = 0).
• After entering tracking mode software must wait a given time (tal) before selecting the PLLCLK
as the source for system and core clocks (PLLSEL = 1).
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 183
4.4.2 System Clocks Generator
Figure 4-17. System Clocks Generator
The clock generator creates the clocks used in the MCU (see Figure 4-17). The gating condition placed on
top of the individual clock gates indicates the dependencies of dif ferent modes (stop, wait) and the setting
of the respective configuration bits.
The peripheral modules use the bus clock. Some peripheral modules also use the oscillator clock. The
memory blocks use the bus clock. If the MCU enters self-clock mode (see Section 4.4.7.2, “Self-Clock
Mode”), oscillator clock source is switched to PLLCLK running at its minimum frequency fSCM. The bus
clock is used to generate the clock visible at the ECLK pin. The core clock signal is the clock for the CPU.
The core clock is twice the bus clock as shown in Figure 4-18. But note that a CPU cycle corresponds to
one bus clock.
PLL clock mode is selected with PLLSEL bit in the CLKSEL register. When selected, the PLL output
clock drives SYSCLK for the main system including the CPU and peripherals. The PLL cannot be turned
off by clearing the PLLON bit, if the PLL clock is selected. When PLLSEL is changed, it takes a maximum
OSCILLATOR
PHASE
LOCK
LOOP
EXTAL
XTAL
SYSCLK
RTI
OSCCLK
PLLCLK
CLOCK PHASE
GENERATOR
Bus Clock
Clock
Monitor
1
0
PLLSEL or SCM
÷2
Core Clock
COP
Oscillator
Oscillator
= Clock Gate
Gating
Condition
WAIT(CWAI,SYSWAI),
STOP
WAIT(RTIWAI),
STOP(PSTP
,PRE),
RTI enable
WAIT(COPWAI),
STOP(PSTP
,PCE),
COP enable
WAIT(SYSWAI),
STOP
STOP(PSTP)
1
0
SCM
WAIT(SYSWAI),
STOP
Clock
Clock
(running during
Pseudo-Stop Mode
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
184 Freescale Semiconductor
of 4 OSCCLK plus 4 PLLCLK cycles to make the transition. During the transition, all clocks freeze and
CPU activity ceases.
Figure 4-18. Core Clock and Bus Clock Relationship
4.4.3 Clock Monitor (CM)
If no OSCCLK edges are detected within a certain time, the clock monitor within the oscillator block
generates a clock monitor fail event. The CRGV4 then asserts self-clock mode or generates a system reset
depending on the state of SCME bit. If the clock monitor is disabled or the presence of clocks is detected
no failure is indicated by the oscillator block.The clock monitor function is enabled/disabled by the CME
control bit.
4.4.4 Clock Quality Checker
The clock monitor performs a coarse check on the incoming clock signal. The clock quality checker
provides a more accurate check in addition to the clock monitor.
A clock quality check is triggered by any of the following events:
• Power-on reset (POR)
• Low voltage reset (LVR)
• Wake-up from full stop mode (exit full stop)
• Clock monitor fail indication (CM fail)
A time window of 50000 VCO clock cycles1 is called check window.
A number greater equal than 4096 rising OSCCLK edges within a check window is called osc ok. Note that
osc ok immediately terminates the current check window. See Figure 4-19 as an example.
1. VCO clock cycles are generated by the PLL when running at minimum frequency fSCM.
CORE CLOCK:
BUS CLOCK / ECLK
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 185
Figure 4-19. Check Window Example
The sequence for clock quality check is shown in Figure 4-20.
Figure 4-20. Sequence for Clock Quality Check
NOTE
Remember that in parallel to additional actions caused by self-clock mode
or clock monitor reset1 handling the clock quality checker continues to
check the OSCCLK signal.
1. A Clock Monitor Reset will always set the SCME bit to logical’1’
12 49999 50000
VCO
clock
check window
12345
4095
4096
3
OSCCLK
osc ok
check window
osc ok
?
SCM
active? Switch to OSCCLK
Exit SCM
Clock OK
num=0
num<50
?
num=num+1
yes
no
yes
SCME=1
?
no
Enter SCM
SCM
active?
yes
Clock Monitor Reset
no
yes
no
num=50
yes
no
POR exit full stop
CM fail
LVR
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
186 Freescale Semiconductor
NOTE
The clock quality checker enables the PLL and the voltage regulator
(VREG) anytime a clock check has to be performed. An ongoing clock
quality check could also cause a running PLL (fSCM) and an active VREG
during pseudo-stop mode or wait mode
4.4.5 Computer Operating Properly Watchdog (COP)
Figure 4-21. Clock Chain for COP
The COP (free running watchdog timer) enables the user to check that a program is running and
sequencing properly. The COP is disabled out of reset. When the COP is being used, software is
responsible for keeping the COP from timing out. If the COP times out it is an indication that the software
is no longer being executed in the intended sequence; thus a system reset is initiated (see Section 4.5.2,
“Computer Operating Properly Watchdog (COP) Reset).” The COP runs with a gated OSCCLK (see
Figure 4-21). Three control bits in the COPCTL register allow selection of seven COP time-out periods.
When COP is enabled, the program must write 0x0055 and 0x00AA (in this order) to the ARMCOP
register during the selected time-out period. As soon as this is done, the COP time-out period is restarted.
If the program fails to do this and the COP times out, the part will reset. Also, if any value other than
0x0055 or 0x00AA is written, the part is immediately reset.
Windowed COP operation is enabled by setting WCOP in the COPCTL register. In this mode, writes to
the ARMCOP register to clear the COP timer must occur in the last 25% of the selected time-out period.
A premature write will immediately reset the part.
If PCE bit is set, the COP will continue to run in pseudo-stop mode.
OSCCLK
CR[2:0]
COP TIMEOUT
0:0:0
0:0:1
0:1:0
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
÷ 4
÷ 4
÷ 2
÷ 4
÷ 2
÷
16384
÷
4
CR[2:0]
= Clock Gate
WAIT(COPWAI),
STOP(PSTP
,PCE),
COP enable
gating condition
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 187
4.4.6 Real-Time Interrupt (RTI)
The RTI can be used to generate a hardware interrupt at a fixed periodic rate. If enabled (by setting
RTIE=1), this interrupt will occur at the rate selected by the RTICTL register. The RTI runs with a gated
OSCCLK (see Figure 4-22). At the end of the RTI time-out period the RTIF flag is set to 1 and a new RTI
time-out period starts immediately.
A write to the RTICTL register restarts the RTI time-out period.
If the PRE bit is set, the RTI will continue to run in pseudo-stop mode.
.
Figure 4-22. Clock Chain for RTI
4.4.7 Modes of Operation
4.4.7.1 Normal Mode
The CRGV4 block behaves as described within this specification in all normal modes.
4.4.7.2 Self-Clock Mode
The VCO has a minimum operating frequency, fSCM. If the external clock frequency is not available due
to a failure or due to long crystal start-up time, the bus clock and the core clock are derived from the VCO
OSCCLK
RTR[6:4]
0:0:0
0:0:1
0:1:0
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
÷ 2
÷ 2
÷ 2
÷ 2
÷ 2
÷ 2
COUNTER (RTR[3:0])
4-BIT MODULUS
÷ 1024
RTI TIMEOUT
= Clock Gate
WAIT(RTIWAI),
STOP(PSTP
,PRE),
RTI enable
gating condition
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
188 Freescale Semiconductor
running at minimum operating frequency; this mode of operation is called self-clock mode. This requires
CME = 1 and SCME = 1. If the MCU was clocked by the PLL clock prior to entering self-clock mode, the
PLLSEL bit will be cleared. If the external clock signal has stabilized again, the CRG will automatically
select OSCCLK to be the system clock and return to normal mode. See Section 4.4.4, “Clock Quality
Checker” for more information on entering and leaving self-clock mode.
NOTE
In order to detect a potential clock loss, the CME bit should be always
enabled (CME=1).
If CME bit is disabled and the MCU is configured to run on PLL clock
(PLLCLK), a loss of external clock (OSCCLK) will not be detected and will
cause the system clock to drift towards the VCO’s minimum frequency
fSCM. As soon as the external clock is available again the system clock
ramps up to its PLL target frequency. If the MCU is running on external
clock any loss of clock will cause the system to go static.
4.4.8 Low-Power Operation in Run Mode
The RTI can be stopped by setting the associated rate select bits to 0.
The COP can be stopped by setting the associated rate select bits to 0.
4.4.9 Low-Power Operation in Wait Mode
The WAI instruction puts the MCU in a low power consumption stand-by mode depending on setting of
the individual bits in the CLKSEL register. All individual wait mode configuration bits can be superposed.
This provides enhanced granularity in reducing the level of power consumption during wait mode.
Table 4-10 lists the individual configuration bits and the parts of the MCU that are affected in wait mode.
After executing the WAI instruction the core requests the CRG to switch MCU into wait mode. The CRG
then checks whether the PLLWAI, CWAI and SYSWAI bits are asserted (see Figure 4-23). Depending on
the configuration the CRG switches the system and core clocks to OSCCLK by clearing the PLLSEL bit,
disables the PLL, disables the core clocks and finally disables the remaining system clocks. As soon as all
clocks are switched off wait mode is active.
Table 4-10. MCU Configuration During Wait Mode
PLLWAI CWAI SYSWAI RTIWAI COPWAI ROAWAI
PLL stopped —————
Core — stopped stopped — — —
System — — stopped — — —
RTI ———stopped——
COP ————stopped—
Oscillator —————reduced
1
1Refer to oscillator block description for availability of a reduced oscillator amplitude.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 189
Figure 4-23. Wait Mode Entry/Exit Sequence
Enter
Wait Mode
PLLWAI=1
?
Exit Wait w.
CMRESET
Exit Wait w.
ext.RESET
Exit
Wait Mode
Enter
SCM
Exit
Wait Mode
Core req’s
Wait Mode.
CWAI or
SYSWAI=1
?
SYSWAI=1
?
Clear PLLSEL,
Disable PLL
Disable
core clocks
Disable
system clocks CME=1
?
INT
?
CM fail
?
SCME=1
?
SCMIE=1
?
Continue w.
normal OP
no
no
no
no
no
no
no
yes
yes
yes
yes
yes
no
yes
yes
yes
Wait Mode left
due to external
reset
Generate
SCM Interrupt
(Wakeup from Wait) SCM=1
?
Enter
SCM
no
yes
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
190 Freescale Semiconductor
There are five different scenarios for the CRG to restart the MCU from wait mode:
• External reset
• Clock monitor reset
•COP reset
• Self-clock mode interrupt
• Real-time interrupt (RTI)
If the MCU gets an external reset during wait mode active, the CRG asynchronously restores all
configuration bits in the register space to its default settings and starts the reset generator. After completing
the reset sequence processing begins by fetching the normal reset vector. W ait mode is exited and the MCU
is in run mode again.
If the clock monitor is enabled (CME=1) the MCU is able to leave wait mode when loss of
oscillator/external clock is detected by a clock monitor fail. If the SCME bit is not asserted the CRG
generates a clock monitor fail reset (CMRESET). The CRG’s behavior for CMRESET is the same
compared to external reset, but another reset vector is fetched after completion of the reset sequence. If the
SCME bit is asserted the CRG generates a SCM interrupt if enabled (SCMIE=1). After generating the
interrupt the CRG enters self-clock mode and starts the clock quality checker (see Section 4.4.4, “Clock
Quality Checker”). Then the MCU continues with normal operation.If the SCM interrupt is blocked by
SCMIE = 0, the SCMIF flag will be asserted and clock quality checks will be performed but the MCU will
not wake-up from wait mode.
If any other interrupt source (e.g. RTI) triggers exit from wait mode the MCU immediately continues with
normal operation. If the PLL has been powered-down during wait mode the PLLSEL bit is cleared and the
MCU runs on OSCCLK after leaving wait mode. The software must manually set the PLLSEL bit again,
in order to switch system and core clocks to the PLLCLK.
If wait mode is entered from self-clock mode, the CRG will continue to check the clock quality until clock
check is successful. The PLL and voltage regulator (VREG) will remain enabled.
Table 4-11 summarizes the outcome of a clock loss while in wait mode.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 191
Table 4-11. Outcome of Clock Loss in Wait Mode
CME SCME SCMIE CRG Actions
0 X X Clock failure -->
No action, clock loss not detected.
1 0 X Clock failure -->
CRG performs Clock Monitor Reset immediately
1 1 0 Clock failure -->
Scenario 1: OSCCLK recovers prior to exiting Wait Mode.
– MCU remains in Wait Mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– Set SCMIF interrupt flag.
Some time later OSCCLK recovers.
– CM no longer indicates a failure,
– 4096 OSCCLK cycles later Clock Quality Check indicates clock o.k.,
– SCM deactivated,
– PLL disabled depending on PLLWAI,
– VREG remains enabled (never gets disabled in Wait Mode).
– MCU remains in Wait Mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit Wait Mode using OSCCLK as system clock (SYSCLK),
– Continue normal operation.
or an External Reset is applied.
– Exit Wait Mode using OSCCLK as system clock,
– Start reset sequence.
Scenario 2: OSCCLK does not recover prior to exiting Wait Mode.
– MCU remains in Wait Mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– Set SCMIF interrupt flag,
– Keep performing Clock Quality Checks (could continue infinitely)
while in Wait Mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit Wait Mode in SCM using PLL clock (fSCM) as system clock,
– Continue to perform additional Clock Quality Checks until OSCCLK
is o.k. again.
or an External RESET is applied.
– Exit Wait Mode in SCM using PLL clock (fSCM) as system clock,
– Start reset sequence,
– Continue to perform additional Clock Quality Checks until OSCCLK
is o.k.again.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
192 Freescale Semiconductor
4.4.10 Low-Power Operation in Stop Mode
All clocks are stopped in STOP mode, dependent of the setting of the PCE, PRE and PSTP bit. The
oscillator is disabled in STOP mode unless the PSTP bit is set. All counters and dividers remain frozen but
do not initialize. If the PRE or PCE bits are set, the RTI or COP continues to run in pseudo-stop mode. In
addition to disabling system and core clocks the CRG requests other functional units of the MCU (e.g.
voltage-regulator) to enter their individual power-saving modes (if available). This is the main dif ference
between pseudo-stop mode and wait mode.
After executing the STOP instructi on the core requests the CRG to switch the MCU into stop mode. If the
PLLSEL bit remains set when entering stop mode, the CRG will switch the system and core clocks to
OSCCLK by clearing the PLLSEL bit. Then the CRG disables the PLL, disables the core clock and finally
disables the remaining system clocks. As soon as all clocks are switched off, stop mode is active.
If pseudo-stop mode (PSTP = 1) is entered from self-clock mode the CRG will continue to check the clock
quality until clock check is successful. The PLL and the voltage regulator (VREG) will remain ena bled. If
full stop mode (PSTP = 0) is entered from self-clock mode an ongoing clock quality check will be stopped.
A complete timeout window check will be started when stop mode is exited again.
Wake-up from stop mode also depends on the setting of the PSTP bit.
1 1 1 Clock failure -->
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– SCMIF set.
SCMIF generates Self-Clock Mode wakeup interrupt.
– Exit Wait Mode in SCM using PLL clock (fSCM) as system clock,
– Continue to perform a additional Clock Quality Checks until OSCCLK
is o.k. again.
Table 4-11. Outcome of Clock Loss in Wait Mode (continued)
CME SCME SCMIE CRG Actions
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 193
Figure 4-24. Stop Mode Entry/Exit Sequence
Exit Stop w.
CMRESET
Exit
Stop Mode
Enter
SCM
Exit
Stop Mode
Core req’s
Stop Mode.
Clear
PLLSEL,
Disable PLL
CME=1
?
INT
?
CM fail
?
SCME=1
?
SCMIE=1
?
Continue w.
normal OP
no
no
no
no
yes
yes
yes
yes
yes
Generate
SCM Interrupt
(Wakeup from Stop)
Enter
Stop Mode
Exit Stop w.
ext.RESET
Wait Mode left
due to external
Clock
OK
?
SCME=1
?
Enter
SCM
yes
no
yes
Exit Stop w.
CMRESET no
no
no PSTP=1
?
INT
?
yesno
yes
Exit
Stop Mode
Exit
Stop Mode
SCM=1
?
Enter
SCM
no
yes
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
194 Freescale Semiconductor
4.4.10.1 Wake-Up from Pseudo-Stop (PSTP=1)
Wake-up from pseudo-stop is the same as wake-up from wait mode. There are also three different
scenarios for the CRG to restart the MCU from pseudo-stop mode:
• External reset
• Clock monitor fail
• Wake-up interrupt
If the MCU gets an external reset during pseudo-stop mode active, the CRG asynchronously restores all
configuration bits in the register space to its default settings and starts the reset generator. After completing
the reset sequence processing begins by fetching the normal reset vector. Pseudo-stop mode is exited and
the MCU is in run mode again.
If the clock monitor is enabled (CME = 1) the MCU is able to leave pseudo-stop mode when loss of
oscillator/external clock is detected by a clock monitor fail. If the SCME bit is not asserted the CRG
generates a clock monitor fail reset (CMRESET). The CRG’s behavior for CMRESET is the same
compared to external reset, but another reset vector is fetched after completion of the reset sequence. If the
SCME bit is asserted the CRG generates a SCM interrupt if enabled (SCMIE=1). After generating the
interrupt the CRG enters self-clock mode and starts the clock quality checker (see Section 4.4.4, “Clock
Quality Checker”). Then the MCU continues with normal operation. If the SCM interrupt is blocked by
SCMIE = 0, the SCMIF flag will be asserted but the CRG will not wake-up from pseudo-stop mode.
If any other interrupt source (e.g. RTI) triggers exit from pseudo-stop mode the MCU immediately
continues with normal operation. Because the PLL has been powered-down during stop mode the PLLSEL
bit is cleared and the MCU runs on OSCCLK after leaving stop mode. The software must set the PLLSEL
bit again, in order to switch system and core clocks to the PLLCLK.
Table 4-12 summarizes the outcome of a clock loss while in pseudo-stop mode.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 195
Table 4-12. Outcome of Clock Loss in Pseudo-Stop Mode
CME SCME SCMIE CRG Actions
0 X X Clock failure -->
No action, clock loss not detected.
1 0 X Clock failure -->
CRG performs Clock Monitor Reset immediately
1 1 0 Clock Monitor failure -->
Scenario 1: OSCCLK recovers prior to exiting Pseudo-Stop Mode.
– MCU remains in Pseudo-Stop Mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– Set SCMIF interrupt flag.
Some time later OSCCLK recovers.
– CM no longer indicates a failure,
– 4096 OSCCLK cycles later Clock Quality Check indicates clock o.k.,
– SCM deactivated,
– PLL disabled,
– VREG disabled.
– MCU remains in Pseudo-Stop Mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit Pseudo-Stop Mode using OSCCLK as system clock (SYSCLK),
– Continue normal operation.
or an External Reset is applied.
– Exit Pseudo-Stop Mode using OSCCLK as system clock,
– Start reset sequence.
Scenario 2: OSCCLK does not recover prior to exiting Pseudo-Stop Mode.
– MCU remains in Pseudo-Stop Mode,
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– Set SCMIF interrupt flag,
– Keep performing Clock Quality Checks (could continue infinitely)
while in Pseudo-Stop Mode.
Some time later either a wakeup interrupt occurs (no SCM interrupt)
– Exit Pseudo-Stop Mode in SCM using PLL clock (fSCM) as system clock
– Continue to perform additional Clock Quality Checks until OSCCLK
is o.k. again.
or an External RESET is applied.
– Exit Pseudo-Stop Mode in SCM using PLL clock (fSCM) as system clock
– Start reset sequence,
– Continue to perform additional Clock Quality Checks until OSCCLK
is o.k.again.
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
196 Freescale Semiconductor
4.4.10.2 Wake-up from Full Stop (PSTP=0)
The MCU requires an external interrupt or an external reset in order to wake-up from stop mode.
If the MCU gets an external reset during full stop mode active, the CRG asynchronously restores all
configuration bits in the register space to its default settings and will perform a maximum of 50 clock
check_windows (see Section 4.4.4, “Clock Quality Checker”). After completing the clock quality check
the CRG starts the reset generator. After completing the reset sequence processing begins by fetching the
normal reset vector. Full stop mode is exited and the MCU is in run mode again.
If the MCU is woken-up by an interrupt, the CRG will also perform a maximum of 50 clock
check_windows (see Section 4.4.4, “Clock Quality Checker”). If the clock quality check is succes sful, the
CRG will release all system and core clocks and will continue with normal operation. If all clock checks
within the timeout-window are failing, the CRG will switch to self-clock mode or generate a clock monitor
reset (CMRESET) depending on the setting of the SCME bit.
Because the PLL has been powered-down during stop mode the PLLSEL bit is cleared and the MCU runs
on OSCCLK after leaving stop mode. The software must manually set the PLLSEL bit again, in order to
switch system and core clocks to the PLLCLK.
NOTE
In full stop mode, the clock monitor is disabled and any loss of clock will
not be detected.
4.5 Resets
This section describes how to reset the CRGV4 and how the CRGV4 itself controls the reset of the MCU.
It explains all special reset requirements. Because the reset gene rator for the MCU is part of the CRG, this
section also describes all automatic actions that occur during or as a result of individual reset conditions.
The reset values of registers and signals are provided in Section 4.3, “Memory Map and Register
1 1 1 Clock failure -->
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– SCMIF set.
SCMIF generates Self-Clock Mode wakeup interrupt.
– Exit Pseudo-Stop Mode in SCM using PLL clock (fSCM) as system clock,
– Continue to perform a additional Clock Quality Checks until OSCCLK
is o.k. again.
Table 4-12. Outcome of Clock Loss in Pseudo-Stop Mode (continued)
CME SCME SCMIE CRG Actions
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 197
Definition.” All reset sources are listed in Table 4-13. Refer to Chapter 1, “MC9S12E256 Device
Overview (MC9S12E256DGV1)” for related vector addresses and priorities.
The reset sequence is initiated by any of the following events:
• Low level is detected at the RESET pin (external reset).
• Power on is detected.
• Low voltage is detected.
• COP watchdog times out.
• Clock monitor failure is detected and self-clock mode was disabled (SCME = 0).
Upon detection of any reset event, an internal circuit drives the RESET pin low for 128 SYSCLK cycles
(see Figure 4-25). Because entry into reset is asynchronous it does not require a running SYSCLK.
However , the internal reset circuit of the CRGV4 cannot sequence out of current reset condition without a
running SYSCLK. The number of 128 SYSCLK cycles might be increased by n = 3 to 6 additional
SYSCLK cycles depending on the internal synchronization latency. After 128+n SYSCLK cycles the
RESET pin is released. The reset generator of the CRGV4 waits for additional 64 SYSCLK cycles and
then samples the RESET pin to determine the originating source. Table 4-14 shows which vector will be
fetched.
NOTE
External circuitry connected to the RESET pin should not include a large
capacitance that would interfere with the ability of this signal to rise to a
valid logic 1 within 64 SYSCLK cycles after the low drive is released.
Table 4-13. Reset Summary
Reset Source Local Enable
Power-on Reset None
Low Voltage Reset None
External Reset None
Clock Monitor Reset PLLCTL (CME=1, SCME=0)
COP Watchdog Reset COPCTL (CR[2:0] nonzero)
Table 4-14. Reset Vector Selection
Sampled RESET Pin
(64 Cycles After
Release)
Clock Monitor
Reset Pending
COP Reset
Pending Vector Fetch
1 0 0 POR / LVR / External Reset
1 1 X Clock Monitor Reset
1 0 1 COP Reset
0 X X POR / LVR / External Reset
with rise of RESET pin
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
198 Freescale Semiconductor
The internal reset of the MCU remains asserted while the reset generator completes the 192 SYSCLK long
reset sequence. The reset generator circuitry always makes sure the internal reset is deasserted
synchronously after completion of the 192 SYSCLK cycles. In case the RESET pin is externally driven
low for more than these 192 SYSCLK cycles (external reset), the internal reset remains asserted too.
Figure 4-25. RESET Timing
4.5.1 Clock Monitor Reset
The CRGV4 generates a clock monitor reset in case all of the following conditions are true:
• Clock monitor is enabled (CME=1)
• Loss of clock is detected
• Self-clock mode is disabled (SCME=0)
The reset event asynchronously forces the configuration registers to their default settings (see Section 4.3,
“Memory Map and Register Definition”). In detail the CME and the SCME are reset to logic al ‘1’ (which
doesn’t change the state of the CME bit, because it has already been set). As a consequence, the CRG
immediately enters self-clock mode and starts its internal reset sequence. In parallel the clock quality
check starts. As soon as clock quality check indicates a valid oscillator clock the CRG switches to
OSCCLK and leaves self-clock mode. Because the clock quality checker is running in parallel to the r eset
generator, the CRG may leave self-clock mode while completing the internal reset sequence. When the
reset sequence is finished the CRG checks the internally latched state of the clock monitor fail circuit. If a
clock monitor fail is indicated processing begins by fetching the clock monitor reset vector.
4.5.2 Computer Operating Properly Watchdog (COP) Reset
When COP is enabled, the CRG expects sequential write of 0x0055 and 0x00AA (in this order) to the
ARMCOP register during the selected time-out period. As soon as this is done, the COP time-out period
restarts. If the program fails to do this the CRG will generate a reset. Also, if any value other than 0x0055
or 0x00AA is written, the CRG immediately generates a reset. In case windowed COP operation is enabled
) ( ) (
)
(
)
SYSCLK
128+n cycles 64 cycles
with n being
min 3 / max 6
cycles depending
on internal
synchronization
delay
CRG drives RESET pin low
possibly
SYSCLK
not
running
possibly
RESET
driven low
externally
)
(
(
RESET
RESET pin
released
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 199
writes (0x0055 or 0x00AA) to the ARMCOP register must occur in the last 25% of the selected time-out
period. A premature write the CRG will immediately generate a reset.
As soon as the reset sequence is completed the reset generator checks the reset condition. If no clock
monitor failure is indicated and the latched state of the COP timeout is true, processing begins by fetching
the COP vector.
4.5.3 Power-On Reset, Low Voltage Reset
The on-chip voltage regulator detects when VDD to the MCU has reached a certain level and asserts
power -on reset or low voltage reset or both. As soon as a power -on reset or low voltage reset is triggered
the CRG performs a quality check on the incoming clock signal. As soon as clock quality check indicates
a valid oscillator clock signal the reset sequence starts using the oscillator clock. If after 50 check windows
the clock quality check indicated a non-valid oscillator clock the reset sequence starts using self-clock
mode.
Figure 4-26 and Figure 4-27 show the power-up sequence for cases when the RESET pin is tied to VDD
and when the RESET pin is held low.
Figure 4-26. RESET Pin Tied to VDD (by a Pull-Up Resistor)
Figure 4-27. RESET Pin Held Low Externally
RESET
Internal POR
128 SYSCLK
64 SYSCLK
Internal RESET
Clock Quality Check
(no Self-Clock Mode)
) (
) (
) (
Clock Quality Check
RESET
Internal POR
Internal RESET
128 SYSCLK
64 SYSCLK
(no Self-Clock Mode)
) (
) (
) (
Chapter 4 Clocks and Reset Generator (CRGV4)
MC9S12E256 Data Sheet, Rev. 1.08
200 Freescale Semiconductor
4.6 Interrupts
The interrupts/reset vectors requested by the CRG are listed in Table 4-15. Refer to Chapter 1,
“MC9S12E256 Device Overview (MC9S12E256DGV1)” for related vector addresses and priorities.
4.6.1 Real-Time Interrupt
The CRGV4 generates a real-time interrupt when the selected interrupt time period elapses. RTI interrupts
are locally disabled by setting the RTIE bit to 0. The real-time interrupt flag (RTIF) is set to 1 when a
timeout occurs, and is cleared to 0 by writing a 1 to the RTIF bit.
The RTI continues to run during pseudo-stop mode if the PRE bit is set to 1. This feature can be used for
periodic wakeup from pseudo-stop if the RTI interrupt is enabled.
4.6.2 PLL Lock Interrupt
The CRGV4 generates a PLL lock interrupt when the LOCK condition of the PLL has changed, either
from a locked state to an unlocked state or vice versa. Lock interrupts are locally disabled by setting the
LOCKIE bit to 0. The PLL Lock interrupt flag (LOCKIF) is set to1 when the LOCK condition has
changed, and is cleared to 0 by writing a 1 to the LOCKIF bit.
4.6.3 Self-Clock Mode Interrupt
The CRGV4 generates a self-clock mode interrupt when the SCM condition of the system has changed,
either entered or exited self-clock mode. SCM conditions can only change if the self-clock mode enable
bit (SCME) is set to 1. SCM conditions are caused by a failing clock quality check after power-on reset
(POR) or low voltage reset (LVR) or recovery from full stop mode (PSTP = 0) or clock monitor failure.
For details on the clock quality check refer to Section 4.4.4, “Clock Quality Checker.” If the clock monitor
is enabled (CME = 1) a loss of external clock will also cause a SCM condition (SCME = 1).
SCM interrupts are locally disabled by setting the SCMIE bit to 0. The SCM inte rrupt flag (SCMIF) is set
to 1 when the SCM condition has changed, and is cleared to 0 by writing a 1 to the SCMIF bit.
Table 4-15. CRG Interrupt Vectors
Interrupt Source CCR
Mask Local Enable
Real-time interrupt I bit CRGINT (RTIE)
LOCK interrupt I bit CRGINT (LOCKIE)
SCM interrupt I bit CRGINT (SCMIE)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 201
Chapter 5
Oscillator (OSCV2)
5.1 Introduction
The OSCV2 module provides two alternative oscillator concepts:
• A low noise and low power Colpitts oscillator with amplitude limitation control (ALC)
• A robust full swing Pierce oscillator with the possibility to feed in an external square wave
5.1.1 Features
The Colpitts OSCV2 option provides the following features:
• Amplitude limitation control (ALC) loop:
— Low power consumption and low current induced RF emission
— Sinusoidal waveform with low RF emission
— Low crystal stress (an external damping resistor is not required)
— Normal and low amplitude mode for further reduction of power and emission
• An external biasing resistor is not required
The Pierce OSC option provides the following features:
• Wider high frequency operation range
• No DC voltage applied across the crystal
• Full rail-to-rail (2.5 V nominal) swing oscillation with low EM susceptibility
• Fast start up
Common features:
• Clock monitor (CM)
• Operation from the VDDPLL 2.5 V (nominal) supply rail
5.1.2 Modes of Operation
Two modes of operation exist:
• Amplitude limitation controlled Colpitts oscillator mode suitable for power and emission critical
applications
• Full swing Pierce oscillator mode that can also be used to feed in an externally generated square
wave suitable for high frequency operation and harsh environments
Chapter 5 Oscillator (OSCV2)
MC9S12E256 Data Sheet, Rev. 1.08
202 Freescale Semiconductor
5.2 External Signal Description
This section lists and describes the signals that connect off chip.
5.2.1 VDDPLL and VSSPLL — PLL Operating Voltage, PLL Ground
These pins provide the operating voltage (VDDPLL) and ground (VSSPLL) for the OSCV2 circuitry. This
allows the supply voltage to the OSCV2 to be independently bypassed.
5.2.2 EXTAL and XTAL — Clock/Crystal Source Pins
These pins provide the interface for either a crystal or a CMOS compatible clock to control the internal
clock generator circuitry. EXTAL is the external clock input or the input to the crystal oscillator amplifier.
XT AL is the output of the crystal oscillator amplifier. All the MCU internal system clocks are derived from
the EXTAL input frequency. In full stop mode (PSTP = 0) the EXTAL pin is pulled down by an internal
resistor of typical 200 kΩ.
NOTE
Freescale Semiconductor recommends an evaluation of the application
board and chosen resonator or crystal by the resonator or crystal supplier.
The Crystal circuit is changed from standard.
The Colpitts circuit is not suited for overtone resonators and crystals.
Figure 5-1. Colpitts Oscillator Connections (XCLKS = 0)
NOTE
The Pierce circuit is not suited for overtone resonators and crystals without
a careful component selection.
MCU
C2
EXTAL
XTAL
VSSPLL
C1
CDC* Crystal or Ceramic
Resonator
* Due to the nature of a translated ground Colpitts oscillator
a DC voltage bias is applied to the crystal.
Please contact the crystal manufacturer for crystal DC bias
conditions and recommended capacitor value CDC.
Chapter 5 Oscillator (OSCV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 203
Figure 5-2. Pierce Oscillator Connections (XCLKS = 1)
Figure 5-3. External Clock Connections (XCLKS = 1)
5.2.3 XCLKS — Colpitts/Pierce Oscillator Selection Signal
The XCLKS is an input signal which controls whether a crystal in combination with the internal Colpitts
(low power) oscillator is used or whether the Pierce oscillator/external clock circuitry is used. The XCLKS
signal is sampled during reset with the rising edge of RESET. Table 5-1 lists the state coding of the
sampled XCLKS signal. Refer to Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)” for
polarity of the XCLKS pin.
Table 5-1. Clock Selection Based on XCLKS
XCLKS Description
0 Colpitts oscillator selected
1 Pierce oscillator/external clock selected
MCU
EXTAL
XTAL RS*
RB
VSSPLL
Crystal or Ceramic
Resonator
C4
C3
* Rs can be zero (shorted) when used with higher frequency crystals.
Refer to manufacturer’s data.
MCU
EXTAL
XTAL
CMOS-Compatible
External Oscillator
Not Connected
(VDDPLL Level)
Chapter 5 Oscillator (OSCV2)
MC9S12E256 Data Sheet, Rev. 1.08
204 Freescale Semiconductor
5.3 Memory Map and Register Definition
The CRG contains the registers and associated bits for controlling and monitoring the OSCV2 module.
5.4 Functional Description
The OSCV2 block has two external pins, EXT AL and XTAL. The oscillator input pin, EXT AL, is intended
to be connected to either a crystal or an external clock source. The selection of Colpitts oscillator or Pierce
oscillator/external clock depends on the XCLKS signal which is sampled during reset. The XTAL pin is
an output signal that provides crystal circuit feedback.
A buffered EXTAL signal, OSCCLK, becomes the internal reference clock. To improve noise immunity,
the oscillator is powered by the VDDPLL and VSSPLL power supply pins.
The Pierce oscillator can be used for higher frequencies compared to the low power Colpitts oscillator.
5.4.1 Amplitude Limitation Control (ALC)
The Colpitts oscillator is equipped with a feedback system which does not waste current by generating
harmonics. Its configuration is “Colpitts oscillator with translated ground.” The transconductor used is
driven by a current source under the control of a peak detector which will measure the amplitude of the
AC signal appearing on EXTAL node in order to implement an amplitude limitation control (ALC) loop.
The ALC loop is in charge of reducing the quiescent current in the transconductor as a result of an increase
in the oscillation amplitude. The oscillation amplitude can be limited to two values. The normal amplitude
which is intended for non power saving modes and a small amplitude which is intended for low power
operation modes. Please refer to Chapter 4, “Clocks and Reset Generator (CRGV4)” for the control and
assignment of the amplitude value to operation modes.
5.4.2 Clock Monitor (CM)
The clock monitor circuit is based on an internal resistor-capacitor (RC) time delay so that it can operate
without any MCU clocks. If no OSCCLK edges are detected within this RC time delay, the clock monitor
indicates a failure which asserts self clock mode or generates a system reset depending on the state of
SCME bit. If the clock monitor is disabled or the presence of clocks is detected no failure is indicated.The
clock monitor function is enabled/disabled by the CME control bit, described in Chapter 4, “Clocks and
Reset Generator (CRGV4)”.
5.5 Interrupts
OSCV2 contains a clock monitor, which can trigger an interrupt or reset. The control bits and status bits
for the clock monitor are described in Chapter 4, “Clocks and Reset Generator (CRGV4)”.
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 205
Chapter 6
Analog-to-Digital Converter (ATD10B16CV4)
6.1 Introduction
The ATD10B16C is a 16-channel, 10-bit, multiplexed input successive approximation analog-to-digital
converter. Refer to Appendix A, “Electrical Characteristics” for ATD accuracy.
6.1.1 Features
• 8-/10-bit resolution
•7 µs, 10-bit single conversion time
• Sample buffer amplifier
• Programmable sample time
• Left/right justified, signed/unsigned result data
• External trigger control
• Conversion completion interrupt generation
• Analog input multiplexer for 16 analog input channels
• Analog/digital input pin multiplexing
• 1 to 16 conversion sequence lengths
• Continuous conversion mode
• Multiple channel scans
• Configurable external trigger functionality on any AD channel or any of four additional trigger
inputs. The four additional trigger inputs can be chip external or internal. Refer to device
specification for availability and connectivity
• Configurable location for channel wrap around (when converting multiple channels in a sequence)
6.1.2 Modes of Operation
There is software programmable selection between performing single or continuous conversion on a
single channel or multiple channels.
6.1.3 Block Diagram
Refer to Figure 6-1 for a block diagram of the ATD10B16C block.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
206 Freescale Semiconductor
Figure 6-1. ATD10B16C Block Diagram
VSSA
AN8
ATD10B16C
Analog
MUX
Mode and
Successive
Approximation
Register (SAR)
Results
ATD 0
ATD 1
ATD 2
ATD 3
ATD 4
ATD 5
ATD 6
ATD 7
and DAC
Sample & Hold
1
1
VDDA
VRL
VRH
Sequence Complete
Interrupt
+
-
Comparator
Clock
Prescaler
Bus Clock ATD clock
ATD 8
ATD 9
ATD 10
ATD 11
ATD 12
ATD 13
ATD 14
ATD 15
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
AN9
AN10
AN11
AN12
AN13
AN14
AN15
ETRIG0
ETRIG1
ETRIG2
ETRIG3
Timing Control
ATDDIEN
ATDCTL1
PORTAD
Trigger
Mux
(See Chapter 1,
“MC9S12E256 Device
Overview
(MC9S12E256DGV1)” for
availability and connectivity)
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 207
6.2 External Signal Description
This section lists all inputs to the ATD10B16C block.
6.2.1 ANx (x = 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) — Analog Input
Channel x Pins
This pin serves as the analog input channel x. It can also be configured as general-purpose digital input
and/or external trigger for the ATD conversion.
6.2.2 ETRIG3, ETRIG2, ETRIG1, ETRIG0 — External Trigger Pins
These inputs can be configured to serve as an external trigger for the ATD conversion.
Refer to Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)” for availability and
connectivity of these inputs.
6.2.3 VRH, VRL — High Reference Voltage Pin, Low Reference Voltage Pin
VRH is the high reference voltage, VRL is the low reference voltage for ATD conversion.
6.2.4 VDDA, VSSA — Analog Circuitry Power Supply Pins
These pins are the power supplies for the analog circuitry of the ATD10B16CV4 block.
6.3 Memory Map and Register Definition
This section provides a detailed description of all registers accessible in the ATD10B16C.
6.3.1 Module Memory Map
Table 6-1 gives an overview of all ATD10B16C registers
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
208 Freescale Semiconductor
.
NOTE
Register Address = Base Address + Address Offset, where the Base Address
is defined at the MCU level and the Address Of fset is defined at the module
level.
Table 6-1. ATD10B16CV4 Memory Map
Address Offset Use Access
0x0000 ATD Control Register 0 (ATDCTL0) R/W
0x0001 ATD Control Register 1 (ATDCTL1) R/W
0x0002 ATD Control Register 2 (ATDCTL2) R/W
0x0003 ATD Control Register 3 (ATDCTL3) R/W
0x0004 ATD Control Register 4 (ATDCTL4) R/W
0x0005 ATD Control Register 5 (ATDCTL5) R/W
0x0006 ATD Status Register 0 (ATDSTAT0) R/W
0x0007 Unimplemented
0x0008 ATD Test Register 0 (ATDTEST0)1
1ATDTEST0 is intended for factory test purposes only.
R
0x0009 ATD Test Register 1 (ATDTEST1) R/W
0x000A ATD Status Register 2 (ATDSTAT2) R
0x000B ATD Status Register 1 (ATDSTAT1) R
0x000C ATD Input Enable Register 0 (ATDDIEN0) R/W
0x000D ATD Input Enable Register 1 (ATDDIEN1) R/W
0x000E Port Data Register 0 (PORTAD0) R
0x000F Port Data Register 1 (PORTAD1) R
0x0010, 0x0011 ATD Result Register 0 (ATDDR0H, ATDDR0L) R/W
0x0012, 0x0013 ATD Result Register 1 (ATDDR1H, ATDDR1L) R/W
0x0014, 0x0015 ATD Result Register 2 (ATDDR2H, ATDDR2L) R/W
0x0016, 0x0017 ATD Result Register 3 (ATDDR3H, ATDDR3L) R/W
0x0018, 0x0019 ATD Result Register 4 (ATDDR4H, ATDDR4L) R/W
0x001A, 0x001B ATD Result Register 5 (ATDDR5H, ATDDR5L) R/W
0x001C, 0x001D ATD Result Register 6 (ATDDR6H, ATDDR6L) R/W
0x001E, 0x001F ATD Result Register 7 (ATDDR7H, ATDDR7L) R/W
0x0020, 0x0021 ATD Result Register 8 (ATDDR8H, ATDDR8L) R/W
0x0022, 0x0023 ATD Result Register 9 (ATDDR9H, ATDDR9L) R/W
0x0024, 0x0025 ATD Result Register 10 (ATDDR10H, ATDDR10L) R/W
0x0026, 0x0027 ATD Result Register 11 (ATDDR11H, ATDDR11L) R/W
0x0028, 0x0029 ATD Result Register 12 (ATDDR12H, ATDDR12L) R/W
0x002A, 0x002B ATD Result Register 13 (ATDDR13H, ATDDR13L) R/W
0x002C, 0x002D ATD Result Register 14 (ATDDR14H, ATDDR14L) R/W
0x002E, 0x002F ATD Result Register 15 (ATDDR15H, ATDDR15L) R/W
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 209
6.3.2 Register Descriptions
This section describes in address order all the ATD10B16C registers and their individual bits.
Register
Name Bit 7654321Bit 0
0x0000
AT D C T L0
R0000
WRAP3 WRAP2 WRAP1 WRAP0
W
0x0001
AT D C T L1
RETRIGSEL 000
ETRIGCH3 ETRIGCH2 ETRIGCH1 ETRIGCH0
W
0x0002
AT D C T L2
RADPU AFFC AWAI ETRIGLE ETRIGP ETRIGE ASCIE ASCIF
W
0x0003
AT D C T L3
R0 S8C S4C S2C S1C FIFO FRZ1 FRZ0
W
0x0004
AT D C T L4
RSRES8 SMP1 SMP0 PRS4 PRS3 PRS2 PRS1 PRS0
W
0x0005
AT D C T L5
RDJM DSGN SCAN MULT CD CC CB CA
W
0x0006
AT D S TAT0
RSCF 0ETORF FIFOR CC3 CC2 CC1 CC0
W
0x0007
Unimplemented
R
W
0x0008
ATDTEST0
R Unimplemented
W
0x0009
ATDTEST1
R Unimplemented SC
W
0x000A
AT D S TAT2
R CCF15 CCF14 CCF13 CCF12 CCF11 CCF10 CCF9 CCF8
W
0x000B
AT D S TAT1
R CCF7 CCF6 CCF5 CCF4 CCF3 CCF2 CCF1 CCF0
W
0x000C
ATDDIEN0
RIEN15 IEN14 IEN13 IEN12 IEN11 IEN10 IEN9 IEN8
W
= Unimplemented or Reserved u = Unaffected
Figure 6-2. ATD Register Summary
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
210 Freescale Semiconductor
6.3.2.1 ATD Control Register 0 (ATDCTL0)
Writes to this register will abort current conversion sequence but will not start a new sequence.
Read: Anytime
Write: Anytime
0x000D
ATDDIEN1
RIEN7 IEN6 IEN5 IEN4 IEN3 IEN2 IEN1 IEN0
W
0x000E
PORTAD0
R PTAD15 PTAD14 PTAD13 PTAD12 PTAD11 PTAD10 PTAD9 PTAD8
W
0x000F
PORTAD1
R PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
W
R BIT 9 MSB
BIT 7 MSB
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
0x0010–0x002F
ATDDRxH–
ATDDRxL
W
R BIT 1
u
BIT 0
u
0
0
0
0
0
0
0
0
0
0
0
0
W
76543210
R0 0 0 0
WRAP3 WRAP2 WRAP1 WRAP0
W
Reset00001111
= Unimplemented or Reserved
Figure 6-3. ATD Control Register 0 (ATDCTL0)
Table 6-2. ATDCTL0 Field Descriptions
Field Description
3:0
WRAP[3:0]
Wrap Around Channel Select Bits — These bits determine the channel for wrap around when doing
multi-channel conversions. The coding is summarized in Tabl e 6 - 3 .
Register
Name Bit 7654321Bit 0
= Unimplemented or Reserved u = Unaffected
Figure 6-2. ATD Register Summary (continued)
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 211
6.3.2.2 ATD Control Register 1 (ATDCTL1)
Writes to this register will abort current conversion sequence but will not start a new sequence.
Read: Anytime
Write: Anytime
Table 6-3. Multi-Channel Wrap Around Coding
WRAP3 WRAP2 WRAP1 WRAP0
Multiple Channel Conversions
(MULT = 1) Wrap Around to AN0
after Converting
0000 Reserved
0001 AN1
0010 AN2
0011 AN3
0100 AN4
0101 AN5
0110 AN6
0111 AN7
1000 AN8
1001 AN9
1010 AN10
1011 AN11
1100 AN12
1101 AN13
1110 AN14
1111 AN15
76543210
R
ETRIGSEL
000
ETRIGCH3 ETRIGCH2 ETRIGCH1 ETRIGCH0
W
Reset00001111
= Unimplemented or Reserved
Figure 6-4. ATD Control Register 1 (ATDCTL1)
Table 6-4. ATDCTL1 Field Descriptions
Field Description
7
ETRIGSEL
External Trigger Source Select — This bit selects the external trigger source to be either one of the AD
channels or one of the ETRIG[3:0] inputs. See device specification for availability and connectivity of
ETRIG[3:0] inputs. If ETRIG[3:0] input option is not available, writing a 1 to ETRISEL only sets the bit but has
no effect, that means one of the AD channels (selected by ETRIGCH[3:0]) remains the source for external
trigger. The coding is summarized in Ta b l e 6 - 5 .
3:0
ETRIGCH[3:0]
External Trigger Channel Select — These bits select one of the AD channels or one of the ETRIG[3:0] inputs
as source for the external trigger. The coding is summarized in Tabl e 6-5.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
212 Freescale Semiconductor
Table 6-5. External Trigger Channel Select Coding
ETRIGSEL ETRIGCH3 ETRIGCH2 ETRIGCH1 ETRIGCH0 External Trigger Source
00000 AN0
00001 AN1
00010 AN2
00011 AN3
00100 AN4
00101 AN5
00110 AN6
00111 AN7
01000 AN8
01001 AN9
01010 AN10
01011 AN11
01100 AN12
01101 AN13
01110 AN14
01111 AN15
10000 ETRIG0
1
1Only if ETRIG[3:0] input option is available (see device specification), else ETRISEL is ignored, that means
external trigger source remains on one of the AD channels selected by ETRIGCH[3:0]
10001 ETRIG1
1
10010 ETRIG2
1
10011 ETRIG3
1
1 0 1 X X Reserved
11XXX Reserved
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 213
6.3.2.3 ATD Control Register 2 (ATDCTL2)
This register controls power down, interrupt and external trigger. Writes to this register will abort current
conversion sequence but will not start a new sequence.
Read: Anytime
Write: Anytime
76543210
RADPU AFFC AWAI ETRIGLE ETRIGP ETRIGE ASCIE ASCIF
W
Reset00000000
= Unimplemented or Reserved
Figure 6-5. ATD Control Register 2 (ATDCTL2)
Table 6-6. ATDCTL2 Field Descriptions
Field Description
7
ADPU
ATD Power Down — This bit provides on/off control over the ATD10B16C block allowing reduced MCU power
consumption. Because analog electronic is turned off when powered down, the ATD requires a recovery time
period after ADPU bit is enabled.
0 Power down ATD
1 Normal ATD functionality
6
AFFC
ATD Fast Flag Clear All
0 ATD flag clearing operates normally (read the status register ATDSTAT1 before reading the result register to
clear the associate CCF flag).
1 Changes all ATD conversion complete flags to a fast clear sequence. Any access to a result register will
cause the associate CCF flag to clear automatically.
5
AWAI
ATD Power Down in Wait Mode — When entering Wait Mode this bit provides on/off control over the
ATD10B16C block allowing reduced MCU power. Because analog electronic is turned off when powered down,
the ATD requires a recovery time period after exit from Wait mode.
0 ATD continues to run in Wait mode
1 Halt conversion and power down ATD during Wait mode
After exiting Wait mode with an interrupt conversion will resume. But due to the recovery time the result of
this conversion should be ignored.
4
ETRIGLE
External Trigger Level/Edge Control — This bit controls the sensitivity of the external trigger signal. See
Ta b l e 6- 7 for details.
3
ETRIGP
External Trigger Polarity — This bit controls the polarity of the external trigger signal. See Tabl e 6 -7 for
details.
2
ETRIGE
External Trigger Mode Enable — This bit enables the external trigger on one of the AD channels or one of
the ETRIG[3:0] inputs as described in Ta b l e 6 - 5 . If external trigger source is one of the AD channels, the digital
input buffer of this channel is enabled. The external trigger allows to synchronize the start of conversion with
external events.
0 Disable external trigger
1 Enable external trigger
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
214 Freescale Semiconductor
1
ASCIE
ATD Sequence Complete Interrupt Enable
0 ATD Sequence Complete interrupt requests are disabled.
1 ATD Interrupt will be requested whenever ASCIF = 1 is set.
0
ASCIF
ATD Sequence Complete Interrupt Flag — If ASCIE = 1 the ASCIF flag equals the SCF flag (see
Section 6.3.2.7, “ATD Status Register 0 (ATDSTAT0)”), else ASCIF reads zero. Writes have no effect.
0 No ATD interrupt occurred
1 ATD sequence complete interrupt pending
Table 6-7. External Trigger Configurations
ETRIGLE ETRIGP External Trigger Sensitivity
0 0 Falling Edge
0 1 Ring Edge
1 0 Low Level
1 1 High Level
Table 6-6. ATDCTL2 Field Descriptions (continued)
Field Description
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 215
6.3.2.4 ATD Control Register 3 (ATDCTL3)
This register controls the conversion sequence length, FIFO for results registers and behavior in Freeze
Mode. Writes to this register will abort current conversion sequence but will not start a new sequence.
Read: Anytime
Write: Anytime
76543210
R0 S8C S4C S2C S1C FIFO FRZ1 FRZ0
W
Reset00100000
= Unimplemented or Reserved
Figure 6-6. ATD Control Register 3 (ATDCTL3)
Table 6-8. ATDCTL3 Field Descriptions
Field Description
6
S8C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Ta b l e 6 - 9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
5
S4C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Ta b l e 6 - 9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
4
S2C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Ta b l e 6 - 9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
3
S1C
Conversion Sequence Length — This bit controls the number of conversions per sequence. Ta b l e 6 - 9 shows
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
2
FIFO
Result Register FIFO Mode —If this bit is zero (non-FIFO mode), the A/D conversion results map into the
result registers based on the conversion sequence; the result of the first conversion appears in the first result
register, the second result in the second result register, and so on.
If this bit is one (FIFO mode) the conversion counter is not reset at the beginning or ending of a conversion
sequence; sequential conversion results are placed in consecutive result registers. In a continuously scanning
conversion sequence, the result register counter will wrap around when it reaches the end of the result register
file. The conversion counter value (CC3-0 in ATDSTAT0) can be used to determine where in the result register
file, the current conversion result will be placed.
Aborting a conversion or starting a new conversion by write to an ATDCTL register (ATDCTL5-0) clears the
conversion counter even if FIFO=1. So the first result of a new conversion sequence, started by writing to
ATDCTL5, will always be place in the first result register (ATDDDR0). Intended usage of FIFO mode is
continuos conversion (SCAN=1) or triggered conversion (ETRIG=1).
Finally, which result registers hold valid data can be tracked using the conversion complete flags. Fast flag clear
mode may or may not be useful in a particular application to track valid data.
0 Conversion results are placed in the corresponding result register up to the selected sequence length.
1 Conversion results are placed in consecutive result registers (wrap around at end).
1:0
FRZ[1:0]
Background Debug Freeze Enable — When debugging an application, it is useful in many cases to have the
ATD pause when a breakpoint (Freeze Mode) is encountered. These 2 bits determine how the ATD will respond
to a breakpoint as shown in Ta ble 6-10. Leakage onto the storage node and comparator reference capacitors
may compromise the accuracy of an immediately frozen conversion depending on the length of the freeze
period.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
216 Freescale Semiconductor
7
Table 6-9. Conversion Sequence Length Coding
S8C S4C S2C S1C Number of Conversions
per Sequence
0000 16
0001 1
0010 2
0011 3
0100 4
0101 5
0110 6
0111 7
1000 8
1001 9
1010 10
1011 11
1100 12
1101 13
1110 14
1111 15
Table 6-10. ATD Behavior in Freeze Mode (Breakpoint)
FRZ1 FRZ0 Behavior in Freeze Mode
0 0 Continue conversion
01 Reserved
1 0 Finish current conversion, then freeze
1 1 Freeze Immediately
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 217
6.3.2.5 ATD Control Register 4 (ATDCTL4)
This register selects the conversion clock frequency , the length of the second phase of the sample time and
the resolution of the A/D conversion (i.e., 8-bits or 10-bits). Writes to this register will abort current
conversion sequence but will not start a new sequence.
Read: Anytime
Write: Anytime
76543210
R
SRES8 SMP1 SMP0 PRS4 PRS3 PRS2 PRS1 PRS0
W
Reset00000101
Figure 6-7. ATD Control Register 4 (ATDCTL4)
Table 6-11. ATDCTL4 Field Descriptions
Field Description
7
SRES8
A/D Resolution Select — This bit selects the resolution of A/D conversion results as either 8 or 10 bits. The
A/D converter has an accuracy of 10 bits. However, if low resolution is required, the conversion can be speeded
up by selecting 8-bit resolution.
0 10 bit resolution
1 8 bit resolution
6:5
SMP[1:0]
Sample Time Select —These two bits select the length of the second phase of the sample time in units of ATD
conversion clock cycles. Note that the ATD conversion clock period is itself a function of the prescaler value
(bits PRS4-0). The sample time consists of two phases. The first phase is two ATD conversion clock cycles long
and transfers the sample quickly (via the buffer amplifier) onto the A/D machine’s storage node. The second
phase attaches the external analog signal directly to the storage node for final charging and high accuracy.
Ta b l e 6- 1 2 lists the lengths available for the second sample phase.
4:0
PRS[4:0]
ATD Clock Prescaler — These 5 bits are the binary value prescaler value PRS. The ATD conversion clock
frequency is calculated as follows:
Note: The maximum ATD conversion clock frequency is half the bus clock. The default (after reset) prescaler
value is 5 which results in a default ATD conversion clock frequency that is bus clock divided by 12.
Ta b l e 6- 1 3 illustrates the divide-by operation and the appropriate range of the bus clock.
Table 6-12. Sample Time Select
SMP1 SMP0 Length of 2nd Phase of Sample Time
0 0 2 A/D conversion clock periods
0 1 4 A/D conversion clock periods
1 0 8 A/D conversion clock periods
1 1 16 A/D conversion clock periods
ATDclock BusClock[]
PRS 1+[]
-------------------------------- 0.5×=
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
218 Freescale Semiconductor
Table 6-13. Clock Prescaler Values
Prescale Value Total Divisor
Value Max. Bus Clock1
1Maximum ATD conversion clock frequency is 2 MHz. The maximum allowed bus clock frequency is
shown in this column.
Min. Bus Clock2
2Minimum ATD conversion clock frequency is 500 kHz. The minimum allowed bus clock frequency is
shown in this column.
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
Divide by 2
Divide by 4
Divide by 6
Divide by 8
Divide by 10
Divide by 12
Divide by 14
Divide by 16
Divide by 18
Divide by 20
Divide by 22
Divide by 24
Divide by 26
Divide by 28
Divide by 30
Divide by 32
Divide by 34
Divide by 36
Divide by 38
Divide by 40
Divide by 42
Divide by 44
Divide by 46
Divide by 48
Divide by 50
Divide by 52
Divide by 54
Divide by 56
Divide by 58
Divide by 60
Divide by 62
Divide by 64
4 MHz
8 MHz
12 MHz
16 MHz
20 MHz
24 MHz
28 MHz
32 MHz
36 MHz
40 MHz
44 MHz
48 MHz
52 MHz
56 MHz
60 MHz
64 MHz
68 MHz
72 MHz
76 MHz
80 MHz
84 MHz
88 MHz
92 MHz
96 MHz
100 MHz
104 MHz
108 MHz
112 MHz
116 MHz
120 MHz
124 MHz
128 MHz
1 MHz
2 MHz
3 MHz
4 MHz
5 MHz
6 MHz
7 MHz
8 MHz
9 MHz
10 MHz
11 MHz
12 MHz
13 MHz
14 MHz
15 MHz
16 MHz
17 MHz
18 MHz
19 MHz
20 MHz
21 MHz
22 MHz
23 MHz
24 MHz
25 MHz
26 MHz
27 MHz
28 MHz
29 MHz
30 MHz
31 MHz
32 MHz
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 219
6.3.2.6 ATD Control Register 5 (ATDCTL5)
This register selects the type of conversion sequence and the analog input channels sampled. W rites to this
register will abort current conversion sequence and start a new conversion sequence. If external trigger is
enabled (ETRIGE = 1) an initial write to ATDCTL5 is required to allow starting of a conversion sequence
which will then occur on each trigger event. S tart of conversion means the beginning of the sampling
phase.
Read: Anytime
Write: Anytime
76543210
R
DJM DSGN SCAN MULT CD CC CB CA
W
Reset00000000
Figure 6-8. ATD Control Register 5 (ATDCTL5)
Table 6-14. ATDCTL5 Field Descriptions
Field Description
7
DJM
Result Register Data Justification — This bit controls justification of conversion data in the result registers.
See Section 6.3.2.16, “ATD Conversion Result Registers (ATDDRx)” for details.
0 Left justified data in the result registers.
1 Right justified data in the result registers.
6
DSGN
Result Register Data Signed or Unsigned Representation — This bit selects between signed and unsigned
conversion data representation in the result registers. Signed data is represented as 2’s complement. Signed
data is not available in right justification. See <st-bold>6.3.2.16 ATD Conversion Result Registers (ATDDRx)
for details.
0 Unsigned data representation in the result registers.
1 Signed data representation in the result registers.
Ta b l e 6- 1 5 summarizes the result data formats available and how they are set up using the control bits.
Ta b l e 6- 1 6 illustrates the difference between the signed and unsigned, left justified output codes for an input
signal range between 0 and 5.12 Volts.
5
SCAN
Continuous Conversion Sequence Mode — This bit selects whether conversion sequences are performed
continuously or only once. If external trigger is enabled (ETRIGE=1) setting this bit has no effect, that means
each trigger event starts a single conversion sequence.
0 Single conversion sequence
1 Continuous conversion sequences (scan mode)
4
MULT
Multi-Channel Sample Mode — When MULT is 0, the ATD sequence controller samples only from the
specified analog input channel for an entire conversion sequence. The analog channel is selected by channel
selection code (control bits CD/CC/CB/CA located in ATDCTL5). When MULT is 1, the ATD sequence controller
samples across channels. The number of channels sampled is determined by the sequence length value (S8C,
S4C, S2C, S1C). The first analog channel examined is determined by channel selection code (CC, CB, CA
control bits); subsequent channels sampled in the sequence are determined by incrementing the channel
selection code or wrapping around to AN0 (channel 0.
0 Sample only one channel
1 Sample across several channels
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
220 Freescale Semiconductor
3:0
C[D:A}
Analog Input Channel Select Code — These bits select the analog input channel(s) whose signals are
sampled and converted to digital codes. Ta ble 6-17 lists the coding used to select the various analog input
channels.
In the case of single channel conversions (MULT = 0), this selection code specified the channel to be examined.
In the case of multiple channel conversions (MULT = 1), this selection code represents the first channel to be
examined in the conversion sequence. Subsequent channels are determined by incrementing the channel
selection code or wrapping around to AN0 (after converting the channel defined by the Wrap Around Channel
Select Bits WRAP[3:0] in ATDCTL0). In case starting with a channel number higher than the one defined by
WRAP[3:0] the first wrap around will be AN15 to AN0.
Table 6-15. Available Result Data Formats.
SRES8 DJM DSGN Result Data Formats
Description and Bus Bit Mapping
1
1
1
0
0
0
0
0
1
0
0
1
0
1
X
0
1
X
8-bit / left justified / unsigned — bits 15:8
8-bit / left justified / signed — bits 15:8
8-bit / right justified / unsigned — bits 7:0
10-bit / left justified / unsigned — bits 15:6
10-bit / left justified / signed -— bits 15:6
10-bit / right justified / unsigned — bits 9:0
Table 6-16. Left Justified, Signed and Unsigned ATD Output Codes.
Input Signal
VRL = 0 Volts
VRH = 5.12 Volts
Signed
8-Bit Codes
Unsigned
8-Bit Codes
Signed
10-Bit Codes
Unsigned
10-Bit Codes
5.120 Volts
5.100
5.080
2.580
2.560
2.540
0.020
0.000
7F
7F
7E
01
00
FF
81
80
FF
FF
FE
81
80
7F
01
00
7FC0
7F00
7E00
0100
0000
FF00
8100
8000
FFC0
FF00
FE00
8100
8000
7F00
0100
0000
Table 6-14. ATDCTL5 Field Descriptions (continued)
Field Description
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 221
Table 6-17. Analog Input Channel Select Coding
CD CC CB CA Analog Input
Channel
00 0 0 AN0
00 0 1 AN1
00 1 0 AN2
00 1 1 AN3
01 0 0 AN4
01 0 1 AN5
01 1 0 AN6
01 1 1 AN7
10 0 0 AN8
10 0 1 AN9
10 1 0 AN10
10 1 1 AN11
11 0 0 AN12
11 0 1 AN13
11 1 0 AN14
11 1 1 AN15
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
222 Freescale Semiconductor
6.3.2.7 ATD Status Register 0 (ATDSTAT0)
This read-only register contains the Sequence Complete Flag, overrun flags for external trigger and FIFO
mode, and the conversion counter.
Read: Anytime
Write: Anytime (No effect on CC[3:0])
76543210
R
SCF
0
ETORF FIFOR
CC3 CC2 CC1 CC0
W
Reset00000000
= Unimplemented or Reserved
Figure 6-9. ATD Status Register 0 (ATDSTAT0)
Table 6-18. ATDSTAT0 Field Descriptions
Field Description
7
SCF
Sequence Complete Flag — This flag is set upon completion of a conversion sequence. If conversion
sequences are continuously performed (SCAN = 1), the flag is set after each one is completed. This flag is
cleared when one of the following occurs:
• Write “1” to SCF
• Write to ATDCTL5 (a new conversion sequence is started)
• If AFFC = 1 and read of a result register
0 Conversion sequence not completed
1 Conversion sequence has completed
5
ETORF
External Trigger Overrun Flag —While in edge trigger mode (ETRIGLE = 0), if additional active edges are
detected while a conversion sequence is in process the overrun flag is set. This flag is cleared when one of the
following occurs:
• Write “1” to ETORF
• Write to ATDCTL0,1,2,3,4 (a conversion sequence is aborted)
• Write to ATDCTL5 (a new conversion sequence is started)
0 No External trigger over run error has occurred
1 External trigger over run error has occurred
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 223
6.3.2.8 Reserved Register 0 (ATDTEST0)
Read: Anytime, returns unpredictable values
Write: Anytime in special modes, unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter functionality.
4
FIFOR
FIFO Over Run Flag — This bit indicates that a result register has been written to before its associated
conversion complete flag (CCF) has been cleared. This flag is most useful when using the FIFO mode because
the flag potentially indicates that result registers are out of sync with the input channels. However, it is also
practical for non-FIFO modes, and indicates that a result register has been over written before it has been read
(i.e., the old data has been lost). This flag is cleared when one of the following occurs:
• Write “1” to FIFOR
• Start a new conversion sequence (write to ATDCTL5 or external trigger)
0 No over run has occurred
1 Overrun condition exists (result register has been written while associated CCFx flag remained set)
3:0
CC[3:0}
Conversion Counter — These 4 read-only bits are the binary value of the conversion counter. The conversion
counter points to the result register that will receive the result of the current conversion. For example, CC3 = 0,
CC2 = 1, CC1 = 1, CC0 = 0 indicates that the result of the current conversion will be in ATD Result Register 6.
If in non-FIFO mode (FIFO = 0) the conversion counter is initialized to zero at the begin and end of the
conversion sequence. If in FIFO mode (FIFO = 1) the register counter is not initialized. The conversion
counters wraps around when its maximum value is reached.
Aborting a conversion or starting a new conversion by write to an ATDCTL register (ATDCTL5-0) clears the
conversion counter even if FIFO=1.
76543210
Ruuuuuuuu
W
Reset10000000
= Unimplemented or Reserved u = Unaffected
Figure 6-10. Reserved Register 0 (ATDTEST0)
Table 6-18. ATDSTAT0 Field Descriptions (continued)
Field Description
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
224 Freescale Semiconductor
6.3.2.9 ATD Test Register 1 (ATDTEST1)
This register contains the SC bit used to enable special channel conversions.
Read: Anytime, returns unpredictable values for bit 7 and bit 6
Write: Anytime
NOTE
Writing to this register when in special modes can alter functionality.
76543210
Ruuuuuuu
SC
W
Reset00000000
= Unimplemented or Reserved u = Unaffected
Figure 6-11. Reserved Register 1 (ATDTEST1)
Table 6-19. ATDTEST1 Field Descriptions
Field Description
0
SC
Special Channel Conversion Bit — If this bit is set, then special channel conversion can be selected using
CC, CB, and CA of ATDCTL5. Tabl e 6 - 2 0 lists the coding.
0 Special channel conversions disabled
1 Special channel conversions enabled
Table 6-20. Special Channel Select Coding
SC CD CC CB CA Analog Input Channel
100 X X Reserved
101 0 0 V
RH
101 0 1 V
RL
101 1 0 (V
RH+VRL) / 2
101 1 1 Reserved
11X X X Reserved
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 225
6.3.2.10 ATD Status Register 2 (ATDSTAT2)
This read-only register contains the Conversion Complete Flags CCF15 to CCF8.
Read: Anytime
Write: Anytime, no effect
76543210
R CCF15 CCF14 CCF13 CCF12 CCF11 CCF10 CCF9 CCF8
W
Reset00000000
= Unimplemented or Reserved
Figure 6-12. ATD Status Register 2 (ATDSTAT2)
Table 6-21. ATDSTAT2 Field Descriptions
Field Description
7:0
CCF[15:8]
Conversion Complete Flag Bits — A conversion complete flag is set at the end of each conversion in a
conversion sequence. The flags are associated with the conversion position in a sequence (and also the result
register number). Therefore, CCF8 is set when the ninth conversion in a sequence is complete and the result
is available in result register ATDDR8; CCF9 is set when the tenth conversion in a sequence is complete and
the result is available in ATDDR9, and so forth. A flag CCFx (x = 15, 14, 13, 12, 11, 10, 9, 8) is cleared when
one of the following occurs:
• Write to ATDCTL5 (a new conversion sequence is started)
• If AFFC = 0 and read of ATDSTAT2 followed by read of result register ATDDRx
• If AFFC = 1 and read of result register ATDDRx
In case of a concurrent set and clear on CCFx: The clearing by method A) will overwrite the set. The clearing
by methods B) or C) will be overwritten by the set.
0 Conversion number x not completed
1 Conversion number x has completed, result ready in ATDDRx
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
226 Freescale Semiconductor
6.3.2.11 ATD Status Register 1 (ATDSTAT1)
This read-only register contains the Conversion Complete Flags CCF7 to CCF0
Read: Anytime
Write: Anytime, no effect
76543210
R CCF7 CCF6 CCF5 CCF4 CCF3 CCF2 CCF1 CCF0
W
Reset00000000
= Unimplemented or Reserved
Figure 6-13. ATD Status Register 1 (ATDSTAT1)
Table 6-22. ATDSTAT1 Field Descriptions
Field Description
7:0
CCF[7:0]
Conversion Complete Flag Bits — A conversion complete flag is set at the end of each conversion in a
conversion sequence. The flags are associated with the conversion position in a sequence (and also the result
register number). Therefore, CCF0 is set when the first conversion in a sequence is complete and the result is
available in result register ATDDR0; CCF1 is set when the second conversion in a sequence is complete and
the result is available in ATDDR1, and so forth. A CCF flag is cleared when one of the following occurs:
• Write to ATDCTL5 (a new conversion sequence is started)
• If AFFC = 0 and read of ATDSTAT1 followed by read of result register ATDDRx
• If AFFC = 1 and read of result register ATDDRx
In case of a concurrent set and clear on CCFx: The clearing by method A) will overwrite the set. The clearing
by methods B) or C) will be overwritten by the set.
Conversion number x not completed
Conversion number x has completed, result ready in ATDDRx
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 227
6.3.2.12 ATD Input Enable Register 0 (ATDDIEN0)
Read: Anytime
Write: anytime
6.3.2.13 ATD Input Enable Register 1 (ATDDIEN1)
Read: Anytime
Write: Anytime
76543210
R
IEN15 IEN14 IEN13 IEN12 IEN11 IEN10 IEN9 IEN8
W
Reset00000000
Figure 6-14. ATD Input Enable Register 0 (ATDDIEN0)
Table 6-23. ATDDIEN0 Field Descriptions
Field Description
7:0
IEN[15:8]
ATD Digital Input Enable on Channel Bits — This bit controls the digital input buffer from the analog input
pin (ANx) to PTADx data register.
0 Disable digital input buffer to PTADx
1 Enable digital input buffer to PTADx.
Note: Setting this bit will enable the corresponding digital input buffer continuously. If this bit is set while
simultaneously using it as an analog port, there is potentially increased power consumption because the
digital input buffer maybe in the linear region.
76543210
R
IEN7 IEN6 IEN5 IEN4 IEN3 IEN2 IEN1 IEN0
W
Reset00000000
Figure 6-15. ATD Input Enable Register 1 (ATDDIEN1)
Table 6-24. ATDDIEN1 Field Descriptions
Field Description
7:0
IEN[7:0]
ATD Digital Input Enable on Channel Bits — This bit controls the digital input buffer from the analog input
pin (ANx) to PTADx data register.
0 Disable digital input buffer to PTADx
1 Enable digital input buffer to PTADx.
Note: Setting this bit will enable the corresponding digital input buffer continuously. If this bit is set while
simultaneously using it as an analog port, there is potentially increased power consumption because the
digital input buffer maybe in the linear region.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
228 Freescale Semiconductor
6.3.2.14 Port Data Register 0 (PORTAD0)
The data port associated with the ATD is input-only. The port pins are shared with the analog A/D inputs
AN[15:8].
Read: Anytime
Write: Anytime, no effect
The A/D input channels may be used for general-purpose digital input.
76543210
R PTAD15 PTAD14 PTAD13 PTAD12 PTAD11 PTAD10 PTAD9 PTAD8
W
Reset11111111
Pin
Function AN15 AN14 AN13 AN12 AN11 AN10 AN9 AN8
= Unimplemented or Reserved
Figure 6-16. Port Data Register 0 (PORTAD0)
Table 6-25. PORTAD0 Field Descriptions
Field Description
7:0
PTAD[15:8]
A/D Channel x (ANx) Digital Input Bits— If the digital input buffer on the ANx pin is enabled (IENx = 1) or
channel x is enabled as external trigger (ETRIGE = 1, ETRIGCH[3-0] = x, ETRIGSEL = 0) read returns the logic
level on ANx pin (signal potentials not meeting VIL or VIH specifications will have an indeterminate value)).
If the digital input buffers are disabled (IENx = 0) and channel x is not enabled as external trigger, read returns
a “1”.
Reset sets all PORTAD0 bits to “1”.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 229
6.3.2.15 Port Data Register 1 (PORTAD1)
The data port associated with the ATD is input-only. The port pins are shared with the analog A/D inputs
AN7-0.
Read: Anytime
Write: Anytime, no effect
The A/D input channels may be used for general-purpose digital input.
76543210
R PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
W
Reset11111111
Pin
Function AN 7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
= Unimplemented or Reserved
Figure 6-17. Port Data Register 1 (PORTAD1)
Table 6-26. PORTAD1 Field Descriptions
Field Description
7:0
PTAD[7:8]
A/D Channel x (ANx) Digital Input Bits — If the digital input buffer on the ANx pin is enabled (IENx=1) or
channel x is enabled as external trigger (ETRIGE = 1, ETRIGCH[3-0] = x, ETRIGSEL = 0) read returns the
logic level on ANx pin (signal potentials not meeting VIL or VIH specifications will have an indeterminate value)).
If the digital input buffers are disabled (IENx = 0) and channel x is not enabled as external trigger, read returns
a “1”.
Reset sets all PORTAD1 bits to “1”.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
230 Freescale Semiconductor
6.3.2.16 ATD Conversion Result Registers (ATDDRx)
The A/D conversion results are stored in 16 read-only result registers. The result data is formatted in the
result registers bases on two criteria. First there is left and right justif ic ation; this selection is made using
the DJM control bit in ATDCTL5. Second there is signed and unsigned data; this selection is made using
the DSGN control bit in ATDCTL5. Signed data is stored in 2’s complement format and only exists in left
justified format. Signed data selected for right justified format is ignored.
Read: Anytime
Write: Anytime in special mode, unimplemented in normal modes
6.3.2.16.1 Left Justified Result Data
76543210
R (10-BIT)
R (8-BIT)
BIT 9 MSB
BIT 7 MSB
BIT 8
BIT 6
BIT 7
BIT 5
BIT 6
BIT 4
BIT 5
BIT 3
BIT 4
BIT 2
BIT 3
BIT 1
BIT 2
BIT 0
W
Reset00000000
= Unimplemented or Reserved
Figure 6-18. Left Justified, ATD Conversion Result Register x, High Byte (ATDDRxH)
76543210
R (10-BIT)
R (8-BIT)
BIT 1
u
BIT 0
u
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset00000000
= Unimplemented or Reserved u = Unaffected
Figure 6-19. Left Justified, ATD Conversion Result Register x, Low Byte (ATDDRxL)
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 231
6.3.2.16.2 Right Justified Result Data
6.4 Functional Description
The ATD10B16C is structured in an analog and a digital sub-block.
6.4.1 Analog Sub-block
The analog sub-block contains all analog electronics required to perform a single conversion. Separate
power supplies VDDA and VSSA allow to isolate noise of other MCU circuitry from the analog sub-block.
6.4.1.1 Sample and Hold Machine
The sample and hold (S/H) machine accepts analog signals from the external world and stores them as
capacitor charge on a storage node.
The sample process uses a two stage approach. During the first stage, the sample amplifier is used to
quickly charge the storage node.The second stage connects the input directly to the storage node to
complete the sample for high accuracy.
When not sampling, the sample and hold machine disables its own clocks. The analog electronics continue
drawing their quiescent current. The power down (ADPU) bit must be set to disable both the digital clocks
and the analog power consumption.
The input analog signals are unipolar and must fall within the potential range of VSSA to VDDA.
76543210
R (10-BIT)
R (8-BIT)
0
0
0
0
0
0
0
0
0
0
0
0
BIT 9 MSB
0
BIT 8
0
W
Reset00000000
= Unimplemented or Reserved
Figure 6-20. Right Justified, ATD Conversion Result Register x, High Byte (ATDDRxH)
76543210
R (10-BIT)
R (8-BIT)
BIT 7
BIT 7 MSB
BIT 6
BIT 6
BIT 5
BIT 5
BIT 4
BIT 4
BIT 3
BIT 3
BIT 2
BIT 2
BIT 1
BIT 1
BIT 0
BIT 0
W
Reset00000000
= Unimplemented or Reserved
Figure 6-21. Right Justified, ATD Conversion Result Register x, Low Byte (ATDDRxL)
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
232 Freescale Semiconductor
6.4.1.2 Analog Input Multiplexer
The analog input multiplexer connects one of the 16 external analog input channels to the sample and hold
machine.
6.4.1.3 Sample Buffer Amplifier
The sample amplifier is used to buffer the input analog signal so that the storage node can be quickly
charged to the sample potential.
6.4.1.4 Analog-to-Digital (A/D) Machine
The A/D machine performs analog to digital conversions. The resolution is program selectable at either 8
or 10 bits. The A/D machine uses a successive approximation architecture. It functions by comparing the
stored analog sample potential with a series of digitally generated analog potentials. By following a binary
search algorithm, the A/D machine locates the approximating potential that is nearest to the sampled
potential.
When not converting the A/D machine disables its own clocks. The analog electronics continue drawing
quiescent current. The power down (ADPU) bit must be set to disable both the digital clocks and the analog
power consumption.
Only analog input signals within the potential range of VRL to VRH (A/D reference potentials) will res ult
in a non-railed digital output codes.
6.4.2 Digital Sub-Block
This subsection explains some of the digital features in more detail. See register descriptions for all details.
6.4.2.1 External Trigger Input
The external trigger feature allows the user to synchronize ATD conversions to the external environment
events rather than relying on software to signal the ATD module when ATD conversions are to take place.
The external trigger signal (out of reset ATD channel 15, configurable in ATDCTL1) is programmable to
be edge or level sensitive with polarity control. Table 6-27 gives a brief description of the different
combinations of control bits and their effect on the external trigger function.
During a conversion, if additional active edges are detected the overrun error flag ETORF is set.
Table 6-27. External Trigger Control Bits
ETRIGLE ETRIGP ETRIGE SCAN Description
X X 0 0 Ignores external trigger. Performs one conversion sequence and stops.
X X 0 1 Ignores external trigger. Performs continuous conversion sequences.
0 0 1 X Falling edge triggered. Performs one conversion sequence per trigger.
0 1 1 X Rising edge triggered. Performs one conversion sequence per trigger.
1 0 1 X Trigger active low. Performs continuous conversions while trigger is active.
1 1 1 X Trigger active high. Performs continuous conversions while trigger is active.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 233
In either level or edge triggered modes, the first conversion begins when the trigger is received. In both
cases, the maximum latency time is one bus clock cycle plus any skew or delay introduced by the trigger
circuitry.
After ETRIGE is enabled, conversions cannot be started by a write to ATDCTL5, but rather must be
triggered externally.
If the level mode is active and the external trigger both de-asserts and re-asserts itself during a conversion
sequence, this does not constitute an overrun. Therefore, the flag is not set. If the trigger remains asserted
in level mode while a sequence is completing, another sequence will be triggered immediately.
6.4.2.2 General-Purpose Digital Input Port Operation
The input channel pins can be multiplexed between analog and digital data. As analog inputs, they are
multiplexed and sampled to supply signals to the A/D converter. As digital inputs, they supply external
input data that can be accessed through the digital port registers (PORTAD0 & PORTAD1) (input-only).
The analog/digital multiplex operation is performed in the input pads. The input pad is always connected
to the analog inputs of the ATD10B16C. The input pad signal is buffered to the dig ital port registers. This
buffer can be turned on or off with the ATDDIEN0 & ATDDIEN1 register. This is important so that the
buffer does not draw excess current when analog potentials are presented at its input.
6.4.3 Operation in Low Power Modes
The ATD10B16C can be configured for lower MCU power consumption in three different ways:
•Stop Mode
Stop Mode: This halts A/D conversion. Exit from Stop mode will resume A/D conversion, But due
to the recovery time the result of this conversion should be ignored.
Entering stop mode causes all clocks to halt and thus the system is placed in a minimum power
standby mode. This halts any conversion sequence in progress. During recovery from stop mode,
there must be a minimum delay for the stop recovery time tSR before initiating a new ATD
conversion sequence.
•Wait Mode
Wait Mode with AWAI = 1: This halts A/D conversion. Exit from Wait mode will resume A/D
conversion, but due to the recovery time the result of this conversion should be ignored.
Entering wait mode, the ATD conversion either continues or halts for low power depending on the
logical value of the AWAIT bit.
•Freeze Mode
Writing ADPU = 0 (Note that all ATD registers remain accessible.): This aborts any A/D
conversion in progress.
In freeze mode, the ATD10B16C will behave according to the logical values of the FRZ1 and
FRZ0 bits. This is useful for debugging and emulation.
NOTE
The reset value for the ADPU bit is zero. Therefore, when this module is
reset, it is reset into the power down state.
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
MC9S12E256 Data Sheet, Rev. 1.08
234 Freescale Semiconductor
6.5 Resets
At reset the ATD10B16C is in a power down state. The reset state of each individual bit is listed within
Section 6.3, “Memory Map and Register Definition,” which details the registers and their bit fields.
6.6 Interrupts
The interrupt requested by the ATD10B16C is listed in Table 6-28. Refer to MCU specification for related
vector address and priority.
See Section 6.3.2, “Register Descriptions,” for further details.
Table 6-28. ATD Interrupt Vectors
Interrupt Source CCR Mask Local Enable
Sequence Complete Interrupt I bit ASCIE in ATDCTL2
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 235
Chapter 7
Digital-to-Analog Converter (DAC8B1CV1)
7.1 Introduction
The DAC8B1C is a 8-bit, 1-channel digital-to-analog converter module.
7.1.1 Features
The DAC8B1C includes these features:
• 8-bit resolution.
• One output independent monotonic channel.
7.1.2 Modes of Operation
The DAC8B1C functions the same in normal, special, and emulation modes. It has two low-power modes,
wait and stop modes.
7.1.2.1 Run Mode
Normal mode of operation.
7.1.2.2 Wait Mode
Entering wait mode, the DAC conversion either continues or aborts for low power, depending on the
logical state of the DACWAI bit.
7.1.2.3 Stop Mode
The DAC8B1C module is disabled in stop mode for reduced power consumption. The STOP instruction
does not affect DAC register states.
7.1.3 Block Diagram
Figure 7-1 illustrates the functional block diagram of the DAC8B1C module.
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
236 Freescale Semiconductor
Figure 7-1. DAC8B1C Functional Block Diagram
7.2 External Signal Description
The DAC8B1C module requires four external pins. These pins are listed in Table 7-1 below.
Table 7-1. DAC8B1C External Pin Descriptions
Name Function
DAO DAC channel output
VDDA DAC power supply
VSSA DAC ground supply
VREF Reference voltage for DAC conversion
VRL Reference ground voltage connected
to VSSA outside the DAC boundary
VDDA
VREF
VRL
VSSA
CONTROL CIRCUIT
ANALOG SUB-BLOCK
O/P VOLTAGE
DAO
DAC
CHANNEL
DACC
DACD
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 237
7.2.1 DAO — DAC Channel Output
This pin is used as the analog output pin of the DAC8B1C module. The value represents the analog voltage
level between VSSA and VREF.
7.2.2 VDDA — DAC Power Supply
This pin serves as the power supply pin.l
7.2.3 VSSA — DAC Ground Supply
This pin serves as an analog ground reference to the DAC.
7.2.4 VREF — DAC Reference Supply
This pin serves as the source for the high reference potential. Separation from the power supply pins
accommodates the filtering necessary to achieve the accuracy of which the system is capable.
7.2.5 VRL — DAC Reference Ground Supply
This pin serves as the ground for the low reference potential. This pin is connected to VSSA outside the
DAC module boundary to accommodate the filtering necessary to achieve the accuracy of which the
system is capable.
7.3 Memory Map and Registers
This section provides a detailed description of all memory and registers accessible to the end user.
7.3.1 Module Memory Map
Figure 7-2 summarizes the DAC8B1C memory map. The base address is defined at the chip level and the
address offset is defined at the module level.
AddressName Bit 765432 1Bit 0
0x0000 DACC0 RDACE DACTE 0 0 DJM DSGN DACWAI DACOE
W
0x0001 DACC1 R0 00000 0 0
W
0x0002 DACD (Left
Justified)
RBIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
W
0x0003 DACD (Right
Justified)
RBIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
W
= Unimplemented or Reserved
Figure 7-2. DAC8B1C Register Summary
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
238 Freescale Semiconductor
7.3.2 Register Descriptions
This section consists of register descriptions arranged in address order. Each description includes a
standard register diagram with an associated figure number. Details of register bit and field function follow
the register diagrams, in descending bit order.
7.3.2.1 DAC Control Register 0 (DACC0)
Read: anytime (reserved locations read zero)
Write: anytime except DACTE is available only in special modes
Module Base + 0x0000
76543210
R
DACE
DACTE 0 0
DJM DSGN DACWAI DACOE
W
Reset00000000
= Unimplemented or Reserved
Figure 7-3. DAC Control Register 0 (DACC0)
Table 7-2. DACC0 Field Descriptions
Field Description
7
DACE
DAC Enable — This bit enables digital-to-analog converter functionality. When enabled, an analog voltage based
on the digital value in the DAC data register will be output. When disabled, DAO pin is high-impedance.
0 DAC is disabled and powered down
1 DAC is enabled for conversion
6
DACTE
DAC Test Enable — This reserved bit is designed for factory test purposes only and is not intended for general
user access. Writing to this bit when in special test modes can alter DAC functionality.
3
DJM
Data Register Data Justification — This bit controls the justification of the data in the DAC data register
(DACD). If DJM is clear (left-justified), the data to be converted must be written to left justified DACD and the right
justified DACD register will read zeroes. If DJM is set (right-justified), the data to be converted is written to right
justified DACD register and left justified DACD register reads zeroes. Data is preserved if DJM bit is changed
after data is written.
0 Left justified data in DAC data register
1 Right justified data in DAC data register
2
DSGN
Data Register Signed — This bit selects between signed and unsigned conversion data representation in the
DAC data register. Signed data is represented as 2’s complement.
0 Unsigned data representation in DAC data register
1 Signed data representation in DAC data register
1
DACWAI
DAC Stop in WAIT Mode — DACWAI disables the DAC8B1C module (no new conversion is done) during wait
mode.
0 DAC is enabled during wait mode
1 DAC is disabled and powered down during wait mode
0
DACOE
DAC Output Enable — This bit enables the output on the DAO pin. To output the DAC voltage, the DACOE bit
and the DACE bit must be set. When disabled, DAO pin is high-impedance.
0 Output is not available for external use
1 Output on DAO pin enabled.
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 239
7.3.2.2 Reserved Register (DACC1)
This register is reserved.
Read: always read $00
Write: unimplemented
7.3.2.3 DAC Data Register — Left Justified (DACD)
Read: read zeroes when DJM is set
Write: unimplemented when DJM is set
The DAC data register is an 8-bit readable/writable register that stores the data to be converted when DJM
bit is clear. When the DACE bit is set, the value in this register is converted into an analog voltage such
that values from $00 to $FF result in equal voltage increments from VSSA to VREF. When DJM bit is set,
this register reads zeroes and cannot be written.
Module Base + 0x0000
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 7-4. Reserved Register (DACC1)
Module Base + 0x0002
76543210
R
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
W
Reset00000000
Figure 7-5. DAC Data Register — Left Justified (DACD)
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
240 Freescale Semiconductor
7.3.2.4 DAC Data Register — Right Justified (DACD)
Read: read zeroes when DJM is clear
Write: unimplemented when DJM is clear
The DAC data register is an 8-bit readable/writable register that stores the data to be converted when DJM
bit is set. When the DACE bit is set, the value in this register is converted into an analog voltage such that
values from $00 to $FF result in equal voltage increments from VSSA to VREF. When DJM bit is clear , this
register reads zeroes and cannot be written.
Module Base + 0x0003
76543210
R
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
W
Reset00000000
Figure 7-6. DAC Data Register — Right Justified (DACD)
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 241
7.4 Functional Description
The DAC8B1C module consists of analog and digital sub-blocks.
7.4.1 Functional Description
Data to be converted is written to DACD register. The data can be mapped either to left end or right end
of DACD register by clearing or setting DJM bit of DACC0 register. Also, the data written to DACD can
be a signed or unsigned data depending on DSGN bit of DACC0 register. See Table 7-3 below for data
formats. The maximum unsigned data that can be written to DACD register is $FF while the minimum
value is $00. If the data is signed, the maximum value that can be written to DACD is $7F while the
minimum value is $80, where $7F (signed) corresponds to $FF (unsigned) and $80 (signed) corresponds
to $00 (unsigned). Table 7-4 shows this characteristic between signed, unsigned data values and their
corresponding voltage output. See Table 7-4 for DAC signed and un-signed data and DAC output codes.
Table 7-3. Data Formats
DJM DSGN Description and Bus Bit Mapping
0 0 8 bit/left justified/unsigned — bits 15–8
0 1 8 bit/left justified/signed — bits 15–8
1 0 8 bit/right justified/unsigned — bits 7–0
1 1 8 bit/right justified/signed bits — 7–0
Table 7-4. Signed and Unsigned Data
and DAC Output Codes
Input signal
VRL = 0
VREF/VRH = 5.12volts
Signed
8-Bit
Codes
Unsigned
8-Bit
Codes
5.12 7F FF
5.08 7E FE
5.07 7D FD
2.580 01 81
2.56 00 80
2.54 FF 7F
2.52 FE 7E
0.020 81 01
0.000 80 00
Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
MC9S12E256 Data Sheet, Rev. 1.08
242 Freescale Semiconductor
Conversion of the data in DACD register takes place as soon as DACE bit of DACC0 is set. The transfer
characteristic of the day module is shown in Figure 7-7.
Figure 7-7. DAC8B1C Transfer Function
7.5 Resets
7.5.1 General
The DAC8B1C module is reset on a system reset. If the system reset signal is activated, the DAC registers
are initialized to their reset state and the DAC8B1C module is powered down. This occurs as a function
of the register file initialization. If the module is performing a conversion, the current conversion is
terminated.
Analog Output Voltage
Digital Input
1 LSB = 21.5 mV when VDDA = 5.5 V
1 LSB = 11.5 mV when VDDA = 3.0 V
$00
$01
$02
$FE
$FF
1 LSB
2 LSB
3 LSB
255 LSB
256 LSB
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 243
Chapter 8
Serial Communication Interface (SCIV4)
8.1 Introduction
This block description chapter provides an overview of serial communication interface (SCI) module.
The SCI allows full duplex, asynchronous, serial communication between the CPU and remote devices,
including other CPUs. The SCI transmitter and receiver operate independently , although they use the same
baud rate generator. The CPU monitors the status of the SCI, writes the data to be transmitted, and
processes received data.
8.1.1 Glossary
IR: infrared
IrDA: Infrared Design Association
IRQ: interrupt request
LSB: least significant bit
MSB: most significant bit
NRZ: non-return-to-Zero
RZI: return-to-zero-inverted
RXD: receive pin
SCI: serial communication interface
TXD: transmit pin
8.1.2 Features
The SCI includes these distinctive features:
• Full-duplex or single-wire operation
• Standard mark/space non-return-to-zero (NRZ) format
• Selectable IrDA 1.4 return-to-zero-inverted (RZI) format with programmable pulse widths
• 13-bit baud rate selection
• Programmable 8-bit or 9-bit data format
• Separately enabled transmitter and receiver
• Programmable polarity for transmitter and receiver
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
244 Freescale Semiconductor
• Programmable transmitter output parity
• Two receiver wakeup methods:
— Idle line wakeup
— Address mark wakeup
• Interrupt-driven operation with eight flags:
— Transmitter empty
— Transmission complete
— Receiver full
— Idle receiver input
— Receiver overrun
— Noise error
— Framing error
— Parity error
• Receiver framing error detection
• Hardware parity checking
• 1/16 bit-time noise detection
8.1.3 Modes of Operation
The SCI functions the same in normal, special, and emulation modes. It has two low-power modes, wait
and stop modes.
8.1.3.1 Run Mode
Normal mode of operation.
8.1.3.2 Wait Mode
SCI operation in wait mode depends on the state of the SCISWAI bit in the SCI control register 1
(SCICR1).
• If SCISWAI is clear, the SCI operates normally when the CPU is in wait mode.
• If SCISWAI is set, SCI clock generation ceases and the SCI module enters a power-conservation
state when the CPU is in wait mode. Setting SCISWAI does not affect the state of the receiver
enable bit, RE, or the transmitter enable bit, TE.
If SCISWAI is set, any transmission or reception in progress stops at wait mode entry. The
transmission or rece ption resumes when either an internal or external interrupt brings the CPU out
of wait mode. Exiting wait mode by reset aborts any transmission or reception in progress and
resets the SCI.
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 245
8.1.3.3 Stop Mode
The SCI is inactive during stop mode for reduced power consumption. The STOP instruction does not
affect the SCI register states, but the SCI bus clock will be disabled. The SCI operation resumes after an
external interrupt br ings the CPU out of stop mode. Exiting stop mode by reset aborts any transmission or
reception in progress and resets the SCI.
8.1.4 Block Diagram
Figure 8-1 is a high level block diagram of the SCI module, showing the interaction of various function
blocks.
Figure 8-1. SCI Block Diagram
SCI Data Register
Receive Shift Register
Receive & Wakeup Control
Data Format Control
Transmit Control
Transmit Shift Register
SCI Data Register
BAUD
Generator
IRQ
Generation
IRQ
Generation
RXD Data In
÷16
Bus Clk
Encoder
Infrared Data Out TXD
Decoder
Infrared
TC Interrupt Request
IDLE Interrupt Request
SCI
Interrupt
Request
RDRF/OR
Interrupt
Request
TDRE
Interrupt
Request
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
246 Freescale Semiconductor
8.2 External Signal Description
The SCI module has a total of two external pins.
8.2.1 TXD — SCI Transmit Pin
The TXD pin transmits SCI (standard or infrared) data. It will idle high in either mode and is high
impedance anytime the transmitter is disabled.
8.2.2 RXD — SCI Receive Pin
The RXD pin receives SCI (standard or infrared) data. An idle line is detected as a li ne high. This input is
ignored when the receiver is disabled and should be terminated to a known voltage.
8.3 Memory Map and Register Definition
This subsection provides a detailed description of all the SCI registers.
8.3.1 Module Memory Map
The memory map for the SCI module is given in Figure 8-2. The address listed for each register is the
address offset. The total address for each register is the sum of the base address for the SCI module and
the address offset for each register.
8.3.2 Register Descriptions
This subsection consists of register descriptions in address order. Each description includes a standard
register diagram with an associated figure number. Writes to reserved register locations do not have any
effect and reads of these locations return a 0. Details of register bit and field function follow the register
diagrams, in bit order.
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 247
Register
Name Bit 7654321Bit 0
SCIBDH R IREN TNP1 TNP0 SBR12 SBR11 SBR10 SBR9 SBR8
W
SCIBDL R SBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
W
SCICR1 R LOOPS SCISWAI RSRC M WAKE ILT PE PT
W
SCICR2 R TIE TCIE RIE ILIE TE RE RWU SBK
W
SCISR1 R TDRE TC RDRF IDLE OR NF FE PF
W
SCISR2 R 0 0 0 TXPOL RXPOL BRK13 TXDIR RAF
W
SCIDRH R R8 T8 000000
W
SCIDRLRR7R6R5R4R3R2R1R0
WT7T6T5T4T3T2T1T0
= Unimplemented or Reserved
Figure 8-2. SCI Registers Summary
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
248 Freescale Semiconductor
8.3.2.1 SCI Baud Rate Registers (SCIBDH and SCIBDL)
76543210
R
IREN TNP1 TNP0 SBR12 SBR11 SBR10 SBR9 SBR8
W
Reset00000000
Figure 8-3. SCI Baud Rate Register High (SCIBDH)
Table 8-1. SCIBDH Field Descriptions
Field Description
7
IREN
Infrared Enable Bit — This bit enables/disables the infrared modulation/demodulation submodule.
0IR disabled
1 IR enabled
6:5
TNP[1:0]
Transmitter Narrow Pulse Bits — These bits determine if the SCI will transmit a 1/16, 3/16, 1/32, or 1/4 narrow
pulse. Refer to Ta b l e 8- 3 .
4:0
SBR[11:8]
SCI Baud Rate Bits — The baud rate for the SCI is determined by the bits in this register. The baud rate is
calculated two different ways depending on the state of the IREN bit.
The formulas for calculating the baud rate are:
When IREN = 0 then,
SCI baud rate = SCI module clock / (16 x SBR[12:0])
When IREN = 1 then,
SCI baud rate = SCI module clock / (32 x SBR[12:1])
76543210
R
SBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
W
Reset00000100
Figure 8-4. SCI Baud Rate Register Low (SCIBDL)
Table 8-2. SCIBDL Field Descriptions
Field Description
7:0
SBR[7:0]
SCI Baud Rate Bits — The baud rate for the SCI is determined by the bits in this register. The baud rate is
calculated two different ways depending on the state of the IREN bit.
The formulas for calculating the baud rate are:
When IREN = 0 then,
SCI baud rate = SCI module clock / (16 x SBR[12:0])
When IREN = 1 then,
SCI baud rate = SCI module clock / (32 x SBR[12:1])
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 249
Read: anytime
NOTE
If only SCIBDH is written to, a read will not return the correct data until
SCIBDL is written to as well, following a write to SCIBDH.
Write: anytime
The SCI baud rate register is used to determine the baud rate of the SCI and to control the infrared
modulation/demodulation submodule.
NOTE
The baud rate generator is disabled after reset and not started until the TE
bit or the RE bit is set for the first time. The baud rate generator is disabled
when (SBR[12:0] = 0 and IREN = 0) or (SBR[12:1] = 0 and IREN = 1).
Writing to SCIBDH has no effect without writing to SCIBDL, because
writing to SCIBDH puts the data in a temporary location until SCIBDL is
written to.
8.3.2.2 SCI Control Register 1 (SCICR1)
Read: anytime
Write: anytime
Table 8-3. IRSCI Transmit Pulse Width
TNP[1:0] Narrow Pulse Width
11 1/4
10 1/32
01 1/16
00 3/16
76543210
R
LOOPS SCISWAI RSRC M WAKE ILT PE PT
W
Reset00000000
Figure 8-5. SCI Control Register 1 (SCICR1)
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
250 Freescale Semiconductor
Table 8-4. SCICR1 Field Descriptions
Field Description
7
LOOPS
Loop Select Bit — LOOPS enables loop operation. In loop operation, the RXD pin is disconnected from the SCI
and the transmitter output is internally connected to the receiver input. Both the transmitter and the receiver must
be enabled to use the loop function.
0 Normal operation enabled
1 Loop operation enabled
The receiver input is determined by the RSRC bit.
6
SCISWAI
SCI Stop in Wait Mode Bit — SCISWAI disables the SCI in wait mode.
0 SCI enabled in wait mode
1 SCI disabled in wait mode
5
RSRC
Receiver Source Bit — When LOOPS = 1, the RSRC bit determines the source for the receiver shift register
input.
0 Receiver input internally connected to transmitter output
1 Receiver input connected externally to transmitter
Refer to Ta b l e 8 - 5 .
4
M
Data Format Mode Bit — MODE determines whether data characters are eight or nine bits long.
0 One start bit, eight data bits, one stop bit
1 One start bit, nine data bits, one stop bit
3
WAKE
Wakeup Condition Bit — WAKE determines which condition wakes up the SCI: a logic 1 (address mark) in the
most significant bit position of a received data character or an idle condition on the RXD pin.
0 Idle line wakeup
1 Address mark wakeup
2
ILT
Idle Line Type Bit — ILT determines when the receiver starts counting logic 1s as idle character bits. The
counting begins either after the start bit or after the stop bit. If the count begins after the start bit, then a string of
logic 1s preceding the stop bit may cause false recognition of an idle character. Beginning the count after the
stop bit avoids false idle character recognition, but requires properly synchronized transmissions.
0 Idle character bit count begins after start bit
1 Idle character bit count begins after stop bit
1
PE
Parity Enable Bit — PE enables the parity function. When enabled, the parity function inserts a parity bit in the
most significant bit position.
0 Parity function disabled
1 Parity function enabled
0
PT
Parity Type Bit — PT determines whether the SCI generates and checks for even parity or odd parity. With even
parity, an even number of 1s clears the parity bit and an odd number of 1s sets the parity bit. With odd parity, an
odd number of 1s clears the parity bit and an even number of 1s sets the parity bit.
0 Even parity
1 Odd parity
Table 8-5. Loop Functions
LOOPS RSRC Function
0 x Normal operation
1 0 Loop mode with transmitter output internally connected to receiver input
1 1 Single-wire mode with TXD pin connected to receiver input
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 251
8.3.2.3 SCI Control Register 2 (SCICR2)
Read: anytime
Write: anytime
76543210
R
TIE TCIE RIE ILIE TE RE RWU SBK
W
Reset00000000
Figure 8-6. SCI Control Register 2 (SCICR2)
Table 8-6. SCICR2 Field Descriptions
Field Description
7
TIE
Transmitter Interrupt Enable Bit —TIE enables the transmit data register empty flag, TDRE, to generate
interrupt requests.
0 TDRE interrupt requests disabled
1 TDRE interrupt requests enabled
6
TCIE
Transmission Complete Interrupt Enable Bit — TCIE enables the transmission complete flag, TC, to generate
interrupt requests.
0 TC interrupt requests disabled
1 TC interrupt requests enabled
5
RIE
Receiver Full Interrupt Enable Bit — RIE enables the receive data register full flag, RDRF, or the overrun flag,
OR, to generate interrupt requests.
0 RDRF and OR interrupt requests disabled
1 RDRF and OR interrupt requests enabled
4
ILIE
Idle Line Interrupt Enable Bit — ILIE enables the idle line flag, IDLE, to generate interrupt requests.
0 IDLE interrupt requests disabled
1 IDLE interrupt requests enabled
3
TE
Transmitter Enable Bit — TE enables the SCI transmitter and configures the TXD pin as being controlled by the
SCI. The TE bit can be used to queue an idle preamble.
0 Transmitter disabled
1 Transmitter enabled
2
RE
Receiver Enable Bit — RE enables the SCI receiver.
0 Receiver disabled
1 Receiver enabled
1
RWU
Receiver Wakeup Bit — Standby state
0 Normal operation.
1 RWU enables the wakeup function and inhibits further receiver interrupt requests. Normally, hardware wakes
the receiver by automatically clearing RWU.
0
SBK
Send Break Bit — Toggling SBK sends one break character (10 or 11 logic 0s, respectively 13 or 14 logics 0s
if BRK13 is set). Toggling implies clearing the SBK bit before the break character has finished transmitting. As
long as SBK is set, the transmitter continues to send complete break characters (10 or 11 bits, respectively 13
or 14 bits).
0 No break characters
1 Transmit break characters
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
252 Freescale Semiconductor
8.3.2.4 SCI Status Register 1 (SCISR1)
The SCISR1 and SCISR2 registers provide inputs to the MCU for generation of SCI interrupts. Also, these
registers can be polled by the MCU to check the status of these bits. The flag-clearing procedures require
that the status register be read followed by a read or write to the SCI data register. It is permissible to
execute other instructions between the two steps as long as it does not compromise the handling of I/O.
Note that the order of operations is important for flag clearing.
Read: anytime
Write: has no meaning or effect
76543210
R TDRE TC RDRF IDLE OR NF FE PF
W
Reset11000000
= Unimplemented or Reserved
Figure 8-7. SCI Status Register 1 (SCISR1)
Table 8-7. SCISR1 Field Descriptions
Field Description
7
TDRE
Transmit Data Register Empty Flag — TDRE is set when the transmit shift register receives a byte from the
SCI data register. When TDRE is 1, the transmit data register (SCIDRH/L) is empty and can receive a new value
to transmit.Clear TDRE by reading SCI status register 1 (SCISR1), with TDRE set and then writing to SCI data
register low (SCIDRL).
0 No byte transferred to transmit shift register
1 Byte transferred to transmit shift register; transmit data register empty
6
TC
Transmit Complete Flag — TC is set low when there is a transmission in progress or when a preamble or break
character is loaded. TC is set high when the TDRE flag is set and no data, preamble, or break character is being
transmitted.When TC is set, the TXD pin becomes idle (logic 1). Clear TC by reading SCI status register 1
(SCISR1) with TC set and then writing to SCI data register low (SCIDRL). TC is cleared automatically when data,
preamble, or break is queued and ready to be sent. TC is cleared in the event of a simultaneous set and clear of
the TC flag (transmission not complete).
0 Transmission in progress
1 No transmission in progress
5
RDRF
Receive Data Register Full Flag — RDRF is set when the data in the receive shift register transfers to the SCI
data register. Clear RDRF by reading SCI status register 1 (SCISR1) with RDRF set and then reading SCI data
register low (SCIDRL).
0 Data not available in SCI data register
1 Received data available in SCI data register
4
IDLE
Idle Line Flag1 — IDLE is set when 10 consecutive logic 1s (if M = 0) or 11 consecutive logic 1s (if M = 1) appear
on the receiver input. After the IDLE flag is cleared, a valid frame must again set the RDRF flag before an idle
condition can set the IDLE flag.Clear IDLE by reading SCI status register 1 (SCISR1) with IDLE set and then
reading SCI data register low (SCIDRL).
0 Receiver input is either active now or has never become active since the IDLE flag was last cleared
1 Receiver input has become idle
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 253
3
OR
Overrun Flag2 — OR is set when software fails to read the SCI data register before the receive shift register
receives the next frame. The OR bit is set immediately after the stop bit has been completely received for the
second frame. The data in the shift register is lost, but the data already in the SCI data registers is not affected.
Clear OR by reading SCI status register 1 (SCISR1) with OR set and then reading SCI data register low
(SCIDRL).
0 No overrun
1Overrun
2
NF
Noise Flag — NF is set when the SCI detects noise on the receiver input. NF bit is set during the same cycle as
the RDRF flag but does not get set in the case of an overrun. Clear NF by reading SCI status register 1(SCISR1),
and then reading SCI data register low (SCIDRL).
0 No noise
1Noise
1
FE
Framing Error Flag — FE is set when a logic 0 is accepted as the stop bit. FE bit is set during the same cycle
as the RDRF flag but does not get set in the case of an overrun. FE inhibits further data reception until it is
cleared. Clear FE by reading SCI status register 1 (SCISR1) with FE set and then reading the SCI data register
low (SCIDRL).
0 No framing error
1 Framing error
0
PF
Parity Error Flag — PF is set when the parity enable bit (PE) is set and the parity of the received data does not
match the parity type bit (PT). PF bit is set during the same cycle as the RDRF flag but does not get set in the
case of an overrun. Clear PF by reading SCI status register 1 (SCISR1), and then reading SCI data register low
(SCIDRL).
0 No parity error
1 Parity error
1When the receiver wakeup bit (RWU) is set, an idle line condition does not set the IDLE flag.
2The OR flag may read back as set when RDRF flag is clear. This may happen if the following sequence of events occurs:
1. After the first frame is received, read status register SCISR1 (returns RDRF set and OR flag clear);
2. Receive second frame without reading the first frame in the data register (the second frame is not received and OR flag
is set);
3. Read data register SCIDRL (returns first frame and clears RDRF flag in the status register);
4. Read status register SCISR1 (returns RDRF clear and OR set).
Event 3 may be at exactly the same time as event 2 or any time after. When this happens, a dummy SCIDRL read following
event 4 will be required to clear the OR flag if further frames are to be received.
Table 8-7. SCISR1 Field Descriptions (continued)
Field Description
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
254 Freescale Semiconductor
8.3.2.5 SCI Status Register 2 (SCISR2)
Read: anytime
Write: anytime
76543210
R0 0 0
TXPOL RXPOL BRK13 TXDIR
RAF
W
Reset00000000
= Unimplemented or Reserved
Figure 8-8. SCI Status Register 2 (SCISR2)
Table 8-8. SCISR2 Field Descriptions
Field Description
4
TXPOL
Transmit Polarity — This bit control the polarity of the transmitted data. In NRZ format, a 1 is represented by a
mark and a 0 is represented by a space for normal polarity, and the opposite for inverted polarity. In IrDA format,
a 0 is represented by short high pulse in the middle of a bit time remaining idle low for a 1 for normal polarity, and
a 0 is represented by short low pulse in the middle of a bit time remaining idle high for a 1 for inverted polarity.
0 Normal polarity
1 Inverted polarity
3
RXPOL
Receive Polarity — This bit control the polarity of the received data. In NRZ format, a 1 is represented by a mark
and a 0 is represented by a space for normal polarity, and the opposite for inverted polarity. In IrDA format, a 0
is represented by short high pulse in the middle of a bit time remaining idle low for a 1 for normal polarity, and a
0 is represented by short low pulse in the middle of a bit time remaining idle high for a 1 for inverted polarity.
0 Normal polarity
1 Inverted polarity
2
BRK13
Break Transmit Character Length — This bit determines whether the transmit break character is 10 or 11 bit
respectively 13 or 14 bits long. The detection of a framing error is not affected by this bit.
0 Break character is 10 or 11 bit long
1 Break character is 13 or 14 bit long
1
TXDIR
Transmitter Pin Data Direction in Single-Wire Mode — This bit determines whether the TXD pin is going to
be used as an input or output, in the single-wire mode of operation. This bit is only relevant in the single-wire
mode of operation.
0 TXD pin to be used as an input in single-wire mode
1 TXD pin to be used as an output in single-wire mode
0
RAF
Receiver Active Flag — RAF is set when the receiver detects a logic 0 during the RT1 time period of the start
bit search. RAF is cleared when the receiver detects an idle character.
0 No reception in progress
1 Reception in progress
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 255
8.3.2.6 SCI Data Registers (SCIDRH and SCIDRL)
Read: anytime; reading accesses SCI receive data register
Write: anytime; writing accesses SCI transmit data register; writing to R8 has no effect
NOTE
If the value of T8 is the same as in the previous transmission, T8 does not
have to be rewritten.The same value is transmitted until T8 is rewritten
In 8-bit data format, only SCI data register low (SCIDRL) needs to be
accessed.
When transmitting in 9-bit data format and using 8-bit write instructions,
write first to SCI data register high (SCIDRH) then to SCIDRL.
76543210
RR8
T8
000000
W
Reset00000000
= Unimplemented or Reserved
Figure 8-9. SCI Data Register High (SCIDRH)
Table 8-9. SCIDRH Field Descriptions
Field Description
7
R8
Received Bit 8 — R8 is the ninth data bit received when the SCI is configured for 9-bit data format (M = 1).
6
T8
Transmit Bit 8 — T8 is the ninth data bit transmitted when the SCI is configured for 9-bit data format (M = 1).
76543210
RR7R6R5R4R3R2R1R0
WT7 T6 T5 T4 T3 T2 T1 T0
Reset00000000
Figure 8-10. SCI Data Register Low (SCIDRL)
Table 8-10. SCIDRL Field Descriptions
Field Description
7:0
R[7:0]
T[7:0}
Received bits 7 through 0 — For 9-bit or 8-bit data formats
Transmit bits 7 through 0 — For 9-bit or 8-bit formats
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
256 Freescale Semiconductor
8.4 Functional Description
This subsection provides a complete functional description of the SCI block, detailing the operation of the
design from the end user’s perspective in a number of descriptions.
Figure 8-11 shows the structure of the SCI module. The SCI allows full duplex, asynchronous, serial
communication between the CPU and remote devices, including other CPUs. The SCI transmitter and
receiver operate independently, although they use the same baud rate generator. The CPU monitors the
status of the SCI, writes the data to be transmitted, and processes received data.
Figure 8-11. Detailed SCI Block Diagram
SCI DATA
RECEIVE
SHIFT REGISTER
SCI DATA
REGISTER
TRANSMIT
SHIFT REGISTER
REGISTER
BAUD RATE
GENERATOR
SBR12–SBR0
BUS
TRANSMIT
CONTROL
÷16
RECEIVE
AND WAKEUP
DATA FORMAT
CONTROL
CONTROL
T8
PF
FE
NF
RDRF
IDLE
TIE
OR
TCIE
TDRE
TC
R8
RAF
LOOPS
RWU
RE
PE
ILT
PT
WAKE
M
CLOCK
ILIE
RIE
RXD
RSRC
SBK
LOOPS
TE
RSRC
IREN
R16XCLK
Ir_RXD
TXD
Ir_TXD
R16XCLK
R32XCLK
TNP[1:0] IREN
TRANSMIT
ENCODER
RECEIVE
DECODER
SCRXD
SCTXD
INFRARED
INFRARED
TC
TDRE
RDRF/OR
IDLE
SCI
Interrupt
Request
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 257
8.4.1 Infrared Interface Submodule
This module provides the capability of transmitting narrow pulses to an IR LED and receiving narrow
pulses and transforming them to serial bits, which are sent to the SCI. The IrDA physical layer
specification defines a half-duplex infrared communication link for exchange data. The full standard
includes data rates up to 16 Mbits/s. This design covers only data rates between 2.4 kbits/s and
115.2 kbits/s.
The infrared submodule consists of two major blocks: the transmit encoder and the receive decoder. The
SCI transmits serial bits of data which are encoded by the infrared submodule to transmit a narrow pulse
for every 0 bit. No pulse is transmitted for every 1 bit. When receiving data, the IR pulses should be
detected using an IR photo diode and transformed to CMOS levels by the IR receive decoder (external
from the MCU). The narrow pulses are then stretched by the infrared submodule to get back to a serial bit
stream to be received by the SCI. The polarity of transmitted pulses and expected receive pulses can be
inverted so that a direct connection can be made to external IrDA transceiver modules that uses active low
pulses.
The infrared submodule receives its clock sources from the SCI. One of these two clocks are selected in
the infrared submodule in order to generate either 3/16, 1/16, 1/32, or 1/4 narrow pulses during
transmission. The infrared block receives two clock sources from the SCI, R16XCLK, and R32XCLK,
which are configured to generate the narrow pulse width during transmission. The R16XCLK and
R32XCLK are internal clocks with frequencies 16 and 32 times the baud rate respectively. Both
R16XCLK and R32XCLK clocks are used for transmitting data. The receive decoder uses only the
R16XCLK clock.
8.4.1.1 Infrared Transmit Encoder
The infrared transmit encoder converts serial bits of data from transmit shift register to the TXD pin. A
narrow pulse is transmitted for a 0 bit and no pulse for a 1 bit. The narrow pulse is sent in the middle of
the bit with a duration of 1/32, 1/16, 3/16, or 1/4 of a bit time. A narrow high pulse is transmitted for a 0 bit
when TXPOL is cleared, while a narrow low pulse is transmitted for a 0 bit when TXPOL is set.
8.4.1.2 Infrared Receive Decoder
The infrared receive block converts data from the RXD pin to the receive shift register. A narrow pulse is
expected for each 0 received and no pulse is expected for each 1 received. A narrow high pulse is expected
for a 0 bit when RXPOL is cleared, while a narrow low pulse is expected for a 0 bit when RXPOL is set.
This receive decoder meets the edge jitter requirement as defined by the IrDA serial infrared physical layer
specification.
8.4.2 Data Format
The SCI uses the standard NRZ mark/space data format. When Infrared is enabled, the SCI uses RZI data
format where 0s are represented by light pulses and 1s remain low. See Figure 8-12.
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
258 Freescale Semiconductor
Figure 8-12. SCI Data Formats
Each data character is contained in a frame that includes a start bit, eight or nine data bits, and a stop bit.
Clearing the M bit in SCI control register 1 configures the SCI for 8-bit data characters. A frame with eight
data bits has a total of 10 bits. Setting the M bit configures the SCI for nine-bit data characters. A frame
with nine data bits has a total of 11 bits
When the SCI is configured for 9-bit data characters, the ninth data bit is the T8 bit in SCI data register
high (SCIDRH). It remains unchanged after transmission and can be used repeatedly without rewriting it.
A frame with nine data bits has a total of 11 bits.
Table 8-12. Example of 9-Bit Data Formats
Table 8-11. Example of 8-bit Data Formats
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
18001
17011
17 1
1
1The address bit identifies the frame as an address
character. See Section 8.4.5.6, “Receiver Wakeup”.
01
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
19001
18011
18 1
1
1The address bit identifies the frame as an address
character. See Section 8.4.5.6, “Receiver Wakeup”.
01
BIT 5
START
BIT BIT 0 BIT 1
NEXT
STOP
BIT
START
BIT
8-BIT DATA FORMAT
(BIT M IN SCICR1 CLEAR)
START
BIT BIT 0
NEXT
STOP
BIT
START
BIT
9-BIT DATA FORMAT
(BIT M IN SCICR1 SET)
BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 BIT 8
BIT 2 BIT 3 BIT 4 BIT 6 BIT 7
POSSIBLE
PARITY
BIT
POSSIBLE
PARITY
BIT STANDARD
SCI DATA
INFRARED
SCI DATA
STANDARD
SCI DATA
INFRARED
SCI DATA
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 259
8.4.3 Baud Rate Generation
A 13-bit modulus counter in the baud rate generator derives the baud rate for both the receiver and the
transmitter. The value from 0 to 8191 written to the SBR[12:0] bits determines the module clock divisor.
The SBR bits are in the SCI baud rate registers (SCIBDH and SCIBDL). The baud rate clock is
synchronized with the bus clock and drives the receiver. The baud rate clock divided by 16 drives the
transmitter. The receiver has an acquisition rate of 16 samples per bit time.
Baud rate generation is subject to one source of error:
• Integer division of the module clock may not give the exact target frequency.
Table 8-13 lists some examples of achieving target baud rates with a module clock frequency of 10.2 MHz.
When IREN = 0 then,
SCI baud rate = SCI module clock / (16 * SCIBR[12:0])
Table 8-13. Baud Rates (Example: Module Clock = 10.2 MHz)
Bits
SBR[12–0]
Receiver
Clock (Hz)
Transmitter
Clock (Hz)
Target Baud
Rate
Error
(%)
17 600,000.0 37,500.0 38,400 2.3
33 309,090.9 19,318.2 19,200 .62
66 154,545.5 9659.1 9600 .62
133 76,691.7 4793.2 4800 .14
266 38,345.9 2396.6 2400 .14
531 19,209.0 1200.6 1200 .11
1062 9604.5 600.3 600 .05
2125 4800.0 300.0 300 .00
4250 2400.0 150.0 150 .00
5795 1760.1 110.0 110 .00
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
260 Freescale Semiconductor
8.4.4 Transmitter
Figure 8-13. Transmitter Block Diagram
8.4.4.1 Transmitter Character Length
The SCI transmitter can accommodate either 8-bit or 9-bit data characters. The state of the M bit in SCI
control register 1 (SCICR1) determines the length of data characters. When transmitting 9-bit data, bit T8
in SCI data register high (SCIDRH) is the ninth bit (bit 8).
8.4.4.2 Character Transmission
To transmit data, the MCU writes the data bits to the SCI data registers (SCIDRH/SCIDRL), which in turn
are transferred to the transmitter shift register. The transmit shift register then shifts a frame out through
the TXD pin, after it has prefaced them with a start bit and appended them with a stop bit. The SCI data
registers (SCIDRH and SCIDRL) are the write-only buffers between the internal data bus and the transmit
shift register.
The SCI also sets a flag, the transmit data register empty flag (TDRE), every time it transfers data from
the buffer (SCIDRH/L) to the transmitter shift register. The transmit driver routine may respond to this
PE
PT
H876543210L
11-BIT TRANSMIT SHIFT REGISTER
STOP
START
T8
TDRE
TIE
TCIE
SBK
TC
PARITY
GENERATION
MSB
SCI DATA REGISTERS
LOAD FROM SCIDR
SHIFT ENABLE
PREAMBLE (ALL ONES)
BREAK (ALL 0s)
TRANSMITTER CONTROL
M
INTERNAL BUS
SBR12–SBR0
BAUD DIVIDER ÷ 16
TDRE INTERRUPT REQUEST
TC INTERRUPT REQUEST
BUS
CLOCK
TE
SCTXD
TXPOL
LOOPS
LOOP
RSRC
CONTROL TO RECEIVER
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 261
flag by writing another byte to the transmitter buffer (SCIDRH/SCIDRL), while the shift register is
shifting out the first byte.
To initiate an SCI transmission:
1. Configure the SCI:
a) Select a baud rate. Write this value to the SCI baud registers (SCIBDH/L) to begin the baud
rate generator. Remember that the baud rate generator is disabled when the baud rate is 0.
Writing to the SCIBDH has no effect without also writing to SCIBDL.
b) Write to SCICR1 to configure word length, parity, and other configuration bits (LOOPS,
RSRC, M, WAKE, ILT, PE, and PT).
c) Enable the transmitter, interrupts, receive, a nd wake up as required, by writing to the SCICR2
register bits (TIE, TCIE, RIE, ILIE, TE, RE, RWU, and SBK). A preamble or idle character
will now be shifted out of the transmitter shift register.
2. Transmit procedure for each byte:
a) Poll the TDRE flag by reading the SCISR1 or responding to the TDRE interrupt. Keep in mind
that the TDRE bit resets to 1.
b) If the TDRE flag is set, write the data to be transmitted to SCIDRH/L, where the ninth bit is
written to the T8 bit in SCIDRH if the SCI is in 9-bit data format. A new transmission will not
result until the TDRE flag has been cleared.
3. Repeat step 2 for each subsequent transmission.
NOTE
The TDRE flag is set when the shift register is loaded with the next data to
be transmitted from SCIDRH/L, which happens, generally speaking, a little
over half-way through the stop bit of the previous frame. Specifically, this
transfer occurs 9/16ths of a bit time AFTER the start of the stop bit of the
previous frame.
Writing the TE bit from 0 to a 1 automatically loads the transmit shift register with a preamble of 10
logic 1s (if M = 0) or 11 logic 1s (if M = 1). After the preamble shifts out, control logic transfers the data
from the SCI data register into the transmit shift register. A logic 0 start bit automatically goes into the
least significant bit position of the transmit shift register. A logic 1 stop bit goes into the most significant
bit position.
Hardware supports odd or even parity. When parity is enabled, the most significant bit (MSB) of the data
character is the parity bit.
The transmit data register empty flag, TDRE, in SCI status register 1 (SCISR1) becomes set when the SCI
data register transfers a byte to the transmit shift register. The TDRE flag indica tes that the SCI data
register can accept new data from the internal data bus. If the transmit interrupt enable bit, TIE, in SCI
control register 2 (SCICR2) is also set, the TDRE flag generates a transmitter interrupt request.
When the transmit shift register is not transmitting a frame, the TXD pin goes to the idle condition, logic 1.
If at any time software clears the TE bit in SCI control r egister 2 (SCICR2), the transmitter enable signal
goes low and the transmit signal goes idle.
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
262 Freescale Semiconductor
If software clears TE while a transmission is in progress (TC = 0), the frame in the transmit shift register
continues to shift out. To avoid accidentally cutting off the last frame in a message, always wait for TDRE
to go high after the last frame before clearing TE.
To separate messages with preambles with minimum idle line time, use this sequence between messages:
1. Write the last byte of the first message to SCIDRH/L.
2. Wait for the TDRE flag to go high, indicating the transfer of the last frame to the transmit shift
register.
3. Queue a preamble by clearing and then setting the TE bit.
4. Write the first byte of the second message to SCIDRH/L.
8.4.4.3 Break Characters
Writing a logic 1 to the send break bit, SBK, in SCI control register 2 (SCICR2) loads the transmit shift
register with a break character. A break character contains all logic 0s and has no start, stop, or parity bit.
Break character length depends on the M bit in SCI control register 1 (SCICR1). As long as SBK is at
logic 1, transmitter logic continuously loads break characters into the transmit shift register. After software
clears the SBK bit, the shift register finishes transmitting the last break character and then transmits at least
one logic 1. The automatic logic 1 at the end of a break character guarantees the recognition of the start bit
of the next frame.
The SCI recognizes a break character when a start bit is followed by eight or nine logic 0 data bits and a
logic 0 where the stop bit should be. Receiving a break character has these effects on SCI registers:
• Sets the framing error flag, FE
• Sets the receive data register full flag, RDRF
• Clears the SCI data registers (SCIDRH/L)
• May set the overrun flag, OR, noise flag, NF, parity error flag, PE, or the receiver active flag, RAF
(see Section 8.3.2.4, “SCI Status Register 1 (SCISR1)” and Section 8.3.2.5, “SCI Status Register
2 (SCISR2)”).
8.4.4.4 Idle Characters
An idle character (or preamble) contains all logic 1s and has no start, stop, or parity bit. Idle character
length depends on the M bit in SCI control register 1 (SCICR1). The preamble is a synchronizing idle
character that begins the first transmission initiated after writing the TE bit from 0 to 1.
If the TE bit is cleared during a transmission, the TXD pin becomes idle after completion of the
transmission in progress. Clearing and then setting the TE bit during a transmission queues an idle
character to be sent after the frame currently being transmitted.
NOTE
When queueing an idle character , return the TE bit to logic 1 before the stop
bit of the current frame shifts out through the TXD pin. Setting TE after the
stop bit appears on TXD causes data previously written to the SCI data
register to be lost. Toggle the TE bit for a queued idle character while the
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 263
TDRE flag is set and immediately before writing the next byte to the SCI
data register.
If the TE bit is clear and the transmission is complete, the SCI is not the
master of the TXD pin
8.4.5 Receiver
Figure 8-14. SCI Receiver Block Diagram
8.4.5.1 Receiver Character Length
The SCI receiver can accommodate either 8-bit or 9-bit data characters. The state of the M bit in SCI
control register 1 (SCICR1) determines the length of data characters. When receiving 9-bit data, bit R8 in
SCI data register high (SCIDRH) is the ninth bit (bit 8).
8.4.5.2 Character Reception
During an SCI reception, the receive shift register shifts a frame in from the RXD pin. The SCI data
register is the read-only buffer between the internal data bus and the receive shift register.
After a complete frame shifts into the receive shift register, the data portion of the frame transfers to the
SCI data register. The receive data register full flag, RDRF, in SCI status register 1 (SCISR1) becomes set,
ALL ONES
M
WAKE
ILT
PE
PT
RE
H876543210L
11-BIT RECEIVE SHIFT REGISTER
STOP
START
DATA
WAKEUP
PARITY
CHECKING
MSB
SCI DATA REGISTER
R8
RIE
ILIE
RWU
RDRF
OR
NF
FE
PE
INTERNAL BUS
BUS
IDLE INTERRUPT REQUEST
RDRF/OR INTERRUPT REQUEST
SBR12–SBR0
BAUD
CLOCK
IDLE
RAF
RECOVERY
LOGIC
RXPOL
LOOPS
LOOP
RSRC
CONTROL
SCRXD
FROM TXD PIN
OR TRANSMITTER
DIVIDER
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
264 Freescale Semiconductor
indicating that the received byte can be read. If the receive interrupt enable bit, RIE, in SCI control register
2 (SCICR2) is also set, the RDRF flag generates an RDRF interrupt request.
8.4.5.3 Data Sampling
The receiver samples the RXD pin at the RT clock rate. The RT clock is an internal signal with a frequency
16 times the baud rate. To adjust for baud rate mismatch, the RT clock (see Figure 8-15) is
re-synchronized:
• After every start bit
• After the receiver detects a data bit change from logic 1 to logic 0 (after the majority of data bit
samples at RT8, RT9, and RT10 returns a valid logic 1 and the majority of th e next RT8, RT9, and
RT10 samples returns a valid logic 0)
To locate the start bit, data recovery logic does an asynchronous search for a logic 0 preceded by three
logic 1s. When the falling edge of a possible start bit occurs, the RT clock begins to count to 16.
Figure 8-15. Receiver Data Sampling
To verify the start bit and to detect noise, data recovery logic takes samples at RT3, RT5, and RT7.
Table 8-14 summarizes the results of the start bit verification samples.
If start bit verification is not successful, the RT clock is reset and a new search for a start bit begins.
Table 8-14. Start Bit Verification
RT3, RT5, and RT7 Samples Start Bit Verification Noise Flag
000 Yes 0
001 Yes 1
010 Yes 1
011 No 0
100 Yes 1
101 No 0
110 No 0
111 No 0
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT5
RT8
RT7
RT6
RT11
RT10
RT9
RT15
RT14
RT13
RT12
RT16
RT1
RT2
RT3
RT4
SAMPLES
RT CLOCK
RT CLOCK COUNT
START BIT
RXD
START BIT
QUALIFICATION
START BIT DATA
SAMPLING
111111110000000
LSB
VERIFICATION
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 265
To determine the value of a data bit and to detect noise, recovery logic takes samples at RT8, RT9, and
RT10. Table 8-15 summarizes the results of the data bit samples.
NOTE
The RT8, RT9, and RT10 samples do not affect start bit ver ification . If any
or all of the RT8, RT9, and RT10 start bit samples are logic 1s following a
successful start bit verification, the noise flag (NF) is set and the receiver
assumes that the bit is a start bit (logic 0).
To verify a stop bit and to detect noise, recovery logic takes samples at RT8, RT9, and RT10. Table 8-16
summarizes the results of the stop bit samples.
Table 8-15. Data Bit Recovery
RT8, RT9, and RT10 Samples Data Bit Determination Noise Flag
000 0 0
001 0 1
010 0 1
011 1 1
100 0 1
101 1 1
110 1 1
111 1 0
Table 8-16. Stop Bit Recovery
RT8, RT9, and RT10 Samples Framing Error Flag Noise Flag
000 1 0
001 1 1
010 1 1
011 0 1
100 1 1
101 0 1
110 0 1
111 0 0
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
266 Freescale Semiconductor
In Figure 8-16 the verification samp les RT3 and RT5 determine that the fir st low d etec ted was noise and
not the beginning of a start bit. The RT clock is reset and the start bit search begins again. The noise flag
is not set because the noise occurred before the start bit was found.
Figure 8-16. Start Bit Search Example 1
In Figure 8-17, verification sample at RT3 is high. The RT3 sample sets the noise flag. Although the
perceived bit time is misaligned, the data samples RT8, RT9, and RT10 are within the bit time and data
recovery is successful.
Figure 8-17. Start Bit Search Example 2
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT5
RT1
RT1
RT2
RT3
RT4
RT7
RT6
RT5
RT10
RT9
RT8
RT14
RT13
RT12
RT11
RT15
RT16
RT1
RT2
RT3
SAMPLES
RT CLOCK
RT CLOCK COUNT
START BIT
RXD
110111100000
LSB
0 0
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT5
RT6
RT7
RT8
RT11
RT10
RT9
RT14
RT13
RT12
RT2
RT1
RT16
RT15
RT3
RT4
RT5
RT6
RT7
SAMPLES
RT CLOCK
RT CLOCK COUNT
ACTUAL START BIT
RXD
1111110000
LSB
00
PERCEIVED START BIT
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 267
In Figure 8-18, a large burst of noise is perceived as the beginning of a start bit, although the test sample
at RT5 is high. The RT5 sample sets the noise flag. Although this is a worst-case misalignment of
perceived bit time, the data samples RT8, RT9, and RT10 are within the bit time and data recovery is
successful.
Figure 8-18. Start Bit Search Example 3
Figure 8-19 shows the effect of noise early in the start bit time. Although this noise does not affect proper
synchronization with the start bit time, it does set the noise flag.
Figure 8-19. Start Bit Search Example 4
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT5
RT6
RT7
RT8
RT9
RT10
RT13
RT12
RT11
RT16
RT15
RT14
RT4
RT3
RT2
RT1
RT5
RT6
RT7
RT8
RT9
SAMPLES
RT CLOCK
RT CLOCK COUNT
ACTUAL START BIT
RXD
101110000
LSB
0
PERCEIVED START BIT
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT7
RT6
RT5
RT10
RT9
RT8
RT14
RT13
RT12
RT11
RT15
RT16
RT1
RT2
RT3
SAMPLES
RT CLOCK
RT CLOCK COUNT
PERCEIVED AND ACTUAL START BIT
RXD
11111001
LSB
11 1 1
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
268 Freescale Semiconductor
Figure 8-20 shows a burst of noise near the beginning of the start bit that resets the RT c lock. The sample
after the reset is low but is not preceded by three high samples that would qualify as a falling edge.
Depending on the timing of the start bit search and on the data, the f rame may be missed entirely or it may
set the framing error flag.
Figure 8-20. Start Bit Search Example 5
In Figure 8-21, a noise burst makes the majority of data samples RT8, RT9, and RT10 high. This sets the
noise flag but does not reset the RT clock. In start bits only, the RT8, RT9, and RT10 data samples are
ignored.
Figure 8-21. Start Bit Search Example 6
8.4.5.4 Framing Errors
If the data recovery logic does not detect a logic 1 where the stop bit should be in an incoming frame, it
sets the framing error flag, FE, in SCI status register 1 (SCISR1). A break character also sets the FE flag
because a break character has no stop bit. The FE flag is set at the same time that the RDRF flag is set.
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT7
RT6
RT5
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
SAMPLES
RT CLOCK
RT CLOCK COUNT
START BIT
RXD
11111010
LSB
11 1 1 1 0000000 0
NO START BIT FOUND
RESET RT CLOCK
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT1
RT2
RT3
RT4
RT7
RT6
RT5
RT10
RT9
RT8
RT14
RT13
RT12
RT11
RT15
RT16
RT1
RT2
RT3
SAMPLES
RT CLOCK
RT CLOCK COUNT
START BIT
RXD
11111000
LSB
11 1 1 0 110
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 269
8.4.5.5 Baud Rate Tolerance
A transmitting device may be operating at a baud rate below or above the receiver baud rate. Accumulated
bit time misalignment can cause one of the three stop bit data samples (RT8, RT9, and RT10) to fall outside
the actual stop bit. A noise error wi ll occur if the RT8, RT9, and RT10 samples are not all the same logical
values. A framing error will occur if the receiver clock is misaligned in such a way that the majority of the
RT8, RT9, and RT10 stop bit samples are a logic 0.
As the receiver samples an incoming frame, it re-synchronizes the RT clock on any valid falling edge
within the frame. Re synchronization within frames will correct a misalignment between transmitter bit
times and receiver bit times.
8.4.5.5.1 Slow Data Tolerance
Figure 8-22 shows how much a slow received frame can be misaligned without causing a noise error or a
framing error. The slow stop bit begins at RT8 instead of RT1 but arrives in time for the stop bit data
samples at RT8, RT9, and RT10.
Figure 8-22. Slow Data
Let’s take RTr as receiver RT clock and RTt as transmitter RT clock.
For an 8-bit data character, it takes the receiver 9 bit times x 16 RTr cycles +7 RTr cycles =151 RTr cycles
to start data sampling of the stop bit.
With the misaligned character shown in Figure 8-22, the receiver counts 151 RTr cycles at the point when
the count of the transmitting device is 9 bit times x 16 RTt cycles = 144 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a slow 8-bit data
character with no errors is:
((151 – 144) / 151) x 100 = 4.63%
For a 9-bit data character, it takes the receiver 10 bit times x 16 RTr cycles + 7 RTr cycles = 167 RTr cycles
to start data sampling of the stop bit.
With the misaligned character shown in Figure 8-22, the receiver counts 167 RTr cycles at the point when
the count of the transmitting device is 10 bit times x 16 RTt cycles = 160 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a slow 9-bit
character with no errors is:
((167 – 160) / 167) X 100 = 4.19%
MSB STOP
RT1
RT2
RT3
RT4
RT5
RT6
RT7
RT8
RT9
RT10
RT11
RT12
RT13
RT14
RT15
RT16
DATA
SAMPLES
RECEIVER
RT CLOCK
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
270 Freescale Semiconductor
8.4.5.5.2 Fast Data Tolerance
Figure 8-23 shows how much a fast received frame can be misaligned. The fast stop bit ends at RT10
instead of RT16 but continues to be sampled at RT8, RT9, and RT10.
Figure 8-23. Fast Data
For an 8-bit data character, it takes the receiver 9 bit times x 16 RTr cycles + 10 RTr cycles = 154 RTr
cycles to finish data sampling of the stop bit.
With the misaligned character shown in Figure 8-23, the receiver counts 154 RTr cycles at the point when
the count of the transmitting device is 10 bit times x 16 RTt cycles = 160 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a fast 8-bit
character with no errors is:
((160 – 154) / 160) x 100 = 3.75%
For a 9-bit data character, it takes the receiver 10 bit times x 16 RTr cycles + 10 RTr cycles = 170 RTr
cycles to finish data sampling of the stop bit.
With the misaligned character shown in Figure 8-23, the receiver counts 170 RTr cycles at the point when
the count of the transmitting device is 11 bit times x 16 RTt cycles = 176 RTt cycles.
The maximum percent difference between the receiver count and the transmitter count of a fast 9-bit
character with no errors is:
((176 – 170) / 176) x 100 = 3.40%
8.4.5.6 Receiver Wakeup
To enable the SCI to ignore transmissions intended only for other receivers in multiple-receiver systems,
the receiver can be put into a standby state. Setting the receiver wakeup bit, RWU, in SCI control register 2
(SCICR2) puts the receiver into standby state during which receiver interrupts are disabled.The SCI will
continue to load the receive data into the SCIDRH/L registers, but it will not set the RDRF flag.
The transmitting device can address messages to selected receivers by including addressing information
in the initial frame or frames of each message.
The WAKE bit in SCI control register 1 (SCICR1) determines how the SCI is brought out of the standby
state to process an incoming message. The WAKE bit enables either idle line wakeup or address mark
wakeup.
IDLE OR NEXT FRAMESTOP
RT1
RT2
RT3
RT4
RT5
RT6
RT7
RT8
RT9
RT10
RT11
RT12
RT13
RT14
RT15
RT16
DATA
SAMPLES
RECEIVER
RT CLOCK
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 271
8.4.5.6.1 Idle Input Line Wakeup (WAKE = 0)
In this wakeup method, an idle condition on the RXD pin clears the RWU bit and wakes up the SCI. The
initial frame or frames of every message contain addressing information. All receivers evaluate the
addressing information, and receivers for which the message is addressed process the frames that follow.
Any receiver for which a message is not addressed can set its R WU bit and return to the standby state. The
RWU bit remains set and the receiver remains on standby until another idle character appears on the RXD
pin.
Idle line wakeup requires that messages be separated by at least one idle character and that no message
contains idle characters.
The idle character that wakes a receiver does not set the receiver idle bit, IDLE, or the receive data register
full flag, RDRF.
The idle line type bit, ILT, determines whether the receiver begins counting logic 1s as idle character bits
after the start bit or after the stop bit. ILT is in SCI control register 1 (SCICR1).
8.4.5.6.2 Address Mark Wakeup (WAKE = 1)
In this wakeup method, a logic 1 in the most significant bit (MSB) position of a frame clears the RWU bit
and wakes up the SCI. The logic 1 in the MSB position marks a frame as an address frame that contains
addressing information. All receivers evaluate the addressing information, and the receivers for which the
message is addressed process the frames that follow. Any receiver for which a message is not addressed
can set its RWU bit and return to the standby state. The RWU bit remains set and the receiver remains on
standby until another address frame appears on the RXD pin.
The logic 1 MSB of an address frame clears the receiver’ s RWU bit before the stop bit is received and sets
the RDRF flag.
Address mark wakeup allows messages to contain idle characters but requires that the MSB be reserved
for use in address frames.
NOTE
With the WAKE bit clear, setting the RWU bit after the RXD pin has been
idle can cause the receiver to wake up immediately.
8.4.6 Single-Wire Operation
Normally, the SCI uses two pins for transmitting and receiving. In single-wire operation, the RXD pin is
disconnected from the SCI. The SCI uses the TXD pin for both receiving and transmitting.
Figure 8-24. Single-Wire Operation (LOOPS = 1, RSRC = 1)
RXD
TRANSMITTER
RECEIVER
TXD
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
272 Freescale Semiconductor
Enable single-wire operation by setting the LOOPS bit and the receiver source bit, RSRC, in SCI control
register 1 (SCICR1). Setting the LOOPS bit disables the path from the RXD pin to the receiver. Setting
the RSRC bit connects the TXD pin to the receiver. Both the transmitter and receiver must be enabled
(TE = 1 and RE = 1).The TXDIR bit (SCISR2[1]) determines whether the TXD pin is going to be used as
an input (TXDIR = 0) or an output (TXDIR = 1) in this mode of operation.
NOTE
In single-wire operation data from the TXD pin is inverted if RXPOL is set.
8.4.7 Loop Operation
In loop operation the transmitter output goes to the receiver input. The RXD pin is disconnected from the
SCI
.
Figure 8-25. Loop Operation (LOOPS = 1, RSRC = 0)
Enable loop operation by setting the LOOPS bit and clearing the RSRC bit in SCI control register 1
(SCICR1). Setting the LOOPS bit disables the path from the RXD pin to the receiver. Clearing the RSRC
bit connects the transmitter output to the receiver input. Both the transmitter and receiver must be enabled
(TE = 1 and RE = 1).
NOTE
In loop operation data from the transmitter is not recognized by the receiver
if RXPOL and TXPOL are not the same.
8.5 Interrupts
This section describes the interrupt originated by the SCI block.The MCU must service the interrupt
requests. Table 8-17 lists the five interrupt sources of the SCI.
Table 8-17. SCI Interrupt Sources
Interrupt Source Local Enable Description
TDRE SCISR1[7] TIE Active high level. Indicates that a byte was transferred from SCIDRH/L to
the transmit shift register.
TC SCISR1[6] TCIE Active high level. Indicates that a transmit is complete.
RDRF SCISR1[5] RIE Active high level. The RDRF interrupt indicates that received data is
available in the SCI data register.
OR SCISR1[3] Active high level. This interrupt indicates that an overrun condition has
occurred.
IDLE SCISR1[4] ILIE Active high level. Indicates that receiver input has become idle.
RXD
TRANSMITTER
RECEIVER
TXD
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 273
8.5.1 Description of Interrupt Operation
The SCI only originates interrupt requests. The following is a description of how the SCI makes a request
and how the MCU should acknowledge that request. The interrupt vector offset and interrupt number are
chip dependent. The SCI only has a single interrupt line (SCI interrupt signal, active high operation) and
all the following interrupts, when generated, are ORed together and issued through that port.
8.5.1.1 TDRE Description
The TDRE interrupt is set high by the SCI when the transmit shift register receives a byte from the SCI
data register. A TDRE interrupt indicates that the transmit data register (SCIDRH/L) is empty and that a
new byte can be written to the SCIDRH/L for transmission.Clear TDRE by reading SCI status register 1
with TDRE set and then writing to SCI data register low (SCIDRL).
8.5.1.2 TC Description
The TC interrupt is set by the SCI when a transmission has been comple ted.A TC interrupt indicates that
there is no transmission in progress. TC is set high when the TDRE flag is set and no data, preamble, or
break character is being transmitted. When TC is set, the TXD pin becomes idle (logic 1). Clear TC by
reading SCI status register 1 (SCISR1) with TC set and then writing to SCI data register low (SCIDRL).TC
is cleared automatically when data, preamble, or break is queued and ready to be sent.
8.5.1.3 RDRF Description
The RDRF interrupt is set when the data in the receive shift register transfers to the SCI data register. A
RDRF interrupt indicates that the received data has been transferred to the SCI data register and that the
byte can now be read by the MCU. The RDRF interrupt is cleared by reading the SCI status register one
(SCISR1) and then reading SCI data register low (SCIDRL).
8.5.1.4 OR Description
The OR interrupt is set when software fails to read the SCI data register before the receive shift register
receives the next frame. The newly acquired data in the shift register will be lost in this case, but the data
already in the SCI data registers is not affected. The OR interrupt is cleared by reading the SCI status
register one (SCISR1) and then reading SCI data register low (SCIDRL).
8.5.1.5 IDLE Description
The IDLE interrupt is set when 10 consecutive logic 1s (if M = 0) or 11 consecutive logic 1s (if M = 1)
appear on the receiver input. After the IDLE is cleared, a valid frame must again set the RDRF flag before
an idle condition can set the IDLE flag. Clear IDLE by reading SCI status register 1 (SCISR1) with IDLE
set and then reading SCI data register low (SCIDRL).
8.5.2 Recovery from Wait Mode
The SCI interrupt request can be used to bring the CPU out of wait mode.
Chapter 8 Serial Communication Interface (SCIV4)
MC9S12E256 Data Sheet, Rev. 1.08
274 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 275
Chapter 9
Serial Peripheral Interface (SPIV3)
9.1 Introduction
The SPI module allows a duplex, synchronous, serial communication between the MCU and peripheral
devices. Software can poll the SPI status flags or the SPI operation can be interrupt driven.
9.1.1 Features
The SPIV3 includes these distinctive features:
• Master mode and slave mode
• Bidirectional mode
• Slave select output
• Mode fault error flag with CPU interrupt capability
• Double-buffered data register
• Serial clock with programmable polarity and phase
• Control of SPI operation during wait mode
9.1.2 Modes of Operation
The SPI functions in three modes, run, wait, and stop.
• Run Mode
This is the basic mode of operation.
• Wait Mode
SPI operation in wait mode is a configurable low power mode, controlled by the SPISWAI bit
located in the SPICR2 register. In wait mode, if the SPISWAI bit is clear, the SPI operates like in
Run Mode. If the SPISWAI bit is set, the SPI goes into a power conservative state, with the SPI
clock generation turned off. If the SPI is configured as a master , any transmission in progress stops,
but is resumed after CPU goes into Run Mode. If the SPI is configured as a slave, reception and
transmission of a byte continues, so that the slave stays synchronized to the master.
• Stop Mode
The SPI is inactive in stop mode for reduced power consumption. If the SPI is configured as a
master , any transmission in progress stops, but is resumed after CPU goes into run mode. If the SPI
is configured as a slave, reception and transmission of a byte continues, so that the slave stays
synchronized to the master.
This is a high level description only , detailed descriptions of operating modes are contained in Section 9.4,
“Functional Description.”
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
276 Freescale Semiconductor
9.1.3 Block Diagram
Figure 9-1 gives an overview on the SPI architecture. The main parts of the SPI are status, control, and
data registers, shifter logic, baud rate generator, master/slave control logic, and port control logic.
Figure 9-1. SPI Block Diagram
9.2 External Signal Description
This section lists the name and description of all ports including inputs and outputs that do, or may , connect
off chip. The SPIV3 module has a total of four external pins.
9.2.1 MOSI — Master Out/Slave In Pin
This pin is used to transmit data out of the SPI module when it is configured as a master and receive data
when it is configured as slave.
SPI Control Register 1
SPI Control Register 2
SPI Baud Rate Register
SPI Status Register
SPI Data Register
Shifter
Port
Control
Logic
MOSI
SCK
Interrupt Control
SPI
MSB LSB
LSBFE=1 LSBFE=0
LSBFE=0 LSBFE=1
data in
LSBFE=1
LSBFE=0
data out
8
8
Baud Rate Generator
Prescaler
Bus Clock
Counter
Clock Select
SPPR 33
SPR
Baud Rate
Phase +
Polarity
Control
Master
Slave
SCK in
SCK out
Master Baud Rate
Slave Baud Rate
Phase +
Polarity
Control
Control
Control CPOL CPHA
2
BIDIROE
SPC0
2
MODFSPIF SPTEF
SPI
Request
Interrupt
SS
Shift
Clock
Sample
Clock
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 277
9.2.2 MISO — Master In/Slave Out Pin
This pin is used to transmit data out of the SPI module when it is configured as a slave and receive data
when it is configured as master.
9.2.3 SS — Slave Select Pin
This pin is used to output the select signal from the SPI module to another peripheral with which a data
transfer is to take place when its configured as a master and its used as an input to receive the slave select
signal when the SPI is configured as slave.
9.2.4 SCK — Serial Clock Pin
This pin is used to output the clock with respect to which the SPI transfer s data or receive clock in case of
slave.
9.3 Memory Map and Register Definition
This section provides a detailed description of address space and registers used by the SPI.
The memory map for the SPIV3 is given below in Table 9-1. The address listed for each register is the sum
of a base address and an address offset. The base addres s is defined at the SoC level and the address offset
is defined at the module level. Reads from the reserved bits return zeros and writes to the reserved bits
have no effect.
9.3.1 Module Memory Map
Table 9-1. SPIV3 Memory Map
Address Use Access
0x0000 SPI Control Register 1 (SPICR1) R/W
0x0001 SPI Control Register 2 (SPICR2) R/W1
1Certain bits are non-writable.
0x0002 SPI Baud Rate Register (SPIBR) R/W1
0x0003 SPI Status Register (SPISR) R2
2Writes to this register are ignored.
0x0004 Reserved — 2,3
3Reading from this register returns all zeros.
0x0005 SPI Data Register (SPIDR) R/W
0x0006 Reserved — 2,3
0x0007 Reserved — 2,3
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
278 Freescale Semiconductor
9.3.2 Register Descriptions
This section consists of register descriptions in address order. Each description includes a standard register
diagram with an associated figure number. Details of register bit and field function follow the register
diagrams, in bit order.
9.3.2.1 SPI Control Register 1 (SPICR1)
Read: anytime
Write: anytime
Name 76543210
SPICR1 RSPIE SPE SPTIE MSTR CPOL CPHA SSOE LSBFE
W
SPICR2 R0 0 0 MODFEN BIDIROE 0SPISWAI SPC0
W
SPIBR R0 SPPR2 SPPR1 SPPR0 0SPR2 SPR1 SPR0
W
SPISR R SPIF 0 SPTEF MODF 0 0 0 0
W
Reserved R
W
SPIDR RBit 7654322Bit 0
W
Reserved R
W
Reserved R
W
= Unimplemented or Reserved
Figure 9-2. SPI Register Summary
76543210
RSPIE SPE SPTIE MSTR CPOL CPHA SSOE LSBFE
W
Reset00000100
Figure 9-3. SPI Control Register 1 (SPICR1)
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 279
Table 9-2. SPICR1 Field Descriptions
Field Description
7
SPIE
SPI Interrupt Enable Bit — This bit enables SPI interrupt requests, if SPIF or MODF status flag is set.
0 SPI interrupts disabled.
1 SPI interrupts enabled.
6
SPE
SPI System Enable Bit — This bit enables the SPI system and dedicates the SPI port pins to SPI system
functions. If SPE is cleared, SPI is disabled and forced into idle state, status bits in SPISR register are reset.
0 SPI disabled (lower power consumption).
1 SPI enabled, port pins are dedicated to SPI functions.
5
SPTIE
SPI Transmit Interrupt Enable — This bit enables SPI interrupt requests, if SPTEF flag is set.
0 SPTEF interrupt disabled.
1 SPTEF interrupt enabled.
4
MSTR
SPI Master/Slave Mode Select Bit — This bit selects, if the SPI operates in master or slave mode. Switching
the SPI from master to slave or vice versa forces the SPI system into idle state.
0 SPI is in slave mode
1 SPI is in master mode
3
CPOL
SPI Clock Polarity Bit — This bit selects an inverted or non-inverted SPI clock. To transmit data between SPI
modules, the SPI modules must have identical CPOL values. In master mode, a change of this bit will abort a
transmission in progress and force the SPI system into idle state.
0 Active-high clocks selected. In idle state SCK is low.
1 Active-low clocks selected. In idle state SCK is high.
2
CPHA
SPI Clock Phase Bit — This bit is used to select the SPI clock format. In master mode, a change of this bit will
abort a transmission in progress and force the SPI system into idle state.
0 Sampling of data occurs at odd edges (1,3,5,...,15) of the SCK clock
1 Sampling of data occurs at even edges (2,4,6,...,16) of the SCK clock
1
SSOE
Slave Select Output Enable — The SS output feature is enabled only in master mode, if MODFEN is set, by
asserting the SSOE as shown in Tabl e 9 - 3 . In master mode, a change of this bit will abort a transmission in
progress and force the SPI system into idle state.
0
LSBFE
LSB-First Enable — This bit does not affect the position of the MSB and LSB in the data register. Reads and
writes of the data register always have the MSB in bit 7. In master mode, a change of this bit will abort a
transmission in progress and force the SPI system into idle state.
0 Data is transferred most significant bit first.
1 Data is transferred least significant bit first.
Table 9-3. SS Input / Output Selection
MODFEN SSOE Master Mode Slave Mode
00 SS
not used by SPI SS input
01 SS
not used by SPI SS input
10SS
input with MODF feature SS input
11 SS
is slave select output SS input
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
280 Freescale Semiconductor
9.3.2.2 SPI Control Register 2 (SPICR2)
Read: anytime
Write: anytime; writes to the reserved bits have no effect
76543210
R0 0 0
MODFEN BIDIROE
0
SPISWAI SPC0
W
Reset00000000
= Unimplemented or Reserved
Figure 9-4. SPI Control Register 2 (SPICR2)
Table 9-4. SPICR2 Field Descriptions
Field Description
4
MODFEN
Mode Fault Enable Bit — This bit allows the MODF failure being detected. If the SPI is in master mode and
MODFEN is cleared, then the SS port pin is not used by the SPI. In slave mode, the SS is available only as an
input regardless of the value of MODFEN. For an overview on the impact of the MODFEN bit on the SS port pin
configuration refer to Tabl e 9-3. In master mode, a change of this bit will abort a transmission in progress and
force the SPI system into idle state.
0SS
port pin is not used by the SPI
1SS port pin with MODF feature
3
BIDIROE
Output Enable in the Bidirectional Mode of Operation — This bit controls the MOSI and MISO output buffer
of the SPI, when in bidirectional mode of operation (SPC0 is set). In master mode this bit controls the output
buffer of the MOSI port, in slave mode it controls the output buffer of the MISO port. In master mode, with SPC0
set, a change of this bit will abort a transmission in progress and force the SPI into idle state.
0 Output buffer disabled
1 Output buffer enabled
1
SPISWAI
SPI Stop in Wait Mode Bit — This bit is used for power conservation while in wait mode.
0 SPI clock operates normally in wait mode
1 Stop SPI clock generation when in wait mode
0
SPC0
Serial Pin Control Bit 0 — This bit enables bidirectional pin configurations as shown in Tabl e 9 - 5 . In master
mode, a change of this bit will abort a transmission in progress and force the SPI system into idle state
Table 9-5. Bidirectional Pin Configurations
Pin Mode SPC0 BIDIROE MISO MOSI
Master Mode of Operation
Normal 0 X Master In Master Out
Bidirectional 1 0 MISO not used by SPI Master In
1 Master I/O
Slave Mode of Operation
Normal 0 X Slave Out Slave In
Bidirectional 1 0 Slave In MOSI not used by SPI
1 Slave I/O
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 281
9.3.2.3 SPI Baud Rate Register (SPIBR)
Read: anytime
Write: anytime; writes to the reserved bits have no effect
The baud rate divisor equation is as follows:
The baud rate can be calculated with the following equation:
76543210
R0
SPPR2 SPPR1 SPPR0
0
SPR2 SPR1 SPR0
W
Reset00000000
= Unimplemented or Reserved
Figure 9-5. SPI Baud Rate Register (SPIBR)
Table 9-6. SPIBR Field Descriptions
Field Description
6:4
SPPR[2:0]
SPI Baud Rate Preselection Bits — These bits specify the SPI baud rates as shown in Ta b l e 9 - 7 . In master
mode, a change of these bits will abort a transmission in progress and force the SPI system into idle state.
2:0
SPR[2:0}
SPI Baud Rate Selection Bits — These bits specify the SPI baud rates as shown in Ta b l e 9 - 7 . In master mode,
a change of these bits will abort a transmission in progress and force the SPI system into idle state.
BaudRateDivisor SPPR 1+()2•SPR 1+()
=
Baud Rate BusClock BaudRateDivisor⁄=
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
282 Freescale Semiconductor
Table 9-7. Example SPI Baud Rate Selection (25 MHz Bus Clock)
SPPR2 SPPR1 SPPR0 SPR2 SPR1 SPR0 Baud Rate
Divisor Baud Rate
000000212.5 MHz
00000146.25 MHz
00001083.125 MHz
000011161.5625 MHz
00010032781.25 kHz
00010164390.63 kHz
000110128195.31 kHz
00011125697.66 kHz
00100046.25 MHz
00100183.125 MHz
001010161.5625 MHz
00101132781.25 kHz
00110064390.63 kHz
001101128195.31 kHz
00111025697.66 kHz
00111151248.83 kHz
01000064.16667 MHz
010001122.08333 MHz
010010241.04167 MHz
01001148520.83 kHz
01010096260.42 kHz
010101192130.21 kHz
01011038465.10 kHz
01011176832.55 kHz
01100083.125 MHz
011001161.5625 MHz
01101032781.25 kHz
01101164390.63 kHz
011100128195.31 kHz
01110125697.66 kHz
01111051248.83 kHz
011111102424.41 kHz
100000102.5 MHz
100001201.25 MHz
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 283
NOTE
In slave mode of SPI S-clock speed DIV2 is not supported.
10001040625 kHz
10001180312.5 kHz
100100160156.25 kHz
10010132078.13 kHz
10011064039.06 kHz
100111128019.53 kHz
101000122.08333 MHz
101001241.04167 MHz
10101048520.83 kHz
10101196260.42 kHz
101100192130.21 kHz
10110138465.10 kHz
10111076832.55 kHz
101111153616.28 kHz
110000141.78571 MHz
11000128892.86 kHz
11001056446.43 kHz
110011112223.21 kHz
110100224111.61 kHz
11010144855.80 kHz
11011089627.90 kHz
110111179213.95 kHz
111000161.5625 MHz
11100132781.25 kHz
11101064390.63 kHz
111011128195.31 kHz
11110025697.66 kHz
11110151248.83 kHz
111110102424.41 kHz
111111204812.21 kHz
Table 9-7. Example SPI Baud Rate Selection (25 MHz Bus Clock) (continued)
SPPR2 SPPR1 SPPR0 SPR2 SPR1 SPR0 Baud Rate
Divisor Baud Rate
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
284 Freescale Semiconductor
9.3.2.4 SPI Status Register (SPISR)
Read: anytime
Write: has no effect
9.3.2.5 SPI Data Register (SPIDR)
Read: anytime; normally read only after SPIF is set
Write: anytime
The SPI Data Register is both the input and output register for SPI data. A write to this register allows a
data byte to be queued and transmitted. For a SPI configured as a master , a queued data byte is transmitted
76543210
R SPIF 0 SPTEF MODF 0 0 0 0
W
Reset00100000
= Unimplemented or Reserved
Figure 9-6. SPI Status Register (SPISR)
Table 9-8. SPISR Field Descriptions
Field Description
7
SPIF
SPIF Interrupt Flag — This bit is set after a received data byte has been transferred into the SPI Data Register.
This bit is cleared by reading the SPISR register (with SPIF set) followed by a read access to the SPI Data
Register.
0 Transfer not yet complete
1 New data copied to SPIDR
5
SPTEF
SPI Transmit Empty Interrupt Flag — If set, this bit indicates that the transmit data register is empty. To clear
this bit and place data into the transmit data register, SPISR has to be read with SPTEF = 1, followed by a write
to SPIDR. Any write to the SPI Data Register without reading SPTEF = 1, is effectively ignored.
0 SPI Data register not empty
1 SPI Data register empty
4
MODF
Mode Fault Flag — This bit is set if the SS input becomes low while the SPI is configured as a master and mode
fault detection is enabled, MODFEN bit of SPICR2 register is set. Refer to MODFEN bit description in
Section 9.3.2.2, “SPI Control Register 2 (SPICR2).” The flag is cleared automatically by a read of the SPI Status
Register (with MODF set) followed by a write to the SPI Control Register 1.
0 Mode fault has not occurred.
1 Mode fault has occurred.
76543210
RBit 7654322Bit 0
W
Reset00000000
Figure 9-7. SPI Data Register (SPIDR)
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 285
immediately after the previous transmission has completed. The SPI T ransmitter Empty Flag SP TEF in the
SPISR register indicates when the SPI Data Register is ready to accept new data.
Reading the data can occur anytime from after the SPIF is set to before the end of the next transfer. If the
SPIF is not serviced by the end of the successive transfers, those data bytes are lost and the data within the
SPIDR retains the first byte until SPIF is serviced.
9.4 Functional Description
The SPI module allows a duplex, synchronous, serial communication between the MCU and peripheral
devices. Software can poll the SPI status flags or SPI operation can be interrupt driven.
The SPI system is enabled by setting the SPI enable (SPE) bit in SPI Control Register 1. While SPE bit is
set, the four associated SPI port pins are dedicated to the SPI function as:
• Slave select (SS)
• Serial clock (SCK)
• Master out/slave in (MOSI)
• Master in/slave out (MISO)
The main element of the SPI system is the SPI Data Register. The 8-bit data register in the master and the
8-bit data register in the slave are linked by the MOSI and MISO pins to form a distributed 16-bit register.
When a data transfer operation is performed, this 16-bit register is serially shifted eight bit positions by the
S-clock from the master , so data is exchanged between the master and the slave. Data written to the master
SPI Data Register becomes the output data for the slave, and data read from the master SPI Data Register
after a transfer operation is the input data from the slave.
A read of SPISR with SPTEF = 1 followed by a write to SPIDR puts data into the transmit data register.
When a transfer is complete, received data is moved into the receive data register. Da ta may be read from
this double-buffered system any time before the next transfer has completed. This 8-bit data register acts
as the SPI receive data register for reads and as the SPI transmit data register for writes. A single SPI
register address is used for reading data from the read data buf fer and for writing data to the transmit data
register.
The clock phase control bit (CPHA) and a clock polarity control bit (CPOL) in the SPI Control Register 1
(SPICR1) select one of four possible clock formats to be used by the SPI system. The CPOL bit simply
selects a non-inverted or inverted clock. The CPHA bit is used to accommodate two fundamentally
different protocols by sampling data on odd numbered SCK edges or on even numbered SCK edges (see
Section 9.4.3, “Transmission Formats”).
The SPI can be configured to operate as a master or as a slave. When the MSTR bit in SPI Control
Register1 is set, master mode is selected, when the MSTR bit is clear, slave mode is selected.
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
286 Freescale Semiconductor
9.4.1 Master Mode
The SPI operates in master mode when the MSTR bit is set. Only a master SPI module can initiate
transmissions. A transmission begins by writing to the master SPI Data Register. If the shift register is
empty, the byte immediately transfers to the shift register. The byte begins shifting out on the MOSI pin
under the control of the serial clock.
•S-clock
The SPR2, SPR1, and SPR0 baud rate selection bits in conjunction with the SPPR2, SPPR1, and
SPPR0 baud rate preselection bits in the SPI Baud Rate register control the baud rate generator and
determine the speed of the transmission. The SCK pin is the SPI clock output. Through the SCK
pin, the baud rate generator of the master controls the shift register of the slave peripheral.
• MOSI and MISO Pins
In master mode, the function of the serial data output pin (MOSI) and the serial data input pin
(MISO) is determined by the SPC0 and BIDIROE control bits.
•SS Pin
If MODFEN and SSOE bit are set, the SS pin is configured as slave select output. The SS output
becomes low during each transmission and is high when the SPI is in idle state.
If MODFEN is set and SSOE is cleared, the SS pin is configured as input for detecting mode fault
error. If the SS input becomes low this indicates a mode fault error where another master tries to
drive the MOSI and SCK lines. In this case, the SPI immediately switches to slave mode, by
clearing the MSTR bit and also disables the slave output buffer MISO (or SISO in bidirectional
mode). So the result is that all outputs are disabled and SCK, MOSI and MISO are inputs. If a
transmission is in progress when the mode fault occurs, the transmission is aborted and the SPI is
forced into idle state.
This mode fault error also sets the mode fault (MODF) flag in the SPI S tatus Register (SPISR). If the SPI
interrupt enable bit (SPIE) is set when the MODF flag gets set, then an SPI interrupt sequence is also
requested.
When a write to the SPI Data Register in the master occurs, there is a half SCK-cycle delay. After the delay ,
SCK is started within the master. Th e rest of the transfer operation differs slightly, depending on the clock
format specified by the SPI clock phase bit, CPHA, in SPI Control Register 1 (see Section 9.4.3,
“Transmission Formats”).
NOTE
A change of the bits CPOL, CPHA, SSOE, LSBFE, MODFEN, SPC0,
BIDIROE with SPC0 set, SPPR2–SPPR0 and SPR2–SPR0 in master mode
will abort a transmission in progress and force the SPI into idle state. The
remote slave cannot detect this, therefore the master has to ensure that the
remote slave is set back to idle state.
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 287
9.4.2 Slave Mode
The SPI operates in slave mode when the MSTR bit in SPI Control Register1 is clear.
• SCK Clock
In slave mode, SCK is the SPI clock input from the master.
• MISO and MOSI Pins
In slave mode, the function of the serial data output pin (MISO) and serial data input pin (MOSI)
is determined by the SPC0 bit and BIDIROE bit in SPI Control Register 2.
•SS Pin
The SS pin is the slave select input. Before a data transmission occurs, the SS pin of the slave SPI
must be low. SS must remain low until the transmission is complete. If SS goes high, the SPI is
forced into idle state.
The SS input also controls the serial data output pin, if SS is high (not selected), the serial data
output pin is high impedance, and, if SS is low the first bit in the SPI Data Register is driven out
of the serial data output pin. Also, if the slave is not selected (SS is high), then the SCK input is
ignored and no internal shifting of the SPI shift register takes place.
Although the SPI is capable of duplex operation, some SPI peripherals are capable of only receiving SPI
data in a slave mode. For these simpler devices, there is no serial data out pin.
NOTE
When peripherals with duplex capability are used, take care not to
simultaneously enable two receivers whose serial outputs drive the same
system slave’s serial data output line.
As long as no more than one slave device drives the system slave’ s serial data output line, it is possible for
several slaves to receive the same transmission from a master, although the master would not receive return
information from all of the receiving slaves.
If the CPHA bit in SPI Control Register 1 is clear, odd numbered edges on the SCK input cause the data
at the serial data input pin to be latched. Even numbered edges cause the value previously latched from the
serial data input pin to shift into the LSB or MSB of the SPI shift register, depending on the LSBFE bit.
If the CPHA bit is set, even numbered edges on the SCK input cause the data at the serial data input pin to
be latched. Odd numbered edges cause the value previously latched from the serial data input pin to shift
into the LSB or MSB of the SPI shift register, depending on the LSBFE bit.
When CPHA is set, the first edge is used to get the first data bit onto the serial data output pin. When CPHA
is clear and the SS input is low (slave selected), the first bit of the SPI data is driven out of the serial data
output pin. After the eighth shift, the transfer is considered complete and the received data is transferred
into the SPI Data Register. To indicate transfer is complete, the SPIF flag in the SPI Status Re gister is set.
NOTE
A change of the bits CPOL, CPHA, SSOE, LSBFE, MODFEN, SPC0 and
BIDIROE with SPC0 set in slave mode will corrupt a transmission in
progress and has to be avoided.
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
288 Freescale Semiconductor
9.4.3 Transmission Formats
During an SPI transmission, data is transmitted (shifted out serially) and received (shifted in serially)
simultaneously. The serial clock (SCK) synchronizes shifting and sampling of the information on the two
serial data lines. A slave select line allows selection of an individual slave SPI device, slave devices that
are not selected do not interfere with SPI bus activities. Optionally, on a master SPI device, the slave select
line can be used to indicate multiple-master bus contention.
Figure 9-8. Master/Slave Transfer Block Diagram
9.4.3.1 Clock Phase and Polarity Controls
Using two bits in the SPI Control Register1, software selects one of four combinations of serial clock phase
and polarity.
The CPOL clock polarity control bit specifies an active high or low clock and has no significant ef fect on
the transmission format.
The CPHA clock phase control bit selects one of two fundamentally different transmission formats.
Clock phase and polarity should be identical for the master SPI device and the communicating slave
device. In some cases, the phase and polarity are changed between transmissions to allow a master device
to communicate with peripheral slaves having different requirements.
9.4.3.2 CPHA = 0 Transfer Format
The first edge on the SCK line is used to clock the first data bit of the slave into the master and the first
data bit of the master into the slave. In some peripherals, the first bit of the slave’s data is available at the
slave’s data out pin as soon as the slave is selected. In this format, the first SCK edge is issued a half cycle
after SS has become low.
A half SCK cycle later , the second edge appears on the SCK line. When this second edge occurs, the value
previously latched from the serial data input pin is shifted into the LSB or MSB of the shift register,
depending on LSBFE bit.
After this second edge, the next bit of the SPI ma ster data is transmitted out of the serial data output pin of
the master to the serial input pin on the slave. This process continues for a total of 16 edges on the SCK
line, with data being latched on odd numbered edges and shifted on even numbered edges.
SHIFT REGISTER
SHIFT REGISTER
BAUD RATE
GENERATOR
MASTER SPI SLAVE SPI
MOSI MOSI
MISO MISO
SCK SCK
SS SS
VDD
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 289
Data reception is double buffered. Data is shifted serially into the SPI shift register during the transfer and
is transferred to the parallel SPI Data Register after the last bit is shifted in.
After the 16th (last) SCK edge:
• Data that was previously in the master SPI Data Register should now be in the slave data register
and the data that was in the slave data register should be in the master.
• The SPIF flag in the SPI Status Register is set indicating that the transfer is complete.
Figure 9-9 is a timing diagram of an SPI transfer where CPHA = 0. SCK waveforms are shown for
CPOL = 0 and CPOL = 1. The diagram may be interpreted as a master or slave timing diagram because
the SCK, MISO, and MOSI pins are connected directly between the master and the slave. The MISO signal
is the output from the slave and the MOSI signal is the output from the master. The SS pin of the master
must be either high or reconfigured as a general-purpose output not affecting the SPI.
Figure 9-9. SPI Clock Format 0 (CPHA = 0)
In slave mode, if the SS line is not deasserted between the successive transmis sions then the content of the
SPI Data Register is not transmitted, instead the last received byte is transmitted. If the SS line is
deasserted for at least minimum idle time (half SCK cycle) between successive transmissions then the
content of the SPI Data Register is transmitted.
tL
Begin End
SCK (CPOL = 0)
SAMPLE I
CHANGE O
SEL SS (O)
Transfer
SCK (CPOL = 1)
MSB first (LSBFE = 0):
LSB first (LSBFE = 1):
MSB
LSB
LSB
MSB
Bit 5
Bit 2
Bit 6
Bit 1
Bit 4
Bit 3
Bit 3
Bit 4
Bit 2
Bit 5
Bit 1
Bit 6
CHANGE O
SEL SS (I)
MOSI pin
MISO pin
Master only
MOSI/MISO
tT
If next transfer begins here
for tT
, tl, tL
Minimum 1/2 SCK
tI tL
tL = Minimum leading time before the first SCK edge
tT = Minimum trailing time after the last SCK edge
tI = Minimum idling time between transfers (minimum SS high time)
tL, tT
, and tI are guaranteed for the master mode and required for the slave mode.
1 234 56 78910111213141516
SCK Edge Nr.
End of Idle State Begin of Idle State
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
290 Freescale Semiconductor
In master mode, with slave select output enabled the SS line is always deasserted and reasserted between
successive transfers for at least minimum idle time.
9.4.3.3 CPHA = 1 Transfer Format
Some peripherals require the first SCK edge before the first data bit becomes available at the data out pin,
the second edge clocks data into the system. In this format, the first SCK edge is issued by setting the
CPHA bit at the beginning of the 8-cycle transfer operation.
The first edge of SCK occurs immediately after the half SCK clock cycle synchronizati on delay. This first
edge commands the slave to transfer its first data bit to the serial data input pin of the master.
A half SCK cycle later, the second edge appears on the SCK pin. This is the latching edge for both the
master and slave.
When the third edge occurs, the value previously latched from the serial data input pin is shifted into the
LSB or MSB of the SPI shift register , depending on LSBFE bit. After this edge, the next bit of the master
data is coupled out of the serial data output pin of the master to the serial input pin on the slave.
This process continues for a total of 16 edges on the SCK line with data being latched on even numbered
edges and shifting taking place on odd numbered edges.
Data reception is double buffered, data is serially shifted into the SPI shift register during the transfer and
is transferred to the parallel SPI Data Register after the last bit is shifted in.
After the 16th SCK edge:
• Data that was previously in the SPI Data Register of the master is now in the data register of the
slave, and data that was in the data register of the slave is in the master.
• The SPIF flag bit in SPISR is set indicating that the transfer is complete.
Figure 9-10 shows two clocking variations for CPHA = 1. The diagram may be interpreted as a master or
slave timing diagram because the SCK, MISO, and MOSI pins are connected directly between the master
and the slave. The MISO signal is the output from the slave, and the MOSI signal is the output from the
master. The SS line is the slave select input to the slave. The SS pin of the master must be either high or
reconfigured as a general-purpose output not affecting the SPI.
The SS line can remain active low between successive transfers (can be tied low at all times). This format
is sometimes preferred in systems having a single fixed master and a single slave that drive the MISO data
line.
• Back-to-back transfers in master mode
In master mode, if a transmission has completed and a new data byte is available in the SPI Data Register ,
this byte is send out immediately without a trailing and minimum idle time.
The SPI interrupt request flag (SPIF) is common to both the master and slave modes. SPIF gets set one
half SCK cycle after the last SCK edge.
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 291
Figure 9-10. SPI Clock Format 1 (CPHA = 1)
9.4.4 SPI Baud Rate Generation
Baud rate generation consists of a series of divider stages. Six bits in the SPI Baud Rate register (SPPR2,
SPPR1, SPPR0, SPR2, SPR1, and SPR0) determine the divisor to the SPI module clock which results in
the SPI baud rate.
The SPI clock rate is determined by the product of the value in the baud rate preselection bits
(SPPR2–SPPR0) and the value in the baud rate selection bits (SPR2–SPR0). The module clock divisor
equation is shown in Figure 9-11
When all bits are clear (the default condition), the SPI module clock is divided by 2. When the selection
bits (SPR2–SPR0) are 001 and the preselection bits (SPPR2–SPPR0) are 000, the module clock divisor
becomes 4. When the selection bits are 010, the module clock divisor becomes 8 etc.
When the preselection bits are 001, the divisor determined by the selection bits is multiplied by 2. When
the preselection bits are 010, the divisor is multiplied by 3, etc. See Table 9-7 for baud rate calculations for
all bit conditions, based on a 25-MHz bus clock. The two sets of selects allows the clock to be divided by
a non-power of two to achieve other baud rates such as divide by 6, divide by 10, etc.
tL tT
for tT
, tl, tL
Minimum 1/2 SCK
tI tL
If next transfer begins here
Begin End
SCK (CPOL = 0)
SAMPLE I
CHANGE O
SEL SS (O)
Transfer
SCK (CPOL = 1)
MSB first (LSBFE = 0):
LSB first (LSBFE = 1):
MSB
LSB
LSB
MSB
Bit 5
Bit 2
Bit 6
Bit 1
Bit 4
Bit 3
Bit 3
Bit 4
Bit 2
Bit 5
Bit 1
Bit 6
CHANGE O
SEL SS (I)
MOSI pin
MISO pin
Master only
MOSI/MISO
tL = Minimum leading time before the first SCK edge, not required for back to back transfers
tT = Minimum trailing time after the last SCK edge
tI = Minimum idling time between transfers (minimum SS high time), not required for back to back transfers
1 234 56 78910111213141516SCK Edge Nr.
End of Idle State Begin of Idle State
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
292 Freescale Semiconductor
The baud rate generator is activated only when the SPI is in the master mode and a ser ial transfer is taking
place. In the other cases, the divider is disabled to decrease IDD current.
Figure 9-11. Baud Rate Divisor Equation
9.4.5 Special Features
9.4.5.1 SS Output
The SS output feature automatically drives the SS pin low during transmission to select external devices
and drives it high during idle to deselect external devices. When SS output is selected, the SS output pin
is connected to the SS input pin of the external device.
The SS output is available only in master mode during normal SPI operation by asserting SSOE and
MODFEN bit as shown in Table 9-3.
The mode fault feature is disabled while SS output is enabled.
NOTE
Care must be taken when using the SS output feature in a multimaster
system because the mode fault feature is not ava ilable for detecting system
errors between masters.
9.4.5.2 Bidirectional Mode (MOSI or MISO)
The bidirectional mode is selected when the SPC0 bit is set in SPI Control Register 2 (see Table 9-9). In
this mode, the SPI uses only one serial data pin for the interface with external device(s). The MSTR bit
decides which pin to use. The MOSI pin becomes the serial data I/O (MOMI) pin for the master mode, and
the MISO pin becomes serial data I/O (SISO) pin for the slave mode. The MISO pin in master mode and
MOSI pin in slave mode are not used by the SPI.
Table 9-9. Normal Mode and Bidirectional Mode
When SPE = 1 Master Mode MSTR = 1 Slave Mode MSTR = 0
Normal Mode
SPC0 = 0
Bidirectional Mode
SPC0 = 1
BaudRateDivisor SPPR 1+()2•SPR 1+()
=
SPI
MOSI
MISO
Serial Out
Serial In
SPI
MOSI
MISO
Serial In
Serial Out
SPI
MOMI
Serial Out
Serial In
BIDIROE SPI
SISO
Serial In
Serial Out
BIDIROE
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 293
The direction of each serial I/O pin depends on the BIDIROE bit. If the pin is configured as an output,
serial data from the shift register is driven out on the pin. The same pin is also the serial input to the shift
register.
The SCK is output for the master mode and input for the slave mode.
The SS is the input or output for the master mode, and it is always the input for the slave mode.
The bidirectional mode does not affect SCK and SS functions.
NOTE
In bidirectional master mode, with mode fault enabled, both data pins MISO
and MOSI can be occupied by the SPI, though MOSI is normally used for
transmissions in bidirectional mode and MISO is not used by the SPI. If a
mode fault occurs, the SPI is automatically switched to slave mode, in this
case MISO becomes occupied by the SPI and MOSI is not used. This has to
be considered, if the MISO pin is used for other purpose.
9.4.6 Error Conditions
The SPI has one error condition:
• Mode fault error
9.4.6.1 Mode Fault Error
If the SS input becomes low while the SPI is configured as a master , it indicates a system error where more
than one master may be trying to drive the MOSI and SCK lines simultaneously. This condition is not
permitted in normal operation, the MODF bit in the SPI Status Register is set automatically provided the
MODFEN bit is set.
In the special case where the SPI is in master mode and MODFEN bit is cleared, the SS pin is not used by
the SPI. In this special case, the mode fault error function is inhibited and MODF remains cleared. In case
the SPI system is configured as a slave, the SS pin is a dedicated input pin. Mode fault error doesn’ t occur
in slave mode.
If a mode fault error occurs the SPI is switched to slave mode, with the exception that the slave output
buffer is disabled. So SCK, MISO and MOSI pins are forced to be high impedance inputs to avoid any
possibility of conflict with another output driver. A transmission in progress is aborted and the SPI is
forced into idle state.
If the mode fault error occurs in the bidirectional mode for a SPI system configured in master mode, output
enable of the MOMI (MOSI in bidirectional mode) is cleared if it was set. No mode fault error occurs in
the bidirectional mode for SPI system configured in slave mode.
The mode fault flag is cleared automatically by a read of the SPI Status Register (with MODF set) followed
by a write to SPI Control Register 1. If the mode fault flag is cleared, the SPI becomes a normal master or
slave again.
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
294 Freescale Semiconductor
9.4.7 Operation in Run Mode
In run mode with the SPI system enable (SPE) bit in the SPI control register clear, the SPI system is in a
low-power, disabled state. SPI registers remain accessible, but clocks to the core of this module are
disabled.
9.4.8 Operation in Wait Mode
SPI operation in wait mode depends upon the state of the SPISWAI bit in SPI Control Register 2.
• If SPISWAI is clear, the SPI operates normally when the CPU is in wait mode
• If SPISWAI is set, SPI clock generation ceases and the SPI module enters a power conservation
state when the CPU is in wait mode.
— If SPISWAI is set and the SPI is configured for master, any transmission and reception in
progress stops at wait mode entry. The transmission and reception resumes when the SPI exits
wait mode.
— If SPISWAI is set and the SPI is configured as a slave, any transmission and reception in
progress continues if the SCK continues to be driven from the master. This keeps the slave
synchronized to the master and the SCK.
If the master transmits several bytes while the slave is in wait mode, the slave will continue to
send out bytes consistent with the operation mode at the start of wait mode (i.e. If the slave is
currently sending its SPIDR to the master, it will continue to send the same byte. Else if the
slave is currently sending the last received byte from the master, it will continue to send each
previous master byte).
NOTE
Care must be taken when expecting data from a master while the slave is in
wait or stop mode. Even though the shift register will continue to operate,
the rest of the SPI is shut down (i.e. a SPIF interrupt will not be generated
until exiting stop or wait mode). Also, the byte from the shift register will
not be copied into the SPIDR register until after the slave SPI has exited wait
or stop mode. A SPIF flag and SPIDR copy is only generated if wait mode
is entered or exited during a tranmission. If the slave enters wait mode in
idle mode and exits wait mode in idle mode, neither a SPIF nor a SPIDR
copy will occur.
9.4.9 Operation in Stop Mode
Stop mode is dependent on the system. The SPI enters stop mode when the module clock is disabled (held
high or low). If the SPI is in master mode and exchanging data when the CPU enters stop mode, the
transmission is frozen until the CPU exits stop mode. After stop, data to and from the external SPI is
exchanged correctly. In slave mode, the SPI will stay synchronized with the master.
The stop mode is not dependent on the SPISWAI bit.
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 295
9.5 Reset
The reset values of registers and signals are described in the Memory Map and Registers section (see
Section 9.3, “Memory Map and Register Definition”) which details the registers and their bit-fields.
• If a data transmission occurs in slave mode after reset without a write to SPIDR, it will transmit
garbage, or the byte last received from the master before the reset.
• Reading from the SPIDR after reset will always read a byte of zeros.
9.6 Interrupts
The SPIV3 only originates interrupt requests when SPI is enabled (SPE bit in SPICR1 set). The following
is a description of how the SPIV3 makes a request and how the MCU should acknowledge that request.
The interrupt vector offset and interrupt priority are chip dependent.
The interrupt flags MODF, SPIF and SPTEF are logically ORed to generate an interrupt request.
9.6.1 MODF
MODF occurs when the master detects an error on the SS pin. The master SPI must be configured for the
MODF feature (see Table 9-3). After MODF is set, the curr ent transf er is aborted and the following bit is
changed:
• MSTR = 0, The master bit in SPICR1 resets.
The MODF interrupt is reflected in the status register MODF flag. Clearing the flag will also clear the
interrupt. This interrupt will stay active while the MODF flag is set. MODF has an automatic clearing
process which is described in Section 9.3.2.4, “SPI Status Register (SPISR).”
9.6.2 SPIF
SPIF occurs when new data has been received and copied to the SPI Data Register. After SPIF is set, it
does not clear until it is serviced. SPIF has an automatic clearing process which is described in
Section 9.3.2.4, “SPI Status Register (SPISR).” In the event that the SPIF is not serviced before the end of
the next transfer (i.e. SPIF remains active throughout another transfer), the latter transfers will be ignored
and no new data will be copied into the SPIDR.
9.6.3 SPTEF
SP TEF occurs when the SPI Data Register is ready to accept new data. After SPTEF is set, it does not clear
until it is serviced. SPTEF has an automatic clearing process which is described in Section 9.3.2.4, “SPI
Status Register (SPISR).”
Chapter 9 Serial Peripheral Interface (SPIV3)
MC9S12E256 Data Sheet, Rev. 1.08
296 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 297
Chapter 10
Inter-Integrated Circuit (IICV2)
10.1 Introduction
The inter-IC bus (IIC) is a two-wire, bidirectional serial bus that provides a simple, efficient method of
data exchange between devices. Being a two-wire device, the IIC bus minimizes the need for large
numbers of connections between devices, and eliminates the need for an address decoder.
This bus is suitable for applicat ions requiring occasional communications over a short distance between a
number of devices. It also provides flexibility, allowing additional devices to be connected to the bus for
further expansion and system development.
The interface is designed to operate up to 100 kbps with maximum bus loading and timing. The device is
capable of operating at higher baud rates, up to a maximum of clock/20, with reduced bus loading. The
maximum communication length and the number of devices that can be connected are limited by a
maximum bus capacitance of 400 pF.
10.1.1 Features
The IIC module has the following key features:
• Compatible with I2C bus standard
• Multi-master operation
• Software programmable for one of 256 different serial clock frequencies
• Software selectable acknowledge bit
• Interrupt driven byte-by-byte data transfer
• Arbitration lost interrupt with automatic mode switching from master to slave
• Calling address identification interrupt
• Start and stop signal generation/detection
• Repeated start signal generation
• Acknowledge bit generation/detection
• Bus busy detection
10.1.2 Modes of Operation
The IIC functions the same in normal, special, and emulation modes. It has two low power modes: wait
and stop modes.
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
298 Freescale Semiconductor
10.1.3 Block Diagram
The block diagram of the IIC module is shown in Figure 10-1.
Figure 10-1. IIC Block Diagram
10.2 External Signal Description
The IICV2 module has two external pins.
10.2.1 IIC_SCL — Serial Clock Line Pin
This is the bidirectional serial clock line (SCL) of the module, compatible to the IIC bus specification.
10.2.2 IIC_SDA — Serial Data Line Pin
This is the bidirectional serial data line (SDA) of the module, compatible to the IIC bus specification.
10.3 Memory Map and Register Definition
This section provides a detailed description of all memory and registers for the IIC module.
10.3.1 Module Memory Map
The memory map for the IIC module is given below in Figure 10-2. The address listed for each register is
the address offset.The total address for each register is the sum of the base address for the IIC module and
the address offset for each register.
In/Out
Data
Shift
Register
Address
Compare
SDA
Interrupt
Clock
Control
Start
Stop
Arbitration
Control
SCL
bus_clock
IIC
Registers
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 299
10.3.2 Register Descriptions
This section consists of register descriptions in address order . Each description includes a standard register
diagram with an associated figure number. Details of register bit and field function follow the register
diagrams, in bit order.
10.3.2.1 IIC Address Register (IBAD)
Read and write anytime
This register contains the address the IIC bus will respond to when addressed as a slave; note that it is not
the address sent on the bus during the address transfer.
Register
Name Bit 7654321Bit 0
IBAD R ADR7 ADR6 ADR5 ADR4 ADR3 ADR2 ADR1 0
W
IBFD R IBC7 IBC6 IBC5 IBC4 IBC3 IBC2 IBC1 IBC0
W
IBCR R IBEN IBIE MS/SL Tx/Rx TXAK 00
IBSWAI
WRSTA
IBSR R TCF IAAS IBB IBAL 0SRW
IBIF RXAK
W
IBDR R D7 D6 D5 D4 D3 D2 D1 D0
W
= Unimplemented or Reserved
Figure 10-2. IIC Register Summary
76543210
R
ADR7 ADR6 ADR5 ADR4 ADR3 ADR2 ADR1
0
W
Reset00000000
= Unimplemented or Reserved
Figure 10-3. IIC Bus Address Register (IBAD)
Table 10-1. IBAD Field Descriptions
Field Description
7:1
ADR[7:1]
Slave Address — Bit 1 to bit 7 contain the specific slave address to be used by the IIC bus module.The default
mode of IIC bus is slave mode for an address match on the bus.
0
Reserved
Reserved — Bit 0 of the IBAD is reserved for future compatibility. This bit will always read 0.
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
300 Freescale Semiconductor
10.3.2.2 IIC Frequency Divider Register (IBFD)
Read and write anytime
76543210
R
IBC7 IBC6 IBC5 IBC4 IBC3 IBC2 IBC1 IBC0
W
Reset00000000
Figure 10-4. IIC Bus Frequency Divider Register (IBFD)
Table 10-2. IBFD Field Descriptions
Field Description
7:0
IBC[7:0]
I Bus Clock Rate 7:0 — This field is used to prescale the clock for bit rate selection. The bit clock generator is
implemented as a prescale divider — IBC7:6, prescaled shift register — IBC5:3 select the prescaler divider and
IBC2-0 select the shift register tap point. The IBC bits are decoded to give the tap and prescale values as shown
in Tabl e 1 0-3.
Table 10-3. I-Bus Tap and Prescale Values
IBC2-0
(bin)
SCL Tap
(clocks)
SDA Tap
(clocks)
000 5 1
001 6 1
010 7 2
011 8 2
100 9 3
101 10 3
110 12 4
111 15 4
IBC5-3
(bin)
scl2start
(clocks)
scl2stop
(clocks)
scl2tap
(clocks)
tap2tap
(clocks)
0002741
0012742
0102964
0116968
10014171416
10130333032
11062656264
111 126 129 126 128
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 301
The number of clocks from the falling edge of SCL to the first tap (Tap[1]) is defined by the values shown
in the scl2tap column of Table 10-3, all subsequent tap points are separated by 2IBC5-3 as shown in the
tap2tap column in Table 10-3. The SCL Tap is used to generated the SCL period and the SDA Tap is used
to determine the delay from the falling edge of SCL to SDA changing, the SDA hold time.
IBC7–6 defines the multiplier factor MUL. The values of MUL are shown in the Table 10-4.
Figure 10-5. SCL Divider and SDA Hold
Table 10-4. Multiplier Factor
IBC7-6 MUL
00 01
01 02
10 04
11 RESERVED
SCL Divider
SDA Hold
SCL
SDA
SDA
SCL
START condition STOP condition
SCL Hold(start) SCL Hold(stop)
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
302 Freescale Semiconductor
The equation used to generate the divider values from the IBFD bits is:
SCL Divider = MUL x {2 x (scl2tap + [(SCL_Tap -1) x tap2tap] + 2)}
The SDA hold delay is equal to the CPU clock period multiplied by the SDA Hold value shown in
Table 10-5. The equation used to generate the SDA Hold value from the IBFD bits is:
SDA Hold = MUL x {scl2tap + [(SDA_Tap - 1) x tap2tap] + 3}
The equation for SCL Hold values to generate the start and stop conditions from the IBFD bits is:
SCL Hold(start) = MUL x [scl2start + (SCL_Tap - 1) x tap2tap]
SCL Hold(stop) = MUL x [scl2stop + (SCL_Tap - 1) x tap2tap]
Table 10-5. IIC Divider and Hold Values (Sheet 1 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
MUL = 1
00 20 7 6 11
01 22 7 7 12
02 24 8 8 13
03 26 8 9 14
04 28 9 10 15
05 30 9 11 16
06 34 10 13 18
07 40 10 16 21
08 28 7 10 15
09 32 7 12 17
0A 36 9 14 19
0B 40 9 16 21
0C 44 11 18 23
0D 48 11 20 25
0E 56 13 24 29
0F 68 13 30 35
10 48 9 18 25
11 56 9 22 29
12 64 13 26 33
13 72 13 30 37
14 80 17 34 41
15 88 17 38 45
16 104 21 46 53
17 128 21 58 65
18 80 9 38 41
19 96 9 46 49
1A 112 17 54 57
1B 128 17 62 65
1C 144 25 70 73
1D 160 25 78 81
1E 192 33 94 97
1F 240 33 118 121
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 303
20 160 17 78 81
21 192 17 94 97
22 224 33 110 113
23 256 33 126 129
24 288 49 142 145
25 320 49 158 161
26 384 65 190 193
27 480 65 238 241
28 320 33 158 161
29 384 33 190 193
2A 448 65 222 225
2B 512 65 254 257
2C 576 97 286 289
2D 640 97 318 321
2E 768 129 382 385
2F 960 129 478 481
30 640 65 318 321
31 768 65 382 385
32 896 129 446 449
33 1024 129 510 513
34 1152 193 574 577
35 1280 193 638 641
36 1536 257 766 769
37 1920 257 958 961
38 1280 129 638 641
39 1536 129 766 769
3A 1792 257 894 897
3B 2048 257 1022 1025
3C 2304 385 1150 1153
3D 2560 385 1278 1281
3E 3072 513 1534 1537
3F 3840 513 1918 1921
MUL = 2
40 40 14 12 22
41 44 14 14 24
42 48 16 16 26
43 52 16 18 28
44 56 18 20 30
45 60 18 22 32
46 68 20 26 36
47 80 20 32 42
48 56 14 20 30
49 64 14 24 34
4A 72 18 28 38
4B 80 18 32 42
Table 10-5. IIC Divider and Hold Values (Sheet 2 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
304 Freescale Semiconductor
4C 88 22 36 46
4D 96 22 40 50
4E 112 26 48 58
4F 136 26 60 70
50 96 18 36 50
51 112 18 44 58
52 128 26 52 66
53 144 26 60 74
54 160 34 68 82
55 176 34 76 90
56 208 42 92 106
57 256 42 116 130
58 160 18 76 82
59 192 18 92 98
5A 224 34 108 114
5B 256 34 124 130
5C 288 50 140 146
5D 320 50 156 162
5E 384 66 188 194
5F 480 66 236 242
60 320 34 156 162
61 384 34 188 194
62 448 66 220 226
63 512 66 252 258
64 576 98 284 290
65 640 98 316 322
66 768 130 380 386
67 960 130 476 482
68 640 66 316 322
69 768 66 380 386
6A 896 130 444 450
6B 1024 130 508 514
6C 1152 194 572 578
6D 1280 194 636 642
6E 1536 258 764 770
6F 1920 258 956 962
70 1280 130 636 642
71 1536 130 764 770
72 1792 258 892 898
73 2048 258 1020 1026
74 2304 386 1148 1154
75 2560 386 1276 1282
76 3072 514 1532 1538
77 3840 514 1916 1922
78 2560 258 1276 1282
Table 10-5. IIC Divider and Hold Values (Sheet 3 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 305
79 3072 258 1532 1538
7A 3584 514 1788 1794
7B 4096 514 2044 2050
7C 4608 770 2300 2306
7D 5120 770 2556 2562
7E 6144 1026 3068 3074
7F 7680 1026 3836 3842
MUL = 4
80 80 28 24 44
81 88 28 28 48
82 96 32 32 52
83 104 32 36 56
84 112 36 40 60
85 120 36 44 64
86 136 40 52 72
87 160 40 64 84
88 112 28 40 60
89 128 28 48 68
8A 144 36 56 76
8B 160 36 64 84
8C 176 44 72 92
8D 192 44 80 100
8E 224 52 96 116
8F 272 52 120 140
90 192 36 72 100
91 224 36 88 116
92 256 52 104 132
93 288 52 120 148
94 320 68 136 164
95 352 68 152 180
96 416 84 184 212
97 512 84 232 260
98 320 36 152 164
99 384 36 184 196
9A 448 68 216 228
9B 512 68 248 260
9C 576 100 280 292
9D 640 100 312 324
9E 768 132 376 388
9F 960 132 472 484
A0 640 68 312 324
A1 768 68 376 388
A2 896 132 440 452
A3 1024 132 504 516
A4 1152 196 568 580
Table 10-5. IIC Divider and Hold Values (Sheet 4 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
306 Freescale Semiconductor
10.3.2.3 IIC Control Register (IBCR)
Read and write anytime
A5 1280 196 632 644
A6 1536 260 760 772
A7 1920 260 952 964
A8 1280 132 632 644
A9 1536 132 760 772
AA 1792 260 888 900
AB 2048 260 1016 1028
AC 2304 388 1144 1156
AD 2560 388 1272 1284
AE 3072 516 1528 1540
AF 3840 516 1912 1924
B0 2560 260 1272 1284
B1 3072 260 1528 1540
B2 3584 516 1784 1796
B3 4096 516 2040 2052
B4 4608 772 2296 2308
B5 5120 772 2552 2564
B6 6144 1028 3064 3076
B7 7680 1028 3832 3844
B8 5120 516 2552 2564
B9 6144 516 3064 3076
BA 7168 1028 3576 3588
BB 8192 1028 4088 4100
BC 9216 1540 4600 4612
BD 10240 1540 5112 5124
BE 12288 2052 6136 6148
BF 15360 2052 7672 7684
76543210
R
IBEN IBIE MS/SL Tx/Rx TXAK
00
IBSWAI
WRSTA
Reset00000000
= Unimplemented or Reserved
Figure 10-6. IIC Bus Control Register (IBCR)
Table 10-5. IIC Divider and Hold Values (Sheet 5 of 5)
IBC[7:0]
(hex)
SCL Divider
(clocks)
SDA Hold
(clocks)
SCL Hold
(start)
SCL Hold
(stop)
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 307
Wait mode is entered via execution of a CPU WAI instruction. In the event that the IBSWAI bit is set, all
clocks internal to the IIC will be stopped and any transmission currently in progress will halt.If the CPU
were woken up by a source other than the IIC module, then clocks would restart and the IIC would resume
Table 10-6. IBCR Field Descriptions
Field Description
7
IBEN
I-Bus Enable — This bit controls the software reset of the entire IIC bus module.
0 The module is reset and disabled. This is the power-on reset situation. When low the interface is held in reset
but registers can be accessed
1 The IIC bus module is enabled.This bit must be set before any other IBCR bits have any effect
If the IIC bus module is enabled in the middle of a byte transfer the interface behaves as follows: slave mode
ignores the current transfer on the bus and starts operating whenever a subsequent start condition is detected.
Master mode will not be aware that the bus is busy, hence if a start cycle is initiated then the current bus cycle
may become corrupt. This would ultimately result in either the current bus master or the IIC bus module losing
arbitration, after which bus operation would return to normal.
6
IBIE
I-Bus Interrupt Enable
0 Interrupts from the IIC bus module are disabled. Note that this does not clear any currently pending interrupt
condition
1 Interrupts from the IIC bus module are enabled. An IIC bus interrupt occurs provided the IBIF bit in the status
register is also set.
5
MS/SL
Master/Slave Mode Select Bit — Upon reset, this bit is cleared. When this bit is changed from 0 to 1, a START
signal is generated on the bus, and the master mode is selected. When this bit is changed from 1 to 0, a STOP
signal is generated and the operation mode changes from master to slave.A STOP signal should only be
generated if the IBIF flag is set. MS/SL is cleared without generating a STOP signal when the master loses
arbitration.
0Slave Mode
1 Master Mode
4
Tx/Rx
Transmit/Receive Mode Select Bit — This bit selects the direction of master and slave transfers. When
addressed as a slave this bit should be set by software according to the SRW bit in the status register. In master
mode this bit should be set according to the type of transfer required. Therefore, for address cycles, this bit will
always be high.
0 Receive
1 Transmit
3
TXAK
Transmit Acknowledge Enable — This bit specifies the value driven onto SDA during data acknowledge cycles
for both master and slave receivers. The IIC module will always acknowledge address matches, provided it is
enabled, regardless of the value of TXAK. Note that values written to this bit are only used when the IIC bus is a
receiver, not a transmitter.
0 An acknowledge signal will be sent out to the bus at the 9th clock bit after receiving one byte data
1 No acknowledge signal response is sent (i.e., acknowledge bit = 1)
2
RSTA
Repeat Start — Writing a 1 to this bit will generate a repeated START condition on the bus, provided it is the
current bus master. This bit will always be read as a low. Attempting a repeated start at the wrong time, if the bus
is owned by another master, will result in loss of arbitration.
1 Generate repeat start cycle
1
RESERVED
Reserved — Bit 1 of the IBCR is reserved for future compatibility. This bit will always read 0.
0
IBSWAI
I Bus Interface Stop in Wait Mode
0 IIC bus module clock operates normally
1 Halt IIC bus module clock generation in wait mode
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
308 Freescale Semiconductor
from where was during the previous transmission. It is not possible for the IIC to wake up the CPU when
its internal clocks are stopped.
If it were the case that the IBSWAI bit was cleared when the WAI instruction was executed, the IIC internal
clocks and interface would remain alive, continuing the operation which was currently underway . It is also
possible to configure the IIC such that it will wake up the CPU via an interrupt at the conclusion of the
current operation. See the discussion on the IBIF and IBIE bits in the IBSR and IBCR, respectively.
10.3.2.4 IIC Status Register (IBSR)
This status register is read-only with exception of bit 1 (IBIF) and bit 4 (IBAL), which are software
clearable.
76543210
R TCF IAAS IBB
IBAL
0SRW
IBIF
RXAK
W
Reset10000000
= Unimplemented or Reserved
Figure 10-7. IIC Bus Status Register (IBSR)
Table 10-7. IBSR Field Descriptions
Field Description
7
TCF
Data Transferring Bit — While one byte of data is being transferred, this bit is cleared. It is set by the falling edge
of the 9th clock of a byte transfer. Note that this bit is only valid during or immediately following a transfer to the
IIC module or from the IIC module.
0 Transfer in progress
1 Transfer complete
6
IAAS
Addressed as a Slave Bit — When its own specific address (I-bus address register) is matched with the calling
address, this bit is set.The CPU is interrupted provided the IBIE is set.Then the CPU needs to check the SRW
bit and set its Tx/Rx mode accordingly.Writing to the I-bus control register clears this bit.
0 Not addressed
1 Addressed as a slave
5
IBB
Bus Busy Bit
0 This bit indicates the status of the bus. When a START signal is detected, the IBB is set. If a STOP signal is
detected, IBB is cleared and the bus enters idle state.
1Bus is busy
4
IBAL
Arbitration Lost — The arbitration lost bit (IBAL) is set by hardware when the arbitration procedure is lost.
Arbitration is lost in the following circumstances:
1. SDA sampled low when the master drives a high during an address or data transmit cycle.
2. SDA sampled low when the master drives a high during the acknowledge bit of a data receive cycle.
3. A start cycle is attempted when the bus is busy.
4. A repeated start cycle is requested in slave mode.
5. A stop condition is detected when the master did not request it.
This bit must be cleared by software, by writing a one to it. A write of 0 has no effect on this bit.
3
RESERVED
Reserved — Bit 3 of IBSR is reserved for future use. A read operation on this bit will return 0.
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 309
10.3.2.5 IIC Data I/O Register (IBDR)
In master transmit mode, when data is wr itten to the IBDR a data transfer is initiated. The most significant
bit is sent first. In master receive mode, reading this register initiates next byte data receiving. In slave
mode, the same functions are available after an addres s match has occurred.Note that the Tx/Rx bit in the
IBCR must correctly reflect the desired direction of transfer in master and slave modes for the transmission
to begin. For instance, if the IIC is configured for master transmit but a master receive is desired, then
reading the IBDR will not initiate the receive.
Reading the IBDR will return the last byte received while the IIC is configured in either master receive or
slave receive modes. The IBDR does not reflect every byte that is transmitted on the IIC bus, nor can
software verify that a byte has been written to the IBDR correctly by reading it back.
In master transmit mode, the first byte of data written to IBDR following assertion of MS/SL is used for
the address transfer and should com.prise of the calling address (in position D7:D1) concatenated with the
required R/W bit (in position D0).
2
SRW
Slave Read/Write — When IAAS is set this bit indicates the value of the R/W command bit of the calling address
sent from the master
This bit is only valid when the I-bus is in slave mode, a complete address transfer has occurred with an address
match and no other transfers have been initiated.
Checking this bit, the CPU can select slave transmit/receive mode according to the command of the master.
0 Slave receive, master writing to slave
1 Slave transmit, master reading from slave
1
IBIF
I-Bus Interrupt — The IBIF bit is set when one of the following conditions occurs:
— Arbitration lost (IBAL bit set)
— Byte transfer complete (TCF bit set)
— Addressed as slave (IAAS bit set)
It will cause a processor interrupt request if the IBIE bit is set. This bit must be cleared by software, writing a one
to it. A write of 0 has no effect on this bit.
0
RXAK
Received Acknowledge — The value of SDA during the acknowledge bit of a bus cycle. If the received
acknowledge bit (RXAK) is low, it indicates an acknowledge signal has been received after the completion of 8
bits data transmission on the bus. If RXAK is high, it means no acknowledge signal is detected at the 9th clock.
0 Acknowledge received
1 No acknowledge received
76543210
R
D7 D6 D5 D4 D3 D2 D1 D0
W
Reset00000000
Figure 10-8. IIC Bus Data I/O Register (IBDR)
Table 10-7. IBSR Field Descriptions (continued)
Field Description
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
310 Freescale Semiconductor
10.4 Functional Description
This section provides a complete functional description of the IICV2.
10.4.1 I-Bus Protocol
The IIC bus system uses a serial data line (SDA) and a serial clock line (SCL) for data transfer. All devices
connected to it must have open drain or open collector outputs. Logic AND function is exercised on both
lines with external pull-up resistors. The value of these resistors is system dependent.
Normally , a standard communication is composed of four parts: ST AR T signal, slave address transmission,
data transfer and STOP signal. They are described briefly in the following sections and illustrated in
Figure 10-9.
Figure 10-9. IIC-Bus Transmission Signals
10.4.1.1 START Signal
When the bus is free, i.e. no master device is engaging the bus (both SCL and SDA lines are at logical
high), a master may initiate communication by sending a START signal.As shown in Figure 10-9, a
START signal is defined as a high-to-low transition of SDA while SCL is high. This signal denotes the
beginning of a new data transfer (each data transfer may contain several bytes of data) and brings all slaves
out of their idle states.
SCL
SDA
Start
Signal
Ack
Bit
12345678
MSB LSB
12345678
MSB LSB
Stop
Signal
No
SCL
SDA
1234567 8
MSB LSB
1 2 5 678
MSB LSB
Repeated
34
9 9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W XXX D7 D6 D5 D4 D3 D2 D1 D0
Calling Address Read/ Data Byte
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
New Calling Address
99
XX
Ack
Bit
Write
Start
Signal
Start
Signal
Ack
Bit
Calling Address Read/
Write
Stop
Signal
No
Ack
Bit
Read/
Write
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 311
Figure 10-10. Start and Stop Conditions
10.4.1.2 Slave Address Transmission
The first byte of data transfer immediately after the START signal is the slave address transmitted by the
master. This is a seven-bit calling address followed by a R/W bit. The R/W bit tells the slave the desired
direction of data transfer.
1 = Read transfer, the slave transmits data to the master.
0 = Write transfer, the master transmits data to the slave.
Only the slave with a calling address that matches the one transmitted by the master will respond by
sending back an acknowledge bit. This is done by pulling the SDA low at the 9th clock (see Figure 10-9).
No two slaves in the system may have the same address. If the IIC bus is master, it must not transmit an
address that is equal to its own slave address. The IIC bus cannot be master and slave at the same
time.However, if arbitration is lost during an address cycle the IIC bus will revert to slave mode and
operate correctly even if it is being addressed by another master.
10.4.1.3 Data Transfer
As soon as successful slave addressing is achieved, the data transfer can proceed byte-by-byte in a
direction specified by the R/W bit sent by the calling master
All transfers that come after an address cycle are referred to as data transfers, even if they carry sub-address
information for the slave device.
Each data byte is 8 bits long. Data may be changed only while SCL is low and must be held stable while
SCL is high as shown in Figure 10-9. There is one clock pulse on SCL for each data bit, the MSB being
transferred first. Each data byte has to be followed by an acknowledge bit, which is signalled from the
receiving device by pulling the SDA low at the ninth clock. So one complete data byte transfer needs nine
clock pulses.
If the slave receiver does not acknowledge the master, the SDA line must be left high by the slave. The
master can then generate a stop signal to abort the data transfer or a start signal (repeated start) to
commence a new calling.
SDA
SCL
START Condition STOP Condition
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
312 Freescale Semiconductor
If the master receiver does not acknowledge the slave transmitter after a byte transmission, it means 'end
of data' to the slave, so the s lave releases the SDA line for the master to generate STOP or START signal.
10.4.1.4 STOP Signal
The master can terminate the communication by generating a STOP signal to free the bus. However, the
master may generate a START signal followed by a calling command without generating a STOP signal
first. This is called repeated START. A STOP signal is defined as a low-to-high transition of SDA while
SCL at logical 1 (see Figure 10-9).
The master can generate a ST OP even if the slave has generated an acknowledge at which point the slave
must release the bus.
10.4.1.5 Repeated START Signal
As shown in Figure 10-9, a repeated START signal is a START signal generated without first generating
a STOP signal to terminate the communication. This is used by the master to communicate with another
slave or with the same slave in different mode (transmit/receive mode) without releasing the bus.
10.4.1.6 Arbitration Procedure
The Inter -IC bus is a true multi-master bus that allows more than one master to be connected on it. If two
or more masters try to control the bus at the same time, a clock synchronization procedure determines the
bus clock, for which the low period is equal to the longest clock low period and the high is equal to the
shortest one among the masters. The relative priority of the contending masters is determined by a data
arbitration procedure, a bus master loses arbitration if it transmits logic 1 while another master transmits
logic 0. The losing masters immediately switch over to slave receive mode and stop driving SDA output.
In this case the transition from master to slave mode does not generate a STOP condition. Meanwhile, a
status bit is set by hardware to indicate loss of arbitration.
10.4.1.7 Clock Synchronization
Because wire-AND logic is performed on SCL line, a high-to-low transition on SCL line affects all the
devices connected on the bus. The devices start counting their low period and as soon as a device's clock
has gone low, it holds the SCL line low until the clock high state is reached.However, the change of low
to high in this device clock may not change the state of the SCL line if another device clock is within its
low period. Therefore, synchronized clock SCL is held low by the device with the longest low period.
Devices with shorter low periods enter a high wait state during this time (see Figure 10-11). When all
devices concerned have counted off their low period, the synchronized clock SCL line is released and
pulled high. There is then no dif ference between the device clocks and the state of the SCL line and all the
devices start counting their high periods.The first device to complete its high period pulls the SCL line low
again.
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 313
Figure 10-11. IIC-Bus Clock Synchronization
10.4.1.8 Handshaking
The clock synchronization mechanism can be used as a handshake in data transfer . Slave devices may hold
the SCL low after completion of one byte transfer (9 bits). In such case, it halts the bus clock and forces
the master clock into wait states until the slave releases the SCL line.
10.4.1.9 Clock Stretching
The clock synchronization mechanism can be used by slaves to slow down the bit rate of a transf er. After
the master has driven SCL low the slave can drive SCL low for the required period and then release it.If
the slave SCL low period is greater than the master SCL low period then the resulting SCL bus signal low
period is stretched.
10.4.2 Operation in Run Mode
This is the basic mode of operation.
10.4.3 Operation in Wait Mode
IIC operation in wait mode can be configured. Depending on the state of internal bits, the IIC can operate
normally when the CPU is in wait mode or the IIC clock generation can be turned of f and the IIC module
enters a power conservation state during wait mode. In the later case, any transmission or reception in
progress stops at wait mode entry.
10.4.4 Operation in Stop Mode
The IIC is inactive in stop mode for reduced power consumption. The STOP instruction does not affect
IIC register states.
SCL1
SCL2
SCL
Internal Counter Reset
WAIT Start Counting High Period
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
314 Freescale Semiconductor
10.5 Resets
The reset state of each individual bit is listed in Section 10.3, “Memory Map and Register Definition,”
which details the registers and their bit-fields.
10.6 Interrupts
IICV2 uses only one interrupt vector.
Table 10-8. Interrupt Summary
Internally there are three types of interrupts in IIC. The interrupt service routine can determine the interrupt
type by reading the status register.
IIC Interrupt can be generated on
1. Arbitration lost condition (IBAL bit set)
2. Byte transfer condition (TCF bit set)
3. Address detect condition (IAAS bit set)
The IIC interrupt is enabled by the IBIE bit in the IIC control register. It must be cleared by writing 0 to
the IBF bit in the interrupt service routine.
10.7 Initialization/Application Information
10.7.1 IIC Programming Examples
10.7.1.1 Initialization Sequence
Reset will put the IIC bus control register to its default status. Before the interface can be used to transfer
serial data, an initialization procedure must be carried out, as follows:
1. Update the frequency divider register (IBFD) and select the required division ratio to obtain SCL
frequency from system clock.
2. Update the IIC bus address register (IBAD) to define its slave address.
3. Set the IBEN bit of the IIC bus control register (IBCR) to enable the IIC interface system.
4. Modify the bits of the IIC bus control register (IBCR) to select master/slave mode, transmit/receive
mode and interrupt enable or not.
Interrupt Offset Vector Priority Source Description
IIC
Interrupt
— — — IBAL, TCF, IAAS
bits in IBSR
register
When either of IBAL, TCF or IAAS bits is set
may cause an interrupt based on arbitration
lost, transfer complete or address detect
conditions
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 315
10.7.1.2 Generation of START
After completion of the initialization procedure, serial data can be transmitted by selecting the 'master
transmitter' mode. If the device is connected to a multi-master bus system, the state of the IIC bus busy bit
(IBB) must be tested to check whether the serial bus is free.
If the bus is free (IBB=0), the start condition and the first byte (the slave address) can be sent. The data
written to the data register comprises the slave calling address and the LSB set to indicate the direction of
transfer required from the slave.
The bus free time (i.e., the time between a STOP condition and the following START condition) is built
into the hardware that generates the START cycle. Depending on the relative frequencies of the system
clock and the SCL period it may be necessary to wait until the IIC is busy after writing the calling address
to the IBDR before proceeding with the following instructions. This is illustrated in the following example.
An example of a program which generates the START signal and transmits the first byte of data (slave
address) is shown below:
10.7.1.3 Post-Transfer Software Response
Transmission or reception of a byte will set the data transferr ing bit (TCF) to 1, which indicates one byte
communication is finished. The IIC bus interrupt bit (IBIF) is set also; an interrupt will be generated if the
interrupt function is enabled during initialization by setting the IBIE bit. Software must clear the IBIF bit
in the interrupt routine first. The TCF bit will be cleared by reading from the IIC bus data I/O register
(IBDR) in receive mode or writing to IBDR in transmit mode.
Software may service the IIC I/O in the main program by monitoring the IBIF bit if the interrupt function
is disabled. Note that polling should monitor the IBIF bit rather than the TCF bit because their operation
is different when arbitration is lost.
Note that when an interrupt occurs at the end of the address cycle the master will always be in transmit
mode, i.e. the address is transmitted. If master receive mode is required, indicated by R/W bit in IBDR,
then the Tx/Rx bit should be toggled at this stage.
During slave mode address cycles (IAAS=1), the SRW bit in the status register is read to determine the
direction of the subsequent transfer and the Tx/Rx bit is programmed accordingly. For slave mode data
cycles (IAAS=0) the SR W bit is not valid, the Tx/Rx bit in the control register should be read to determine
the direction of the current transfer.
The following is an example of a software response by a 'master transmitter' in the interrupt routine.
CHFLAG BRSET IBSR,#$20,* ;WAIT FOR IBB FLAG TO CLEAR
TXSTART BSET IBCR,#$30 ;SET TRANSMIT AND MASTER MODE;i.e. GENERATE START CONDITION
MOVB CALLING,IBDR ;TRANSMIT THE CALLING ADDRESS, D0=R/W
IBFREE BRCLR IBSR,#$20,* ;WAIT FOR IBB FLAG TO SET
ISR BCLR IBSR,#$02 ;CLEAR THE IBIF FLAG
BRCLR IBCR,#$20,SLAVE ;BRANCH IF IN SLAVE MODE
BRCLR IBCR,#$10,RECEIVE ;BRANCH IF IN RECEIVE MODE
BRSET IBSR,#$01,END ;IF NO ACK, END OF TRANSMISSION
TRANSMIT MOVB DATABUF,IBDR ;TRANSMIT NEXT BYTE OF DATA
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
316 Freescale Semiconductor
10.7.1.4 Generation of STOP
A data transfer ends with a ST OP signal generated by the 'master' device. A master transmitter can simply
generate a STOP signal afte r all the data has been transmitted. The following is an example showing how
a stop condition is generated by a master transmitter.
If a master receiver wants to terminate a data transfer, it must inform the slave transmitter by not
acknowledging the last byte of data which can be done by setting the transmit acknowledge bit (TXAK)
before reading the 2nd last byte of data. Before reading the last byte of data, a STOP signal must be
generated first. The following is an example showing how a ST OP signal is generated by a master receiver .
10.7.1.5 Generation of Repeated START
At the end of data transfer, if the master continues to want to communicate on the bus, it can generate
another START signal followed by another slave address without first generating a STOP signal. A
program example is as shown.
10.7.1.6 Slave Mode
In the slave interrupt service routine, the module addressed as slave bit (IAAS) should be tested to check
if a calling of its own address has just been received. If IAAS is set, software should set the
transmit/receive mode select bit (Tx/Rx bit of IBCR) according to the R/W command bit (SRW). Writing
to the IBCR clears the IAAS automatically . Note that the only time IAAS is read as set is from the interrupt
at the end of the address cycle where an address match occurred, interr upts resulting from subsequent data
transfers will have IAAS cleared. A data transfer may now be initiated by writing information to IBDR,
for slave transmits, or dummy reading from IBDR, in slave receive mode. The slave will drive SCL low
in-between byte transfers, SCL is released when the IBDR is accessed in the required mode.
MASTX TST TXCNT ;GET VALUE FROM THE TRANSMITING COUNTER
BEQ END ;END IF NO MORE DATA
BRSET IBSR,#$01,END ;END IF NO ACK
MOVB DATABUF,IBDR ;TRANSMIT NEXT BYTE OF DATA
DEC TXCNT ;DECREASE THE TXCNT
BRA EMASTX ;EXIT
END BCLR IBCR,#$20 ;GENERATE A STOP CONDITION
EMASTX RTI ;RETURN FROM INTERRUPT
MASR DEC RXCNT ;DECREASE THE RXCNT
BEQ ENMASR ;LAST BYTE TO BE READ
MOVB RXCNT,D1 ;CHECK SECOND LAST BYTE
DEC D1 ;TO BE READ
BNE NXMAR ;NOT LAST OR SECOND LAST
LAMAR BSET IBCR,#$08 ;SECOND LAST, DISABLE ACK
;TRANSMITTING
BRA NXMAR
ENMASR BCLR IBCR,#$20 ;LAST ONE, GENERATE ‘STOP’ SIGNAL
NXMAR MOVB IBDR,RXBUF ;READ DATA AND STORE
RTI
RESTART BSET IBCR,#$04 ;ANOTHER START (RESTART)
MOVB CALLING,IBDR ;TRANSMIT THE CALLING ADDRESS;D0=R/W
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 317
In slave transmitter routine, the received acknowledge bit (RXAK) must be tested before transmitting the
next byte of data. Setting RXAK means an 'end of data' signal from the master receiver , after which it must
be switched from transmitter mode to receiver mode by software. A dummy read then releases the SCL
line so that the master can generate a STOP signal.
10.7.1.7 Arbitration Lost
If several masters try to engage the bus simultaneously, only one master wins and the others lose
arbitration. The devices which lost arbitration are immediately switched to slave receive mode by the
hardware. Their data output to the SDA line is stopped, but SCL continues to be generated until the end of
the byte during which arbitration was lost. An interrupt occurs at the falling edge of the ninth clock of this
transfer with IBAL=1 and MS/SL=0. If one master attempts to start transmission while the bus is being
engaged by another master, the hardware will inhibit the transmission; switch the MS/SL bit from 1 to 0
without generating STOP condition; generate an interrupt to CPU and set the IBAL to indicate that the
attempt to engage the bus is failed. When considering these cases, the slave service routine should test the
IBAL first and the software should clear the IBAL bit if it is set.
Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E256 Data Sheet, Rev. 1.08
318 Freescale Semiconductor
Figure 10-12. Flow-Chart of Typical IIC Interrupt Routine
Clear
Master
Mode
?
Tx/Rx
?
Last Byte
Transmitted
?
RXAK=0
?
End Of
Addr Cycle
(Master Rx)
?
Write Next
Byte To IBDR
Switch To
Rx Mode
Dummy Read
From IBDR
Generate
Stop Signal
Read Data
From IBDR
And Store
Set TXAK =1 Generate
Stop Signal
2nd Last
Byte To Be Read
?
Last
Byte To Be Read
?
Arbitration
Lost
?
Clear IBAL
IAAS=1
?
IAAS=1
?
SRW=1
?
TX/RX
?
Set TX
Mode
Write Data
To IBDR
Set RX
Mode
Dummy Read
From IBDR
ACK From
Receiver
?
Tx Next
Byte
Read Data
From IBDR
And Store
Switch To
Rx Mode
Dummy Read
From IBDR
RTI
YN
Y
YY
Y
Y
Y
Y
Y
Y
N
N
N
N
N
N
N
N
N
Y
TX RX
RX
TX
(Write)
(Read)
N
IBIF
Address Transfer Data Transfer
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 319
Chapter 11
Pulse Width Modulator with Fault Protection (PMF15B6CV2)
11.1 Introduction
The Pulse width Modulator with Fault protection (PMF) module can be configured for one, two, or three
complementary pairs. For example:
• One complementary pair and four independent PWM outputs
• Two complementary pair and two independent PWM outputs
• Three complementary pair and zero independent PWM outputs
• Zero complementary pair and six independent PWM outputs
All PWM outputs can be generated from the same counter , or each pair can have its own counter for three
independent PWM frequencies. Complementary operation permits programmable dead-time insertion,
distortion correction through current sensing by software, and separate top and bottom output polarity
control. Each counter value is programmable to support a continuously variable PWM frequency. Both
edge- and center-aligned synchronous pulse width-control and full range modulation from 0 percent to 100
percent, are supported. The PMF is capable of controlling most motor types: AC induction motors
(ACIM), both brushless (BLDC) and brush DC motors (BDC), switched (SRM), and variable reluctance
motors (VRM), and stepper motors.
11.1.1 Features
• Three complementary PWM signal pairs, or six independent PWM signals
• Three 15-bit counters
• Features of complementary channel operation
— Deadtime insertion
— Separate top and bottom pulse width correction via current status inputs or software
— Separate top and bottom polarity control
• Edge-aligned or center-aligned PWM signals
• Half-cycle reload capability
• Integral reload rates from 1 to 16
• Individual software-controlled PWM output
• Programmable fault protection
• Polarity control
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
320 Freescale Semiconductor
11.1.2 Modes of Operation
Care must be exercised when using this module in the modes listed in Table 11-1. PWM outputs are placed
in their inactive states in stop mode, and optionally under WAIT and freeze modes. PWM outputs will be
reactivated (assuming they were active to begin with) when these modes are exited.
11.1.3 Block Diagrams
Figure 11-1 provides an overview of the PMF module.
The Mux/Swap/Current Sense block is tightly integrated with the dead time insertion block. This detail is
shown in Figure 11-2.
NOTE
It is possible to have both channels of a complementary pair to be high. For
example, if the TOPNEGA (negative polarity for PWM0), BOTNEGA
(negative polarity for PWM1), MASK0, and MASK1 bits are set, both the
PWM complementary outputs of generator A will be high. See
Section 11.3.2.2, “PMF Configure 1 Register (PMFCFG1)” for the
description of TOPNEG and BOTNEG bits, and Section 11.3.2.3, “PMF
Configure 2 Register (PMFCFG2)” for the description of the MSK0 and
MSK1 bits.
Table 11-1. Modes When PWM Operation is Restricted
Mode Description
Stop PWM outputs are disabled
Wait PWM outputs are disabled as a function of the PMFWAI bit.
Freeze PWM outputs are disabled as a function of the PMFFRZ bit.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 321
Figure 11-1. PMF Block Diagram
PMFDTM
REGISTER
REGISTERS
PMFMOD
PWMRIE
PWMEN
LDOK
EDGE
OUTCTL0
OUT0
PRESCALER
PWM0 PIN
PWM1 PIN
PWM2 PIN
PWM3 PIN
PWM4 PIN
PWM5 PIN
PWM
PRSC0
INTERRUPT
CONTROL
FAULT
BUS
REGISTERS
PMFVAL0-5
PMFCNT
REGISTERS
CLOCK
GENERATORS
MUX,
SWAP &
CURRENT
SENSE
OUT2
OUT4
PROTECTION
FAULT3 PIN
FAULT0 PIN
FAULT1 PIN
FAULT2 PIN
REGISTERS
PMDISMAP POLARITY
CONTROL
FAULT
PIN
FILTERS
FFLAG0
PWMRF
RELOAD A INTERRUPT REQUEST
FAULT0 INTERRUPT REQUEST
FAULT1 INTERRUPT REQUEST
FAULT2 INTERRUPT REQUEST
FAULT3 INTERRUPT REQUEST
ISENS1
ISENS0
FINT0
FINT1
FINT2
FINT3
FFLAG0
FFLAG1
FFLAG2
FFLAG3
FMODE0
FMODE1
FMODE2
FMODE3
REGISTER
PMFFPIN
FFLAG2
FFLAG1
FFLAG3
LDFQ2
LDFQ3
PRSC1
OUTCTL2
OUTCTL4
OUTCTL1
OUT1
OUT3
OUT5
OUTCTL3
OUTCTL5
LDFQ1
LDFQ0
HALF
PWMRF
INDEP
TOPNEG
BOTNEG
TOP/BOTTOM
GENERATION
IPOL
DT 0—5
6
IS0 IS1 IS2
PIN PIN PIN
DEADTIME INSERTION
MULTIPLE REGISTERS OR BITS
FOR TIMEBASE A, B, OR C
A,B,C
MTG
RELOAD B INTERRUPT REQUEST
RELOAD A INTERRUPT REQUEST
RELOAD C INTERRUPT REQUEST
QSMP0
QSMP2
QSMP1
QSMP3
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
322 Freescale Semiconductor
Figure 11-2. Detail of Mux, Swap, and Deadtime Functions
11.2 External Signal Description
The pulse width modulator has external pins named PWM0–5, FAULT0–3, and IS0–IS2.
11.2.1 PWM0–PWM5 Pins
PWM0–PWM5 are the output pins of the six PWM channels.
11.2.2 FAULT0–FAULT3 Pins
FAULT0–FAULT3 are input pins for disabling selected PWM outputs.
11.2.3 IS0–IS2 Pins
IS0–IS2 are current status pins for top/bottom pulse width correction in complementary channel operation
while deadtime is asserted.
PWM source selection is based on a number of factors:
— State of current sense pins
— IPOL bit
— OUTCTL bit
— Center vs edge aligned
PWM
GENERATOR
0
PWM
GENERATOR
SWAPA
OUT0
OUT1 1
1
GENERATE
COMPLEMENT &
INSERT DEADTIME
1
1
INDEPA
FAULT
&
POLARITY
CONTROL
PA D 0
PA D 1
MSK0
MSK1
OUTCTL1
OUTCTL0
1
IPOLA or
ISENS0 or
OUTCTL0
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 323
11.3 Memory Map and Registers
11.3.1 Module Memory Map
Address Name Bit 7 6 5 4 3 2 1 Bit 0
0x0000 PMFCFG0 RWP MTG EDGEC EDGEB EDGEA INDEPC INDEPB INDEPA
W
0x0001 PMFCFG1 RENHA 0BOTNEGC TOPNEGC BOTNEGB TOPNEGB BOTNEGA TOPNEGA
W
0x0002 PMFCFG2 R0 0 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0
W
0x0003 PMFCFG3 RPMFWAI PMFFRZ 0VLMODE SWAPC SWAPB SWAPA
W
0x0004 PMFFCTL RFMODE3 FIE3 FMODE2 FIE2 FMODE1 FIE1 FMODE0 FIE0
W
0x0005 PMFFPIN R0 FPINE3 0FPINE2 0FPINE1 0FPINE0
W
0x0006 PMFFSTA R0 FFLAG3 0FFLAG2 0FFLAG1 0FFLAG0
W
0x0007 PMFQSMP RQSMP3 QSMP2 QSMP1 QSMP0
W
0x0008 PMFDMPA RDMP13 DMP12 DMP11 DMP10 DMP03 DMP02 DMP01 DMP00
W
0x0009 PMFDMPB RDMP33 DMP32 DMP31 DMP30 DMP23 DMP22 DMP21 DMP20
W
0x000A PMFDMPC RDMP53 DMP52 DMP51 DMP50 DMP43 DMP42 DMP41 DMP40
W
0x000B Reserved R
W
0x000C PMFOUTC R0 0 OUTCTL5 OUTCTL4 OUTCTL3 OUTCTL2 OUTCTL1 OUTCTL0
W
0x000D PMFOUTB R0 0 OUT5 OUT4 OUT3 OUT2 OUT1 OUT0
W
0x000E PMFDTMS R 0 0 DT5 DT4 DT3 DT2 DT1 DT0
W
0x000F PMFCCTL R0 0 ISENS 0IPOLC IPOLB IPOLA
W
0x0010 PMFVAL0 RPMFVAL0
W
0x0011 PMFVAL0 RPMFVAL0
W
= Unimplemented or Reserved
Figure 11-3. PMF15B6C Register Summary (Sheet 1 of 3)
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
324 Freescale Semiconductor
0x0012 PMFVAL1 RPMFVAL1
W
0x0013 PMFVAL1 RPMFVAL1
W
0x0014 PMFVAL2 RPMFVAL2
W
0x0015 PMFVAL2 RPMFVAL2
W
0x0016 PMFVAL3 RPMFVAL3
W
0x0017 PMFVAL3 RPMFVAL3
W
0x0018 PMFVAL4 RPMFVAL4
W
0x0019 PMFVAL4 RPMFVAL4
W
0x001A PMFVAL5 RPMFVAL5
W
0x001B PMFVAL5 RPMFVAL5
W
0x001C
↓
0X001F
Reserved
R
W
0x0020 PMFENCA RPWMENA 00000
LDOKA PWMRIEA
W
0x0021 PMFFQCA RLDFQA HALFA PRSCA PWMRFA
W
0x0022 PMFCNTA R 0 PMFCNTA
W
0x0023 PMFCNTA R PMFCNTA
W
0x0024 PMFMODA R0 PMFMODA
W
0x0025 PMFMODA RPMFMODA
W
0x0026 PMFDTMA R0 0 0 0 PMFDTMA
W
0x0027 PMFDTMA RPMFDTMA
W
Address Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented or Reserved
Figure 11-3. PMF15B6C Register Summary (Sheet 2 of 3)
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 325
0x0028 PMFENCB RPWMENB 00000
LDOKB PWMRIEB
W
0x0029 PMFFQCB RLDFQB HALFB PRSCB PWMRFB
W
0x002A PMFCNTB R 0 PMFCNTB
W
0x002B PMFCNTB R PMFCNTB
W
0x002C PMFMODB R0 PMFMODB
W
0x002D PMFMODB RPMFMODB
W
0x002E PMFDTMB R0 0 0 0 PMFDTMB
W
0x002F PMFDTMB RPMFDTMB
W
0x0030 PMFENCC RPWMENC 00000
LDOKC PWMRIEC
W
0x0031 PMFFQCC RLDFQC HALFC PRSCC PWMRFC
W
0x0032 PMFCNTC R 0 PMFCNTC
W
0x0033 PMFCNTC R PMFCNTC
W
0x0034 PMFMODC R0 PMFMODC
W
0x0035 PMFMODC RPMFMODC
W
0x0036 PMFDTMC R0 0 0 0 PMFDTMC
W
0x0037 PMFDTMC RPMFDTMC
W
0x0038
↓
0X003F
Reserved
R
W
Address Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented or Reserved
Figure 11-3. PMF15B6C Register Summary (Sheet 3 of 3)
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
326 Freescale Semiconductor
11.3.2 Register Descriptions
The address of a register is the sum of a base address and an address of fset. The base address is defined at
the chip level and the address offset is defined at the module level.
11.3.2.1 PMF Configure 0 Register (PMFCFG0)
Read anytime.
See bit description for write conditions.
Module Base + 0x0000
76543210
R
WP MTG EDGEC EDGEB EDGEA INDEPC INDEPB INDEPA
W
Reset00000000
Figure 11-4. PMF Configure 0 Register (PMFCFG0)
Table 11-2. PMFCFG0 Field Descriptions
Field Description
7
WP
Write Protect — This bit enables write protection to be used for all write-protectable registers. While clear, WP
allows write-protected registers to be written. When set, WP prevents any further writes to write-protected
registers. Once set, WP can be cleared only by reset.
0 Write-protectable registers may be written.
1 Write-protectable registers are write-protected.
6
MTG
Multiple Timebase Generators — This bit determines the number of timebase counters used. Once set, MTG
can be cleared only by reset.
If MTG is set, PWM generators B and C and registers $xx28–$xx37 are available. The three generators have
their own variable frequencies and are not synchronized.
If MTG is cleared, PMF registers from $xx28–$xx37 can not be written and read zeroes, and bits EDGEC and
EDGEB are ignored. Pair A, Pair B and Pair C PWMs are synchronized to PWM generator A and use registers
from $xx20–$xx27.
0 Single timebase generator.
1 Multiple timebase generators.
5
EDGEC
Edge-Aligned or Center-Aligned PWM for Pair C — This bit determines whether PWM4 and PWM5 channels
will use edge-aligned or center-aligned waveforms. This bit has no effect if MTG bit is cleared. This bit cannot be
modified after the WP bit is set.
0 PWM4 and PWM5 are center-aligned PWMs
1 PWM4 and PWM5 are edge-aligned PWMs
4
EDGEB
Edge-Aligned or Center-Aligned PWM for Pair B — This bit determines whether PWM2 and PWM3 channels
will use edge-aligned or center-aligned waveforms. This bit has no effect if MTG bit is cleared. This bit cannot be
modified after the WP bit is set.
0 PWM2 and PWM3 are center-aligned PWMs
1 PWM2 and PWM3 are edge-aligned PWMs
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 327
3
EDGEA
Edge-Aligned or Center-Aligned PWM for Pair A — This bit determines whether PWM0 and PWM1 channels
will use edge-aligned or center-aligned waveforms. It determines waveforms for Pair B and Pair C if the MTG bit
is cleared. This bit cannot be modified after the WP bit is set.
0 PWM0 and PWM1 are center-aligned PWMs
1 PWM0 and PWM1 are edge-aligned PWMs
2
INDEPC
Independent or Complimentary Operation for Pair C — This bit determines if the PWM channels 4 and 5 will
be independent PWMs or complementary PWMs. This bit cannot be modified after the WP bit is set.
0 PWM4 and PWM5 are complementary PWM pair
1 PWM4 and PWM5 are independent PWMs
1
INDEPB
Independent or Complimentary Operation for Pair B — This bit determines if the PWM channels 2 and 3 will
be independent PWMs or complementary PWMs. This bit cannot be modified after the WP bit is set.
0 PWM2 and PWM3 are complementary PWM pair
1 PWM2 and PWM3 are independent PWMs
0
INDEPA
Independent or Complimentary Operation for Pair A — This bit determines if the PWM channels 0 and 1 will
be independent PWMs or complementary PWMs. This bit cannot be modified after the WP bit is set.
0 PWM0 and PWM1 are complementary PWM pair
1 PWM0 and PWM1 are independent PWMs
Table 11-2. PMFCFG0 Field Descriptions (continued)
Field Description
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
328 Freescale Semiconductor
11.3.2.2 PMF Configure 1 Register (PMFCFG1)
Read anytime. This register cannot be modified after the WP bit is set.
A normal PWM output or positive polarity means that the PWM channel outputs high when the counter
value is smaller than or equal to the pulse width value and outputs low otherwise. An inverted output or
negative polarity means that the PWM channel outputs low when the counter value is smaller than or equal
to the pulse width value and outputs high otherwise.
Module Base + 0x0001
76543210
R
ENHA
0
BOTNEGC TOPNEGC BOTNEGB TOPNEGB BOTNEGA TOPNEGA
W
Reset00000000
= Unimplemented or Reserved
Figure 11-5. PMF Configure 1 Register (PMFCFG1)
Table 11-3. PMFCFG1 Field Descriptions
Field Description
7
ENHA
Enable Hardware Acceleration — This bit enables writing to the VLMODE[1:0], SWAPC, SWAPB, and SWAPA
bits in the PMFCFG3 register. This bit cannot be modified after the WP bit is set.
0 Disable writing to VLMODE[1:0], SWAPC, SWAPB, and SWAPA bits
1 Enable writing to VLMODE[1:0], SWAPC, SWAPB, and SWAPA bits
5
BOTNEGC
Pair C Bottom-side PWM Polarity — This bit determines the polarity for Pair C bottom-side PWM (PWM5). This
bit cannot be modified after the WP bit is set.
0 Positive PWM5 polarity
1 Negative PWM5 polarity
4
TOPNEGC
Pair C Top-side PWM Polarity — This bit determines the polarity for Pair C top-side PWM (PWM4). This bit
cannot be modified after the WP bit is set.
0 Positive PWM4 polarity
1 Negative PWM4 polarity
3
BOTNEGB
Pair B Bottom-side PWM Polarity — This bit determines the polarity for Pair B bottom-side PWM (PWM3). This
bit cannot be modified after the WP bit is set.
0 Positive PWM3 polarity
1 Negative PWM3 polarity
2
TOPNEGB
Pair B Top-side PWM Polarity — This bit determines the polarity for Pair B top-side PWM (PWM2). This bit
cannot be modified after the WP bit is set.
0 Positive PWM2 polarity
1 Negative PWM2 polarity
1
BOTNEGA
Pair A Bottom-side PWM Polarity — This bit determines the polarity for Pair A bottom-side PWM (PWM1). This
bit cannot be modified after the WP bit is set.
0 Positive PWM1 polarity
1 Negative PWM1 polarity
0
TOPNEGA
Pair A Top-side PWM Polarity — This bit determines the polarity for Pair A top-side PWM (PWM0). This bit
cannot be modified after the WP bit is set.
0 Positive PWM0 polarity
1 Negative PWM0 polarity
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 329
11.3.2.3 PMF Configure 2 Register (PMFCFG2)
Read and write anytime.
Module Base + 0x0002
76543210
R0 0
MSK5 MSK4 MSK3 MSK2 MSK1 MSK0
W
Reset00000000
= Unimplemented or Reserved
Figure 11-6. PMF Configure 2 Register (PMFCFG2)
Table 11-4. PMFCFG2 Field Descriptions
Field Description
5–0
MSK[5:0]
Mask PWMx— Where x is 0, 1, 2, 3, 4, and 5.
0 PWMx is unmasked.
1 PWMx is masked and the channel is set to a value of 0 percent duty cycle.
WARNING
When using the TOPNEG/BOTNEG bits and the MSKx bits at the same time, when in complementary mode,
it is possible to have both pmf channel outputs of a channel pair set to one.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
330 Freescale Semiconductor
11.3.2.4 PMF Configure 3 Register (PMFCFG3)
Read and write anytime.
Module Base + 0x0003
76543210
R
PMFWAI PMFFRZ
0
VLMODE SWAPC SWAPB SWAPA
W
Reset00000000
= Unimplemented or Reserved
Figure 11-7. PMF Configure 3 Register (PMFCFG3)
Table 11-5. PMFCFG3 Field Descriptions
Field Description
7
PMFWAI
PMF Stops While in Wait Mode — When set to zero, the PWM generators will continue to run while the chip is
in wait mode. In this mode, the peripheral clock continues to run but the CPU clock does not. If the device enters
wait mode and this bit is one, then the PWM outputs will be switched to their inactive state until wait mode is
exited. At that point the PWM pins will resume operation as programmed in the PWM registers.
0 PMF continues to run in wait mode.
1 PMF is disabled in wait mode.
6
PMFFRZ
PMF Stops While in Freeze Mode — When set to zero, the PWM generators will continue to run while the chip
is in freeze mode. If the device enters freeze mode and this bit is one, then the PWM outputs will be switched to
their inactive state until freeze mode is exited. At that point the PWM pins will resume operation as programmed
in the PWM registers.
0 PMF continues to run in freeze mode.
1 PMF is disabled in freeze mode.
4–3
VLMODE
Value Register Load Mode — This field determines the way the value registers are being loaded. This field can
only be written if ENHA is set.
00 = Each value register is accessed independently
01 = Writing to value register zero also writes to value registers one to five
10 = Writing to value register zero also writes to value registers one to three
11 = Reserved (defaults to independent access)
2
SWAPC
Swap Pair C — This bit can only be written if ENHA is set.
0No swap.
1 PWM4 and PWM5 are swapped only in complementary mode.
1
SWAPB
Swap Pair B — This bit can only be written if ENHA is set.
0No swap.
1 PWM2 and PWM3 are swapped only in complementary mode.
0
SWAPC
Swap Pair A —This bit can only be written if ENHA is set.
0No swap.
1 PWM0 and PWM1 are swapped only in complementary mode.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 331
11.3.2.5 PMF Fault Control Register (PMFFCTL)
Read and write anytime.
11.3.2.6 PMF Fault Pin Enable Register (PMFFPIN)
Read anytime. This register cannot be modified after the WP bit is set.
Module Base + 0x0004
76543210
R
FMODE3 FIE3 FMODE2 FIE2 FMODE1 FIE1 FMODE0 FIE0
W
Reset00000000
Figure 11-8. PMF Fault Control Register (PMFFCTL))
Table 11-6. PMFFCTL Field Descriptions
Field Description
7, 5, 3, 1
FMODE[3:0]
Fault x Pin Clearing Mode — This bit selects automatic or manual clearing of FAULTx pin faults. See
Section 11.4.8.2, “Automatic Fault Clearing” and Section 11.4.8.3, “Manual Fault Clearing” for more details.
0 Manual fault clearing of FAULTx pin faults.
1 Automatic fault clearing of FAULTx pin faults.
where x is 0, 1, 2, and 3.
6, 4, 2, 0
FIE[3:0]
Fault x Pin Interrupt Enable — This bit enables CPU interrupt requests to be generated by the FAULTx pin. The
fault protection circuit is independent of the FIEx bit and is active when FPINEx is set. If a fault is detected, the
PWM pins are disabled according to the PMF Disable Mapping registers.
0 Fault x CPU interrupt requests disabled.
1 Fault x CPU interrupt requests enabled.
where x is 0, 1, 2 and 3.
Module Base + 0x0005
76543210
R0
FPINE3
0
FPINE2
0
FPINE1
0
FPINE0
W
Reset00000000
= Unimplemented or Reserved
Figure 11-9. PMF Fault Pin Enable Register (PMFFPIN)
Table 11-7. PMFFPIN Field Descriptions
Field Description
6, 4, 2, 0
FPINE[2:0]
Fault x Pin Enable — Where x is 0, 1, 2 and 3.
0 FAULTx pin is disabled for fault protection.
1 FAULTx pin is enabled for fault protection.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
332 Freescale Semiconductor
11.3.2.7 PMF Fault Status Register (PMFFSTA)
Read and write anytime.
11.3.2.8 PMF Fault Qualifying Samples Register (PMFQSMP)
Read anytime. This register cannot be modified after the WP bit is set.
Module Base + 0x0006
76543210
R0
FFLAG3
0
FFLAG2
0
FFLAG1
0
FFLAG0
W
Reset00000000
= Unimplemented or Reserved
Figure 11-10. PMF Fault Flag Register (PMFFSTA)
Table 11-8. PMFFSTA Field Descriptions
Field Description
6, 4, 2, 0
FFLAG[3:0]
Fault x Pin Flag — This flag is set after the required number of samples have been detected after a rising edge
on the FAULTx pin. Writing a logic one to FFLAGx clears it. Writing a logic zero has no effect. The fault protection
is enabled when FPINEx is set even when the PWMs are not enabled; therefore, a fault will be latched in,
requiring to be cleared in order to prevent an interrupt.
0 No fault on the FAULTx pin.
1 Fault on the FAULTx pin.
Note: Clearing FFLAGx satisfies pending FFLAGx CPU interrupt requests.
where x is 0, 1, 2 and 3.
Module Base + 0x0007
76543210
R
QSMP3 QSMP2 QSMP1 QSMP0
W
Reset00000000
Figure 11-11. PMF Fault Qualifying Samples Register (PMFQSMP)
Table 11-9. PMFQSMP Field Descriptions
Field Description
7–0
QSMP[3:0]
Fault x Qualifying Samples — This field indicates the number of consecutive samples taken at the FAULTx pin
to determine if a fault is detected. The first sample is qualified after two bus cycles from the time the fault is
present and each sample after that is taken every four bus cycles. See Table 11-10.
where x is 0, 1, 2 and 3.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 333
11.3.2.9 PMF Disable Mapping Registers
Read anytime. These registers cannot be modified after the WP bit is set.
Table 11-10. Qualifying Samples
QSMPx Number of Samples
00 1 sample1
1There is an asynchronous path from fault pin to disable
PWMs immediately but the fault is qualified in two bus
cycles.
01 5 samples
10 10 samples
11 15 samples
Module Base + 0x0008
76543210
R
DMP13 DMP12 DMP11 DMP10 DMP03 DMP02 DMP01 DMP00
W
Reset00000000
Figure 11-12. PMF Disable Mapping A Register (PMFDMPA)
Module Base + 0x0009
76543210
R
DMP33 DMP32 DMP31 DMP30 DMP23 DMP22 DMP21 DMP20
W
Reset00000000
Figure 11-13. PMF Disable Mapping B Register (PMFDMPB)
Module Base + 0x000A
76543210
R
DMP53 DMP52 DMP51 DMP50 DMP43 DMP42 DMP41 DMP40
W
Reset00000000
Figure 11-14. PMF Disable Mapping C Register (PMFDMPC)
Table 11-11. PMFDMPA, PMFDMPB, and PMFDMPC Field Descriptions
Field Description
7–0
DMP[00:53]
PMF Disable Mapping Bits — The fault decoder disables PWM pins selected by the fault logic and the disable
mapping registers. See Figure 11-15. Each bank of four bits in the disable mapping registers control the mapping
of a single PWM pin. Refer to Table 11-12.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
334 Freescale Semiconductor
Figure 11-15. Fault Decoder
11.3.2.10 PMF Output Control Register (PMFOUTC)
Read and write anytime.
Table 11-12. Fault Mapping
PWM Pin Controlling Register Bits
PWM0 DMP03 – DMP00
PWM1 DMP13 – DMP10
PWM2 DMP23 – DMP20
PWM3 DMP33 – DMP30
PWM4 DMP43 – DMP40
PWM5 DMP53 – DMP50
Module Base + 0x000C
76543210
R0 0
OUTCTL5 OUTCTL4 OUTCTL3 OUTCTL2 OUTCTL1 OUTCTL0
W
Reset00000000
= Unimplemented or Reserved
Figure 11-16. PMF Output Control Register (PMFOUTC)
Table 11-13. PMFOUTC Field Descriptions
Field Description
5–0
OUTCTL[5:0]
PMF Output Control Bits — These bits enable software control of their corresponding PWM pin. When
OUTCTLx is set, the OUTx bit activates and deactivates the PWMx output.
When operating the PWM in complementary mode, these bits must be switched in pairs for proper operation.
That is OUTCTL0 and OUTCTL1 must have the same value; OUTCTL2 and OUTCTL3 must have the same
value; and OUTCTL4 and OUTCTL5 must have the same value.
0 Software control disabled
1 Software control enabled
where X is 0, 1, 2, 3, 4 and 5
DMPx0
DMPx1
DMPx2
DMPx3
DISABLE PWM PIN x
Fault0
Fault1
Fault2
Fault3 where X is 0, 1, 2, 3, 4, 5
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 335
11.3.2.11 PMF Output Control Bit Register (PMFOUTB)
Read and write anytime.
Table 11-15. Software Output Control
Module Base + 0x000D
76543210
R0 0
OUT5 OUT4 OUT3 OUT2 OUT1 OUT0
W
Reset00000000
= Unimplemented or Reserved
Figure 11-17. PMF Output Control Bit Register (PMFOUTB)
Table 11-14. PMFOUTB Field Descriptions
Field Description
5–0
OUT[5:0]
PMF Output Control Bits — When the corresponding OUTCTL bit is set, these bits control the PWM pins,
illustrated in Table 11-15.
OUTx Bit Complementary Channel Operation Independent Channel Operation
OUT0 1—PWM0 is active
0—PWM0 is inactive
1—PWM0 is active
0—PWM0 is inactive
OUT1 1—PWM1 is complement of PWM0
0—PWM1 is inactive
1—PWM1 is active
0—PWM1 is inactive
OUT2 1—PWM2 is active
0—PWM2 is inactive
1—PWM2 is active
0—PWM2 is inactive
OUT3 1—PWM3 is complement of PWM2
0—PWM3 is inactive
1—PWM3 is active
0—PWM3 is inactive
OUT4 1—PWM4 is active
0—PWM4 is inactive
1—PWM4 is active
0—PWM4 is inactive
OUT5 1—PWM5 is complement of PWM4
0—PWM5 is inactive
1—PWM5 is active
0—PWM5 is inactive
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
336 Freescale Semiconductor
11.3.2.12 PMF Deadtime Sample Register (PMFDTMS)
Read anytime and writes have no effect.
11.3.2.13 PMF Correction Control Register (PMFCCTL)
Read and write anytime.
Module Base + 0x000E
76543210
R 0 0 DT5 DT4 DT3 DT2 DT1 DT0
W
Reset00000000
= Unimplemented or Reserved
Figure 11-18. PMF Deadtime Sample Register (PMFDTMS))
Table 11-16. PMFDTMS Field Descriptions
Field Description
5–0
DT[5:0]
PMF Deadtime Sample Bits — The DTx bits are grouped in pairs, DT0 and DT1, DT2 and DT3, DT4, and DT5.
Each pair reflects the corresponding ISx pin value as sampled at the end of deadtime.
Module Base + 0x000F
76543210
R0 0
ISENS
0
IPOLC IPOLB IPOLA
W
Reset00000000
= Unimplemented or Reserved
Figure 11-19. PMF Correction Control Register (PMFCCTL)
Table 11-17. PMFCCTL Field Descriptions
Field Description
5–4
ISENS
Current Status Sensing Method — This field selects the top/bottom correction scheme, illustrated in
Ta b le 1 1 - 1 8 .
Note: Assume the user will provide current sensing circuitry causing the voltage at the corresponding input pin
to be low for positive current and high for negative current. In addition, it assumes the top PWMs are PWM
0, 2, and 4 while the bottom PWMs are PWM 1, 3, and 5.
Note: The ISENS bits are not buffered. Changing the current status sensing method can affect the present PWM
cycle.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 337
Table 11-18. Correction Method Selection
2
IPOLC
Current Polarity — This buffered bit selects the PMF Value register for the PWM4 and PWM5 pins in top/bottom
software correction in complementary mode.
0 PMF Value 4 register in next PWM cycle.
1 PMF Value 5 register in next PWM cycle.
Note: The IPOLx bits take effect at the beginning of the next load cycle, regardless of the state of the load okay
bit, LDOK. Select top/bottom software correction by writing 01 to the current select bits, ISENS[1:0], in the
PWM control register. Reading the IPOLx bits read the buffered value and not necessarily the value
currently in effect.
1
IPOLB
Current Polarity — This buffered bit selects the PMF Value register for the PWM2 and PWM3 pins in top/bottom
software correction in complementary mode.
0 PMF Value 2 register in next PWM cycle.
1 PMF Value 3 register in next PWM cycle.
Note: The IPOLx bits take effect at the beginning of the next load cycle, regardless of the state of the load okay
bit, LDOK. Select top/bottom software correction by writing 01 to the current select bits, ISENS[1:0], in the
PWM control register. Reading the IPOLx bits read the buffered value and not necessarily the value
currently in effect.
0
IPOLA
Current Polarity — This buffered bit selects the PMF Value register for the PWM0 and PWM1 pins in top/bottom
software correction in complementary mode.
0 PMF Value 0 register in next PWM cycle.
1 PMF Value 1 register in next PWM cycle.
Note: The IPOLx bits take effect at the beginning of the next load cycle, regardless of the state of the load okay
bit, LDOK. Select top/bottom software correction by writing 01 to the current select bits, ISENS[1:0], in the
PWM control register. Reading the IPOLx bits read the buffered value and not necessarily the value
currently in effect.
ISENS Correction Method
00 No correction1
1The current status pins can be used as general purpose input/output ports.
01 Manual correction
10 Current status sample correction on pins IS0, IS1, and IS2 during deadtime2
2The polarity of the ISx pin is latched when both the top and bottom PWMs are off. At the 0%
and 100% duty cycle boundaries, there is no deadtime, so no new current value is sensed.
11 Current status sample on pins IS0, IS1, and IS23
At the half cycle in center-aligned operation
At the end of the cycle in edge-aligned operation
3Current is sensed even with 0% or 100% duty cycle.
Table 11-17. PMFCCTL Field Descriptions (continued)
Field Description
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
338 Freescale Semiconductor
11.3.2.14 PMF Value 0 Register (PMFVAL0)
Read and write anytime.
11.3.2.15 PMF Value 1 Register (PMFVAL1)
Read and write anytime.
Module Base + 0x0010
1514131211109876543210
RPMFVAL0
W
Reset0000000000000000
Figure 11-20. PMF Value 0 Register (PMFVAL0)
Table 11-19. PMFVAL0 Field Descriptions
Field Description
16–0
PMFVAL0
PMF Value 0 Bits — The 16-bit signed value in this buffered register is the pulse width in PWM0 clock period.
A value less than or equal to zero deactivates the PWM output for the entire PWM period. A value greater than,
or equal to the modulus, activates the PWM output for the entire PWM period. See Table 11-46. The terms
activate and deactivate refer to the high and low logic states of the PWM output.
Note: PMFVAL0 is buffered. The value written does not take effect until the LDOK bit is set and the next PWM
load cycle begins Reading PMFVAL0 reads the value in the buffer and not necessarily the value the PWM
generator is currently using.
Module Base + 0x0012
1514131211109876543210
RPMFVAL1
W
Reset0000000000000000
Figure 11-21. PMF Value 1 Register (PMFVAL1)
Table 11-20. PMFVAL1 Field Descriptions
Field Description
16–0
PMFVAL1
PMF Value 1 Bits — The 16-bit signed value in this buffered register is the pulse width in PWM1 clock period.
A value less than or equal to zero deactivates the PWM output for the entire PWM period. A value greater than,
or equal to the modulus, activates the PWM output for the entire PWM period. See Table 11-46. The terms
activate and deactivate refer to the high and low logic states of the PWM output.
Note: PMFVAL1 is buffered. The value written does not take effect until the LDOK bit is set and the next PWM
load cycle begins. Reading PMFVAL1 reads the value in the buffer and not necessarily the value the PWM
generator is currently using.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 339
11.3.2.16 PMF Value 2 Register (PMFVAL2)
Read and write anytime.
11.3.2.17 PMF Value 3 Register (PMFVAL3)
Read and write anytime.
Module Base + 0x0014
1514131211109876543210
RPMFVAL2
W
Reset0000000000000000
Figure 11-22. PMF Value 2 Register (PMFVAL2)
Table 11-21. PMFVAL2 Field Descriptions
Field Description
16–0
PMFVAL2
PMF Value 2 Bits — The 16-bit signed value in this buffered register is the pulse width in PWM2 clock period.
A value less than or equal to zero deactivates the PWM output for the entire PWM period. A value greater than,
or equal to the modulus, activates the PWM output for the entire PWM period. See Table 11-46. The terms
activate and deactivate refer to the high and low logic states of the PWM output.
Note: PMFVAL2 is buffered. The value written does not take effect until the LDOK bit is set and the next PWM
load cycle begins. Reading PMFVAL2 reads the value in the buffer and not necessarily the value the PWM
generator is currently using.
Module Base + 0x0016
1514131211109876543210
RPMFVAL3
W
Reset0000000000000000
Figure 11-23. PMF Value 3 Register (PMFVAL3)
Table 11-22. PMFVAL3 Field Descriptions
Field Description
16–0
PMFVAL3
PMF Value 3 Bits — The 16-bit signed value in this buffered register is the pulse width in PWM3 clock period.
A value less than or equal to zero deactivates the PWM output for the entire PWM period. A value greater than,
or equal to the modulus, activates the PWM output for the entire PWM period. See Table 11-46. The terms
activate and deactivate refer to the high and low logic states of the PWM output.
Note: PMFVAL3 is buffered. The value written does not take effect until the LDOK bit is set and the next PWM
load cycle begins. Reading PMFVAL3 reads the value in the buffer and not necessarily the value the PWM
generator is currently using.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
340 Freescale Semiconductor
11.3.2.18 PMF Value 4 Register (PMFVAL4)
Read and write anytime.
11.3.2.19 PMF Value 5 Register (PMFVAL5)
Read and write anytime.
Module Base + 0x0018
1514131211109876543210
RPMFVAL4
W
Reset0000000000000000
Figure 11-24. PMF Value 4 Register (PMFVAL4)
Table 11-23. PMFVAL4 Field Descriptions
Field Description
16–0
PMFVAL4
PMF Value 4 Bits — The 16-bit signed value in this buffered register is the pulse width in PWM4 clock period.
A value less than or equal to zero deactivates the PWM output for the entire PWM period. A value greater than,
or equal to the modulus, activates the PWM output for the entire PWM period. See Table 11-46. The terms
activate and deactivate refer to the high and low logic states of the PWM output.
Note: PMFVAL4 is buffered. The value written does not take effect until the LDOK bit is set and the next PWM
load cycle begins. Reading PMFVAL4 reads the value in the buffer and not necessarily the value the PWM
generator is currently using.
Module Base + 0x001A
1514131211109876543210
RPMFVAL5
W
Reset0000000000000000
Figure 11-25. PMF Value 5 Register (PMFVAL5)
Table 11-24. PMFVAL5 Field Descriptions
Field Description
16–0
PMFVAL5
PMF Value 5 Bits — The 16-bit signed value in this buffered register is the pulse width in PWM5 clock period.
A value less than or equal to zero deactivates the PWM output for the entire PWM period. A value greater than,
or equal to the modulus, activates the PWM output for the entire PWM period. See Table 11-46. The terms
activate and deactivate refer to the high and low logic states of the PWM output.
Note: PMFVAL5 is buffered. The value written does not take effect until the LDOK bit is set and the next PWM
load cycle begins. Reading PMFVAL5 reads the value in the buffer and not necessarily the value the PWM
generator is currently using.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 341
11.3.2.20 PMF Enable Control A Register (PMFENCA)
Read and write anytime.
Module Base + 0x0020
76543210
R
PWMENA
00000
LDOKA PWMRIEA
W
Reset00000000
= Unimplemented or Reserved
Figure 11-26. PMF Enable Control A Register (PMFENCA)
Table 11-25. PMFENCA Field Descriptions
Field Description
7
PWMENA
PWM Generator A Enable — When MTG is clear, this bit when set enables the PWM generators A, B and C
and the PWM0–5 pins. When PWMENA is clear, PWM generators A, B and C are disabled, and the PWM0–5
pins are in their inactive states unless the corresponding OUTCTLx bits are set.
When MTG is set, this bit when set enables the PWM generator A and the PWM0 and PWM1 pins. When
PWMENA is clear, the PWM generator A is disabled and PWM0 and PWM1 pins are in their inactive states
unless the OUTCTL0 and OUTCTL1 bits are set.
0 PWM generator A and PWM0–1 (2–5 if MTG=0) pins disabled unless the respective OUTCTL bit is set.
1 PWM generator A and PWM0–1 (2–5 if MTG=0) pins enabled.
1
LDOKA
Load Okay A — When MTG is clear, this bit allows loads of the PRSCA bits, the PMFMODA register and the
PWMVAL0–5 registers into a set of buffers. The buffered prescaler A divisor, PWM counter modulus A value, and
all PWM pulse widths take effect at the next PWM reload.
When MTG is set, this bit allows loads of the PRSCA bits, the PMFMODA register and the PWMVAL0–1 registers
into a set of buffers. The buffered prescaler divisor A, PWM counter modulus A value, PWM0–1 pulse widths take
effect at the next PWM reload.
Set LDOKA by reading it when it is logic zero and then writing a logic one to it. LDOKA is automatically cleared
after the new values are loaded, or can be manually cleared before a reload by writing a logic zero to it. Reset
clears LDOKA.
0 Do not load new modulus A, prescaler A, and PWM0–1 (2–5 if MTG=0) values
1 Load prescaler A, modulus A, and PWM0–1 (2–5 if MTG=0) values
Note: Do not set PWMENA bit before setting the LDOKA bit and do not clear the LDOKA bit at the same time as
setting the PWMENA bit.
0
PWMRIEA
PWM Reload Interrupt Enable A — This bit enables the PWMRFA flag to generate CPU interrupt requests.
0 PWMRFA CPU interrupt requests disabled
1 PWMRFA CPU interrupt requests enabled
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
342 Freescale Semiconductor
11.3.2.21 PMF Frequency Control A Register (PMFFQCA)
Read and write anytime.
Module Base + 0x0021
76543210
R
LDFQA HALFA PRSCA PWMRFA
W
Reset00000000
Figure 11-27. PMF Frequency Control A Register (PMFFQCA)
Table 11-26. PMFFQCA Field Descriptions
Field Description
7–4
LDFQA
Load Frequency A — This field selects the PWM load frequency according to Table 11-27. See
Section 11.4.7.2, “Load Frequency” for more details.
Note: The LDFQA field takes effect when the current load cycle is complete, regardless of the state of the load
okay bit, LDOKA. Reading the LDFQA field reads the buffered value and not necessarily the value
currently in effect.
3
HALFA
Half Cycle Reload A — This bit enables half-cycle reloads in center-aligned PWM mode. This bit has no effect
on edge-aligned PWMs.
0 Half-cycle reloads disabled
1 Half-cycle reloads enabled
2–1
PRSCA
Prescaler A — This buffered field selects the PWM clock frequency illustrated in Table 11-28.
Note: Reading the PRSCA field reads the buffered value and not necessarily the value currently in effect. The
PRSCA field takes effect at the beginning of the next PWM cycle and only when the load okay bit, LDOKA,
is set.
0
PWMRFA
PWM Reload Flag A — This flag is set at the beginning of every reload cycle regardless of the state of the
LDOKA bit. Clear PWMRFA by reading PMFFQCA with PWMRFA set and then writing a logic one to the
PWMRFA bit. If another reload occurs before the clearing sequence is complete, writing logic one to PWMRFA
has no effect.
0 No new reload cycle since last PWMRFA clearing
1 New reload cycle since last PWMRFA clearing
Note: Clearing PWMRFA satisfies pending PWMRFA CPU interrupt requests.
Table 11-27. PWM Reload Frequency A
LDFQA PWM Reload Frequency LDFQ[3:0] PWM Reload Frequency
0000 Every PWM opportunity 1000 Every 9 PWM opportunities
0001 Every 2 PWM opportunities 1001 Every 10 PWM opportunities
0010 Every 3 PWM opportunities 1010 Every 11 PWM opportunities
0011 Every 4 PWM opportunities 1011 Every 12 PWM opportunities
0100 Every 5 PWM opportunities 1100 Every 13 PWM opportunities
0101 Every 6 PWM opportunities 1101 Every 14 PWM opportunities
0110 Every 7 PWM opportunities 1110 Every 15 PWM opportunities
0111 Every 8 PWM opportunities 1111 Every 16 PWM opportunities
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 343
11.3.2.22 PMF Counter A Register (PMFCNTA)
Read anytime and writes have no effect.
11.3.2.23 PMF Counter Modulo A Register (PMFMODA)
Read and write anytime.
Table 11-28. PWM Prescaler A
PRSCA PWM Clock Frequency
00 fbus
01 fbus/2
10 fbus/4
11 fbus/8
Module Base + 0x0022
1514131211109876543210
R 0 PMFCNTA
W
Reset0000000000000000
= Unimplemented or Reserved
Figure 11-28. PMF Counter A Register (PMFCNTA)
Table 11-29. PMFCNTA Field Descriptions
Field Description
14–0
PMFCNTA
PMF Counter A Bits — This register displays the state of the 15-bit PWM A counter.
Module Base + 0x0024
1514131211109876543210
R0 PMFMODA
W
Reset0000000000000000
= Unimplemented or Reserved
Figure 11-29. PMF Counter Modulo A Register (PMFMODA)
Table 11-30. PMFMODA Field Descriptions
Field Description
14–0
PMFMODA
PMF Counter Modulo A Bits — The 15-bit unsigned value written to this register is the PWM period in PWM
clock periods. Do not write a modulus value of zero.
Note: The PWM counter modulo register is buffered. The value written does not take effect until the LDOKA bit
is set and the next PWM load cycle begins. Reading PMFMODA reads the value in the buffer. It is not
necessarily the value the PWM generator A is currently using.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
344 Freescale Semiconductor
11.3.2.24 PMF Deadtime A Register (PMFDTMA)
Read anytime. This register cannot be modified after the WP bit is set.
11.3.2.25 PMF Enable Control B Register (PMFENCB)
Read anytime and write only if MTG is set.
Module Base + 0x0026
1514131211109876543210
R0000 PMFDTMA
W
Reset0000111111111111
= Unimplemented or Reserved
Figure 11-30. PMF Deadtime A Register (PMFDTMA)
Table 11-31. PMFDTMA Field Descriptions
Field Description
11–0
PMFDTMA
PMF Deadtime A Bits — The 12-bit value written to this register is the number of PWM clock cycles in
complementary channel operation. A reset sets the PWM deadtime register to a default value of 0x0FFF,
selecting a deadtime of 256-PWM clock cycles minus one bus clock cycle.
Note: Deadtime is affected by changes to the prescaler value. The deadtime duration is determined as follows:
DT = P × PMFDTMA – 1, where DT is deadtime, P is the prescaler value, PMFDTMA is the programmed
value of dead time. For example: if the prescaler is programmed for a divide-by-two and the PMFDTMA is
set to five, then P = 2 and the deadtime value is equal to DT = 2 × 5 – 1 = 9 IPbus clock cycles. A special
case exists when the P = 1, then DT = PMFDTMA.
Module Base + 0x0028
76543210
R
PWMENB
00000
LDOKB PWMRIEB
W
Reset00000000
= Unimplemented or Reserved
Figure 11-31. PMF Enable Control B Register (PMFENCB)
Table 11-32. PMFENCB Field Descriptions
Field Description
7
PWMENB
PWM Generator B Enable — If MTG is clear, this bit reads zero and cannot be written.
If MTG is set, this bit when set enables the PWM generator B and the PWM2 and PWM3 pins. When PWMENB
is clear, PWM generator B is disabled, and the PWM2 and PWM3 pins are in their inactive states unless the
OUTCTL2 and OUTCTL3 bits are set.
0 PWM generator B and PWM2–3 pins disabled unless the respective OUTCTL bit is set.
1 PWM generator B and PWM2–3 pins enabled.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 345
11.3.2.26 PMF Frequency Control B Register (PMFFQCB)
Read anytime and write only if MTG is set.
1
LDOKB
Load Okay B — If MTG is clear, this bit reads zero and cannot be written.
If MTG is set, this bit loads the PRSCB bits, the PMFMODB register and the PWMVAL2–3 registers into a set of
buffers. The buffered prescaler divisor B, PWM counter modulus B value, PWM2–3 pulse widths take effect at
the next PWM reload.
Set LDOKB by reading it when it is logic zero and then writing a logic one to it. LDOKB is automatically cleared
after the new values are loaded, or can be manually cleared before a reload by writing a logic zero to it. Reset
clears LDOKB.
0 Do not load new modulus B, prescaler B, and PWM2–3 values.
1 Load prescaler B, modulus B, and PWM2–3 values.
Note: Do not set PWMENB bit before setting the LDOKB bit and do not clear the LDOKB bit at the same time as
setting the PWMENB bit.
0
PWMRIEB
PWM Reload Interrupt Enable B — If MTG is clear, this bit reads zero and cannot be written.
If MTG is set, this bit enables the PWMRFB flag to generate CPU interrupt requests.
0 PWMRFB CPU interrupt requests disabled
1 PWMRFB CPU interrupt requests enabled
Module Base + 0x0029
76543210
R
LDFQB HALFB PRSCB PWMRFB
W
Reset00000000
Figure 11-32. PMF Frequency Control B Register (PMFFQCB)
Table 11-33. PMFFQCB Field Descriptions
Field Description
7–4
LDFQB
Load Frequency B — This field selects the PWM load frequency according to Table 11-34. See
Section 11.4.7.2, “Load Frequency” for more details.
Note: The LDFQB field takes effect when the current load cycle is complete, regardless of the state of the load
okay bit, LDOKB. Reading the LDFQB field reads the buffered value and not necessarily the value
currently in effect.
3
HALFB
Half Cycle Reload B — This bit enables half-cycle reloads in center-aligned PWM mode. This bit has no effect
on edge-aligned PWMs.
0 Half-cycle reloads disabled
1 Half-cycle reloads enabled
Table 11-32. PMFENCB Field Descriptions (continued)
Field Description
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
346 Freescale Semiconductor
2–1
PRSCB
Prescaler B — This buffered field selects the PWM clock frequency illustrated in Ta b l e 11 - 35 .
Note: Reading the PRSCB field reads the buffered value and not necessarily the value currently in effect. The
PRSCB field takes effect at the beginning of the next PWM cycle and only when the load okay bit, LDOKB,
is set.
0
PWMRFB
PWM Reload Flag B — This flag is set at the beginning of every reload cycle regardless of the state of the
LDOKB bit. Clear PWMRFB by reading PMFFQCB with PWMRFB set and then writing a logic one to the
PWMRFB bit. If another reload occurs before the clearing sequence is complete, writing logic one to PWMRFB
has no effect.
0 No new reload cycle since last PWMRFB clearing
1 New reload cycle since last PWMRFB clearing
Note: Clearing PWMRFB satisfies pending PWMRFB CPU interrupt requests.
Table 11-34. PWM Reload Frequency B
LDFQB PWM Reload Frequency LDFQ[3:0] PWM Reload Frequency
0000 Every PWM opportunity 1000 Every 9 PWM opportunities
0001 Every 2 PWM opportunities 1001 Every 10 PWM opportunities
0010 Every 3 PWM opportunities 1010 Every 11 PWM opportunities
0011 Every 4 PWM opportunities 1011 Every 12 PWM opportunities
0100 Every 5 PWM opportunities 1100 Every 13 PWM opportunities
0101 Every 6 PWM opportunities 1101 Every 14 PWM opportunities
0110 Every 7 PWM opportunities 1110 Every 15 PWM opportunities
0111 Every 8 PWM opportunities 1111 Every 16 PWM opportunities
Table 11-35. PWM Prescaler B
PRSCB PWM Clock Frequency
00 fbus
01 fbus/2
10 fbus/4
11 fbus/8
Table 11-33. PMFFQCB Field Descriptions (continued)
Field Description
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 347
11.3.2.27 PMF Counter B Register (PMFCNTB)
Read anytime and writes have no effect.
11.3.2.28 PMF Counter Modulo B Register (PMFMODB)
Read anytime and write only if MTG is set.
Module Base + 0x002A
1514131211109876543210
R 0 PMFCNTB
W
Reset0000000000000000
= Unimplemented or Reserved
Figure 11-33. PMF Counter B Register (PMFCNTB)
Table 11-36. PMFCNTB Field Descriptions
Field Description
14–0
PMFCNTB
PMF Counter B — This register displays the state of the 15-bit PWM B counter.
Module Base + 0x002C
1514131211109876543210
R0 PMFMODB
W
Reset0000000000000000
= Unimplemented or Reserved
Figure 11-34. PMF Counter Modulo B Register (PMFMODB)
Table 11-37. PMFMODB Field Descriptions
Field Description
14–0
PMFMODB
PMF Counter Modulo B — The 15-bit unsigned value written to this register is the PWM period in PWM clock
periods. Do not write a modulus value of zero.
Note: The PWM counter modulo register is buffered. The value written does not take effect until the LDOKB bit
is set and the next PWM load cycle begins. Reading PMFMODB reads the value in the buffer. It is not
necessarily the value the PWM generator B is currently using.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
348 Freescale Semiconductor
11.3.2.29 PMF Deadtime B Register (PMFDTMB)
Read anytime and write only if MTG is set. This register cannot be modified after the WP bit is set.
11.3.2.30 PMF Enable Control C Register (PMFENCC)
Read anytime and write only if MTG is set.
Module Base + 0x002E
1514131211109876543210
R0000 PMFDTMB
W
Reset0000111111111111
= Unimplemented or Reserved
Figure 11-35. PMF Deadtime B Register (PMFDTMB)
Table 11-38. PMFDTMB Field Descriptions
Field Description
11–0
PMFDTMB
PMF Deadtime B — The 12-bit value written to this register is the number of PWM clock cycles in
complementary channel operation. A reset sets the PWM deadtime register to a default value of 0x0FFF,
selecting a deadtime of 256-PWM clock cycles minus one bus clock cycle.
Note: Deadtime is affected by changes to the prescaler value. The deadtime duration is determined as follows:
DT = P × PMFDTMB – 1, where DT is deadtime, P is the prescaler value, PMFDTMB is the programmed
value of dead time. For example: if the prescaler is programmed for a divide-by-two and the PMFDTMB is
set to five, then P = 2 and the deadtime value is equal to DT = 2 × 5 – 1 = 9 IPbus clock cycles. A special
case exists when the P = 1, then DT = PMFDTMB.
Module Base + 0x0030
76543210
R
PWMENC
00000
LDOKC PWMRIEC
W
Reset00000000
= Unimplemented or Reserved
Figure 11-36. PMF Enable Control C Register (PMFENCC)
Table 11-39. PMFENCC Field Descriptions
Field Description
7
PWMENC
PWM Generator C Enable — If MTG is clear, this bit reads zero and cannot be written.
If MTG is set, this bit when set enables the PWM generator C and the PWM4 and PWM5 pins. When PWMENC
is clear, PWM generator C is disabled, and the PWM4 and PWM5 pins are in their inactive states unless the
OUTCTL4 and OUTCTL5 bits are set.
0 PWM generator C and PWM4–5 pins disabled unless the respective OUTCTL bit is set.
1 PWM generator C and PWM4–5 pins enabled.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 349
11.3.2.31 PMF Frequency Control C Register (PMFFQCC)
Read anytime and write only if MTG is set.
1
LDOKC
Load Okay C — If MTG is clear, this bit reads zero and can not be written.
If MTG is set, this bit loads the PRSCC bits, the PMFMODC register and the PWMVAL4–5 registers into a set of
buffers. The buffered prescaler divisor C, PWM counter modulus C value, PWM4–5 pulse widths take effect at
the next PWM reload.
Set LDOKC by reading it when it is logic zero and then writing a logic one to it. LDOKC is automatically cleared
after the new values are loaded, or can be manually cleared before a reload by writing a logic zero to it. Reset
clears LDOKC.
0 Do not load new modulus C, prescaler C, and PWM4–5 values.
1 Load prescaler C, modulus C, and PWM4–5 values.
Note: Do not set PWMENC bit before setting the LDOKC bit and do not clear the LDOKC bit at the same time
as setting the PWMENC bit.
0
PWMRIEC
PWM Reload Interrupt Enable C — If MTG is clear, this bit reads zero and cannot be written.
If MTG is set, this bit enables the PWMRFC flag to generate CPU interrupt requests.
0 PWMRFC CPU interrupt requests disabled
1 PWMRFC CPU interrupt requests enabled
Module Base + 0x0031
76543210
R
LDFQC HALFC PRSCC PWMRFC
W
Reset00000000
Figure 11-37. PMF Frequency Control C Register (PMFFQCC)
Table 11-40. PMFFQCC Field Descriptions
Field Description
7–4
LDFQC
Load Frequency C — This field selects the PWM load frequency according to Table 11-41. See
Section 11.4.7.2, “Load Frequency” for more details.
Note: The LDFQC field takes effect when the current load cycle is complete, regardless of the state of the load
okay bit, LDOKC. Reading the LDFQC field reads the buffered value and not necessarily the value
currently in effect.
3
HALFC
Half Cycle Reload C — This bit enables half-cycle reloads in center-aligned PWM mode. This bit has no effect
on edge-aligned PWMs.
0 Half-cycle reloads disabled
1 Half-cycle reloads enabled
Table 11-39. PMFENCC Field Descriptions (continued)
Field Description
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
350 Freescale Semiconductor
2
PRSCC
Prescaler C — This buffered field selects the PWM clock frequency illustrated in Table 11-42.
Note: Reading the PRSCC field reads the buffered value and not necessarily the value currently in effect. The
PRSCC field takes effect at the beginning of the next PWM cycle and only when the load okay bit, LDOKC,
is set.
0
PWMRFC
PWM Reload Flag C — This flag is set at the beginning of every reload cycle regardless of the state of the
LDOKC bit. Clear PWMRFC by reading PMFFQCC with PWMRFC set and then writing a logic one to the
PWMRFC bit. If another reload occurs before the clearing sequence is complete, writing logic one to PWMRFC
has no effect.
0 No new reload cycle since last PWMRFC clearing
1 New reload cycle since last PWMRFC clearing
Note: Clearing PWMRFC satisfies pending PWMRFC CPU interrupt requests.
Table 11-41. PWM Reload Frequency C
LDFQC PWM Reload Frequency LDFQ[3:0] PWM Reload Frequency
0000 Every PWM opportunity 1000 Every 9 PWM opportunities
0001 Every 2 PWM opportunities 1001 Every 10 PWM opportunities
0010 Every 3 PWM opportunities 1010 Every 11 PWM opportunities
0011 Every 4 PWM opportunities 1011 Every 12 PWM opportunities
0100 Every 5 PWM opportunities 1100 Every 13 PWM opportunities
0101 Every 6 PWM opportunities 1101 Every 14 PWM opportunities
0110 Every 7 PWM opportunities 1110 Every 15 PWM opportunities
0111 Every 8 PWM opportunities 1111 Every 16 PWM opportunities
Table 11-42. PWM Prescaler C
PRSCC PWM Clock Frequency
00 fbus
01 fbus/2
10 fbus/4
11 fbus/8
Table 11-40. PMFFQCC Field Descriptions (continued)
Field Description
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 351
11.3.2.32 PMF Counter C Register (PMFCNTC)
Read anytime and writes have no effect.
11.3.2.33 PMF Counter Modulo C Register (PMFMODC)
Read anytime and write only if MTG is set.
Module Base + 0x0032
1514131211109876543210
R 0 PMFCNTC
W
Reset0000000000000000
= Unimplemented or Reserved
Figure 11-38. PMF Counter C Register (PMFCNTC)
Table 11-43. PMFCNTC Field Descriptions
Field Description
14–0
PMFCNTC‘
PMF Counter C — This register displays the state of the 15-bit PWM C counter.
Module Base + 0x0034
1514131211109876543210
R0 PMFMODC
W
Reset0000000000000000
= Unimplemented or Reserved
Figure 11-39. PMF Counter Modulo C Register (PMFMODC)
Table 11-44. PMFMODC Field Descriptions
Field Description
14–0
PMFMODC
PMF Couner Modulo C — The 15-bit unsigned value written to this register is the PWM period in PWM clock
periods. Do not write a modulus value of zero.
Note: The PWM counter modulo register is buffered. The value written does not take effect until the LDOKC bit
is set and the next PWM load cycle begins. Reading PMFMODC reads the value in the buffer. It is not
necessarily the value the PWM generator A is currently using.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
352 Freescale Semiconductor
11.3.2.34 PMF Deadtime C Register (PMFDTMC)
Read anytime and write only if MTG is set. This register cannot be modified after the WP bit is set.
Module Base + 0x0000
1514131211109876543210
R0000 PMFDTMC
W
Reset0000111111111111
= Unimplemented or Reserved
Figure 11-40. PMF Deadtime C Register (PMFDTMC)
Table 11-45. PMFDTMC Field Descriptions
Field Description
11–0
PMFDTMC
PMF Deadtime C — The 12-bit value written to this register is the number of PWM clock cycles in
complementary channel operation. A reset sets the PWM deadtime register to a default value of 0x0FFF,
selecting a deadtime of 4096-PWM clock cycles minus one bus clock cycle.
Note: Deadtime is affected by changes to the prescaler value. The deadtime duration is determined as follows:
DT = P × PMFDTMC – 1, where DT is deadtime, P is the prescaler value, PMFDTMC is the programmed
value of dead time. For example: if the prescaler is programmed for a divide-by-two and the PMFDTMC is
set to five, then P = 2 and the deadtime value is equal to DT = 2 × 5 – 1 = 9 IPbus clock cycles. A special
case exists when the P = 1, then DT = PMFDTMC.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 353
11.4 Functional Description
11.4.1 Block Diagram
A block diagram of the PMF is shown in Figure 11-1. The MTG bit allows the use of multiple PWM
generators (A, B, and C) or just a single generator (A). PWM0 and PWM1 constitute Pair A, PWM2 and
PWM3 constitute Pair B, and PWM4 and PWM5 constitute Pair C.
11.4.2 Prescaler
To permit lower PWM frequencies, the prescaler produces the PWM clock frequency by dividing the bus
clock frequency by one, two, four, and eight. Each PWM generator has its own prescaler divisor. Each
prescaler is buffered and will not be used by its PWM generator until the corresponding Load OK bit is set
and a new PWM reload cycle begins.
11.4.3 PWM Generator
Each PWM generator contains a 15-bit up/down PWM counter producing output signals with
software-selectables:
• Alignment—The logic state of each pair EDGE bit determines whether the PWM pair outputs are
edge-aligned or center-aligned
• Period—The value written to each pair PWM counter modulo register is used to determine the
PWM pair period. The period can also be varied by using the prescaler
— With edge-aligned output, the modulus is the period of the PWM output in clock cycles
— With center-aligned output, the modulus is one-half of the PWM output period in clock cycles
• Pulse width—The number written to the PWM value register determines the pulse width duty cycle
of the PWM output in clock cycles
— With center-aligned output, the pulse width is twice the value written to the PWM value register
— With edge-aligned output, the pulse width is the value written to the PWM value register
11.4.3.1 Alignment
Each edge-align bit, EDGEx, selects either center-aligned or edge-aligned PWM generator outputs.
Figure 11-41. Center-Aligned PWM Output
UP/DOWN COUNTER
MODULUS = 4
ALIGNMENT REFERENCE
PWM OUTPUT
DUTY CYCLE = 50%
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
354 Freescale Semiconductor
Figure 11-42. Edge-Aligned PWM Output
NOTE
Because of the equals-comparator architecture of this PMF, the modulus
equals zero case is considered illegal. Therefore, the modulus register does
not return to zero, and a modulus value of zero will result in waveforms
inconsistent with the other modulus waveforms. If a modulus of zero is
loaded, the counter will continually count down from $7FFF. This operation
will not be tested or guaranteed. Consider it illegal. However , the dead-time
constraints and fault conditions will still be guaranteed.
11.4.3.2 Period
A PWM period is determined by the value written to the PWM counter modulo register.
The PWM counter is an up/down counter in a center-aligned operation. In this mode the PWM highest
output resolution is two bus clock cycles.
PWM period = (PWM modulus) × (PWM clock period) × 2
Figure 11-43. Center-Aligned PWM Period
UP COUNTER
MODULUS = 4
ALIGNMENT REFERENCE
PWM OUTPUT
DUTY CYCLE = 50%
UP/DOWN COUNTER
PWM CLOCK PERIOD
PWM PERIOD = 8 x PWM CLOCK PERIOD
MODULUS = 4
COUNT 12343210
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 355
In an edge-aligned operation, the PWM counter is an up counter. The PWM output resolution is one bus
clock cycle.
PWM period = PWM modulus × PWM clock period
Figure 11-44. Edge-Aligned PWM Period
11.4.3.3 Duty Cycle
The signed 16-bit number written to the PMF value register s is the pulse width in PWM clock periods of
the PWM generator output.
NOTE
A PWM value less than or equal to ze ro deactivates the PWM output for the
entire PWM period. A PWM value greater than or equal to the modulus
activates the PWM output for the entire PWM period.
Table 11-46. PWM Value and Underflow Conditions
PMFVALx Condition PWM Value Used
$0000–$7FFF Normal Value in registers
$8000–$FFFF Underflow $0000
UP COUNTER
PWM CLOCK PERIOD
PWM PERIOD = 4 x PWM CLOCK PERIOD
MODULUS = 4
COUNT 1 2 3 4
Duty cycle PMFVAL
MODULUS
--------------------------------100×=
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
356 Freescale Semiconductor
Center-aligned operation is illustrated in Figure 11-45.
PWM pulse width = (PWM value) × (PWM clock period) × 2
Figure 11-45. Center-Aligned PWM Pulse Width
Edge-aligned operation is illustrated in Figure 11-46.
PWM pulse width = (PWM value) × (PWM clock period)
Figure 11-46. Edge-Aligned PWM Pulse Width
UP/DOWN COUNTER
MODULUS = 4
PWM VALUE = 0
0/4 = 0%
PWM VALUE = 1
1/4 = 25%
PWM VALUE = 2
2/4 = 50%
PWM VALUE = 3
3/4 = 75%
PWM VALUE = 4
4/4 = 100%
COUNT 0123432101234321
UP COUNTER
PWM VALUE = 0
MODULUS = 4
PWM VALUE = 1
PWM VALUE = 2
PWM VALUE = 3
PWM VALUE = 4
0/4 = 0%
1/4 = 25%
2/4 = 50%
3/4 = 75%
4/4 = 100%
COUNT 1 2 3 0
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 357
11.4.4 Independent or Complementary Channel Operation
Writing a logic one to a INDEPx bit configures a pair of the PWM outputs as two independent PWM
channels. Each PWM output has its own PWM value register operating independently of the other
channels in independent channel operation.
Writing a logic zero to a INDEPx bit configures the PWM output as a pair of complementary channels.
The PWM pins are paired as shown in Figure 11-47 in complementary channel operation.
Figure 11-47. Complementary Channel Pairs
The complementary channel operation is for driving top and bottom transistors in a motor drive circuit,
such as the one in Figure 11-48.
Figure 11-48. Typical 3 Phase AC Motor Drive
PWM CHANNELS 0 AND 1
PMFVAL1
PWM CHANNELS 2 AND 3
PWM CHANNELS 4 AND 5
REGISTER
TOP
BOTTOM
TOP
BOTTOM
TOP
BOTTOM
PMFVAL0
REGISTER
PMFVAL3
REGISTER
PMFVAL2
REGISTER
PMFVAL5
REGISTER
PMFVAL4
REGISTER
PAIR A
PAIR B
PAIR C
PWM
0
PWM
2
AC
INPUTS
TO
MOTOR
PWM
4
PWM
3
PWM
5
PWM
1
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
358 Freescale Semiconductor
In complementary channel operation, there are three additional features:
• Deadtime insertion
• Separate top and bottom pulse width correction for distortions are caused by deadtime inserted and
the motor drive characteristics
• Separate top and bottom output polarity control
• Swap functionality
11.4.5 Deadtime Generators
While in the comp lementary mode, each PWM pair can be used to drive top/bottom transistors, as shown
in Figure 11-49. Ideally, the PWM pairs are an inversion of each other. When the top PWM channel is
active, the bottom PWM channel is inactive, and vice versa.
NOTE
To avoid a short-circuit on the DC bus and endangering the transistor , there
must be no overlap of conducting intervals between top and bottom
transistor. But the transistor’s characteristics make its switching-off time
longer than switching-on time. To avoid the conducting overlap of top and
bottom transistors, deadtime needs to be inserted in the switching period.
Deadtime generators automatically insert software-selectable activation delays into each pair of PWM
outputs. The deadtime register (PMFDTMx) specifies the number of PWM clock cycles to use for
deadtime delay. Every time the deadtime generator inputs changes state, deadtime is inserted. Deadtime
forces both PWM outputs in the pair to the inactive state.
A method of correcting this, adding to or subtracting from the PWM value used, is discussed next.
Figure 11-49. Deadtime Generators
MUX
OUT0
OUTCTL0
MUX
OUT2
OUTCTL2
MUX
OUT4
OUTCTL4
PWM
GENERATOR
CURRENT
STATUS
DEADTIME
GENERATOR
OUT1
DEADTIME
GENERATOR
DEADTIME
GENERATOR
PWM0 &
PWM2 &
PWM4 &
OUT3
OUT5
TOP/BOTTOM
GENERATOR
TOP/BOTTOM
GENERATOR
TOP/BOTTOM
GENERATOR
TOP (PWM0)
TO FAULT
PROTECTION
TO FAULT
PROTECTION
TO FAULT
PROTECTION
BOTTOM (PWM1)
TOP (PWM2)
BOTTOM (PWM3)
TOP (PWM4)
BOTTOM (PWM5)
PWM1
PWM3
PWM5
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 359
Figure 11-50. Deadtime Insertion, Center Alignment
Figure 11-51. Deadtime at Duty Cycle Boundaries
Figure 11-52. Deadtime and Small Pulse Widths
NOTE
The waveform at the pad is delayed by two bus clock cycles for deadtime
insertion.
PWM0, NO DEADTIME
PWM1, NO DEADTIME
PWM0, DEADTIME = 1
PWM1, DEADTIME = 1
MODULUS = 4
PWM VALUE = 2
PWM0, NO DEADTIME
PWM1, NO DEADTIME
PWM0, DEADTIME = 2
PWM1, DEADTIME = 2
MODULUS = 3
PWM Value = 3 PWM VALUE = 3 PWM VALUE = 3
PWM VALUE = 1
MODULUS = 3
PWM0, NO DEADTIME
PWM0, DEADTIME = 3
PWM1, NO DEADTIME
PWM1, DEADTIME = 3
2PWM VALUE PWM
VALUE = 1
PWM VALUE = 2
PWM VALUE = 3
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
360 Freescale Semiconductor
11.4.5.1 Top/Bottom Correction
In complementary mode, either the top or the bottom transistor controls the output voltage. However,
deadtime has to be inserted to avoid overlap of conducting interval between the top and bottom transistor.
Both transistors in complementary mode are off during deadtime, allowing the output voltage to be
determined by the current status of load and introduce distortion in the output voltage. See Figure 11-53.
On AC induction motors running open-loop, the distortion typically manifests itself as poor low-speed
performance, such as torque ripple and rough operation.
Figure 11-53. Deadtime Distortion
During deadtime, load inductance distorts output voltage by keeping current flowing through the diodes.
This deadtime current flow creates a load voltage that varies with current direction. W ith a positive current
flow, the load voltage during deadtime is equal to the bottom supply, putting the top transistor in control.
W ith a negative current flow , the load voltage during deadtime is equal to the top supply putting the bottom
transistor in control.
Remembering that the original PWM pulse widths were shortened by deadtime insertion, the averaged
sinusoidal output will be less than desired value. However, when deadtime is inserted, it creates a
distortion in motor current waveform. This distortion is aggravated by dissimilar turn-on and turn-off
delays of each of the transistors. By giving the PWM module information on which transistor is controlling
at a given time this distortion can be corrected.
For a typical circuit in complementary channel operation, only one of the transistors will be effective in
controlling the output voltage at any given time. This depends on the direction of the motor current for that
pair. See Figure 11-53. T o correct distortion one of two different factors must be added to the desired PWM
value, depending on whether the top or bottom transistor is controlling the output voltage. Therefore, the
software is responsible for calculating both compensated PWM values prior to placing them in an
odd-numbered/even numbered PWM register pair. Either the odd or the even PMFVAL register controls
the pulse width at any given time.
DESIRED
DEADTIME
PWM TO TOP
POSITIVE
NEGATIVE
PWM TO BOTTOM
POSITIVE CURRENT
NEGATIVE CURRENT
LOAD VOLTAGE
TRANSISTOR
TRANSISTOR
LOAD VOLTAGE
LOAD VOLTAGE
CURRENT
CURRENT
V+
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 361
For a given PWM pair, whether the odd or even PMFVAL register is active depends on either:
• The state of the current status pin, ISx, for that driver
• The state of the odd/even correction bit, IPOLx, for that driver
To correct deadtime distortion, software can decrease or increase the value in the appropriate PMFVAL
register.
• In edge-aligned operation, decreasing or increasing the PWM value by a correction value equal to
the deadtime typically compensates for deadtime distortion.
• In center-aligned operation, decreasing or increasing the PWM value by a correction value equal
to one-half the deadtime typically compensates for deadtime distortion.
In the complementary channel operation, ISENS selects one of three correction methods:
• Manual correction
• Automatic current status correction during deadtime
• Automatic current status correction when the PWM counter value equals the value in the PWM
counter modulus registers
NOTE
Assume the user will provide current status sensing circuitry causing the
voltage at the corresponding input pin to be low for positive current and high
for negative current. In addition, it assumes the top PWMs are PWM 0, 2,
and 4 while the bottom PWMS are PWM 1, 3, and 5.
Table 11-47. Correction Method Selection
ISENS Correction Method
00 No correction1
1The current status pins can be used as general purpose input/output ports.
01 Manual correction
10 Current status sample correction on pins IS0, IS1, and IS2 during deadtime2
2The polarity of the ISx pin is latched when both the top and bottom PWMs are off. At the 0%
and 100% duty cycle boundaries, there is no deadtime, so no new current value is sensed.
11 Current status sample on pins IS0, IS1, and IS23
At the half cycle in center-aligned operation
At the end of the cycle in edge-aligned operation
3Current is sensed even with 0% or 100% duty cycle.
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
362 Freescale Semiconductor
11.4.5.2 Manual Correction
The IPOLx bits select either the odd or the even PWM value registers to use in the next PWM cycle.
Table 11-48. Top/Bottom Manual Correction
NOTE
IPOLx bits are buffered so only one PW M register is used per PWM cycle.
If an IPOLx bit changes during a PWM period, the new value does not take
effect until the next PWM period.
IPOLx bits take effect at the end of each PWM cycle regardless of the state
of the load okay bit, LDOK.
Figure 11-54. Internal Correction Logic when ISENS = 01
To detect the current status, the voltage on each ISx pin is sampled twice in a PWM period, at the end of
each deadtime. The value is stored in the DTx bits in the PMF Deadtime Sample register (PMFDTMS).
The DTx bits are a timing marker especially indicating when to toggle between PWM value registers.
Software can then set the IPOLx bit to toggle PMFVAL registers according to DTx values.
Bit Logic Atate Output Control
IPOLA 0 PMFVAL0 controls PWM0/PWM1 pair
1 PMFVAL1 controls PWM0/PWM1 pair
IPOLB 0 PMFVAL2 controls PWM2/PWM3 pair
1 PMFVAL3 controls PWM2/PWM3 pair
IPOLC 0 PMFVAL4 controls PWM4/PWM5 pair
1 PMFVAL5 controls PWM4/PWM5 pair
DEADTIME
GENERATOR
DQ
CLK
IPOLx BIT
A/B
A
B
TOP PWM
BOTTOM PWM
PWM CYCLE START
PWM CONTROLLED BY
ODD PWMVALREGISTER
PWM CONTROLLED BY EVEN
PWMVAL REGISTER
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 363
Figure 11-55. Current-Status Sense Scheme for Deadtime Correction
If both D flip-flops latch low, DT0 = 0, DT1 = 0, during deadtime periods if current is large and flowing
out of the complementary circuit. See Figure 11-55. If both D flip-flops latch the high, DT0 = 1, DT1 = 1,
during deadtime periods if current is also large and flowing into the complementary circuit. However,
under low-current, the output voltage of the complementary circuit during deadtime is somewhere between
the high and low levels. The current cannot free-wheel throughout the opposition anti-body diode,
regardless of polarity, giving additional distortion when the current crosses zero. Sampled results will be
DT0 = 0 and DT1 = 1. Thus, the best time to change one PWM value register to another is just before the
current zero crossing.
Figure 11-56. Output Voltage Waveforms
PWM0
PWM1 DQ
CLK
DQ
CLK
VOLTAGE
SENSOR
IS0 PIN
PWM0
PWM1
DT0
DT1
POSITIVE
CURRENT
NEGATIVE
CURRENT
DEADTIME
PWM TO TOP
POSITIVE
NEGATIVE
PWM TO BOTTOM
LOAD VOLTAGE WITH
LOAD VOLTAGE WITH
TRANSISTOR
TRANSISTOR
HIGH POSITIVE CURRENT
LOW POSITIVE CURRENT
CURRENT
CURRENT
LOAD VOLTAGE WITH
HIGH NEGATIVE CURRENT
LOAD VOLTAGE WITH
NEGATIVE CURRENT
TBTB
T = DEADTIME INTERVAL BEFORE ASSERTION OF TOP PWM
B = DEADTIME INTERVAL BEFORE ASSERTION OF BOTTOM PWM
V
+
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
364 Freescale Semiconductor
11.4.5.3 Current-Sensing Correction
A current sense pin, ISx, for a PWM pair selects either the odd or the even PWM value registers to use in
the next PWM cycle. The selection is based on user-provided current sense circuitry driving the ISx pin
high for negative current and low for positive current.
Previously shown, the current direction can be determined by the output voltage during deadtime. Thus, a
simple external voltage sensor can be used when current status is completed during deadtime, ISENS =
10. Deadtime does not exists at the 100 percent and zero percent duty cycle boundaries. Therefore, the
second automatic mode must be used for correction, ISENS = 11, where current status is sampled at the
half cycle in center-aligned operation and at the end of cycle in edge-aligned operation. Using this mode
requires external circuitry. It actually senses current direction.
Figure 11-57. Internal Correction Logic when ISENS = 10
Figure 11-58. Internal Correction Logic when ISENS = 11
Table 11-49. Top/Bottom Current-Sense Correction
Pin Logic State Output Control
IS0 0 PMFVAL0 controls PWM0/PWM1 pair
1 PMFVAL1 controls PWM0/PWM1 pair
IS1 0 PMFVAL2 controls PWM2/PWM3 pair
1 PMFVAL3 controls PWM2/PWM3 pair
IS2 0 PMFVAL4 controls PWM4/PWM5 pair
1 PMFVAL5 controls PWM4/PWM5 pair
DQ
CLK
PWM CONTROLLED BY
PWM CONTROLLED BY
DEADTIME
GENERATOR
DQ
CLK
ISx PIN
A/B
A
B
PWM CYCLE START
TOP PWM
BOTTOM PWM
INITIAL VALUE = 0
ODD PWMVAL REGISTER
EVEN PWMVAL REGISTER
IN DEADTIME
DQ
CLK
PWM CONTROLLED BY
PWM CONTROLLED BY
DEADTIME
GENERATOR
DQ
CLK
ISx PIN
A/B
A
B
PWM CYCLE START
TOP PWM
BOTTOM PWM
INITIAL VALUE = 0
ODD PWMVAL REGISTER
EVEN PWMVAL REGISTER
PMFCNT = PMFMOD
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 365
NOTE
Values latched on the ISx pins are buffered so only one PWM register is
used per PWM cycle. If a current status changes during a PWM period, the
new value does not take effect until the next PWM period.
When initially enabled by setting the PWMEN bit, no curre nt status has previously been sampled. PWM
value registers one, three, and five initially control the three PWM pairs when configured for current status
correction.
11.4.5.4 Output Polarity
Output polarity of the PWMs is determined by two options: TOPNEG and BOTNEG. The top polarity
option, TOPNEG, controls the polarity of PWM0, PWM2 and PWM4. The bottom polarity option,
BOTNEG, controls the polarity of PWM1, PWM3 and PWM5. Positive polarity means when the PWM is
active its output is high. Conversely, negative polarity means when the PWM is active its output is low.
The TOPNEG and BOTNEG are in th e configure register. T OPNEG is the output of PWM0, PWM2 and
PWM4. They are active low. If T OPNEG is set, PWM0, PWM2, and PWM4 outputs become active-low.
When BOTNEG is set, PWM1, PWM3, and PWM5 outputs are active-low. When these bits are clear, their
respective PWM pins are active-high. See Figure 11-59 and Figure 11-60.
Figure 11-59. Correction with Positive Current
Figure 11-60. Correction with Negative Current
DESIRED LOAD VOLTAGE
BOTTOM PWM
LOAD VOLTAGE
TOP PWM
DESIRED LOAD VOLTAGE
BOTTOM PWM
LOAD VOLTAGE
TOP PWM
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
366 Freescale Semiconductor
Figure 11-61. PWM Polarity
11.4.6 Software Output Control
Setting output control enable bit, OUTCTLx, enables software to drive the PWM outputs rather than the
PWM generator. In an independent mode, with OUTCTLx = 1, the output bit OUTx, controls the PWMx
channel. In a complementary channel operation the even OUTCTL bit is used to enable software output
control for the pair. But the OUTCTL bits must be switched in pairs for proper operation. The OUTCTLx
and OUTx bits are in the PWM output control register.
NOTE
During software output control, TOPNEG and BOTNEG still control output
polarity . It will take upto 3 clock cycles to see the effect of output control on
the PWM output pins.
In independent PWM operation, setting or clearing the OUTx bit activates or deactivates the PWMx
output.
In complementary channel operation, the even-numbered OUTx bits replace the PWM generator outputs
as inputs to the deadtime generators. Complementary channel pairs still cannot be active simultaneously,
and the deadtime generators continue to insert deadtime in both channels of that pair, whenever an even
OUTx bit toggles. Even OUTx bits control the top PWM signals while the odd OUTx bits control the
bottom PWM signals with respect to the even OUTx bits. Setting the odd OUTx bit makes its
corresponding PWMx the complement of its even pair, while clearing the odd OUTx bit deactivates the
odd PWMx.
UP/DOWN COUNTER
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
EDGE-ALIGNED
MODULUS = 4
UP/DOWN COUNTER
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
MODULUS = 4
UP COUNTER
PWM = 0
PWM = 2
PWM = 3
PWM = 4
PWM = 1
MODULUS = 4
CENTER-ALIGNED
POSITIVE POLARITY POSITIVE POLARITY
UP COUNTER
PWM = 0
PWM = 2
PWM = 3
PWM = 4
PWM = 1
MODULUS = 4
CENTER-ALIGNED
NEGATIVE POLARITY
EDGE-ALIGNED
NEGATIVE POLARITY
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 367
Setting the OUTCTLx bits do not disable the PWM generators and current status sensing circuitry. They
continue to run, but no longer control the output pins. When the OUTCTLx bits are cleared, the outputs of
the PWM generator become the inputs to the deadtime generators at the beginning of the next PWM cycle.
Software can drive the PWM outputs even when PWM enable bit (PWMEN) is set to zero.
NOTE
Avoid an unexpected deadtime insertion by clearing the OUTx bits before
setting and after clearing the OUTCTLx bits.
Figure 11-62. Setting OUT0 with OUTCTL Set in Complementary Mode
MODULUS = 4
PWM VALUE = 2
DEADTIME = 2
PWM0
PWM1
PWM0 WITH DEADTIME
PWM1 WITH DEADTIME
OUTCTL0
OUT0
PWM0
PWM1
OUT1
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
368 Freescale Semiconductor
Figure 11-63. Clearing OUT0 with OUTCTL Set In Complementary Mode
Figure 11-64. Setting OUTCTL with OUT0 Set in Complementary Mode
MODULUS = 4
PWM VALUE = 2
DEADTIME = 2
PWM0
PWM1
PWM0 WITH DEADTIME
PWM1 WITH DEADTIME
OUTCTL0
OUT0
PWM0
PWM1
OUT1
MODULUS = 4
PWM VALUE = 2
DEADTIME = 2
PWM0
PWM1
PWM0 WITH DEADTIME
PWM1 WITH DEADTIME
OUTCTL0
OUT0
PWM0
PWM1
OUT1
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 369
11.4.7 PWM Generator Loading
11.4.7.1 Load Enable
The load okay bit, LDOK, enables loading the PWM generator with:
• A prescaler divisor—from the PRSC1 and PRSC0 bits in PWM control register
• A PWM period—from the PWM counter modulus registers
• A PWM pulse width—from the PWM value registers
LDOK prevents reloading of these PWM parameters before softwa re is finished calculat ing them Setting
LDOK allows the prescaler bits, PMFMOD and PMFVALx registers to be loaded into a set of buffers. The
loaded buffers use the PWM generator at the beginning of the next PWM reload cycle. Set LDOK by
reading it when it is a logic zero and then writing a logic one to it. After loading, LDOK is automatically
cleared.
11.4.7.2 Load Frequency
The LDFQ3, LDFQ2, LDFQ1, and LDFQ0 bits in the PWM control register (PWMCTL) select an integral
loading frequency of one to 16-PWM reload opportunities. The LDFQ bits take effect at every PWM
reload opportunity, regardless the state of the load okay bit, LDOK. The half bit in the PWMCTL register
controls half-cycle reloads for center-aligned PWMs. If the half bit is set, a reload opportunity occurs at
the beginning of every PWM cycle and half cycle when the count equals the modulus. If the half bit is not
set, a reload opportunity occurs only at the beginning of every cycle. Reload opportunities can only occur
at the beginning of a PWM cycle in edge-aligned mode.
NOTE
Loading a new modulus on a half cycle will force the count to the new
modulus value minus one on the next clock cycle. Half cycle reloads are
possible only in center-aligned mode. Enabling or disabling half-cycle
reloads in edge-aligned mode will have no ef fect on the reload rate.
Figure 11-65. Full Cycle Reload Frequency Change
Figure 11-66. Half Cycle Reload Frequency Change
RELOAD
CHANGE
UP/DOWN
TO EVERY
TWO OPPORTUNITIES
TO EVERY
OPPORTUNITY
COUNTER
RELOAD
FREQUENCY
TO EVERY
FOUR OPPORTUNITIES
RELOAD
CHANGE
UP/DOWN
TO EVERY
TWO OPPORTUNITIES
TO EVERY
OPPORTUNITY
COUNTER
RELOAD
FREQUENCY
TO EVERY
TWO OPPORTUNITIES
TO EVERY
FOUR OPPORTUNITIES
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
370 Freescale Semiconductor
11.4.7.3 Reload Flag
With a reload opportunity, regardless an actual reload occurs as determined by LDOK bit, the PWMF
reload flag is set. If the PWM reloa d interrupt enable bit, PWMRIE is set, the PWMF flag generates CPU
interrupt requests allowing software to calculate new PWM parameters in real time. When PWMRIE is
not set, reloads still occur at the selected reload rate without generating CPU interrupt requests.
Figure 11-67. PWMRF Reload Interrupt Request
Figure 11-68. Full-Cycle Center-Aligned PWM Value Loading
Figure 11-69. Full-Cycle Center-Aligned Modulus Loading
Vdd
CPU Interrupt
PWM Reload Request
DQ
CLK
CLR
READ PWMRF AS 1 THEN
WRITE 0 TO PWMF
RESET
PWMRF
PWMRIE
PWM
HALF = 0, LDFQ[3:0] = 00 = Reload every cycle
LDOK = 1
MODULUS = 3
PWM VALUE = 1
PWMRF = 1
0
3
2
1
1
3
2
1
0
3
1
1
UP/DOWN
COUNTER
Up/Down
PWM
HALF = 0, LDFQ[3:0] = 00 = Reload every cycle
LDOK = 1
MODULUS = 2
PWM VALUE = 1
PWMRF = 1
1
3
1
1
1
2
1
1
1
1
1
1
0
2
1
1
COUNTER
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 371
Figure 11-70. Half-Cycle Center-Aligned PWM Value Loading
Figure 11-71. Half-Cycle Center-Aligned Modulus Loading
Figure 11-72. Edge-Aligned PWM Value Loading
PWM
HALF = 1, LDFQ[3:0] = 00 = Reload EVERY HALF-CYCLE
LDOK = 1
MODULUS = 3
PWM VALUE = 1
PWMRF = 1
0
3
2
1
1
3
1
1
0
3
3
1
UP/DOWN
COUNTER
1
3
2
1
0
3
2
1
1
3
3
1
1
3
1
1
Up/Down
PWM
HALF = 1, LDFQ[3:0] = 00 = Reload every HALF-cycle
LDOK = 1
MODULUS = 2
PWM VALUE = 1
PWMRF = 1
0
3
1
1
0
4
1
1
1
1
1
1
0
2
1
1
COUNTER
0
2
1
1
1
4
1
1
1
4
1
1
Up-Only
PWM
LDFQ[3:0] = 00 = Reload every cycle
COUNTER
LDOK = 1
MODULUS = 3
PWM VALUE = 1
PWMRF = 1
0
3
2
1
1
3
2
1
0
3
1
1
0
3
1
1
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
372 Freescale Semiconductor
Figure 11-73. Untitled Figure
11.4.7.4 Initialization
Initialize all registers and set the LDOK bit before setting the PWMEN bit. With LDOK set, setting
PWMEN for the first time after res et, immediately loads the PWM generator thereby setting the PWMRF
flag. PWMRF generates a CPU interrupt request if the PWMRIE bit is set. In complementary channel
operation with current-status correction selected, PWM value registers one, three, and five control the
outputs for the first PWM cycle.
NOTE
Even if LDOK is not set, setting PWMEN also sets the PWMRF flag. To
prevent a CPU interrupt request, clear the PWMRIE bit before setting
PWMEN.
Setting PWMEN for the first time after reset without first setting LDOK loads a prescaler divisor of one,
a PWM value of $0000, and an unknown modulus. The PWM generator uses the last values loaded if
PWMEN is cleared and then set while LDOK equals zero.Initializing the deadtime register, after setting
PWMEN or OUTCTLx, can cause an improper deadtime insertion. However, the deadtime can never be
shorter than the specified value.
Figure 11-74. PWMEN and PWM Pins in Independent Operation
Figure 11-75. PWMEN and PWM Pins in Complementary Operation
Up-Only
PWM
LDFQ[3:0] = 00 = Reload every cycle
LDOK = 1
MODULUS = 3
PWM VALUE = 2
PWMRF = 1
COUNTER
1
4
2
1
1
2
2
1
0
1
2
1
HI-Z
ACTIVE HI-Z
IPBus
PWMEN
PWM
CLOCK
BIT
PINS
HI-Z
ACTIVE
IPBus
PWMEN
PWM
CLOCK
BIT
PINS
HI-Z
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 373
When the PWMEN bit is cleared:
• The PWMx outputs will be tri-stated unless OUTCTLx = 1
• The PWM counter is cleared and does not count
• The PWM generator forces its outputs to zero
• The PWMRF flag and pending CPU interrupt requests are not cleared
• All fault circuitry remains active unless FPINEx = 0
• Software output control remains active
• Deadtime insertion continues during software output control
11.4.8 Fault Protection
Fault protection can disable any combination of PWM pins. Faults are generated by a logic one on any of
the FAULT pins. Each FAULT pin can be mapped arbitrarily to any of the PWM pins.
When fault protection hardware disables PWM pins, the PWM generator continues to run, only the output
pins are deactivated.
The fault decoder disables PWM pins selected by the fault logic and the disable mapping register. See
Figure 11-15. Each bank of four bits in the disable mapping register control the mapping for a single PWM
pin. Refer to Table 11-12.
The fault protection is enabled even when the PWM is not enabled; therefore, a fault will be latched in and
will be cleared in order to prevent an interrupt when the PWM is enabled.
11.4.8.1 Fault Pin Sample Filter
Each fault pin has a sample filter to test for fault conditions. After every bus cycle setting the FAULTx pin
at logic zero, the filter synchronously samples the pin once every four bus cycles. QSMP determines the
number of consecutive samples that must be logic one for a fault to be detected. When a fault is detected,
the corresponding FAULTx pin flag, FFLAGx, is set. Clear FFLAGx by writing a logic one to it.
If the FIEx, FAULTx pin interrupt enable bit is set, the FFLAGx flag generates a CPU interrupt request.
The interrupt request latch remains set until:
• Software clears the FFLAGx flag by writing a logic one to it
• Software clears the FIEx bit by writing a logic zero to it
• A reset occurs
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
374 Freescale Semiconductor
11.4.8.2 Automatic Fault Clearing
Setting a fault mode bit, FMODEx, configures faults from the FAULTx pin for automatic clearing.
When FMODEx is set, disabled PWM pins are enabled when the FAULTx pin returns to logic zero and a
new PWM half cycle begins. See Figure 11-76. Clearing the FFLAGx flag does not affect disabled PWM
pins when FMODEx is set.
Figure 11-76. Automatic Fault Clearing
11.4.8.3 Manual Fault Clearing
Clearing a fault mode bit, FMODEx, configures faults from the FAULTx pin for manual clearing:
• PWM pins disabled by the FAULT0 pin or the FAULT2 pin are enabled by clearing the
corresponding FFLAGx flag. The time at which the PWM pins are enabled depends on the
corresponding QSMPx bit setting. If QSMPx = 00, the PWM pins are enabled on the next IP bus
cycle when the logic level detected by the filter at the fault pin is logic zero. If QSMPx = 01,10 or
11, the PWMs are enabled when the next PWM half cycle begins regardless of the state of the logic
level detected by the filter at the fault. See Figure 11-77 and Figure 11-78.
• PWM pins disabled by the FAULT1 pin or the FAULT3 pin are enabled when
— Software clears the corresponding FFLAGx flag
— The filter detects a logic zero on the fault pin at the start of the next PWM half cycle boundary.
See Figure 11-79.
Figure 11-77. Manual Fault Clearing (Faults 0 & 2) — QSMP = 00
PWMS ENABLED PWMS DISABLED PWMS ENABLED
FAULT PIN
DISABLEDENABLED
PWMS ENABLED
FAULT0 OR
FAULT2
PWMS ENABLED PWMS DISABLED
FFLAGx
CLEARED
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 375
Figure 11-78. Manual Fault Clearing (Faults 0 & 2) - QSMP=01, 10, or 11
Figure 11-79. Manual Fault Clearing (Faults 1 & 3)
NOTE
PWM half-cycle boundaries occur at both the PWM cycle start and when
the counter equals the modulus, so in edge-aligned operation full-cycles and
half-cycles are equal.
NOTE
Fault protection also applies during software output control when the
OUTCTLx bits are set. Fault clearing still occurs at half PWM cycle
boundaries while the PWM generator is engaged, PWMEN equals one. But
the OUTx bits can control the PWM pins while the PWM generator is off,
PWMEN equals zero. Thus, fault clearing occurs at IPbus cycles while the
PWM generator is off and at the start of PWM cycles when the generator is
engaged.
11.5 Resets
All PWM registers are reset to their default values upon any system reset.
11.6 Clocks
The system bus clock is the only clock required by this module.
PWMS ENABLED
FAULT0 OR
FAULT2
PWMS ENABLED PWMS DISABLED
FFLAGx
CLEARED
PWMS ENABLED
FAULT1 OR
FAULT3
PWMS ENABLED PWMS DISABLED
FFLAGx
CLEARED
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E256 Data Sheet, Rev. 1.08
376 Freescale Semiconductor
11.7 Interrupts
Seven PWM sources can generate CPU interrupt requests:
• Reload flag x (PWMRFx)—PWMRFx is set at the beginning of every PWM Generator x reload
cycle. The reload interrupt enable bit, PWMRIEx, enables PWMRFx to generate CPU interrupt
requests.
where x is A, B and C.
• Fault flag x (FFLAGx)—The FFLAGx bit is set when a logic one occurs on the FAULTx pin. The
fault pin interrupt enable x bit, FIEx, enables the FFLAGx flag to generate CPU interrupt requests.
where x is 0, 1, 2 and 3.
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 377
Chapter 12
Pulse-Width Modulator (PWM8B6CV1)
12.1 Introduction
The pulse width modulation (PWM) definition is based on the HC12 PWM definitions. The
PWM8B6CV1 module contains the basic features from the HC11 with some of the enhancements
incorporated on the HC12, that is center aligned output mode and four available clock sources. The
PWM8B6CV1 module has six channels with independent control of left and center aligned outputs on
each channel.
Each of the six PWM channels has a programmable period and duty cycle as well as a dedicated counter.
A flexible clock select scheme allows a total of four different clock sources to be used with the counters.
Each of the modulators can create independent continuous waveforms with software-selectable duty rates
from 0% to 100%. The PWM outputs can be programmed as left aligned outputs or center aligned outputs
12.1.1 Features
• Six independent PWM channels with programmable period and duty cycle
• Dedicated counter for each PWM channel
• Programmable PWM enable/disable for each channel
• Software selection of PWM duty pulse polarity for each channel
• Period and duty cycle are double buffered. Change takes effect when the end of the effective period
is reached (PWM counter reaches 0) or when the channel is disabled.
• Programmable center or left aligned outputs on individual channels
• Six 8-bit channel or three 16-bit channel PWM resolution
• Four clock sources (A, B, SA, and SB) provide for a wide range of frequencies.
• Programmable clock select logic
• Emergency shutdown
12.1.2 Modes of Operation
There is a software programmable option for low power consumption in wait mode that disables the input
clock to the prescaler.
In freeze mode there is a software programmable option to disable the input clock to the prescaler. This is
useful for emulation.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
378 Freescale Semiconductor
12.1.3 Block Diagram
Figure 12-1. PWM8B6CV1 Block Diagram
12.2 External Signal Description
The PWM8B6CV1 module has a total of six external pins.
12.2.1 PWM5 — Pulse Width Modulator Channel 5 Pin
This pin serves as waveform output of PWM channel 5 and as an input for the emergency shutdown
feature.
12.2.2 PWM4 — Pulse Width Modulator Channel 4 Pin
This pin serves as waveform output of PWM channel 4.
12.2.3 PWM3 — Pulse Width Modulator Channel 3 Pin
This pin serves as waveform output of PWM channel 3.
Period and Duty Counter
Channel 5
Bus Clock Clock Select PWM Clock
Period and Duty Counter
Channel 4
Period and Duty Counter
Channel 3
Period and Duty Counter
Channel 2
Period and Duty Counter
Channel 1
Period and Duty Counter
Channel 0
PWM Channels
Alignment
Polarity
Control
PWM8B6C
PWM5
PWM4
PWM3
PWM2
PWM1
PWM0
Enable
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 379
12.2.4 PWM2 — Pulse Width Modulator Channel 2 Pin
This pin serves as waveform output of PWM channel 2.
12.2.5 PWM1 — Pulse Width Modulator Channel 1 Pin
This pin serves as waveform output of PWM channel 1.
12.2.6 PWM0 — Pulse Width Modulator Channel 0 Pin
This pin serves as waveform output of PWM channel 0.
12.3 Memory Map and Register Definition
This subsection describes in detail all the registers and register bits in the PWM8B6CV1 module.
The special-purpose registers and register bit functions that would not normally be made available to
device end users, such as factory test control registers and reserved registers are clearly identified by means
of shading the appropriate portions of address maps and register diagrams. Notes explaining the reasons
for restricting access to the registers and functions are also explained in the individual register descriptions.
12.3.1 Module Memory Map
The following paragraphs describe the content of the registers in the PWM8B6CV1 module. The base
address of the PWM8B6CV1 module is determined at the MCU level when the MCU is defined. The
register decode map is fixed and begins at the first address of the module address offset. Table 12-1 shows
the registers associated with the PWM and their relative offset from the base address. The register detail
description follows the order in which they appear in the register map.
Reserved bits within a register will always read as 0 and the write will be unimplemented. Unimplemented
functions are indicated by shading the bit.
Table 12-1 shows the memory map for the PWM8B6CV1 module.
NOTE
Register address = base address + address offset, where the base address is
defined at the MCU level and the address offset is defined at the module
level.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
380 Freescale Semiconductor
Table 12-1. PWM8B6CV1 Memory Map
Address
Offset Register Access
0x0000 PWM Enable Register (PWME) R/W
0x0001 PWM Polarity Register (PWMPOL) R/W
0x0002 PWM Clock Select Register (PWMCLK) R/W
0x0003 PWM Prescale Clock Select Register (PWMPRCLK) R/W
0x0004 PWM Center Align Enable Register (PWMCAE) R/W
0x0005 PWM Control Register (PWMCTL) R/W
0x0006 PWM Test Register (PWMTST)1
1PWMTST is intended for factory test purposes only.
R/W
0x0007 PWM Prescale Counter Register (PWMPRSC)2
2PWMPRSC is intended for factory test purposes only.
R/W
0x0008 PWM Scale A Register (PWMSCLA) R/W
0x0009 PWM Scale B Register (PWMSCLB) R/W
0x000A PWM Scale A Counter Register (PWMSCNTA)3
3PWMSCNTA is intended for factory test purposes only.
R/W
0x000B PWM Scale B Counter Register (PWMSCNTB)4
4PWMSCNTB is intended for factory test purposes only.
R/W
0x000C PWM Channel 0 Counter Register (PWMCNT0) R/W
0x000D PWM Channel 1 Counter Register (PWMCNT1) R/W
0x000E PWM Channel 2 Counter Register (PWMCNT2) R/W
0x000F PWM Channel 3 Counter Register (PWMCNT3) R/W
0x0010 PWM Channel 4 Counter Register (PWMCNT4) R/W
0x0011 PWM Channel 5 Counter Register (PWMCNT5) R/W
0x0012 PWM Channel 0 Period Register (PWMPER0) R/W
0x0013 PWM Channel 1 Period Register (PWMPER1) R/W
0x0014 PWM Channel 2 Period Register (PWMPER2) R/W
0x0015 PWM Channel 3 Period Register (PWMPER3) R/W
0x0016 PWM Channel 4 Period Register (PWMPER4) R/W
0x0017 PWM Channel 5 Period Register (PWMPER5) R/W
0x0018 PWM Channel 0 Duty Register (PWMDTY0) R/W
0x0019 PWM Channel 1 Duty Register (PWMDTY1) R/W
0x001A PWM Channel 2 Duty Register (PWMDTY2) R/W
0x001B PWM Channel 3 Duty Register (PWMDTY3) R/W
0x001C PWM Channel 4 Duty Register (PWMDTY4) R/W
0x001D PWM Channel 5 Duty Register (PWMDTY5) R/W
0x001E PWM Shutdown Register (PWMSDN) R/W
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 381
12.3.2 Register Descriptions
The following paragraphs describe in detail all the registers and register bits in the PWM8B6CV1 module.
Register
Name Bit 7 6 5 4 3 2 1 Bit 0
PWME R 0 0 PWME5 PWME4 PWME3 PWME2 PWME1 PWME0
W
PWMPOL R 0 0 PPOL5 PPOL4 PPOL3 PPOL2 PPOL1 PPOL0
W
PWMCLK R 0 0 PCLK5 PCLK4 PCLK3 PCLK2 PCLK1 PCLK0
W
PWMPRCLK R 0 PCKB2 PCKB1 PCKB0 0PCKA2 PCKA1 PCKA0
W
PWMCAE R 0 0 CAE5 CAE4 CAE2 CAE2 CAE1 CAE0
W
PWMCTL R 0 CON45 CON23 CON01 PSWAI PFRZ 00
W
PWMTSTR00 0 0000 0
W
PWMPRSC R 0 0 0 0 0 0 0 0
W
PWMSCLA R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMSCLB R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMSCNTA R 0 0 0 0 0 0 0 0
W
PWMSCNTB R 0 0 0 0 0 0 0 0
W
PWMCNT0 R Bit 7 6 5 4 3 2 1 Bit 0
W00 0 0000 0
PWMCNT1 R Bit 7 6 5 4 3 2 1 Bit 0
W00 0 0000 0
PWMCNT2 R Bit 7 6 5 4 3 2 1 Bit 0
W00 0 0000 0
= Unimplemented or Reserved
Figure 12-2. PWM Register Summary
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
382 Freescale Semiconductor
PWMCNT3 R Bit 7 6 5 4 3 2 1 Bit 0
W00 0 0000 0
PWMCNT4 R Bit 7 6 5 4 3 2 1 Bit 0
W00 0 0000 0
PWMCNT5 R Bit 7 6 5 4 3 2 1 Bit 0
W00 0 0000 0
PWMPER0 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER1 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER2 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER3 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER4 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER5 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMDTY0 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER1 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER2 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER3 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER4 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMPER5 R Bit 7 6 5 4 3 2 1 Bit 0
W
PWMSDB R PWMIF PWMIE 0PWMLVL 0PWM5IN
PWM5INL PWM5ENA
WPWMRSTRT
Register
Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented or Reserved
Figure 12-2. PWM Register Summary (continued)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 383
12.3.2.1 PWM Enable Register (PWME)
Each PWM channel has an enable bit (PWMEx) to start its waveform output. When any of the PWMEx
bits are set (PWMEx = 1), the associated PWM output is enabled imme diately. However , the actual PWM
waveform is not available on the associated PWM output until its clock source begins its next cycle due
to the synchronization of PWMEx and the clock source.
NOTE
The first PWM cycle after enabling the channel can be irregular.
An exception to this is when channels are concatenated. After concatenated mode is enabled (CONxx bits
set in PWMCTL register), enabling/disabling the corresponding 16-bit PWM channel is controlled by the
low-order PWMEx bit. In this case, the high-order bytes PWMEx bits have no effect and their
corresponding PWM output lines are disabled.
While in run mode, if all six PWM channels are disabled (PWME5–PWME0 = 0), the prescaler counter
shuts off for power savings.
Read: anytime
Write: anytime
76543210
R0 0 PWME5 PWME4 PWME3 PWME2 PWME1 PWME0
W
Reset00000000
= Unimplemented or Reserved
Figure 12-3. PWM Enable Register (PWME)
Table 12-2. PWME Field Descriptions
Field Description
5
PWME5
Pulse Width Channel 5 Enable
0 Pulse width channel 5 is disabled.
1 Pulse width channel 5 is enabled. The pulse modulated signal becomes available at PWM,output bit 5 when
its clock source begins its next cycle.
4
PWME4
Pulse Width Channel 4 Enable
0 Pulse width channel 4 is disabled.
1 Pulse width channel 4 is enabled. The pulse modulated signal becomes available at PWM, output bit 4 when
its clock source begins its next cycle. If CON45 = 1, then bit has no effect and PWM output line 4 is disabled.
3
PWME3
Pulse Width Channel 3 Enable
0 Pulse width channel 3 is disabled.
1 Pulse width channel 3 is enabled. The pulse modulated signal becomes available at PWM, output bit 3 when
its clock source begins its next cycle.
2
PWME2
Pulse Width Channel 2 Enable
0 Pulse width channel 2 is disabled.
1 Pulse width channel 2 is enabled. The pulse modulated signal becomes available at PWM, output bit 2 when
its clock source begins its next cycle. If CON23 = 1, then bit has no effect and PWM output line 2 is disabled.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
384 Freescale Semiconductor
12.3.2.2 PWM Polarity Register (PWMPOL)
The starting polarity of each PWM channel waveform is determined by the associated PPOLx bit in the
PWMPOL register. If the polarity bit is 1, the PWM channel output is high at the beginning of the cycle
and then goes low when the duty count is reached. Conversely, if the polarity bit is 0 the output starts low
and then goes high when the duty count is reached.
Read: anytime
Write: anytime
NOTE
PPOLx register bits can be written anytime. If the polarity is changed while
a PWM signal is being generated, a truncated or stretched pulse can occur
during the transition
1
PWME1
Pulse Width Channel 1 Enable
0 Pulse width channel 1 is disabled.
1 Pulse width channel 1 is enabled. The pulse modulated signal becomes available at PWM, output bit 1 when
its clock source begins its next cycle.
0
PWME0
Pulse Width Channel 0 Enable
0 Pulse width channel 0 is disabled.
1 Pulse width channel 0 is enabled. The pulse modulated signal becomes available at PWM, output bit 0 when
its clock source begins its next cycle. If CON01 = 1, then bit has no effect and PWM output line 0 is disabled.
76543210
R0 0 PPOL5 PPOL4 PPOL3 PPOL2 PPOL1 PPOL0
W
Reset00000000
= Unimplemented or Reserved
Figure 12-4. PWM Polarity Register (PWMPOL)
Table 12-3. PWMPOL Field Descriptions
Field Description
5
PPOL5
Pulse Width Channel 5 Polarity
0 PWM channel 5 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 5 output is high at the beginning of the period, then goes low when the duty count is reached.
4
PPOL4
Pulse Width Channel 4 Polarity
0 PWM channel 4 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 4 output is high at the beginning of the period, then goes low when the duty count is reached.
3
PPOL3
Pulse Width Channel 3 Polarity
0 PWM channel 3 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 3 output is high at the beginning of the period, then goes low when the duty count is reached.
Table 12-2. PWME Field Descriptions (continued)
Field Description
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 385
12.3.2.3 PWM Clock Select Register (PWMCLK)
Each PWM channel has a choice of two clocks to use as the clock source for that channel as described
below.
Read: anytime
Write: anytime
NOTE
Register bits PCLK0 to PCLK5 can be written anytime. If a clock select is
changed while a PWM signal is being generated, a truncated or stretched
pulse can occur during the transition.
2
PPOL2
Pulse Width Channel 2 Polarity
0 PWM channel 2 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 2 output is high at the beginning of the period, then goes low when the duty count is reached.
1
PPOL1
Pulse Width Channel 1 Polarity
0 PWM channel 1 output is low at the beginning of the period, then goes high when the duty count is reached.
1 PWM channel 1 output is high at the beginning of the period, then goes low when the duty count is reached.
0
PPOL0
Pulse Width Channel 0 Polarity
0 PWM channel 0 output is low at the beginning of the period, then goes high when the duty count is reached
1 PWM channel 0 output is high at the beginning of the period, then goes low when the duty count is reached.
76543210
R0 0 PCLK5 PCLK4 PCLK3 PCLK2 PCLK1 PCLK0
W
Reset00000000
= Unimplemented or Reserved
Figure 12-5. PWM Clock Select Register (PWMCLK)
Table 12-4. PWMCLK Field Descriptions
Field Description
5
PCLK5
Pulse Width Channel 5 Clock Select
0 Clock A is the clock source for PWM channel 5.
1 Clock SA is the clock source for PWM channel 5.
4
PCLK4
Pulse Width Channel 4 Clock Select
0 Clock A is the clock source for PWM channel 4.
1 Clock SA is the clock source for PWM channel 4.
3
PCLK3
Pulse Width Channel 3 Clock Select
0 Clock B is the clock source for PWM channel 3.
1 Clock SB is the clock source for PWM channel 3.
Table 12-3. PWMPOL Field Descriptions (continued)
Field Description
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
386 Freescale Semiconductor
12.3.2.4 PWM Prescale Clock Select Register (PWMPRCLK)
This register selects the prescale clock source for clocks A and B independently.
Read: anytime
Write: anytime
NOTE
PCKB2–PCKB0 and PCKA2–PCKA0 register bits can be written anytime.
If the clock prescale is changed while a PWM signal is being generated, a
truncated or stretched pulse can occur during the transition.
2
PCLK2
Pulse Width Channel 2 Clock Select
0 Clock B is the clock source for PWM channel 2.
1 Clock SB is the clock source for PWM channel 2.
1
PCLK1
Pulse Width Channel 1 Clock Select
0 Clock A is the clock source for PWM channel 1.
1 Clock SA is the clock source for PWM channel 1.
0
PCLK0
Pulse Width Channel 0 Clock Select
0 Clock A is the clock source for PWM channel 0.
1 Clock SA is the clock source for PWM channel 0.
76543210
R0 PCKB2 PCKB1 PCKB0 0PCKA2 PCKA1 PCKA0
W
Reset00000000
= Unimplemented or Reserved
Figure 12-6. PWM Prescaler Clock Select Register (PWMPRCLK)
Table 12-5. PWMPRCLK Field Descriptions
Field Description
6:5
PCKB[2:0]
Prescaler Select for Clock B — Clock B is 1 of two clock sources which can be used for channels 2 or 3. These
three bits determine the rate of clock B, as shown in Tabl e 1 2 - 6 .
2:0
PCKA[2:0]
Prescaler Select for Clock A — Clock A is 1 of two clock sources which can be used for channels 0, 1, 4, or 5.
These three bits determine the rate of clock A, as shown in Table 12-7.
Table 12-4. PWMCLK Field Descriptions (continued)
Field Description
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 387
12.3.2.5 PWM Center Align Enable Register (PWMCAE)
The PWMCAE register contains six control bits for the selection of center aligned outputs or left aligned
outputs for each PWM channel. If the CAEx bit is set to a 1, the corresponding PWM output will be center
aligned. If the CAEx bit is cleared, the corresponding PWM output will be left aligned. Reference
Section 12.4.2.5, “Left Aligned Outputs,” and Section 12.4.2.6, “Center Aligned Outputs,” for a more
detailed description of the PWM output modes.
Read: anytime
Write: anytime
NOTE
Write these bits only when the corresponding channel is disabled.
Table 12-6. Clock B Prescaler Selects
PCKB2 PCKB1 PCKB0 Value of Clock B
0 0 0 Bus Clock
0 0 1 Bus Clock / 2
0 1 0 Bus Clock / 4
0 1 1 Bus Clock / 8
1 0 0 Bus Clock / 16
1 0 1 Bus Clock / 32
1 1 0 Bus Clock / 64
1 1 1 Bus Clock / 128
Table 12-7. Clock A Prescaler Selects
PCKA2 PCKA1 PCKA0 Value of Clock A
0 0 0 Bus Clock
0 0 1 Bus Clock / 2
0 1 0 Bus Clock / 4
0 1 1 Bus Clock / 8
1 0 0 Bus Clock / 16
1 0 1 Bus Clock / 32
1 1 0 Bus Clock / 64
1 1 1 Bus Clock / 128
76543210
R0 0 CAE5 CAE4 CAE3 CAE2 CAE1 CAE0
W
Reset00000000
= Unimplemented or Reserved
Figure 12-7. PWM Center Align Enable Register (PWMCAE)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
388 Freescale Semiconductor
12.3.2.6 PWM Control Register (PWMCTL)
The PWMCTL register provides for various control of the PWM module.
Read: anytime
Write: anytime
There are three control bits for concatenation, each of which is used to concatenate a pair of PWM channels
into one 16-bit channel. When channels 4 and 5 are concatenated, channel 4 registers become the
high-order bytes of the double-byte channel. When channels 2 and 3 are concatenated, channel 2 registers
become the high-order bytes of the double-byte channel. When channels 0 and 1 are concatenated,
channel 0 registers become the high-order bytes of the double-byte channel.
Table 12-8. PWMCAE Field Descriptions
Field Description
5
CAE5
Center Aligned Output Mode on Channel 5
0 Channel 5 operates in left aligned output mode.
1 Channel 5 operates in center aligned output mode.
4
CAE4
Center Aligned Output Mode on Channel 4
0 Channel 4 operates in left aligned output mode.
1 Channel 4 operates in center aligned output mode.
3
CAE3
Center Aligned Output Mode on Channel 3
1 Channel 3 operates in left aligned output mode.
1 Channel 3 operates in center aligned output mode.
2
CAE2
Center Aligned Output Mode on Channel 2
0 Channel 2 operates in left aligned output mode.
1 Channel 2 operates in center aligned output mode.
1
CAE1
Center Aligned Output Mode on Channel 1
0 Channel 1 operates in left aligned output mode.
1 Channel 1 operates in center aligned output mode.
0
CAE0
Center Aligned Output Mode on Channel 0
0 Channel 0 operates in left aligned output mode.
1 Channel 0 operates in center aligned output mode.
76543210
R0 CON45 CON23 CON01 PSWAI PFRZ 00
W
Reset00000000
= Unimplemented or Reserved
Figure 12-8. PWM Control Register (PWMCTL)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 389
Reference Section 12.4.2.7, “PWM 16-Bit Functions,” for a more detailed description of the concatenation
PWM function.
NOTE
Change these bits only when both corresponding channels are disabled.
Table 12-9. PWMCTL Field Descriptions
Field Description
6
CON45
Concatenate Channels 4 and 5
0 Channels 4 and 5 are separate 8-bit PWMs.
1 Channels 4 and 5 are concatenated to create one 16-bit PWM channel. Channel 4 becomes the high-order
byte and channel 5 becomes the low-order byte. Channel 5 output pin is used as the output for this 16-bit PWM
(bit 5 of port PWMP). Channel 5 clock select control bit determines the clock source, channel 5 polarity bit
determines the polarity, channel 5 enable bit enables the output and channel 5 center aligned enable bit
determines the output mode.
5
CON23
Concatenate Channels 2 and 3
0 Channels 2 and 3 are separate 8-bit PWMs.
1 Channels 2 and 3 are concatenated to create one 16-bit PWM channel. Channel 2 becomes the high-order
byte and channel 3 becomes the low-order byte. Channel 3 output pin is used as the output for this 16-bit PWM
(bit 3 of port PWMP). Channel 3 clock select control bit determines the clock source, channel 3 polarity bit
determines the polarity, channel 3 enable bit enables the output and channel 3 center aligned enable bit
determines the output mode.
4
CON01
Concatenate Channels 0 and 1
0 Channels 0 and 1 are separate 8-bit PWMs.
1 Channels 0 and 1 are concatenated to create one 16-bit PWM channel. Channel 0 becomes the high-order
byte and channel 1 becomes the low-order byte. Channel 1 output pin is used as the output for this 16-bit PWM
(bit 1 of port PWMP). Channel 1 clock select control bit determines the clock source, channel 1 polarity bit
determines the polarity, channel 1 enable bit enables the output and channel 1 center aligned enable bit
determines the output mode.
3
PSWAI
PWM Stops in Wait Mode — Enabling this bit allows for lower power consumption in wait mode by disabling the
input clock to the prescaler.
0 Allow the clock to the prescaler to continue while in wait mode.
1 Stop the input clock to the prescaler whenever the MCU is in wait mode.
2
PFRZ
PWM Counters Stop in Freeze Mode — In freeze mode, there is an option to disable the input clock to the
prescaler by setting the PFRZ bit in the PWMCTL register. If this bit is set, whenever the MCU is in freeze mode
the input clock to the prescaler is disabled. This feature is useful during emulation as it allows the PWM function
to be suspended. In this way, the counters of the PWM can be stopped while in freeze mode so that after normal
program flow is continued, the counters are re-enabled to simulate real-time operations. Because the registers
remain accessible in this mode, to re-enable the prescaler clock, either disable the PFRZ bit or exit freeze mode.
0 Allow PWM to continue while in freeze mode.
1 Disable PWM input clock to the prescaler whenever the part is in freeze mode. This is useful for emulation.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
390 Freescale Semiconductor
12.3.2.7 Reserved Register (PWMTST)
This register is reserved for factory testing of the PWM module and is not available in normal modes.
Read: always read 0x0000 in normal modes
Write: unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter the PWM
functionality.
12.3.2.8 Reserved Register (PWMPRSC)
This register is reserved for factory testing of the PWM module and is not available in normal modes.
Read: always read 0x0000 in normal modes
Write: unimplemented in normal modes
NOTE
Writing to this register when in special modes can alter the PWM
functionality.
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 12-9. Reserved Register (PWMTST)
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 12-10. Reserved Register (PWMPRSC)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 391
12.3.2.9 PWM Scale A Register (PWMSCLA)
PWMSCLA is the programmable scale value used in scaling clock A to generate clock SA. Clock SA is
generated by taking clock A, dividing it by the value in the PWMSCLA register and dividing that by two.
Clock SA = Clock A / (2 * PWMSCLA)
NOTE
When PWMSCLA = 0x0000, PWMSCLA value is considered a full scale
value of 256. Clock A is thus divided by 512.
Any value written to this register will cause the scale counter to load the new scale value (PWMSCLA).
Read: anytime
Write: anytime (causes the scale counter to load the PWMSCLA value)
12.3.2.10 PWM Scale B Register (PWMSCLB)
PWMSCLB is the programmable scale value used in scaling clock B to generate clock SB. Clock SB is
generated by taking clock B, dividing it by the value in the PWMSCLB register and dividing that by two.
Clock SB = Clock B / (2 * PWMSCLB)
NOTE
When PWMSCLB = 0x0000, PWMSCLB value is considered a full scale
value of 256. Clock B is thus divided by 512.
Any value written to this register will cause the scale counter to load the new scale value (PWMSCLB).
Read: anytime
Write: anytime (causes the scale counter to load the PWMSCLB value).
76543210
RBit 7 6 5 4 3 2 1 Bit 0
W
Reset00000000
Figure 12-11. PWM Scale A Register (PWMSCLA)
76543210
RBit 7 6 5 4 3 2 1 Bit 0
W
Reset00000000
Figure 12-12. PWM Scale B Register (PWMSCLB)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
392 Freescale Semiconductor
12.3.2.11 Reserved Registers (PWMSCNTx)
The registers PWMSCNTA and PWMSCNTB are reserved for factory testing of the PWM module and
are not available in normal modes.
Read: always read 0x0000 in normal modes
Write: unimplemented in normal modes
NOTE
Writing to these registers when in special modes can alter the PWM
functionality.
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 12-13. Reserved Register (PWMSCNTA)
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 12-14. Reserved Register (PWMSCNTB)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 393
12.3.2.12 PWM Channel Counter Registers (PWMCNTx)
Each channel has a dedicated 8-bit up/down counter which runs at the rate of the selected clock source.
The counter can be read at any time without affecting the count or the operation of the PWM channel. In
left aligned output mode, the counter counts from 0 to the value in the period register – 1. In center aligned
output mode, the counter counts from 0 up to the value in the period register and then back down to 0.
Any value written to the counter causes the counter to reset to 0x0000, the counter direction to be set to
up, the immediate load of both duty and period registers with values from the buffers, and the output to
change according to the polarity bit. The counter is also cleared at the end of the effective period (see
Section 12.4.2.5, “Left Aligned Outputs,” and Section 12.4.2.6, “Center Aligned Outputs,” for more
details). When the channel is disabled (PWMEx = 0), the PWMCNTx register does not count. When a
channel becomes enabled (PWMEx = 1), the associated PWM counter starts at the count in the
PWMCNTx register. For more detailed information on the operation of the counters, reference
Section 12.4.2.4, “PWM Timer Counters.”
In concatenated mode, writes to the 16-bit counter by using a 16-bit access or writes to either the low- or
high-order byte of the counter will reset the 16-bit counter. Reads of the 16-bit counter must be made by
16-bit access to maintain data coherency.
NOTE
Writing to the counter while the channel is enabled can cause an irregular
PWM cycle to occur.
76543210
R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Reset00000000
Figure 12-15. PWM Channel Counter Registers (PWMCNT0)
76543210
R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Reset00000000
Figure 12-16. PWM Channel Counter Registers (PWMCNT1)
76543210
R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Reset00000000
Figure 12-17. PWM Channel Counter Registers (PWMCNT2)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
394 Freescale Semiconductor
Read: anytime
Write: anytime (any value written causes PWM counter to be reset to 0x0000).
12.3.2.13 PWM Channel Period Registers (PWMPERx)
There is a dedicated period register for each channel. The value in this register determines the period of
the associated PWM channel.
The period registers for each channel are double buffered so that if they change while the channel is
enabled, the change will NOT take effect until one of the following occurs:
• The effective period ends
• The counter is written (counter resets to 0x0000)
• The channel is disabled
In this way, the output of the PWM will always be either the old waveform or the new waveform, not some
variation in between. If the channel is not enable d, then writes to the period register will go directly to the
latches as well as the buffer.
NOTE
Reads of this register return the most recent value written. Reads do not
necessarily return the value of the currently active period due to the double
buffering scheme.
Reference Section 12.4.2.3, “PWM Period and Duty,” for more information.
76543210
R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Reset00000000
Figure 12-18. PWM Channel Counter Registers (PWMCNT3)
76543210
R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Reset00000000
Figure 12-19. PWM Channel Counter Registers (PWMCNT4)
76543210
R Bit 7 6 5 4 3 2 1 Bit 0
W00000000
Reset00000000
Figure 12-20. PWM Channel Counter Registers (PWMCNT5)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 395
To calculate the output period, take the selected clock source period for the channel of interest (A, B, SA,
or SB) and multiply it by the value in the period register for that channel:
• Left aligned output (CAEx = 0)
• PWMx period = channel clock period * PWMPERx center aligned output (CAEx = 1)
• PWMx period = channel clock period * (2 * PWMPERx)
For boundary case programming values, please refer to Section 12.4.2.8, “PWM Boundary Cases.”
76543210
RBit 7654321Bit 0
W
Reset00000000
Figure 12-21. PWM Channel Period Registers (PWMPER0)
76543210
RBit 7654321Bit 0
W
Reset00000000
Figure 12-22. PWM Channel Period Registers (PWMPER1)
76543210
RBit 7654321Bit 0
W
Reset00000000
Figure 12-23. PWM Channel Period Registers (PWMPER2)
76543210
RBit 7654321Bit 0
W
Reset00000000
Figure 12-24. PWM Channel Period Registers (PWMPER3)
76543210
RBit 7654321Bit 0
W
Reset00000000
Figure 12-25. PWM Channel Period Registers (PWMPER4)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
396 Freescale Semiconductor
Read: anytime
Write: anytime
12.3.2.14 PWM Channel Duty Registers (PWMDTYx)
There is a dedicated duty register for each channel. The value in this register determines the duty of the
associated PWM channel. The duty value is compared to the counter and if it is equal to the counter value
a match occurs and the output changes state.
The duty registers for each channel are double buffered so that if they change while the channel is enabled,
the change will NOT take effect until one of the following occurs:
• The effective period ends
• The counter is written (counter resets to 0x0000)
• The channel is disabled
In this way, the output of the PWM will always be either the old duty waveform or the new duty waveform,
not some variation in between. If the channel is not enabled, then writes to the duty register will go directly
to the latches as well as the buffer.
NOTE
Reads of this register return the most recent value written. Reads do not
necessarily return the value of the currently active duty due to the double
buffering scheme.
Reference Section 12.4.2.3, “PWM Period and Duty,” for more information.
NOTE
Depending on the polarity bit, the duty registers will contain the count of
either the high time or the low time. If the polarity bit is 1, the output starts
high and then goes low when the duty count is reached, so the duty registers
contain a count of the high time. If the polarity bit is 0, the output starts low
and then goes high when the duty count is reached, so the duty registers
contain a count of the low time.
To calculate the output duty cycle (high time as a % of period) for a particular channel:
• Polarity = 0 (PPOLx = 0)
Duty cycle = [(PWMPERxšPWMDTYx)/PWMPERx] * 100%
• Polarity = 1 (PPOLx = 1)
Duty cycle = [PWMDTYx / PWMPERx] * 100%
• For boundary case programming values, please refer to Section 12.4.2.8, “PWM Boundary Cases.”
76543210
RBit 7654321Bit 0
W
Reset00000000
Figure 12-26. PWM Channel Period Registers (PWMPER5)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 397
Read: anytime
Write: anytime
76543210
RBit 7654321Bit 0
W
Reset11111111
Figure 12-27. PWM Channel Duty Registers (PWMDTY0)
76543210
RBit 7654321Bit 0
W
Reset11111111
Figure 12-28. PWM Channel Duty Registers (PWMDTY1)
76543210
RBit 7654321Bit 0
W
Reset11111111
Figure 12-29. PWM Channel Duty Registers (PWMDTY2)
76543210
RBit 7654321Bit 0
W
Reset11111111
Figure 12-30. PWM Channel Duty Registers (PWMDTY3)
76543210
RBit 7654321Bit 0
W
Reset11111111
Figure 12-31. PWM Channel Duty Registers (PWMDTY4)
76543210
RBit 7654321Bit 0
W
Reset11111111
Figure 12-32. PWM Channel Duty Registers (PWMDTY5)
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
398 Freescale Semiconductor
12.3.2.15 PWM Shutdown Register (PWMSDN)
The PWMSDN register provides for the shutdown functionality of the PWM module in the emergency
cases.
Read: anytime
Write: anytime
76543210
RPWMIF PWMIE 0PWMLVL 0PWM5IN
PWM5INL PWM5ENA
WPWMRSTRT
Reset00000000
= Unimplemented or Reserved
Figure 12-33. PWM Shutdown Register (PWMSDN)
Table 12-10. PWMSDN Field Descriptions
Field Description
7
PWMIF
PWM Interrupt Flag — Any change from passive to asserted (active) state or from active to passive state will be
flagged by setting the PWMIF flag = 1. The flag is cleared by writing a logic 1 to it. Writing a 0 has no effect.
0 No change on PWM5IN input.
1 Change on PWM5IN input
6
PWMIE
PWM Interrupt Enable — If interrupt is enabled an interrupt to the CPU is asserted.
0 PWM interrupt is disabled.
1 PWM interrupt is enabled.
5
PWMRSTRT
PWM Restart — The PWM can only be restarted if the PWM channel input 5 is deasserted. After writing a logic 1
to the PWMRSTRT bit (trigger event) the PWM channels start running after the corresponding counter passes
next “counter = 0” phase.
Also, if the PWM5ENA bit is reset to 0, the PWM do not start before the counter passes 0x0000.
The bit is always read as 0.
4
PWMLVL
PWM Shutdown Output Level — If active level as defined by the PWM5IN input, gets asserted all enabled PWM
channels are immediately driven to the level defined by PWMLVL.
0 PWM outputs are forced to 0
1 PWM outputs are forced to 1.
2
PWM5IN
PWM Channel 5 Input Status — This reflects the current status of the PWM5 pin.
1
PWM5INL
PWM Shutdown Active Input Level for Channel 5 — If the emergency shutdown feature is enabled
(PWM5ENA = 1), this bit determines the active level of the PWM5 channel.
0 Active level is low
1 Active level is high
0
PWM5ENA
PWM Emergency Shutdown Enable — If this bit is logic 1 the pin associated with channel 5 is forced to input
and the emergency shutdown feature is enabled. All the other bits in this register are meaningful only if
PWM5ENA = 1.
0 PWM emergency feature disabled.
1 PWM emergency feature is enabled.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 399
12.4 Functional Description
12.4.1 PWM Clock Select
There are four available clocks called clock A, clock B, clock SA (scaled A), and clock SB (scaled B).
These four clocks are based on the bus clock.
Clock A and B can be software selected to be 1, 1/2, 1/4, 1/8,..., 1/64, 1/128 times the bus clock. Clock SA
uses clock A as an input and divides it further with a reloadable counter. Similarly, clock SB uses clock B
as an input and divides it further with a reloadable counter. The rates available for clock SA are software
selectable to be clock A divided by 2, 4, 6, 8, ..., or 512 in increments of divide by 2. Similar rates are
available for clock SB. Each PWM channel has the capability of selecting one of two clocks, either the
pre-scaled clock (clock A or B) or the scaled clock (clock SA or SB).
The block diagram in Figure 12-34 shows the four different clocks and how the scaled clocks are created.
12.4.1.1 Prescale
The input clock to the PWM prescaler is the bus clock. It can be disabled whenever the part is in freeze
mode by setting the PFRZ bit in the PWMCTL register. If this bit is set, whenever the MCU is in freeze
mode the input clock to the prescaler is disabled. This is useful for emulation in order to freeze the PWM.
The input clock can also be disabled when all six PWM channels are disabled (PWME5–PWME0 = 0)
This is useful for reducing power by disabling the prescale counter.
Clock A and clock B are scaled values of the input clock. The value is software selectable for both clock A
and clock B and has options of 1, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, or 1/128 times the bus clock. The value
selected for clock A is determined by the PCKA2, PCKA1, and PCKA0 bits in the PWMPRCLK register.
The value selected for clock B is determined by the PCKB2, PCKB1, and PCKB0 bits also in the
PWMPRCLK register.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
400 Freescale Semiconductor
Figure 12-34. PWM Clock Select Block Diagram
2
4 8 16 32 64 128
PCKB2
PCKB1
PCKB0
M
U
X
Clock A
Clock B
Clock SA
Clock A/2, A/4, A/6,....A/512
PRESCALE SCALE
Divide by Prescaler Taps:
PFRZ
FREEZE
Bus Clock
CLOCK SELECT
M
U
X
PCLK0
Clock to
PWM Ch 0
M
U
X
PCLK2
Clock to
PWM Ch 2
M
U
X
PCLK1
Clock to
PWM Ch 1
M
U
X
PCLK4
Clock to
PWM Ch 4
M
U
X
PCLK5
Clock to
PWM Ch 5
M
U
X
PCLK3
Clock to
PWM Ch 3
Load
DIV 2PWMSCLB
8-Bit Down Counter
Clock SB
Clock B/2, B/4, B/6,....B/512
M
U
X
PCKA2
PCKA1
PCKA0
PWME5:0
Count = 1
Load
DIV 2PWMSCLA
8-Bit Down Counter Count = 1
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 401
12.4.1.2 Clock Scale
The scaled A clock uses clock A as an input and divides it further with a user programmable value and
then divides this by 2. The scaled B clock uses clock B as an input and divides it further with a user
programmable value and then divides this by 2. The rates available for clock SA are software selectable
to be clock A divided by 2, 4, 6, 8, ..., or 512 in increments of divide by 2. Similar rates are available for
clock SB.
Clock A is used as an input to an 8-bit down counter. This down counter loads a user programmable scale
value from the scale register (PWMSCLA). When the down counter reaches 1, two things happen; a pulse
is output and the 8-bit counter is re-loaded. The output signal from this circuit is further divided by two.
This gives a greater range with only a slight reduction in granularity. Clock SA equals clock A divided by
two times the value in the PWMSCLA register.
NOTE
Clock SA = Clock A / (2 * PWMSCLA)
When PWMSCLA = 0x0000, PWMSCLA value is considered a full scale
value of 256. Clock A is thus divided by 512.
Similarly, clock B is used as an input to an 8-bit down counter followed by a divide by two producing clock
SB. Thus, clock SB equals clock B divided by two times the value in the PWMSCLB register.
NOTE
Clock SB = Clock B / (2 * PWMSCLB)
When PWMSCLB = 0x0000, PWMSCLB value is considered a full scale
value of 256. Clock B is thus divided by 512.
As an example, consider the case in which the user writes 0x00FF into the PWMSCLA register. Clock A
for this case will be bus clock divided by 4. A pulse will occur at a rate of once every 255 x 4 bus cycles.
Passing this through the divide by two circuit produces a clock signal at a bus clock divided by 2040 rate.
Similarly, a value of 0x0001 in the PWMSCLA register when clock A is bus clock divided by 4 will
produce a bus clock divided by 8 rate.
Writing to PWMSCLA or PWMSCLB causes the associated 8-bit down counter to be re-loaded.
Otherwise, when changing rates the counter would have to count down to 0x0001 before counting at the
proper rate. Forcing the associated counter to re-load the scale register value every time PWMSCLA or
PWMSCLB is written prevents this.
NOTE
Writing to the scale registers while channels are operating can cause
irregularities in the PWM outputs.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
402 Freescale Semiconductor
12.4.1.3 Clock Select
Each PWM channel has the capability of selecting one of two clocks. For channels 0, 1, 4, and 5 the clock
choices are clock A or clock SA. For channels 2 and 3 the choices are clock B or clock SB. The clock
selection is done with the PCLKx control bits in the PWMCLK register.
NOTE
Changing clock control bits while channels are operating can cause
irregularities in the PWM outputs.
12.4.2 PWM Channel Timers
The main part of the PWM module are the actual timers. Each of the timer channels has a counter, a period
register and a duty register (each are 8 bit). The waveform output period is controlled by a match between
the period register and the value in the counter. The duty is controlled by a match between the duty register
and the counter value and causes the state of the output to change during the period. The starting polarity
of the output is also selectable on a per channel basis. Figure 12-35 shows a block diagram for PWM timer.
Figure 12-35. PWM Timer Channel Block Diagram
Clock Source
T
R
Q
Q
M
U
X
PPOLx
From Port PWMP
Data Register
PWMEx
(clock edge sync)
To P in
Driver
GATE
8-Bit Compare =
PWMDTYx
8-Bit Compare =
PWMPERx
M
U
X
CAEx
up/down
T
R
Q
Q
reset
8-Bit Counter
PWMCNTx
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 403
12.4.2.1 PWM Enable
Each PWM channel has an enable bit (PWMEx) to start its waveform output. When any of the PWMEx
bits are set (PWMEx = 1), the associated PWM output signal is enabled immediately. However, the actual
PWM waveform is not available on the associated PWM output until its clock source begins its next cycle
due to the synchronization of PWMEx and the clock source. An exception to this is when channels are
concatenated. Refer to Section 12.4.2.7, “PWM 16-Bit Functions,” for more detail.
NOTE
The first PWM cycle after enabling the channel can be irregular.
On the front end of the PWM timer, the clock is enabled to the PWM circuit by the PWMEx bit being high.
There is an edge-synchronizing circuit to guarantee that the clock will only be enabled or disabled at an
edge. When the channel is disabled (PWMEx = 0), the counter for the channel does not count.
12.4.2.2 PWM Polarity
Each channel has a polarity bit to allow starting a waveform cycle with a high or low signal. This is shown
on the block diagram as a mux select of either the Q output or the Q output of the PWM output flip-flop.
When one of the bits in the PWMPOL register is set, the associated PWM channel output is high at the
beginning of the waveform, then goes low when the duty count is reached. Conversely, if the polarity bit
is 0, the output starts low and then goes high when the duty count is reached.
12.4.2.3 PWM Period and Duty
Dedicated period and duty registers exist for each channel and are double buffered so that if they change
while the channel is enabled, the change will NOT take effect until one of the following occurs:
• The effective period ends
• The counter is written (counter resets to 0x0000)
• The channel is disabled
In this way, the output of the PWM will always be either the old waveform or the new waveform, not some
variation in between. If the channel is not enabled, then writes to the period and duty registers will go
directly to the latches as well as the buffer.
A change in duty or period can be forced into effect “immediately” by writing the new value to the duty
and/or period registers and then writing to the counter. This forces the counter to reset and the new duty
and/or period values to be latched. In addition, because the counter is readable it is possible to know where
the count is with respect to the duty value and software can be used to make adjustments.
NOTE
When forcing a new period or duty into effect immediately, an irregular
PWM cycle can occur.
Depending on the polarity bit, the duty registers will contain the count of
either the high time or the low time.
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
404 Freescale Semiconductor
12.4.2.4 PWM Timer Counters
Each channel has a dedicated 8-bit up/down counter which runs at the rate of the selected clock source
(reference Figure 12-34 for the available clock sources and rates). The counter compares to two registers,
a duty register and a period register as shown in Figure 12-35. When the PWM counter matches the duty
register the output flip-flop changes state causing the PWM waveform to also change state. A match
between the PWM counter and the period register behaves differently depending on what output mode is
selected as shown in Figure 12-35 and described in Section 12.4.2.5, “Left Aligned Outputs,” and
Section 12.4.2.6, “Center Aligned Outputs.”
Each channel counter can be read at anytime without affecting the count or the operation of the PWM
channel.
Any value written to the counter causes the counter to reset to 0x0000, the counter direction to be set to
up, the immediate load of both duty and period registers with values from the buffers, and the output to
change according to the polarity bit. When the channel is disabled (PWMEx = 0), the counter stops. When
a channel becomes enabled (PWMEx = 1), the associated PWM counter continues from the count in the
PWMCNTx register. This allows the waveform to resume when the channel is re-enabled. When the
channel is disabled, writing 0 to the period register will cause the counter to reset on the next selected
clock.
NOTE
If the user wants to start a new “clean” PWM waveform without any
“history” from the old waveform, the user must write to channel counter
(PWMCNTx) prior to enabling the PWM channel (PWMEx = 1).
Generally, writes to the counter are done prior to enabling a channel to start from a known state. However,
writing a counter can also be done while the PWM channel is enabled (counting). The effect is similar to
writing the counter when the channel is disabled except that the new period is started immediately with the
output set according to the polarity bit.
NOTE
Writing to the counter while the channel is enabled can cause an irregular
PWM cycle to occur.
The counter is cleared at the end of the effective period (see Section 12.4.2.5, “Left Aligned Outputs,” and
Section 12.4.2.6, “Center Aligned Outputs,” for more details).
Table 12-11. PWM Timer Counter Conditions
Counter Clears (0x0000) Counter Counts Counter Stops
When PWMCNTx register
written to any value
When PWM channel is
enabled (PWMEx = 1). Counts
from last value in PWMCNTx.
When PWM channel is
disabled (PWMEx = 0)
Effective period ends
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 405
12.4.2.5 Left Aligned Outputs
The PWM timer provides the choice of two types of outputs, left aligned or center aligned outputs. They
are selected with the CAEx bits in the PWMCAE register. If the CAEx bit is cleared (CAEx = 0), the
corresponding PWM output will be left aligned.
In left aligned output mode, the 8-bit counter is configured as an up counter only. It compares to two
registers, a duty register and a period register as shown in the block diagram in Figure 12-35. When the
PWM counter matches the duty register the output flip-flop changes state causing the PWM waveform to
also change state. A match between the PWM counter and the period register resets the counter and the
output flip-flop as shown in Figure 12-35 as well as performing a load from the double buffer period and
duty register to the associated registers as described in Section 12.4.2.3, “PWM Period and Duty.” The
counter counts from 0 to the value in the period register – 1.
NOTE
Changing the PWM output mode from left aligned output to center aligned
output (or vice versa) while channels are operating can cause irregularities
in the PWM output. It is recommended to program the output mode before
enabling the PWM channel.
Figure 12-36. PWM Left Aligned Output Waveform
To calculate the output frequency in left aligned output mode for a particular channel, take the selected
clock source frequency for the channel (A, B, SA, or SB) and divide it by the value in the period register
for that channel.
• PWMx frequency = clock (A, B, SA, or SB) / PWMPERx
• PWMx duty cycle (high time as a% of period):
— Polarity = 0 (PPOLx = 0)
Duty cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
— Polarity = 1 (PPOLx = 1)
Duty cycle = [PWMDTYx / PWMPERx] * 100%
As an example of a left aligned output, consider the following case:
Clock source = bus clock, where bus clock = 10 MHz (100 ns period)
PPOLx = 0
PWMPERx = 4
PWMDTYx = 1
PWMx frequency = 10 MHz/4 = 2.5 MHz
PWMx period = 400 ns
PWMx duty cycle = 3/4 *100% = 75%
PWMDTYx
Period = PWMPERx
PPOLx = 0
PPOLx = 1
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
406 Freescale Semiconductor
Shown below is the output waveform generated.
Figure 12-37. PWM Left Aligned Output Example Waveform
12.4.2.6 Center Aligned Outputs
For center aligned output mode selection, set the CAEx bit (CAEx = 1) in the PWMCAE register and the
corresponding PWM output will be center aligned.
The 8-bit counter operates as an up/down counter in this mode and is set to up whenever the counter is
equal to 0x0000. The counter compares to two registers, a duty register and a period register as shown in
the block diagram in Figure 12-35. When the PWM counter matches the duty register the output flip-flop
changes state causing the PWM waveform to also change state. A match between the PWM counter and
the period register changes the counter direction from an up-count to a down-count. When the PWM
counter decrements and matches the duty register again, the output flip-flop changes state causing the
PWM output to also change state. When the PWM counter decrements and reaches 0, the counter direction
changes from a down-count back to an up-count and a load from the double buffer period and duty
registers to the associated registers is performed as described in Section 12.4.2.3, “PWM Period and
Duty.” The counter counts from 0 up to the value in the period register and then back down to 0. Thus the
effective period is PWMPERx*2.
NOTE
Changing the PWM output mode from left aligned output to center aligned
output (or vice versa) while channels are operating can cause irregularities
in the PWM output. It is recommended to program the output mode before
enabling the PWM channel.
Figure 12-38. PWM Center Aligned Output Waveform
E = 100 ns
DUTY CYCLE = 75%
PERIOD = 400 ns
PPOLx = 0
PPOLx = 1
PWMDTYx PWMDTYx
Period = PWMPERx*2
PWMPERx PWMPERx
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 407
To calculate the output frequency in center aligned output mode for a particular channel, take the selected
clock source frequency for the channel (A, B, SA, or SB) and divide it by twice the value in the period
register for that channel.
• PWMx frequency = clock (A, B, SA, or SB) / (2*PWMPERx)
• PWMx duty cycle (high time as a% of period):
— Polarity = 0 (PPOLx = 0)
Duty cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
— Polarity = 1 (PPOLx = 1)
Duty cycle = [PWMDTYx / PWMPERx] * 100%
As an example of a center aligned output, consider the following case:
Clock source = bus clock, where bus clock = 10 MHz (100 ns period)
PPOLx = 0
PWMPERx = 4
PWMDTYx = 1
PWMx frequency = 10 MHz/8 = 1.25 MHz
PWMx period = 800 ns
PWMx duty cycle = 3/4 *100% = 75%
Shown below is the output waveform generated.
Figure 12-39. PWM Center Aligned Output Example Waveform
12.4.2.7 PWM 16-Bit Functions
The PWM timer also has the option of generating 6-channels of 8-bits or 3-channels of 16-bits for greater
PWM resolution}. This 16-bit channel option is achieved through the concatenation of two 8-bit channels.
The PWMCTL register contains three control bits, each of which is used to concatenate a pair of PWM
channels into one 16-bit channel. Channels 4 and 5 are concatenated with the CON45 bit, channels 2 and 3
are concatenated with the CON23 bit, and channels 0 and 1 are concatenated with the CON01 bit.
NOTE
Change these bits only when both corresponding channels are disabled.
When channels 4 and 5 are concatenated, channel 4 registers become the high-order bytes of the double
byte channel as shown in Figure 12-40. Similarly, when channels 2 and 3 are concatenated, channel 2
registers become the high-order bytes of the double byte channel. When channels 0 and 1 are concatenated,
channel 0 registers become the high-order bytes of the double byte channel.
E = 100 ns E = 100 ns
PERIOD = 800 ns
DUTY CYCLE = 75%
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
408 Freescale Semiconductor
Figure 12-40. PWM 16-Bit Mode
When using the 16-bit concatenated mode, the clock source is determined by the low-order 8-bit channel
clock select control bits. That is channel 5 when channels 4 and 5 are concatenated, channel 3 when
channels 2 and 3 are concatenated, and channel 1 when channels 0 and 1 are concatenated. The resulting
PWM is output to the pins of the corresponding low-order 8-bit channel as also shown in Figure 12-40.
The polarity of the resulting PWM output is controlled by the PPOLx bit of the corresponding low-order
8-bit channel as well.
After concatenated mode is enabled (CONxx bits set in PWMCTL register), enabling/disabling the
corresponding 16-bit PWM channel is controlled by the low-order PWMEx bit. In this case, the high-order
bytes PWMEx bits have no effect and their corresponding PWM output is disabled.
In concatenated mode, writes to the 16-bit counter by using a 16-bit access or writes to either the low or
high-order byte of the counter will reset the 16-bit counter. Reads of the 16-bit counter must be made by
16-bit access to maintain data coherency.
Either left aligned or center aligned output mode can be used in concatenated mode and is controlled by
the low-order CAEx bit. The high-order CAEx bit has no effect.
PWMCNT4 PWCNT5
PWM5
Clock Source 5
High Low
Period/Duty Compare
PWMCNT2 PWCNT3
PWM3
Clock Source 3
High Low
Period/Duty Compare
PWMCNT0 PWCNT1
PWM1
Clock Source 1
High Low
Period/Duty Compare
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 409
Table 12-12 is used to summarize which channels are used to set the various control bits when in 16-bit
mode.
12.4.2.8 PWM Boundary Cases
Table 12-13 summarizes the boundary conditions for the PWM regardless of the output mode (left aligned
or center aligned) and 8-bit (normal) or 16-bit (concatenation):
12.5 Resets
The reset state of each individual bit is listed within the register description section (see Section 12.3,
“Memory Map and Register Definition,” which details the registers and their bit-fields. All special
functions or modes which are initialized during or just following reset are described within this section.
• The 8-bit up/down counter is configured as an up counter out of reset.
• All the channels are disabled and all the counters don’t count.
12.6 Interrupts
The PWM8B6CV1 module has only one interrupt which is generated at the time of emer gency shutdown,
if the corresponding enable bit (PWMIE) is set. This bit is the enable for the interrupt. The interrupt flag
PWMIF is set whenever the input level of the PWM5 channel changes while PWM5ENA=1 or when
PWMENA is being asserted while the level at PWM5 is active.
A description of the registers involved and affected due to this interrupt is explained in Section 12.3.2.15,
“PWM Shutdown Register (PWMSDN).”
Table 12-12. 16-bit Concatenation Mode Summary
CONxx PWMEx PPOLx PCLKx CAEx PWMx Output
CON45 PWME5 PPOL5 PCLK5 CAE5 PWM5
CON23 PWME3 PPOL3 PCLK3 CAE3 PWM3
CON01 PWME1 PPOL1 PCLK1 CAE1 PWM1
Table 12-13. PWM Boundary Cases
PWMDTYx PWMPERx PPOLx PWMx Output
0x0000
(indicates no duty)
>0x0000 1 Always Low
0x0000
(indicates no duty)
>0x0000 0 Always High
XX 0x00001
(indicates no period)
1Counter = 0x0000 and does not count.
1 Always High
XX 0x00001
(indicates no period)
0 Always Low
>= PWMPERx XX 1 Always High
>= PWMPERx XX 0 Always Low
Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
MC9S12E256 Data Sheet, Rev. 1.08
410 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 411
Chapter 13
Timer Module (TIM16B4CV1)
13.1 Introduction
The basic timer consists of a 16-bit, software-programmable counter driven by a seven-stage
programmable prescaler.
This timer can be used for many purposes, including input waveform measurements while simultaneously
generating an output waveform. Pulse widths can vary from microseconds to many seconds.
This timer contains 4 complete input capture/output compare channels IOC[7:4] and one pulse
accumulator. The input capture function is used to detect a selected transition edge and record the time.
The output compare function is used for generating output signals or for timer software delays. The 16-bit
pulse accumulator is used to operate as a simple event counter or a gated time accumulator. The pulse
accumulator shares timer channel 7 when in event mode.
A full access for the counter registers or the input capture/output compare registers should take place in
one clock cycle. Accessing high byte and low byte separately for all of these registers may not yield the
same result as accessing them in one word.
13.1.1 Features
The TIM16B4CV1 includes these distinctive features:
• Four input capture/output compare channels
• Clock prescaling
• 16-bit counter
• 16-bit pulse accumulator
13.1.2 Modes of Operation
Stop: Timer is off because clocks are stopped.
Freeze: Timer counter keep on running, unless TSFRZ in TSCR (0x0006) is set to 1.
Wait: Counters keep on running, unless TSWAI in TSCR (0x0006) is set to 1.
Normal: Timer counter keep on running, unless TEN in TSCR (0x0006) is cleared to 0.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
412 Freescale Semiconductor
13.1.3 Block Diagrams
Figure 13-1. TIM16B4CV1 Block Diagram
Prescaler
16-bit Counter
16-bit
Pulse accumulator
IOC5
IOC4
IOC6
IOC7
PA input
interrupt
PA overflow
interrupt
Timer overflow
interrupt
Timer channel 4
interrupt
Timer channel 7
interrupt
Registers
Bus clock
Input capture
Output compare
Input capture
Output compare
Input capture
Output compare
Input capture
Output compare
Channel 4
Channel 5
Channel 6
Channel 7
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 413
Figure 13-2. 16-Bit Pulse Accumulator Block Diagram
Figure 13-3. Interrupt Flag Setting
Figure 13-4. Channel 7 Output Compare/Pulse Accumulator Logic
NOTE
For more information see the respective functional descriptions in
Section 13.4, “Functional Description,” of this document.
EDGE DETECTOR
INTERMODULE BUS
PT7
M CLOCK
DIVIDE BY 64
CLOCK SELECT
CLK0
CLK1 4:1 MUX
TIMCLK
PACL K
PACLK / 256
PACLK / 65536
PRESCALED CLOCK
(PCLK)
(TIMER CLOCK)
INTERRUPT
MUX
(PAMOD)
PACNT
PTn
EDGE
16-BIT MAIN TIMER
TCn INPUT SET CnF INTERRUPT
DETECTOR
CAPTURE REGISTER
PULSE
ACCUMULATOR PAD
OM7
OL7
OC7M7
CHANNEL 7 OUTPUT COMPARE
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
414 Freescale Semiconductor
13.2 External Signal Description
The TIM16B4CV1 module has a total of four external pins.
13.2.1 IOC7 — Input Capture and Output Compare Channel 7 Pin
This pin serves as input capture or output compare for channel 7. This can also be configured as pulse
accumulator input.
13.2.2 IOC6 — Input Capture and Output Compare Channel 6 Pin
This pin serves as input capture or output compare for channel 6.
13.2.3 IOC5 — Input Capture and Output Compare Channel 5 Pin
This pin serves as input capture or output compare for channel 5.
13.2.4 IOC4 — Input Capture and Output Compare Channel 4 Pin
This pin serves as input capture or output compare for channel 4.
NOTE
For the description of interrupts see Section 13.6, “Interrupts”.
13.3 Memory Map and Register Definition
This section provides a detailed description of all memory and registers.
13.3.1 Module Memory Map
The memory map for the TIM16B4CV1 module is given below in Table 13-1. The address listed for each
register is the address offset. The total address for each register is the sum of the base address for the
TIM16B4CV1 module and the address offset for each register.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 415
Table 13-1. TIM16B4CV1 Memory Map
Address Offset Use Access
0x0000 Timer Input Capture/Output Compare Select (TIOS) R/W
0x0001 Timer Compare Force Register (CFORC) R/W1
1 Always read 0x0000.
0x0002 Output Compare 7 Mask Register (OC7M) R/W
0x0003 Output Compare 7 Data Register (OC7D) R/W
0x0004 Timer Count Register (TCNT(hi)) R/W2
2Only writable in special modes (test_mode = 1).
0x0005 Timer Count Register (TCNT(lo)) R/W2
0x0006 Timer System Control Register1 (TSCR1) R/W
0x0007 Timer Toggle Overflow Register (TTOV) R/W
0x0008 Timer Control Register1 (TCTL1) R/W
0x0009 Reserved — 3
3Write has no effect; return 0 on read
0x000A Timer Control Register3 (TCTL3) R/W
0x000B Reserved — 3
0x000C Timer Interrupt Enable Register (TIE) R/W
0x000D Timer System Control Register2 (TSCR2) R/W
0x000E Main Timer Interrupt Flag1 (TFLG1) R/W
0x000F Main Timer Interrupt Flag2 (TFLG2) R/W
0x0010 - 0x0017 Reserved — 3
0x0018 Timer Input Capture/Output Compare Register4 (TC4(hi)) R/W4
4Write to these registers have no meaning or effect during input capture.
0x0019 Timer Input Capture/Output Compare Register 4 (TC4(lo)) R/W4
0x001A Timer Input Capture/Output Compare Register 5 (TC5(hi)) R/W4
0x001B Timer Input Capture/Output Compare Register 5 (TC5(lo)) R/W4
0x001C Timer Input Capture/Output Compare Register 6 (TC6(hi)) R/W4
0x001D Timer Input Capture/Output Compare Register 6 (TC6(lo)) R/W4
0x001E Timer Input Capture/Output Compare Register 7 (TC7(hi)) R/W4
0x001F Timer Input Capture/Output Compare Register 7 (TC7(lo)) R/W4
0x0020 16-Bit Pulse Accumulator Control Register (PACTL) R/W
0x0021 Pulse Accumulator Flag Register (PAFLG) R/W
0x0022 Pulse Accumulator Count Register (PACNT(hi)) R/W
0x0023 Pulse Accumulator Count Register (PACNT(lo)) R/W
0x0024 – 0x002C Reserved — 3
0x002D Timer Test Register (TIMTST) R/W2
0x002E – 0x002F Reserved — 3
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
416 Freescale Semiconductor
13.3.2 Register Descriptions
This section consists of register descriptions in address order . Each description includes a standard register
diagram with an associated figure number. Details of register bit and field function follow the register
diagrams, in bit order.
Register
Name Bit 7654321Bit 0
0x0000
TIOS
RIOS7IOS6IOS5IOS4IOS3IOS2IOS1IOS0
W
0x0001
CFORC
R00000000
W FOC7 FOC6 FOC5 FOC4 FOC3 FOC2 FOC1 FOC0
0x0002
OC7M
ROC7M7OC7M6OC7M5OC7M4OC7M3OC7M2OC7M1OC7M0
W
0x0003
OC7D
ROC7D7 OC7D6 OC7D5 OC7D4 OC7D3 OC7D2 OC7D1 OC7D0
W
0x0004
TCNTH
RTCNT15 TCNT14 TCNT13 TCNT12 TCNT11 TCNT10 TCNT9 TCNT8
W
0x0005
TCNTL
RTCNT7 TCNT6 TCNT5 TCNT4 TCNT3 TCNT2 TCNT1 TCNT0
W
0x0006
TSCR2
RTEN TSWAI TSFRZ TFFCA 0000
W
0x0007
TTOV
RTOV7 TOV6 TOV5 TOV4 TOV3 TOV2 TOV1 TOV0
W
0x0008
TCTL1
ROM7 OL7 OM6 OL6 OM5 OL5 OM4 OL4
W
0x0009
Reserved
R00000000
W
0x000A
TCTL3
REDG7B EDG7A EDG6B EDG6A EDG5B EDG5A EDG4B EDG4A
W
0x000B
Reserved
R00000000
W
0x000C
TIE
RC7I C6I C5I C4I C3I C2I C1I C0I
W
= Unimplemented or Reserved
Figure 13-5. TIM16B4CV1 Register Summary
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 417
0x000D
TSCR2
RTOI 000
TCRE PR2 PR1 PR0
W
0x000E
TFLG1
RC7F C6F C5F C4F C3F C2F C1F C0F
W
0x000F
TFLG2
RTOF 0000000
W
0x0010–0x0017
Reserved
R00000000
W
0x0018–0x001F
TCxH–TCxL
RBit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
RBit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
W
0x0020
PAC T L
R0 PAEN PAMOD PEDGE CLK1 CLK0 PAOVI PAI
W
0x0021
PAF LG
R000000
PAOV F PA I F
W
0x0022
PACNTH
RPACNT15 PACNT14 PACNT13 PACNT12 PACNT11 PACNT10 PACNT9 PACNT8
W
0x0023
PACNTL
RPACNT7 PACNT6 PACNT5 PACNT4 PACNT3 PACNT2 PACNT1 PACNT0
W
0x0024–0x002F
Reserved
R
W
Register
Name Bit 7654321Bit 0
= Unimplemented or Reserved
Figure 13-5. TIM16B4CV1 Register Summary (continued)
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
418 Freescale Semiconductor
13.3.2.1 Timer Input Capture/Output Compare Select (TIOS)
Read: Anytime
Write: Anytime
13.3.2.2 Timer Compare Force Register (CFORC)
Read: Anytime but will always return 0x0000 (1 state is transient)
Write: Anytime
76543210
R
IOS7 IOS6 IOS5 IOS4
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-6. Timer Input Capture/Output Compare Select (TIOS)
Table 13-2. TIOS Field Descriptions
Field Description
7:4
IOS[7:4]
Input Capture or Output Compare Channel Configuration
0 The corresponding channel acts as an input capture.
1 The corresponding channel acts as an output compare.
76543210
R00000000
W FOC7 FOC6 FOC5 FOC4
Reset00000000
= Unimplemented or Reserved
Figure 13-7. Timer Compare Force Register (CFORC)
Table 13-3. CFORC Field Descriptions
Field Description
7:4
FOC[7:4]
Force Output Compare Action for Channel 7:4 — A write to this register with the corresponding data bit(s) set
causes the action which is programmed for output compare “x” to occur immediately. The action taken is the
same as if a successful comparison had just taken place with the TCx register except the interrupt flag does not
get set.
Note: A successful channel 7 output compare overrides any channel 6:4 compares. If forced output compare on
any channel occurs at the same time as the successful output compare then forced output compare action
will take precedence and interrupt flag won’t get set.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 419
13.3.2.3 Output Compare 7 Mask Register (OC7M)
Read: Anytime
Write: Anytime
13.3.2.4 Output Compare 7 Data Register (OC7D)
Read: Anytime
Write: Anytime
76543210
R
OC7M7 OC7M6 OC7M5 OC7M4
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-8. Output Compare 7 Mask Register (OC7M)
Table 13-4. OC7M Field Descriptions
Field Description
7:4
OC7M[7:4]
Output Compare 7 Mask — Setting the OC7Mx (x ranges from 4 to 6) will set the corresponding port to be an
output port when the corresponding TIOSx (x ranges from 4 to 6) bit is set to be an output compare.
Note: A successful channel 7 output compare overrides any channel 6:4 compares. For each OC7M bit that is
set, the output compare action reflects the corresponding OC7D bit.
76543210
R
OC7D7 OC7D6 OC7D5 OC7D4
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-9. Output Compare 7 Data Register (OC7D)
Table 13-5. OC7D Field Descriptions
Field Description
7:4
OC7D[7:4]
Output Compare 7 Data — A channel 7 output compare can cause bits in the output compare 7 data register
to transfer to the timer port data register depending on the output compare 7 mask register.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
420 Freescale Semiconductor
13.3.2.5 Timer Count Register (TCNT)
The 16-bit main timer is an up counter.
A full access for the counter register should take place in one clock cycle. A separate read/write for high
byte and low byte will give a different result than accessing them as a word.
Read: Anytime
Write: Has no meaning or effect in the normal mode; only writable in special modes (test_mode = 1).
The period of the first count after a write to the TCNT registers may be a different size because the write
is not synchronized with the prescaler clock.
15 14 13 12 11 10 9 9
R
TCNT15 TCNT14 TCNT13 TCNT12 TCNT11 TCNT10 TCNT9 TCNT8
W
Reset00000000
Figure 13-10. Timer Count Register High (TCNTH)
76543210
R
TCNT7 TCNT6 TCNT5 TCNT4 TCNT3 TCNT2 TCNT1 TCNT0
W
Reset00000000
Figure 13-11. Timer Count Register Low (TCNTL)
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 421
13.3.2.6 Timer System Control Register 1 (TSCR1)
Read: Anytime
Write: Anytime
76543210
R
TEN TSWAI TSFRZ TFFCA
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-12. Timer System Control Register 1 (TSCR2)
Table 13-6. TSCR1 Field Descriptions
Field Description
7
TEN
Timer Enable
0 Disables the main timer, including the counter. Can be used for reducing power consumption.
1 Allows the timer to function normally.
If for any reason the timer is not active, there is no ÷64 clock for the pulse accumulator because the ÷64 is
generated by the timer prescaler.
6
TSWAI
Timer Module Stops While in Wait
0 Allows the timer module to continue running during wait.
1 Disables the timer module when the MCU is in the wait mode. Timer interrupts cannot be used to get the MCU
out of wait.
TSWAI also affects pulse accumulator.
5
TSFRZ
Timer Stops While in Freeze Mode
0 Allows the timer counter to continue running while in freeze mode.
1 Disables the timer counter whenever the MCU is in freeze mode. This is useful for emulation.
TSFRZ does not stop the pulse accumulator.
4
TFFCA
Timer Fast Flag Clear All
0 Allows the timer flag clearing to function normally.
1 For TFLG1(0x000E), a read from an input capture or a write to the output compare channel (0x0010–0x001F)
causes the corresponding channel flag, CnF, to be cleared. For TFLG2 (0x000F), any access to the TCNT
register (0x0004, 0x0005) clears the TOF flag. Any access to the PACNT registers (0x0022, 0x0023) clears
the PAOVF and PAIF flags in the PAFLG register (0x0021). This has the advantage of eliminating software
overhead in a separate clear sequence. Extra care is required to avoid accidental flag clearing due to
unintended accesses.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
422 Freescale Semiconductor
13.3.2.7 Timer Toggle On Overflow Register 1 (TTOV)
Read: Anytime
Write: Anytime
13.3.2.8 Timer Control Register 1 (TCTL1)
Read: Anytime
Write: Anytime
76543210
R
TOV7 TOV6 TOV5 TOV4
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-13. Timer Toggle On Overflow Register 1 (TTOV)
Table 13-7. TTOV Field Descriptions
Field Description
7:4
TOV[7:4]
Toggle On Overflow Bits — TOVx toggles output compare pin on overflow. This feature only takes effect when
in output compare mode. When set, it takes precedence over forced output compare but not channel 7 override
events.
0 Toggle output compare pin on overflow feature disabled.
1 Toggle output compare pin on overflow feature enabled.
76543210
R
OM7 OL7 OM6 OL6 OM5 OL5 OM4 OL4
W
Reset00000000
Figure 13-14. Timer Control Register 1 (TCTL1)
Table 13-8. TCTL1/TCTL2 Field Descriptions
Field Description
7:4
OMx
Output Mode — These four pairs of control bits are encoded to specify the output action to be taken as a result
of a successful OCx compare. When either OMx or OLx is 1, the pin associated with OCx becomes an output
tied to OCx.
Note: To enable output action by OMx bits on timer port, the corresponding bit in OC7M should be cleared.
7:4
OLx
Output Level — These four pairs of control bits are encoded to specify the output action to be taken as a result
of a successful OCx compare. When either OMx or OLx is 1, the pin associated with OCx becomes an output
tied to OCx.
Note: To enable output action by OLx bits on timer port, the corresponding bit in OC7M should be cleared.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 423
To operate the 16-bit pulse accumulator independently of input capture or output compare 7 and 4
respectively the user must set the corresponding bits IOSx = 1, OMx = 0 and OLx = 0. OC7M7 in the
OC7M register must also be cleared.
13.3.2.9 Timer Control Register 3 (TCTL3)
Read: Anytime
Write: Anytime.
Table 13-9. Compare Result Output Action
OMx OLx Action
0 0 Timer disconnected from output pin logic
0 1 Toggle OCx output line
1 0 Clear OCx output line to zero
1 1 Set OCx output line to one
76543210
R
EDG7B EDG7A EDG6B EDG6A EDG5B EDG5A EDG4B EDG4A
W
Reset00000000
Figure 13-15. Timer Control Register 3 (TCTL3)
Table 13-10. TCTL3/TCTL4 Field Descriptions
Field Description
7:0
EDGnB
EDGnA
Input Capture Edge Control — These eight pairs of control bits configure the input capture edge detector
circuits.
Table 13-11. Edge Detector Circuit Configuration
EDGnB EDGnA Configuration
0 0 Capture disabled
0 1 Capture on rising edges only
1 0 Capture on falling edges only
1 1 Capture on any edge (rising or falling)
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
424 Freescale Semiconductor
13.3.2.10 Timer Interrupt Enable Register (TIE)
Read: Anytime
Write: Anytime.
13.3.2.11 Timer System Control Register 2 (TSCR2)
Read: Anytime
Write: Anytime.
76543210
R
C7I C6I C5I C4I
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-16. Timer Interrupt Enable Register (TIE)
Table 13-12. TIE Field Descriptions
Field Description
7:4
C7I:C0I
Input Capture/Output Compare “x” Interrupt Enable — The bits in TIE correspond bit-for-bit with the bits in
the TFLG1 status register. If cleared, the corresponding flag is disabled from causing a hardware interrupt. If set,
the corresponding flag is enabled to cause a interrupt.
76543210
R
TOI
000
TCRE PR2 PR1 PR0
W
Reset00000000
= Unimplemented or Reserved
Figure 13-17. Timer System Control Register 2 (TSCR2)
Table 13-13. TSCR2 Field Descriptions
Field Description
7
TOI
Timer Overflow Interrupt Enable
0 Interrupt inhibited.
1 Hardware interrupt requested when TOF flag set.
3
TCRE
Timer Counter Reset Enable — This bit allows the timer counter to be reset by a successful output compare 7
event. This mode of operation is similar to an up-counting modulus counter.
0 Counter reset inhibited and counter free runs.
1 Counter reset by a successful output compare 7.
If TC7 = 0x0000 and TCRE = 1, TCNT will stay at 0x0000 continuously. If TC7 = 0xFFFF and TCRE = 1, TOF
will never be set when TCNT is reset from 0xFFFF to 0x0000.
2
PR[2:0]
Timer Prescaler Select — These three bits select the frequency of the timer prescaler clock derived from the
Bus Clock as shown in Table 13-14.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 425
NOTE
The newly selected prescale factor will not take effect until the next
synchronized edge where all prescale counter stages equal zero.
13.3.2.12 Main Timer Interrupt Flag 1 (TFLG1)
Read: Anytime
W rite: Used in the clearing mechanism (set bits cause corresponding bits to be cleared). Writing a zero will
not affect current status of the bit.
Table 13-14. Timer Clock Selection
PR2 PR1 PR0 Timer Clock
0 0 0 Bus Clock / 1
0 0 1 Bus Clock / 2
0 1 0 Bus Clock / 4
0 1 1 Bus Clock / 8
1 0 0 Bus Clock / 16
1 0 1 Bus Clock / 32
1 1 0 Bus Clock / 64
1 1 1 Bus Clock / 128
76543210
R
C7F C6F C5F C4F
0000
W
Reset00000000
= Unimplemented or Reserved
Figure 13-18. Main Timer Interrupt Flag 1 (TFLG1)
Table 13-15. TFLG1 Field Descriptions
Field Description
7:4
C[7:4]F
Input Capture/Output Compare Channel “x” Flag — These flags are set when an input capture or output
compare event occurs. Clear a channel flag by writing one to it.
When TFFCA bit in TSCR register is set, a read from an input capture or a write into an output compare channel
(0x0010–0x001F) will cause the corresponding channel flag CxF to be cleared.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
426 Freescale Semiconductor
13.3.2.13 Main Timer Interrupt Flag 2 (TFLG2)
TFLG2 indicates when interrupt conditions have occurred. To clear a bit in the flag register, write the bit
to one.
Read: Anytime
Write: Used in clearing mechanism (set bits cause corresponding bits to be cleared).
Any access to TCNT will clear TFLG2 register if the TFFCA bit in TSCR register is set.
76543210
R
TOF
0000000
W
Reset00000000
Unimplemented or Reserved
Figure 13-19. Main Timer Interrupt Flag 2 (TFLG2)
Table 13-16. TFLG2 Field Descriptions
Field Description
7
TOF
Timer Overflow Flag — Set when 16-bit free-running timer overflows from 0xFFFF to 0x0000. This bit is cleared
automatically by a write to the TFLG2 register with bit 7 set. (See also TCRE control bit explanation.)
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 427
13.3.2.14 Timer Input Capture/Output Compare Registers High and Low 4–7
(TCxH and TCxL)
Depending on the TIOS bit for the corresponding channel, these registers are used to latch the value of the
free-running counter when a defined transition is sensed by the corresponding input capture edge detector
or to trigger an output action for output compare.
Read: Anytime
Write: Anytime for output compare function.Writes to these registers have no meaning or effect during
input capture. All timer input capture/output compare registers are reset to 0x0000.
NOTE
Read/W rite access in byte mode for high byte should takes place before low
byte otherwise it will give a different result.
15 14 11 12 11 10 9 0
R
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
Reset00000000
Figure 13-20. Timer Input Capture/Output Compare Register x High (TCxH)
76543210
R
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
W
Reset00000000
Figure 13-21. Timer Input Capture/Output Compare Register x Low (TCxL)
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
428 Freescale Semiconductor
13.3.2.15 16-Bit Pulse Accumulator Control Register (PACTL)
When PAEN is set, the PACT is enabled.The PACT shares the input pin with IOC7.
Read: Any time
Write: Any time
76543210
R0
PAEN PAMOD PEDGE CLK1 CLK0 PAOVI PAI
W
Reset00000000
Unimplemented or Reserved
Figure 13-22. 16-Bit Pulse Accumulator Control Register (PACTL)
Table 13-17. PACTL Field Descriptions
Field Description
6
PAEN
Pulse Accumulator System Enable — PAEN is independent from TEN. With timer disabled, the pulse
accumulator can function unless pulse accumulator is disabled.
0 16-Bit Pulse Accumulator system disabled.
1 Pulse Accumulator system enabled.
5
PAMOD
Pulse Accumulator Mode — This bit is active only when the Pulse Accumulator is enabled (PAEN = 1). See
Ta b le 1 3 - 1 8 .
0 Event counter mode.
1 Gated time accumulation mode.
4
PEDGE
Pulse Accumulator Edge Control — This bit is active only when the Pulse Accumulator is enabled (PAEN = 1).
For PAMOD bit = 0 (event counter mode). See Table 13-18.
0 Falling edges on IOC7 pin cause the count to be incremented.
1 Rising edges on IOC7 pin cause the count to be incremented.
For PAMOD bit = 1 (gated time accumulation mode).
0 IOC7 input pin high enables M (bus clock) divided by 64 clock to Pulse Accumulator and the trailing falling
edge on IOC7 sets the PAIF flag.
1 IOC7 input pin low enables M (bus clock) divided by 64 clock to Pulse Accumulator and the trailing rising edge
on IOC7 sets the PAIF flag.
3:2
CLK[1:0]
Clock Select Bits — Refer to Table 13-19.
1
PAOV I
Pulse Accumulator Overflow Interrupt Enable
0 Interrupt inhibited.
1 Interrupt requested if PAOVF is set.
0
PAI
Pulse Accumulator Input Interrupt Enable
0 Interrupt inhibited.
1 Interrupt requested if PAIF is set.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 429
NOTE
If the timer is not active (TEN = 0 in TSCR), there is no divide-by-64
because the ÷64 clock is generated by the timer prescaler.
For the description of PACLK please refer Figure 13-22.
If the pulse accumulator is disabled (PAEN = 0), the prescaler clock from the timer is always used as an
input clock to the timer counter. The change from one selected clock to the other happens immediately
after these bits are written.
Table 13-18. Pin Action
PAMOD PEDGE Pin Action
0 0 Falling edge
0 1 Rising edge
1 0 Div. by 64 clock enabled with pin high level
1 1 Div. by 64 clock enabled with pin low level
Table 13-19. Timer Clock Selection
CLK1 CLK0 Timer Clock
0 0 Use timer prescaler clock as timer counter clock
0 1 Use PACLK as input to timer counter clock
1 0 Use PACLK/256 as timer counter clock frequency
1 1 Use PACLK/65536 as timer counter clock frequency
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
430 Freescale Semiconductor
13.3.2.16 Pulse Accumulator Flag Register (PAFLG)
Read: Anytime
Write: Anytime
When the TFFCA bit in the TSCR register is set, any access to the PACNT register will clear all the flags
in the PAFLG register.
76543210
R000000
PAOV F PA I F
W
Reset00000000
Unimplemented or Reserved
Figure 13-23. Pulse Accumulator Flag Register (PAFLG)
Table 13-20. PAFLG Field Descriptions
Field Description
1
PAOV F
Pulse Accumulator Overflow Flag — Set when the 16-bit pulse accumulator overflows from 0xFFFF to 0x0000.
This bit is cleared automatically by a write to the PAFLG register with bit 1 set.
0
PAIF
Pulse Accumulator Input edge Flag — Set when the selected edge is detected at the IOC7 input pin.In event
mode the event edge triggers PAIF and in gated time accumulation mode the trailing edge of the gate signal at
the IOC7 input pin triggers PAIF.
This bit is cleared by a write to the PAFLG register with bit 0 set.
Any access to the PACNT register will clear all the flags in this register when TFFCA bit in register TSCR(0x0006)
is set.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 431
13.3.2.17 Pulse Accumulators Count Registers (PACNT)
Read: Anytime
Write: Anytime
These registers contain the number of active input edges on its input pin since the last reset.
When PACNT overflows from 0xFFFF to 0x0000, the Interrupt flag PAOVF in PAFLG (0x0021) is set.
Full count register access should take place in one clock cycle. A separate read/write for high byte and low
byte will give a different result than accessing them as a word.
NOTE
Reading the pulse accumulator counter registers immediately after an
active edge on the pulse accumulator input pin may miss the last count
because the input has to be synchronized with the bus clock first.
15 14 13 12 11 10 9 0
R
PACNT15 PACNT14 PACNT13 PACNT12 PACNT11 PACNT10 PACNT9 PACNT8
W
Reset00000000
Figure 13-24. Pulse Accumulator Count Register High (PACNTH)
76543210
R
PACNT7 PACNT6 PACNT5 PACNT4 PACNT3 PACNT2 PACNT1 PACNT0
W
Reset00000000
Figure 13-25. Pulse Accumulator Count Register Low (PACNTL)
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
432 Freescale Semiconductor
13.4 Functional Description
This section provides a complete functional description of the timer TIM16B4CV1 block. Please refer to
the detailed timer block diagram in Figure 13-26 as necessary.
Figure 13-26. Detailed Timer Block Diagram
PRESCALER
CHANNEL 4
IOC4 PIN
16-BIT COUNTER
LOGIC
PR[2:1:0]
DIVIDE-BY-64
TC4
EDGE
DETECT
PACNT(hi):PACNT(lo)
PAOVF PEDGE
PAOVI
PAMOD
PAE
16-BIT COMPARATOR
TCNT(hi):TCNT(lo)
16-BIT COUNTER
INTERRUPT
LOGIC
TOF
TOI
C4F
EDGE
DETECT
CxF
CHANNEL7
TC7
16-BIT COMPARATOR C7F
IOC7 PIN
LOGIC
EDGE
DETECT
OM:OL4
TOV4
OM:OL7
TOV7
EDG7A
EDG7B
EDG4B
TCRE
PAIF
CLEAR COUNTER
PAIF
PAI
INTERRUPT
LOGIC
CxI
INTERRUPT
REQUEST
PAOVF
CH. 7 COMPARE
CH.7 CAPTURE
MUX
CLK[1:0]
PACLK
PACLK/256
PACLK/65536
IOC4 PIN
IOC7 PIN
PACLK
PACLK/256
PACLK/65536
TE
CH. 4 COMPARE
CH. 4 CAPTURE
PA INPUT
EDG4A
CHANNEL 7 OUTPUT
COMPARE
IOC4
IOC7
BUS CLOCK
BUS CLOCK
PAOVF
PAOVI
TOF
C4F
C7F
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 433
13.4.1 Prescaler
The prescaler divides the bus clock by 1,2,4,8,16,32,64 or 128. The prescaler select bits, PR[2:0], select
the prescaler divisor. PR[2:0] are in timer system control register 2 (TSCR2).
13.4.2 Input Capture
Clearing the I/O (input/output) select bit, IOSx, configures channel x as an input capture channel. The
input capture function captures the time at which an external event occurs. When an active edge occurs on
the pin of an input capture channel, the timer transfers the value in the timer counter into the timer channel
registers, TCx.
The minimum pulse width for the input capture input is greater than two bus clocks.
An input capture on channel x sets the CxF flag. The CxI bit enables the CxF flag to generate interrupt
requests.
13.4.3 Output Compare
Setting the I/O select bit, IOSx, configures channel x as an output compare channel. The output compare
function can generate a periodic pulse with a programmable polarity, duration, and frequency. When the
timer counter reaches the value in the channel registers of an output compare channel, the timer can set,
clear , or toggle the channel pin. An output compare on channel x sets the CxF flag. The CxI bit enables the
CxF flag to generate interrupt requests.
The output mode and level bits, OMx and OLx, select set, clear, toggle on output compare. Clearing both
OMx and OLx disconnects the pin from the output logic.
Setting a force output compare bit, FOCx, causes an output compare on channel x. A forced output
compare does not set the channel flag.
A successful output compare on channel 7 overrides output compares on all other output compare
channels. The output compare 7 mask register masks the bits in the output compare 7 data register. The
timer counter reset enable bit, TCRE, enables channel 7 output compares to reset the timer counter. A
channel 7 output compare can reset the timer counter even if the IOC7 pin is being used as the pulse
accumulator input.
Writing to the timer port bit of an output compare pin does not affect the pin state. The value written is
stored in an internal latch. When the pin becomes available for general-purpose output, the last value
written to the bit appears at the pin.
13.4.4 Pulse Accumulator
The pulse accumulator (PACNT) is a 16-bit counter that can operate in two modes:
Event counter mode — Counting edges of selected polarity on the pulse accumulator input pin, PAI.
Gated time accumulation mode — Counting pulses from a divide-by-64 clock. The PAMOD bit selects the
mode of operation.
The minimum pulse width for the PAI input is greater than two bus clocks.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
434 Freescale Semiconductor
13.4.5 Event Counter Mode
Clearing the PAMOD bit configures the PACNT for event counter operation. An active edge on the IOC7
pin increments the pulse accumulator counter. The PEDGE bit selects falling edges or rising edges to
increment the count.
NOTE
The PACNT input and timer channel 7 use the same pin IOC7. To use the
IOC7, disconnect it from the output logic by clearing the channel 7 output
mode and output level bits, OM7 and OL7. Also clear the channel 7 output
compare 7 mask bit, OC7M7.
The Pulse Accumulator counter register reflect the number of active input edges on the PACNT input pin
since the last reset.
The PAOVF bit is set when the accumulator rolls over from 0xFFFF to 0x0000. The pulse accumulator
overflow interrupt enable bit, PAOVI, enables the PAOVF flag to generate interrupt requests.
NOTE
The pulse accumulator counter can operate in event counter mode even
when the timer enable bit, TEN, is clear.
13.4.6 Gated Time Accumulation Mode
Setting the PAMOD bit configures the pulse accumulator for gated time accumulation operation. An active
level on the PACNT input pin enables a divided-by-64 clock to drive the pulse accumulator. The PEDGE
bit selects low levels or high levels to enable the divided-by-64 clock.
The trailing edge of the active level at the IOC7 pin sets the PAIF. The PAI bit enables the PAIF flag to
generate interrupt requests.
The pulse accumulator counter register reflect the number of pulses from the divided-by-64 clock since
the last reset.
NOTE
The timer prescaler generates the divided-by-64 clock. If the timer is not
active, there is no divided-by-64 clock.
13.5 Resets
The reset state of each individual bit is listed within Section 13.3, “Memory Map and Register Definition”
which details the registers and their bit fields.
13.6 Interrupts
This section describes interrupts originated by the TIM16B4CV1 block. Table 13-21 lists the interrupts
generated by the TIM16B4CV1 to communicate with the MCU.
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 435
The TIM16B4CV1 uses a total of 7 interrupt vectors. The interrupt vector offsets and interrupt numbers
are chip dependent.
13.6.1 Channel [7:4] Interrupt (C[7:4]F)
This active high outputs will be asserted by the module to request a timer channel 7 – 4 interrupt to be
serviced by the system controller.
13.6.2 Pulse Accumulator Input Interrupt (PAOVI)
This active high output will be asserted by the module to request a timer pulse accumulator input interrupt
to be serviced by the system controller.
13.6.3 Pulse Accumulator Overflow Interrupt (PAOVF)
This active high output will be asserted by the module to request a timer pulse accumulator overflow
interrupt to be serviced by the system controller.
13.6.4 Timer Overflow Interrupt (TOF)
This active high output will be asserted by the module to request a timer overflow interrupt to be serviced
by the system controller.
Table 13-21. TIM16B8CV1 Interrupts
Interrupt Offset1
1Chip Dependent.
Vector1Priority1Source Description
C[7:4]F — — — Timer Channel 7–4 Active high timer channel interrupts 7–4
PAOVI — — — Pulse Accumulator
Input
Active high pulse accumulator input interrupt
PAOVF — — — Pulse Accumulator
Overflow
Pulse accumulator overflow interrupt
TOF — — — Timer Overflow Timer Overflow interrupt
Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E256 Data Sheet, Rev. 1.08
436 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 437
Chapter 14
Dual Output Voltage Regulator (VREG3V3V2)
14.1 Introduction
The VREG is a dual output voltage regulator providing two separate 2.5 V (typical) supplies differing in
the amount of current that can be sourced. The regulator input voltage range is from 3.3 V up to 5 V
(typical).
14.1.1 Features
The block VREG includes these distinctive features:
• Two parallel, linear voltage regulators
— Bandgap reference
• Low-voltage detect (LVD) with low-voltage interrupt (LVI)
• Power-on reset (POR)
• Low-voltage reset (LVR)
14.1.2 Modes of Operation
There are three modes VREG can operate in:
• Full-performance mode (FPM) (MCU is not in stop mode)
The regulator is active, providing the nominal supply voltage of 2.5 V with full current sourcing
capability at both outputs. Features LVD (low-voltage detect), LVR (low-voltage reset), and POR
(power-on reset) are available.
• Reduced-power mode (RPM) (MCU is in stop mode)
The purpose is to reduce power consumption of the device. The output voltage may degrade to a
lower value than in full-performance mode, additionally the current sourcing capability is
substantially reduced. Only the POR is available in this mode, LVD and LVR are disabled.
• Shutdown mode
Controlled by VREGEN (see Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)”
for connectivity of VREGEN).
This mode is characterized by minimum power consumption. The regulator outputs are in a high
impedance state, only the POR feature is available, LVD and LVR are disabled.
This mode must be used to disable the chip internal regulator VREG, i.e., to bypass the VREG to
use external supplies.
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
438 Freescale Semiconductor
14.1.3 Block Diagram
Figure 14-1 shows the function principle of VREG by means of a block diagram. The regulator core REG
consists of two parallel sub-blocks, REG1 and REG2, providing two independent output voltages.
Figure 14-1. VREG3V3 Block Diagram
LVR
LVD POR
VDDR
VDD
LVI
POR
LVR
CTRL
VSS
VDDPLL
VSSPLL
VREGEN
REG
REG2
REG1
PIN
VDDA
VSSA
REG: Regulator Core
LVD: Low Voltage Detect
CTRL: Regulator Control
LVR: Low Voltage Reset
POR: Power-on Reset
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 439
14.2 External Signal Description
Due to the nature of VREG being a voltage regulator providing the chip internal power supply voltages
most signals are power supply signals connected to pads.
Table 14-1 shows all signals of VREG associated with pins.
NOTE
Check Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)” for connectivity of the signals.
14.2.1 VDDR — Regulator Power Input
Signal VDDR is the power input of VREG. All currents sourced into the regulator loads flow through this
pin. A chip external decoupling capacitor (100 nF...220 nF, X7R ceramic) between VDDR and VSSR can
smoothen ripple on VDDR.
For entering shutdown mode, pin VDDR should also be tied to ground on devices without a VREGEN pin.
14.2.2 VDDA, VSSA — Regulator Reference Supply
Signals VDDA/VSSA which are supposed to be relatively quiet are used to supply the analog parts of the
regulator. Internal precision reference circuits are supplied from these signals. A chip external decoupling
capacitor (100 nF...220 nF, X7R ceramic) between VDDA and VSSA can further improve the quality of this
supply.
Table 14-1. VREG — Signal Properties
Name Port Function Reset State Pull Up
VDDR — VREG power input (positive supply) — —
VDDA — VREG quiet input (positive supply) — —
VSSA — VREG quiet input (ground) — —
VDD — VREG primary output (positive supply) — —
VSS — VREG primary output (ground) — —
VDDPLL — VREG secondary output (positive supply) — —
VSSPLL — VREG secondary output (ground) — —
VREGEN (optional) — VREG (Optional) Regulator Enable — —
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
440 Freescale Semiconductor
14.2.3 VDD, VSS — Regulator Output1 (Core Logic)
Signals VDD/VSS are the primary outputs of VREG that provide the power supply for the core logic. These
signals are connected to device pins to allow external decoupling capacitors (100 nF...220 nF, X7R
ceramic).
In shutdown mode an external supply at VDD/VSS can replace the voltage regulator.
14.2.4 VDDPLL, VSSPLL — Regulator Output2 (PLL)
Signals VDDPLL/VSSPLL are the secondary outputs of VREG that provide the power supply for the PLL
and oscillator. These signals are connected to device pins to allow external decoupling capacitors (100
nF...220 nF, X7R ceramic).
In shutdown mode an external supply at VDDPLL/VSSPLL can replace the voltage regulator.
14.2.5 VREGEN — Optional Regulator Enable
This optional signal is used to shutdown VREG. In that case VDD/VSS and VDDPLL/VSSPLL must be
provided externally. shutdown mode is entered with VREGEN being low. If VREGEN is high, the VREG is
either in full-performance mode or in reduced-power mode.
For the connectivity of VREGEN see Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)”.
NOTE
Switching from FPM or RPM to shutdown of VREG and vice versa is not
supported while the MCU is powered.
14.3 Memory Map and Register Definition
This subsection provides a detailed description of all registers accessible in VREG.
14.3.1 Module Memory Map
Figure 14-2 provides an overview of all used registers.
Table 14-2. VREG Memory Map
Address
Offset Use Access
0x0000 VREG Control Register (VREGCTRL) R/W
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 441
14.3.2 Register Descriptions
The following paragraphs describe, in address order, all the VREG registers and their individual bits.
14.3.2.1 VREG — Control Register (VREGCTRL)
The VREGCTRL register allows to separately enable features of VREG.
NOTE
On entering the reduced-power mode the LVIF is not cleared by the VREG.
14.4 Functional Description
Block VREG is a voltage regulator as depicted in Figure 14-1. The regulator functional elements are the
regulator core (REG), a low-voltage detect module (LVD), a power-on reset module (POR) and a
low-voltage reset module (LVR). There is also the regulator control block (CTRL) which represents the
interface to the digital core logic but also manages the operating modes of VREG.
14.4.1 REG — Regulator Core
VREG, respectively its regulator core has two parallel, independent regulation loops (REG1 and REG2)
that differ only in the amount of current that can be sourced to the connected loads. Therefore, only REG1
providing the supply at VDD/VSS is explained. The principle is also valid for REG2.
76543210
R00000LVDS
LVIE LVIF
W
Reset00000000
= Unimplemented or Reserved
Figure 14-2. VREG3V3 — Control Register (VREGCTRL)
Table 14-3. VREGCTRL Field Descriptions
Field Description
2
LVDS
Low-Voltage Detect Status Bit — This read-only status bit reflects the input voltage. Writes have no effect.
0 Input voltage VDDA is above level VLVID or RPM or shutdown mode.
1 Input voltage VDDA is below level VLV IA and FPM.
1
LVIE
Low-Voltage Interrupt Enable Bit
0 Interrupt request is disabled.
1 Interrupt will be requested whenever LVIF is set.
0
LVIF
Low-Voltage Interrupt Flag — LVIF is set to 1 when LVDS status bit changes. This flag can only be cleared by
writing a 1. Writing a 0 has no effect. If enabled (LVIE = 1), LVIF causes an interrupt request.
0 No change in LVDS bit.
1 LVDS bit has changed.
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
442 Freescale Semiconductor
The regulator is a linear series regulator with a bandgap reference in its full-performance mode and a
voltage clamp in reduced-power mode. All load currents flow from input VDDR to VSS or VSSPLL, the
reference circuits are connected to VDDA and VSSA.
14.4.2 Full-Performance Mode
In full-performance mode, a fraction of the output voltage (VDD) and the bandgap reference voltage are
fed to an operational amplifier. The amplified input voltage difference controls the gate of an output driver
which basically is a large NMOS transistor connected to the output.
14.4.3 Reduced-Power Mode
In reduced-power mode, the driver gate is connected to a buffered fraction of the input voltage (VDDR).
The operational amplifier and the bandgap are disabled to reduce power consumption.
14.4.4 LVD — Low-Voltage Detect
sub-block LVD is responsible for generating the low-voltage interrupt (LVI). LVD monitors the input
voltage (VDDA–VSSA) and continuously updates the status flag LVDS. Interrupt flag LVIF is set whenever
status flag LVDS changes its value. The LVD is available in FPM and is inactive in reduced-power mode
and shutdown mode.
14.4.5 POR — Power-On Reset
This functional block monitors output VDD. If VDD is below VPORD, signal POR is high, if it exceeds
VPORD, the signal goes low. The transition to low forces the CPU in the power-on sequence.
Due to its role during chip power-up this module must be active in all operating modes of VREG.
14.4.6 LVR — Low-Voltage Reset
Block LVR monitors the primary output voltage VDD. If it drops below the assertion level (VLVRA) signal
LVR asserts and when rising above the deassertion level (VLVRD) signal LVR negates again. The LVR
function is available only in full-performance mode.
14.4.7 CTRL — Regulator Control
This part contains the register block of VREG and further digital functionality needed to control the
operating modes. CTRL also represents the interface to the digital core logic.
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 443
14.5 Resets
This subsection describes how VREG controls the reset of the MCU.The reset values of registers and
signals are provided in Section 14.3, “Memory Map and Register Definition”. Possible reset sources are
listed in Table 14-4.
14.5.1 Power-On Reset
During chip power-up the digital core may not work if its supply voltage VDD is below the POR
deassertion level (VPORD). Therefore, signal POR which forces the other blocks of the device into reset is
kept high until VDD exceeds VPORD. Then POR becomes low and the reset generator of the device
continues the start-up sequence. The power-on reset is active in all operation modes of VREG.
14.5.2 Low-Voltage Reset
For details on low-voltage reset see Section 14.4.6, “LVR — Low-Voltage Reset”.
14.6 Interrupts
This subsection describes all interrupts originated by VREG.
The interrupt vectors requested by VREG are listed in Table 14-5. Vector addresses and interrupt priorities
are defined at MCU level.
14.6.1 LVI — Low-Voltage Interrupt
In FPM VREG monitors the input voltage VDDA. Whenever VDDA drops below level VLVIA the status bit
LVDS is set to 1. Vice versa, LVDS is reset to 0 when VDDA rises above level VLVID. An interrupt,
indicated by flag LVIF = 1, is triggered by any change of the status bit LVDS if interrupt enable bit
LVIE = 1.
NOTE
On entering the reduced-power mode, the LVIF is not cleared by the VREG.
Table 14-4. VREG — Reset Sources
Reset Source Local Enable
Power-on reset Always active
Low-voltage reset Available only in full-performance mode
Table 14-5. VREG — Interrupt Vectors
Interrupt Source Local Enable
Low Voltage Interrupt (LVI) LVIE = 1; Available only in full-performance mode
Chapter 14 Dual Output Voltage Regulator (VREG3V3V2)
MC9S12E256 Data Sheet, Rev. 1.08
444 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 445
Chapter 15
Background Debug Module (BDMV4)
15.1 Introduction
This section describes the functionality of the background debug module (BDM) sub-block of the HCS12
core platform.
A block diagram of the BDM is shown in Figure 15-1.
Figure 15-1. BDM Block Diagram
The background debug module (BDM) sub-block is a single-wire, background debug system implemented
in on-chip hardware for minimal CPU intervention. All interfacing with the BDM is done via the BKGD
pin.
BDMV4 has enhanced capability for maintaining synchronization between the target and host while
allowing more flexibility in clock rates. This includes a sync signal to show the clock rate and a handshake
signal to indicate when an operation is complete. The system is backwards compa tible with older external
interfaces.
ENBDM
SDV
16-BIT SHIFT REGISTER
BKGD
CLOCKS
DATA
ADDRESS
HOST
SYSTEM
BUS INTERFACE
AND
CONTROL LOGIC
INSTRUCTION DECODE
AND EXECUTION
STANDARD BDM
FIRMWARE
LOOKUP TABLE
CLKSW
BDMACT
ENTAG
TRACE
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
446 Freescale Semiconductor
15.1.1 Features
• Single-wire communication with host development system
• BDMV4 (and BDM2): Enhanced capability for allowing more flexibility in clock rates
• BDMV4: SYNC command to determine communication rate
• BDMV4: GO_UNTIL command
• BDMV4: Hardware handshake protocol to increase the performance of the serial communication
• Active out of reset in special single-chip mode
• Nine hardware commands using free cycles, if available, for minimal CPU intervention
• Hardware commands not requiring active BDM
• 15 firmware commands execute from the standard BDM firmware lookup table
• Instruction tagging capability
• Software control of BDM operation during wait mode
• Software selectable clocks
• When secured, hardware commands are allowed to access the register space in special single-chip
mode, if the FLASH and EEPROM erase tests fail.
15.1.2 Modes of Operation
BDM is available in all operating modes but must be enabled before firmware commands are executed.
Some system peripherals may have a control bit which allows suspending the peripheral function during
background debug mode.
15.1.2.1 Regular Run Modes
All of these operations refer to the part in run mode. The BDM does not provide controls to conserve power
during run mode.
• Normal operation
General operation of the BDM is available and operates the same in all normal modes.
• Special single-chip mode
In special single-chip mode, background operation is enabled and active out of reset. This allows
programming a system with blank memory.
• Special peripheral mode
BDM is enabled and active immediately out of reset. BDM can be disabled
by clearing the BDMACT bit in the BDM status (BDMSTS) register. The
BDM serial system should not be used in special peripheral mode.
• Emulation modes
General operation of the BDM is available and operates the same as in normal modes.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 447
15.1.2.2 Secure Mode Operation
If the part is in secure mode, the operation of the BDM is reduced to a small subset of its regular run mode
operation. Secure operation prevents access to FLASH or EEPROM other than allowing erasure.
15.2 External Signal Description
A single-wire interface pin is used to communicate with the BDM system. Two additional pins are used
for instruction tagging. These pins are part of the multiplexed external bus interface (MEBI) sub-block and
all interfacing between the MEBI and BDM is done within the core interface boundary. Functional
descriptions of the pins are provided below for completeness.
• BKGD — Background interface pin
• TAGHI — High byte instruction tagging pin
•TAGLO — Low byte instruction tagging pin
• BKGD and TAGHI share the same pin.
•TAGLO and LSTRB share the same pin.
NOTE
Generally these pins are shared as described, but it is best to check
Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)” to
make certain. All MCUs at the time of this writing have followed this pin
sharing scheme.
15.2.1 BKGD — Background Interface Pin
Debugging control logic communicates with external devices serially via the single-wire background
interface pin (BKGD). During reset, this pin is a mode select input which selects between normal and
special modes of operation. After reset, this pin becomes the dedicated serial interface pin for the
background debug mode.
15.2.2 TAGHI — High Byte Instruction Tagging Pin
This pin is used to tag the high byte of an instruction. When instruction tagging is on, a logic 0 at the falling
edge of the external clock (ECLK) tags the high half of the instruction word being read into the instruction
queue.
15.2.3 TAGLO — Low Byte Instruction Tagging Pin
This pin is used to tag the low byte of an instruction. When instruction tagging is on and low strobe is
enabled, a logic 0 at the falling edge of the external clock (ECLK) tags the low half of the instruction word
being read into the instruction queue.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
448 Freescale Semiconductor
15.3 Memory Map and Register Definition
A summary of the registers associated with the BDM is shown in Figure 15-2. Registers are accessed by
host-driven communications to the BDM hardware using READ_BD and WRITE_BD commands.
Detailed descriptions of the registers and associated bits are given in the subsections that follow.
15.3.1 Module Memory Map
Table 15-1. BDM Memory Map
Register
Address Use Access
Reserved —
BDM Status Register (BDMSTS) R/W
Reserved —
BDM CCR Holding Register (BDMCCR) R/W
7 BDM Internal Register Position (BDMINR) R
8– Reserved —
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 449
15.3.2 Register Descriptions
Register
Name Bit 7654321Bit 0
ReservedRXXXXXX00
W
BDMSTS R ENBDM BDMACT ENTAG SDV TRACE CLKSW UNSEC 0
W
Reserved RXXXXXXXX
W
Reserved RXXXXXXXX
W
ReservedRXXXXXXXX
W
ReservedRXXXXXXXX
W
BDMCCR R CCR7 CCR6 CCR5 CCR4 CCR3 CCR2 CCR1 CCR0
W
BDMINR R 0 REG14 REG13 REG12 REG11 0 0 0
W
ReservedR00000000
W
Reserved R00000000
W
Reserved RXXXXXXXX
W
Reserved RXXXXXXXX
W
= Unimplemented, Reserved = Implemented (do not alter)
X = Indeterminate 0 = Always read zero
Figure 15-2. BDM Register Summary
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
450 Freescale Semiconductor
15.3.2.1 BDM Status Register (BDMSTS)
Read: All modes through BDM operation
Write: All modes but subject to the following:
• BDMACT can only be set by BDM hardware upon entry into BDM. It can only be cleared by the
standard BDM firmware lookup table upon exit from BDM active mode.
• CLKSW can only be written via BDM hardware or standard BDM firmware write commands.
• All other bits, while writable via BDM hardware or standard BDM firmware write commands,
should only be altered by the BDM hardware or standard firmware lookup table as part of BDM
command execution.
• ENBDM should only be set via a BDM hardware command if the BDM firmware commands are
needed. (This does not apply in special single-chip mode).
76543210
RENBDM BDMACT ENTAG SDV TRACE CLKSW UNSEC 0
W
Reset:
Special single-chip mode:
Special peripheral mode:
All other modes:
11
0
0
0
1ENBDM is read as "1" by a debugging environment in Special single-chip mode when the device is not secured or secured but
fully erased (Flash and EEPROM).This is because the ENBDM bit is set by the standard firmware before a BDM command
can be fully transmitted and executed.
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
02
0
0
0
2UNSEC is read as "1" by a debugging environment in Special single-chip mode when the device is secured and fully erased,
else it is "0" and can only be read if not secure (see also bit description).
0
0
0
0
= Unimplemented or Reserved = Implemented (do not alter)
Figure 15-3. BDM Status Register (BDMSTS)
Note:
Table 15-2. BDMSTS Field Descriptions
Field Description
7
ENBDM
Enable BDM — This bit controls whether the BDM is enabled or disabled. When enabled, BDM can be made
active to allow firmware commands to be executed. When disabled, BDM cannot be made active but BDM
hardware commands are allowed.
0BDM disabled
1 BDM enabled
Note: ENBDM is set by the firmware immediately out of reset in special single-chip mode. In secure mode, this
bit will not be set by the firmware until after the EEPROM and FLASH erase verify tests are complete.
6
BDMACT
BDM Active Status — This bit becomes set upon entering BDM. The standard BDM firmware lookup table is
then enabled and put into the memory map. BDMACT is cleared by a carefully timed store instruction in the
standard BDM firmware as part of the exit sequence to return to user code and remove the BDM memory from
the map.
0 BDM not active
1 BDM active
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 451
5
ENTAG
Tagging Enable — This bit indicates whether instruction tagging in enabled or disabled. It is set when the
TAGGO command is executed and cleared when BDM is entered. The serial system is disabled and the tag
function enabled 16 cycles after this bit is written. BDM cannot process serial commands while tagging is active.
0 Tagging not enabled or BDM active
1 Tagging enabled
4
SDV
Shift Data Valid — This bit is set and cleared by the BDM hardware. It is set after data has been transmitted as
part of a firmware read command or after data has been received as part of a firmware write command. It is
cleared when the next BDM command has been received or BDM is exited. SDV is used by the standard BDM
firmware to control program flow execution.
0 Data phase of command not complete
1 Data phase of command is complete
3
TRACE
TRACE1 BDM Firmware Command is Being Executed — This bit gets set when a BDM TRACE1 firmware
command is first recognized. It will stay set as long as continuous back-to-back TRACE1 commands are
executed. This bit will get cleared when the next command that is not a TRACE1 command is recognized.
0 TRACE1 command is not being executed
1 TRACE1 command is being executed
2
CLKSW
Clock Switch — The CLKSW bit controls which clock the BDM operates with. It is only writable from a hardware
BDM command. A 150 cycle delay at the clock speed that is active during the data portion of the command will
occur before the new clock source is guaranteed to be active. The start of the next BDM command uses the new
clock for timing subsequent BDM communications.
Ta b le 1 5 - 3 shows the resulting BDM clock source based on the CLKSW and the PLLSEL (Pll select from the
clock and reset generator) bits.
Note: The BDM alternate clock source can only be selected when CLKSW = 0 and PLLSEL = 1. The BDM serial
interface is now fully synchronized to the alternate clock source, when enabled. This eliminates frequency
restriction on the alternate clock which was required on previous versions. Refer to Chapter 1,
“MC9S12E256 Device Overview (MC9S12E256DGV1)” to determine which clock connects to the
alternate clock source input.
Note: If the acknowledge function is turned on, changing the CLKSW bit will cause the ACK to be at the new rate
for the write command which changes it.
1
UNSEC
Unsecure — This bit is only writable in special single-chip mode from the BDM secure firmware and always gets
reset to zero. It is in a zero state as secure mode is entered so that the secure BDM firmware lookup table is
enabled and put into the memory map along with the standard BDM firmware lookup table.
The secure BDM firmware lookup table verifies that the on-chip EEPROM and FLASH EEPROM are erased. This
being the case, the UNSEC bit is set and the BDM program jumps to the start of the standard BDM firmware
lookup table and the secure BDM firmware lookup table is turned off. If the erase test fails, the UNSEC bit will
not be asserted.
0 System is in a secured mode
1 System is in a unsecured mode
Note: When UNSEC is set, security is off and the user can change the state of the secure bits in the on-chip
FLASH EEPROM. Note that if the user does not change the state of the bits to “unsecured” mode, the
system will be secured again when it is next taken out of reset.
Table 15-3. BDM Clock Sources
PLLSEL CLKSW BDMCLK
0 0 Bus clock
0 1 Bus clock
1 0 Alternate clock (refer to Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)”
to determine the alternate clock source)
1 1 Bus clock dependent on the PLL
Table 15-2. BDMSTS Field Descriptions (continued)
Field Description
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
452 Freescale Semiconductor
15.3.2.2 BDM CCR Holding Register (BDMCCR)
Read: All modes
Write: All modes
NOTE
When BDM is made active, the CPU stores the value of the CCR register in
the BDMCCR register. However, out of special single-chip reset, the
BDMCCR is set to 0xD8 and not 0xD0 which is the reset value of the CCR
register.
When entering background debug mode, the BDM CCR holding register is used to save the contents of
the condition code register of the user’ s program. It is also used for temporary storage in the standard BDM
firmware mode. The BDM CCR holding register can be written to modify the CCR value.
15.3.2.3 BDM Internal Register Position Register (BDMINR)
Read: All modes
Write: Never
76543210
RCCR7 CCR6 CCR5 CCR4 CCR3 CCR2 CCR1 CCR0
W
Reset00000000
Figure 15-4. BDM CCR Holding Register (BDMCCR)
76543210
R 0 REG14 REG13 REG12 REG11 0 0 0
W
Reset00000000
= Unimplemented or Reserved
Figure 15-5. BDM Internal Register Position (BDMINR)
Table 15-4. BDMINR Field Descriptions
Field Description
6:3
REG[14:11]
Internal Register Map Position — These four bits show the state of the upper five bits of the base address for
the system’s relocatable register block. BDMINR is a shadow of the INITRG register which maps the register
block to any 2K byte space within the first 32K bytes of the 64K byte address space.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 453
15.4 Functional Description
The BDM receives and executes commands from a host via a single wire serial interface. There are two
types of BDM commands, namely, hardware commands and firmware commands.
Hardware commands are used to read and write target system memory locations and to enter active
background debug mode, see Section 15.4.3, “BDM Hardware Commands.” Target system memory
includes all memory that is accessible by the CPU.
Firmware commands are used to read and write CPU resources and to exit from active background debug
mode, see Section 15.4.4, “Standard BDM Firmware Commands.” The CPU resources referred to are the
accumulator (D), X index register (X), Y index register (Y), stack pointer (SP), and program counter (PC).
Hardware commands can be executed at any time and in any mode excluding a few exceptions as
highlighted, see Section 15.4.3, “BDM Hardware Commands.” Firmware commands can only be executed
when the system is in active background debug mode (BDM).
15.4.1 Security
If the user resets into special single-chip mode with the system secured, a secured mode BDM firmware
lookup table is brought into the map overlapping a portion of the standard BDM firmware lookup table.
The secure BDM firmware verifies that the on-chip EEPROM and FLASH EEPROM are erased. This
being the case, the UNSEC bit will get set. The BDM program jumps to the start of the standard BDM
firmware and the secured mode BDM firmware is turned off and all BDM commands are allowed. If the
EEPROM or FLASH do not verify as erased, the BDM firmware sets the ENBDM bit, without asserting
UNSEC, and the firmware enters a loop. This causes the BDM hardware commands to become enabled,
but does not enable the firmware commands. This allows the BDM hardware to be used to erase the
EEPROM and FLASH. After execution of the secure firmware, regardless of the results of the erase tests,
the CPU registers, INITEE and PPAGE, will no longer be in their reset state.
15.4.2 Enabling and Activating BDM
The system must be in active BDM to execute standard BDM firmware commands. BDM can be activated
only after being enabled. BDM is enabled by setting the ENBDM bit in the BDM status (BDMSTS)
register. The ENBDM bit is set by writing to the BDM status (BDMSTS) register, via the single-wire
interface, using a hardware command such as WRITE_BD_BYTE.
After being enabled, BDM is activated by one of the following1:
• Hardware BACKGROUND command
• BDM external instruction tagging mechanism
• CPU BGND instruction
• Breakpoint sub-block’s force or tag mechanism2
1. BDM is enabled and active immediately out of special single-chip reset.
2. This method is only available on systems that have a a breakpoint or a debug sub-block.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
454 Freescale Semiconductor
When BDM is activated, the CPU finishes executing the current instruction and then begins executing the
firmware in the standard BDM firmware lookup table. When BDM is activated by the breakpoint
sub-block, the type of breakpoint used determines if BDM becomes active before or after execution of the
next instruction.
NOTE
If an attempt is made to activate BDM before being enabled, the CPU
resumes normal instruction execution after a brief delay. If BDM is not
enabled, any hardware BACKGROUND commands issued are ignored by
the BDM and the CPU is not delayed.
In active BDM, the BDM registers and standard BDM firmware lookup table are mapped to addresses
0xFF00 to 0xFFFF. BDM registers are mapped to addresses 0xFF00 to 0xFF07. The BDM uses these
registers which are readable anytime by the BDM. However, these registers are not readable by user
programs.
15.4.3 BDM Hardware Commands
Hardware commands are used to read and write target system memory locations and to enter active
background debug mode. Target system memory includes all memory that is accessible by the CPU such
as on-chip RAM, EEPROM, FLASH EEPROM, I/O and control registers, and all external memory.
Hardware commands are executed with minimal or no CPU intervention and do not require the system to
be in active BDM for execution, although they can continue to be executed in this mode. When executing
a hardware command, the BDM sub-block waits for a free CPU bus cycle so that the background access
does not disturb the running application program. If a free cycle is not found within 128 clock cycles, the
CPU is momentarily frozen so that the BDM can steal a cycle. When the BDM finds a free cycle, the
operation does not intrude on normal CPU operation provided that it can be completed in a single cycle.
However, if an operation requires multiple cycles the CPU is frozen until the operation is complete, even
though the BDM found a free cycle.
The BDM hardware commands are listed in Table 15-5.
Table 15-5. Hardware Commands
Command Opcode
(hex) Data Description
BACKGROUND 90 None Enter background mode if firmware is enabled. If enabled, an ACK will
be issued when the part enters active background mode.
ACK_ENABLE D5 None Enable handshake. Issues an ACK pulse after the command is
executed.
ACK_DISABLE D6 None Disable handshake. This command does not issue an ACK pulse.
READ_BD_BYTE E4 16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table in map.
Odd address data on low byte; even address data on high byte.
READ_BD_WORD EC 16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table in map.
Must be aligned access.
READ_BYTE E0 16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table out of
map. Odd address data on low byte; even address data on high byte.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 455
NOTE:
If enabled, ACK will occur when data is ready for transmission for all BDM READ commands and will occur after the write is
complete for all BDM WRITE commands.
The READ_BD and WRITE_BD commands allow access to the BDM register locations. These locations
are not normally in the system memory map but share addresses with the application in memory. To
distinguish between physical memory locations that share the same address, BDM memory resources are
enabled just for the READ_BD and WRITE_BD access cycle. This allows the BDM to access BDM
locations unobtrusively, even if the addresses conflict with the application memory map.
15.4.4 Standard BDM Firmware Commands
Firmware commands are used to access and manipulate CPU resources. The system must be in active
BDM to execute standard BDM firmware commands, see Section 15.4.2, “Enabling and Activating
BDM.” Normal instruction execution is suspended while the CPU executes the firmware located in the
standard BDM firmware lookup table. The hardware command BACKGROUND is the usual way to
activate BDM.
As the system enters active BDM, the standard BDM firmware lookup table and BDM registers become
visible in the on-chip memory map at 0xFF00–0xFFFF, and the CPU begins executing the standard BDM
firmware. The standard BDM firmware watches for serial commands and executes them as they are
received.
The firmware commands are shown in Table 15-6.
READ_WORD E8 16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table out of
map. Must be aligned access.
WRITE_BD_BYTE C4 16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table in map. Odd
address data on low byte; even address data on high byte.
WRITE_BD_WORD CC 16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table in map. Must
be aligned access.
WRITE_BYTE C0 16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table out of map.
Odd address data on low byte; even address data on high byte.
WRITE_WORD C8 16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table out of map.
Must be aligned access.
Table 15-5. Hardware Commands (continued)
Command Opcode
(hex) Data Description
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
456 Freescale Semiconductor
15.4.5 BDM Command Structure
Hardware and firmware BDM commands start with an 8-bit opcode followed by a 16-bit address and/or a
16-bit data word depending on the command. All the read commands return 16 bits of data despite the byte
or word implication in the command name.
NOTE
8-bit reads return 16-bits of data, of which, only one byte will contain valid
data. If reading an even address, the valid data will appear in the MSB. If
reading an odd address, the valid data will appear in the LSB.
NOTE
16-bit misaligned reads and writes are not allowed. If attempted, the BDM
will ignore the least significant bit of the address and will assume an even
address from the remaining bits.
Table 15-6. Firmware Commands
Command1
1If enabled, ACK will occur when data is ready for transmission for all BDM READ commands and will occur after the write is
complete for all BDM WRITE commands.
Opcode (hex) Data Description
READ_NEXT 62 16-bit data out Increment X by 2 (X = X + 2), then read word X points to.
READ_PC 63 16-bit data out Read program counter.
READ_D 64 16-bit data out Read D accumulator.
READ_X 65 16-bit data out Read X index register.
READ_Y 66 16-bit data out Read Y index register.
READ_SP 67 16-bit data out Read stack pointer.
WRITE_NEXT 42 16-bit data in Increment X by 2 (X = X + 2), then write word to location pointed to by X.
WRITE_PC 43 16-bit data in Write program counter.
WRITE_D 44 16-bit data in Write D accumulator.
WRITE_X 45 16-bit data in Write X index register.
WRITE_Y 46 16-bit data in Write Y index register.
WRITE_SP 47 16-bit data in Write stack pointer.
GO 08 None Go to user program. If enabled, ACK will occur when leaving active
background mode.
GO_UNTIL2
2Both WAIT (with clocks to the S12 CPU core disabled) and STOP disable the ACK function. The GO_UNTIL command will not
get an Acknowledge if one of these two CPU instructions occurs before the “UNTIL” instruction. This can be a problem for any
instruction that uses ACK, but GO_UNTIL is a lot more difficult for the development tool to time-out.
0C None Go to user program. If enabled, ACK will occur upon returning to active
background mode.
TRACE1 10 None Execute one user instruction then return to active BDM. If enabled, ACK
will occur upon returning to active background mode.
TAGGO 18 None Enable tagging and go to user program. There is no ACK pulse related to
this command.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 457
For hardware data read commands, the external host must wait 150 bus clock cycles after sending the
address before attempting to obtain the read data. This is to be certain that valid data is available in the
BDM shift register, ready to be shifted out. For hardware write commands, the external host must wait
150 bus clock cycles after sending the data to be written before attempting to send a new command. This
is to avoid disturbing the BDM shift register before the write has been completed. The 150 bus clock cycle
delay in both cases includes the maximum 128 cycle delay that can be incurred as the BDM waits for a
free cycle before stealing a cycle.
For firmware read commands, the external host should wait 44 bus clock cycles after sending the command
opcode and before attempting to obtain the read data. This includes the potential of an extra 7 cycles when
the access is external with a narrow bus access (+1 cycle) and / or a stretch (+1, 2, or 3 cycles), (7 cycles
could be needed if both occur). The 44 cycle wait allows enough time for the requested data to be made
available in the BDM shift register, ready to be shifted out.
NOTE
This timing has increased from previous BDM modules due to the new
capability in which the BDM serial inte rface can potentially run faster than
the bus. On previous BDM modules this extra time could be hidden within
the serial time.
For firmware write commands, the external host must wait 32 bus clock cycles after sending the data to be
written before attempting to send a new command. This is to avoid disturbing the BDM shift register
before the write has been completed.
The external host should wait 64 bus clock cycles after a TRACE1 or GO command before starting any
new serial command. This is to allow the CPU to exit gracefully from the standard BDM firmware lookup
table and resume execution of the user code. Disturbing the BDM shift register prematurely may adversely
affect the exit from the standard BDM firmware lookup table.
NOTE
If the bus rate of the target proces sor is unknown or could be changing, it is
recommended that the ACK (acknowledge function) be used to indicate
when an operation is complete. When using ACK, the delay times are
automated.
Figure 15-6 represents the BDM command structure. The command blocks illustrate a series of eight bit
times starting with a falling edge. The bar across the top of the blocks indicates that the BKGD line idles
in the high state. The time for an 8-bit command is 8 × 16 target clock cycles.1
1. Target clock cycles are cycles measured using the target MCU’s serial clock rate. See Section 15.4.6, “BDM Serial Interface,”
and Section 15.3.2.1, “BDM Status Register (BDMSTS),” for information on how serial clock rate is selected.
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
458 Freescale Semiconductor
Figure 15-6. BDM Command Structure
15.4.6 BDM Serial Interface
The BDM communicates with external devices serially via the BKGD pin. During reset, this pin is a mode
select input which selects between normal and special modes of operation. After reset, this pin becomes
the dedicated serial interface pin for the BDM.
The BDM serial interface is timed using the clock selected by the CLKSW bit in the status register see
Section 15.3.2.1, “BDM Status Register (BDMSTS).” This clock will be referred to as the tar get clock in
the following explanation.
The BDM serial interface uses a clocking scheme in which the external host generates a falling edge on
the BKGD pin to indicate the start of each bit time. This falling edge is sent for every bit whether data is
transmitted or received. Data is transferred most significant bit (MSB) first at 16 target clock cycles per
bit. The interface times out if 512 clock cycles occur between falling edges from the host.
The BKGD pin is a pseudo open-drain pin and has an weak on-chip active pull-up that is enabled at all
times. It is assumed that there is an external pull-up and that drivers connected to BKGD do not typically
drive the high level. Because R-C rise time could be unacceptably long, the target system and host provide
brief driven-high (speedup) pulses to drive BKGD to a logic 1. The source of this speedup pulse is the host
for transmit cases and the target for receive cases.
The timing for host-to-target is shown in Figure 15-7 and that of target-to-host in Figure 15-8 and
Figure 15-9. All four cases begin when the host drives the BKGD pin low to generate a falling edge.
Because the host and target are operating from separate clocks, it can take the tar get system up to one full
clock cycle to recognize this edge. The target measures delays from this perceived start of the bit time
while the host measures delays from the point it actually drove BKGD low to start the bit up to one target
HARDWARE
HARDWARE
FIRMWARE
FIRMWARE
GO,
44-BC
BC = BUS CLOCK CYCLES
COMMAND ADDRESS
150-BC
DELAY
NEXT
DELAY
8 BITS
AT ∼16 TC/BIT
16 BITS
AT ∼16 TC/BIT
16 BITS
AT ∼16 TC/BIT
COMMAND ADDRESS DATA NEXT
DATA
READ
WRITE
READ
WRITE
TRACE
COMMAND NEXT
COMMAND DATA
64-BC
DELAY
NEXT
COMMAND
150-BC
DELAY
32-BC
DELAY
COMMAND
COMMAND
COMMAND
COMMAND
DATA
NEXT
COMMAND
TC = TARGET CLOCK CYCLES
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 459
clock cycle earlier. Synchronization between the host and target is established in this manner at the start
of every bit time.
Figure 15-7 shows an external host transmit ting a logic 1 and transmitting a logic 0 to the BKGD pin of a
target system. The host is asynchronous to the target, so there is up to a one clock-cycle delay from the
host-generated falling edge to where the target recognizes this edge as the beginning of the bit time. Ten
target clock cycles later, the target senses the bit level on the BKGD pin. Internal glitch detect logic
requires the pin be driven high no later that eight target clock cycles after the falling edge for a logic 1
transmission.
Because the host drives the high speedup pulses in these two cases, the rising edges look like digitally
driven signals.
Figure 15-7. BDM Host-to-Target Serial Bit Timing
The receive cases are more complicated. Figure 15-8 shows the host receiving a logic 1 from the target
system. Because the host is asynchronous to the target, there is up to one clock-cycle delay from the
host-generated falling edge on BKGD to the perceived start of the bit time in the target. The host holds the
BKGD pin low long enough for the target to recognize it (at least two tar get clock cycles). The host must
release the low drive before the target drives a brief high speedup pulse se ven target clock cycles after the
perceived start of the bit time. The host should sample the bit level about 10 target clock cycles after it
started the bit time.
EARLIEST
START OF
NEXT BIT
TARGET SENSES BIT
10 CYCLES
SYNCHRONIZATION
UNCERTAINTY
CLOCK
TARGET SYSTEM
HOST
TRANSMIT 1
HOST
TRANSMIT 0
PERCEIVED
S
TART OF BIT TIME
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
460 Freescale Semiconductor
Figure 15-8. BDM Target-to-Host Serial Bit Timing (Logic 1)
Figure 15-9 shows the host receiving a logic 0 from the target. Because the host is asynchronous to the
target, there is up to a one clock-cy cle delay from the host-generated falling edge on BKGD to the start of
the bit time as perceived by the targ et. The host initiates the bit time but the tar get finishes it. Because the
target wants the host to receive a logic 0, it drives the BKGD pin low for 13 target clock cycles then briefly
drives it high to speed up the rising edge. The host samples the bit level about 10 tar get clock cycles after
starting the bit time.
Figure 15-9. BDM Target-to-Host Serial Bit Timing (Logic 0)
HIGH-IMPEDANCE
EARLIEST
START OF
NEXT BIT
R-C RISE
10 CYCLES
10 CYCLES
HOST SAMPLES
BKGD PIN
PERCEIVED
START OF BIT TIME
BKGD PIN
CLOCK
TARGET SYSTEM
HOST
DRIVE TO
BKGD PIN
TARGET SYSTEM
SPEEDUP
PULSE
HIGH-IMPEDANCE
HIGH-IMPEDANCE
EARLIEST
START OF
NEXT BIT
CLOCK
TARGET SYS.
HOST
DRIVE TO
BKGD PIN
BKGD PIN
PERCEIVED
START OF BIT TIME
10 CYCLES
10 CYCLES
HOST SAMPLES
BKGD PIN
TARGET SYS.
DRIVE AND
SPEEDUP PULSE
SPEEDUP PULSE
HIGH-IMPEDANCE
Chapter 15 Background Debug Module (BDMV4)
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Freescale Semiconductor 461
15.4.7 Serial Interface Hardware Handshake Protocol
BDM commands that require CPU execution are ultimately treated at the MCU bus rate. Because the BDM
clock source can be asynchronously related to the bus frequency, when CLKSW = 0, it is very helpful to
provide a handshake protocol in which the host could determine when an issued command is executed by
the CPU. The alternative is to always wait the amount of time equal to the appropriate number of cycles
at the slowest possible rate the clock could be running. This sub-section will describe the hardware
handshake protocol.
The hardware handshake protocol signals to the host controller when an issued command was successfully
executed by the target. This protocol is implemented by a 16 serial clock cycle low pulse followed by a
brief speedup pulse in the BKGD pin. This pulse is generated by the target MCU when a command, issued
by the host, has been successfully executed (see Figure 15-10). This pulse is referred to as the ACK pulse.
After the ACK pulse has finished: the host can start the bit retrieval if the last issued command was a read
command, or start a new command if the last command was a write command or a control command
(BACKGROUND, GO, GO_UNTIL, or TRACE1). The ACK pulse is not issued earlier than 32 serial
clock cycles after the BDM command was issued. The end of the BDM command is assumed to be the
16th tick of the last bit. This minimum delay assures enough time for the host to perceive the ACK pulse.
Note also that, there is no upper limit for the delay between the command and the related ACK pulse,
because the command execution depends upon the CPU bus frequency , which in some cases could be very
slow compared to the serial communication rate. This protocol allows a great flexibility for the POD
designers, because it does not rely on any accurate time measurement or short response time to any event
in the serial communication.
Figure 15-10. Target Acknowledge Pulse (ACK)
NOTE
If the ACK pulse was issued by the target, the host assumes the previous
command was executed. If the CPU enters WAIT or STOP prior to
executing a hardware command, the ACK pulse will not be issued meaning
that the BDM command was not executed. After entering wait or stop mode,
the BDM command is no longer pending.
16 CYCLES
BDM CLOCK
(TARGET MCU)
TARGET
TRANSMITS
PULSE
ACK
HIGH-IMPEDANCE
BKGD PIN
MINIMUM DELAY
FROM THE BDM COMMAND
32 CYCLES
EARLIEST
START OF
NEXT BIT
SPEEDUP PULSE
16th TICK OF THE
LAST COMMAD BIT
HIGH-IMPEDANCE
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
462 Freescale Semiconductor
Figure 15-11 shows the ACK handshake protocol in a command level timing diagram. The READ_BYTE
instruction is used as an example. First, the 8-bit instruction opcode is sent by the host, followed by the
address of the memory location to be read. The target BDM decodes the instruction. A bus cycle is grabbed
(free or stolen) by the BDM and it executes the READ_BYTE operation. Having retrieved the data, the
BDM issues an ACK pulse to the host controller, indicating that the addressed byte is ready to be retrieved.
After detecting the ACK pulse, the host initiates the byte retrieval process. Note that data is sent in the
form of a word and the host needs to determine which is the appropriate byte based on whether the address
was odd or even.
Figure 15-11. Handshake Protocol at Command Level
Differently from the normal bit transfer (where the host initiates the transmission), the serial interface
ACK handshake pulse is initiated by the target MCU by issuing a falling edge in the BKGD pin. The
hardware handshake protocol in Figure 15-10 specifies the timing when the BKGD pin is being driven, so
the host should follow this timing constraint in order to avoid the risk of an electrical conflict in the BKGD
pin.
NOTE
The only place the BKGD pin can have an electrical conflict is when one
side is driving low and the other side is issuing a speedup pulse (high). Other
“highs” are pulled rather than driven. However, at low rates the time of the
speedup pulse can become lengthy and so the potential conflict time
becomes longer as well.
The ACK handshake protocol does not support nested ACK pulses. If a BDM command is not
acknowledge by an ACK pulse, the host needs to abort the pending command first in order to be able to
issue a new BDM command. When the CPU enters WAIT or ST OP while the host issues a command that
requires CPU execution (e.g., WRITE_BYTE), the target discards the incoming command due to the
WAIT or STOP being detected. Therefore, the co mmand is not acknowledged by the tar get, which means
that the ACK pulse will not be issued in this case. After a certain time the host should decide to abort the
ACK sequence in order to be free to issue a new command. Therefore, the protocol should provide a
mechanism in which a command, and therefore a pending ACK, could be aborted.
NOTE
Differently from a regular BDM command, the ACK pulse does not provide
a time out. This means that in the case of a WAIT or STOP instruction being
executed, the ACK would be prevented from being issued. If not aborted,
the ACK would remain pending indefinitely. See the handshake abort
procedure described in Section 15.4.8, “Hardware Handshake Abort
Procedure.”
READ_BYTE
BDM ISSUES THE
BKGD PIN BYTE ADDRESS
BDM EXECUTES THE
READ_BYTE COMMAND
HOST TARGET
HOST TARGET
BDM DECODES
THE COMMAND
ACK PULSE (OUT OF SCALE)
HOST TARGET
(2) BYTES ARE
RETRIEVED
NEW BDM
COMMAND
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15.4.8 Hardware Handshake Abort Procedure
The abort procedure is based on the SYNC command. In order to abort a command, which had not issued
the corresponding ACK pulse, the host controller should generate a low pulse in the BKGD pin by driving
it low for at least 128 serial clock cycles and then driving it high for one serial clock cycle, providing a
speedup pulse. By detecting this long low pulse in the BKGD pin, the target executes the SYNC protocol,
see Section 15.4.9, “SYNC — Request T imed Reference Pulse,” and assumes that the pending command
and therefore the related ACK pulse, are being aborted. Therefore, after the SYNC protocol has been
completed the host is free to issue new BDM commands.
Although it is not recommended, the host could abort a pending BDM command by issuing a low pulse in
the BKGD pin shorter than 128 serial clock cycles, which will not be interpreted as the SYNC command.
The ACK is actually aborted when a falling edge is perceived by the target in the BKGD pin. The short
abort pulse should have at least 4 clock cycles keeping the BKGD pin low, in order to allow the falling
edge to be detected by the target. In this case, the target will not execute the SYNC protocol but the pending
command will be aborted along with the ACK pulse. The potential problem with this abort procedure is
when there is a conflict between the ACK pulse and the short abort pu lse. In this c ase, the target may not
perceive the abort pulse. The worst case is when the pending command is a read command (i.e.,
READ_BYTE). If the abort pulse is not perceived by the target the host will attempt to send a new
command after the abort pulse was issued, while the target expects the host to retrieve the accessed
memory byte. In this case, host and target will run out of synchronism. However, if the command to be
aborted is not a read command the short abort pulse could be used. After a command is aborted the tar get
assumes the next falling edge, after the abort pulse, is the first bit of a new BDM command.
NOTE
The details about the short abort pulse are being provided only as a reference
for the reader to better understand the BDM internal behavior. It is not
recommended that this procedure be used in a real application.
Because the host knows the target serial clock freque ncy , the SYNC command (u sed to abort a command)
does not need to consider the lower possible target frequency. In this case, the host could issue a SYNC
very close to the 128 serial clock cycles length. Providing a small overhead on the pulse length in order to
assure the SYNC pulse will not be misinterpreted by the target. See Section 15.4.9, “SYNC — Request
Timed Reference Pulse.”
Figure 15-12 shows a SYNC command being issued after a READ_BYTE, which aborts the
READ_BYTE command. Note that, after the command is aborted a new command could be issued by the
host computer.
NOTE
Figure 15-12 does not represent the signals in a true timing scale
Chapter 15 Background Debug Module (BDMV4)
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464 Freescale Semiconductor
Figure 15-12. ACK Abort Procedure at the Command Level
Figure 15-13 shows a conflict between the ACK pulse and the SYNC request pulse. This conflict could
occur if a POD device is connected to the target BKGD pin and the tar get is already in debug active mode.
Consider that the target CPU is executing a pending BDM command at the exact moment the POD is being
connected to the BKGD pin. In this case, an ACK pulse is issued along with the SYNC command. In this
case, there is an electrical conflict between the ACK speedup pulse and the SYNC pulse. Because this is
not a probable situation, the protocol does not prevent this conflict from happening.
Figure 15-13. ACK Pulse and SYNC Request Conflict
NOTE
This information is being provided so that the MCU integrator will be aware
that such a conflict could eventually occur.
The hardware handshake protocol is enabled by the ACK_ENABLE and disabled by the ACK_DISABLE
BDM commands. This provides backwards compatibility with the existing POD devices which are not
able to execute the hardware handshake protocol. It also allows for new POD devices, that support the
hardware handshake protocol, to freely communicate with the target device. If desired, without the need
for waiting for the ACK pulse.
READ_BYTE READ_STATUSBKGD PIN MEMORY ADDRESS NEW BDM COMMAND
NEW BDM COMMAND
HOST TARGET HOST TARGET HOST TARGET
SYNC RESPONSE
FROM THE TARGET
(OUT OF SCALE)
BDM DECODE
AND STARTS TO EXECUTES
THE READ_BYTE CMD
READ_BYTE CMD IS ABORTED
BY THE SYNC REQUEST
(OUT OF SCALE)
BDM CLOCK
(TARGET MCU)
TARGET MCU
DRIVES TO
BKGD PIN
BKGD PIN
16 CYCLES
SPEEDUP PULSE
HIGH-IMPEDANCE
HOST
DRIVES SYNC
TO BKGD PIN
ACK PULSE
HOST SYNC REQUEST PULSE
AT LEAST 128 CYCLES
ELECTRICAL CONFLICT
HOST AND
TARGET DRIVE
TO BKGD PIN
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Freescale Semiconductor 465
The commands are described as follows:
• ACK_ENABLE — enables the hardware handshake protocol. The targe t will issue the ACK pulse
when a CPU command is executed by the CPU. The ACK_ENABLE command itself also has the
ACK pulse as a response.
• ACK_DISABLE — disables the ACK pulse protocol. In this case, the host needs to use the worst
case delay time at the appropriate places in the protocol.
The default state of the BDM after reset is hardware handshake protocol disabled.
All the read commands will ACK (if enabled) when the data bus cy cle has completed and the data is then
ready for reading out by the BKGD serial pin. All the write commands will ACK (if enabled) after the data
has been received by the BDM through the BKGD serial pin and when the data bus cycle is complete. See
Section 15.4.3, “BDM Hardware Commands,” and Section 15.4.4, “Standard BDM Firmware
Commands,” for more information on the BDM commands.
The ACK_ENABLE sends an ACK pulse when the command has been completed. This feature could be
used by the host to evaluate if the target supports the hardware handshake protocol. If an ACK pulse is
issued in response to this command, the host knows that the target supports the hardware handshake
protocol. If the target does not support the hardware handshake protocol the ACK pulse is not issued. In
this case, the ACK_ENABLE command is ignored by the target because it is not recognized as a valid
command.
The BACKGROUND command will issue an ACK pulse when the CPU changes from normal to
background mode. The ACK pulse related to this command could be aborted using the SYNC command.
The GO command will issue an ACK pulse when the CPU exits from background mode. The ACK pulse
related to this command could be aborted using the SYNC command.
The GO_UNTIL command is equivalent to a GO command with exception that the ACK pulse, in this
case, is issued when the CPU enters into background mode. This command is an alternative to the GO
command and should be used when the host wants to trace if a breakpoint match occurs and causes the
CPU to enter active background mode. Note that the ACK is issued whenever the CPU enters BDM, which
could be caused by a breakpoint match or by a BGND instruction being executed. The ACK pulse related
to this command could be aborted using the SYNC command.
The TRACE1 command has the related ACK pulse issued when the CPU enters background active mode
after one instruction of the application program is executed. The ACK pulse related to this command could
be aborted using the SYNC command.
The TAGGO command will not issue an ACK pulse because this would interfere with the tagging function
shared on the same pin.
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466 Freescale Semiconductor
15.4.9 SYNC — Request Timed Reference Pulse
The SYNC command is unlike other BDM commands because the host does not necessarily know the
correct communication speed to use for BDM communications until after it has analyzed the response to
the SYNC command. To issue a SYNC command, the host should perform the following steps:
1. Drive the BKGD pin low for at least 128 cycles at the lowest possible BDM serial communication
frequency (the lowest serial communication frequency is determined by the crystal oscillator or the
clock chosen by CLKSW.)
2. Drive BKGD high for a brief speedup pulse to get a fast rise time (this speedup pulse is typically
one cycle of the host clock.)
3. Remove all drive to the BKGD pin so it reverts to high impedance.
4. Listen to the BKGD pin for the sync response pulse.
Upon detecting the SYNC request from the host, the target performs the following steps:
1. Discards any incomplete command received or bit retrieved.
2. Waits for BKGD to return to a logic 1.
3. Delays 16 cycles to allow the host to stop driving the high speedup pulse.
4. Drives BKGD low for 128 cycles at the current BDM serial communication frequency.
5. Drives a one-cycle high speedup pulse to force a fast rise time on BKGD.
6. Removes all drive to the BKGD pin so it reverts to high impedance.
The host measures the low time of this 128 cycle SYNC response pulse and determines the correct speed
for subsequent BDM communications. Typically , the host can determine the correct communication speed
within a few percent of the actual target speed and the communication protocol can easily tolerate speed
errors of several percent.
As soon as the SYNC request is detected by the tar get, any partially received command or bit retrieved is
discarded. This is referred to as a soft-reset, equivalent to a time-out in the serial communication. After the
SYNC response, the target will consider the next falling edge (issued by the host) as the start of a new
BDM command or the start of new SYNC request.
Another use of the SYNC command pulse is to abort a pending ACK pulse. The behavior is exactly the
same as in a regular SYNC command. Note that one of the possible causes for a command to not be
acknowledged by the target is a host-target synchronization problem. In this case, the command may not
have been understood by the target and so an ACK response pulse will not be issued.
15.4.10 Instruction Tracing
When a TRACE1 command is issued to the BDM in active BDM, the CPU exits the standard BDM
firmware and executes a single instruction in the user code. As soon as this has occurred, the CPU is forced
to return to the standard BDM firmware and the BDM is active and ready to receive a new command. If
the TRACE1 command is issued again, the next user instruction will be executed. This facilitates stepping
or tracing through the user code one instruction at a time.
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MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 467
If an interrupt is pending when a TRACE1 command is issued, the interrupt stackin g operation occurs but
no user instruction is executed. Upon return to standard BDM firmware execution, the program counter
points to the first instruction in the interrupt service routine.
15.4.11 Instruction Tagging
The instruction queue and cycle-by-cycle CPU activity are reconstructible in real time or from trace
history that is captured by a logic analyzer. However, the reconstructed queue cannot be used to stop the
CPU at a specific instruction. This is because execution already has begun by the time an operation is
visible outside the system. A separate instruction tagging mechanism is provided for this purpose.
The tag follows program information as it advances through the instruction queue. When a tagged
instruction reaches the head of the queue, the CPU enters active BDM rather than executing the instruction.
NOTE
T agging is disabled when BDM becomes active and BDM serial commands
are not processed while tagging is active.
Executing the BDM T AGGO command configures two system pins for tagging. The T AGLO signal shares
a pin with the LSTRB signal, and the TAGHI signal shares a pin with the BKGD signal.
Table 15-7 shows the functions of the two tagging pins. The pins operate independently, that is the state of
one pin does not affect the function of the other. The presence of logic level 0 on either pin at the fall of
the external clock (ECLK) performs the indicated function. High tagging is allowed in all modes. Low
tagging is allowed only when low strobe is enabled (LSTRB is allowed only in wide expanded modes and
emulation expanded narrow mode).
15.4.12 Serial Communication Time-Out
The host initiates a host-to-target serial transmission by generating a falling edge on the BKGD pin. If
BKGD is kept low for more than 128 target clock cycles, the target understands that a SYNC command
was issued. In this case, the target will keep waiting for a rising edge on BKGD in order to answer the
SYNC request pulse. If the rising edge is not detected, the target will keep waiting forever without any
time-out limit.
Consider now the case where the host returns BKGD to logic one before 128 cycles. This is interpreted as
a valid bit transmission, and not as a SYNC request. The tar get will keep waiting for another falling edge
marking the start of a new bit. If, however , a new falling edge is not detected by the target within 512 clock
cycles since the last falling edge, a time-out occurs and the current command is discarded without affecting
memory or the operating mode of the MCU. This is referred to as a soft-reset.
Table 15-7. Tag Pin Function
TAGHI TAGLO Tag
11No tag
10Low byte
0 1 High byte
0 0 Both bytes
Chapter 15 Background Debug Module (BDMV4)
MC9S12E256 Data Sheet, Rev. 1.08
468 Freescale Semiconductor
If a read command is issued but the data is not retrieved within 512 serial clock cycles, a soft-reset will
occur causing the command to be disregarded. The data is not available for retrieval after the time-out has
occurred. This is the expected behavior if the handshake protocol is not enabled. However, consider the
behavior where the BDC is running in a frequency much greater than the CPU frequency. In this case, the
command could time out before the data is ready to be retrieved. In order to allow the data to be retrieved
even with a large clock frequency mismatch (between BDC and CPU) when the hardware handshake
protocol is enabled, the time out between a read command and the data retrieval is disabled. Therefore, the
host could wait for more then 512 serial clock cycles and continue to be able to retrieve the data from an
issued read command. However, as soon as the handshake pulse (ACK pulse) is issued, the time-out
feature is re-activated, meaning that the target will time out after 512 clock cycles. Therefore, the host
needs to retrieve the data within a 512 serial clock cycles time frame after the ACK pulse had been issued.
After that period, the read command is discarded and the data is no longer available for retrieval. Any
falling edge of the BKGD pin after the time-out period is considered to be a new command or a SYNC
request.
Note that whenever a partially issued command, or partially retrieved data, has occurred the time out in
the serial communication is active. This means that if a time frame higher than 512 serial clock cycles is
observed between two consecutive negative edges and the command being issued or data being retrieved
is not complete, a soft-reset will occur causing the partially received command or data retrieved to be
disregarded. The next falling edge of the BKGD pin, after a soft-reset has occurred, is considered by the
target as the start of a new BDM command, or the start of a SYNC request pulse.
15.4.13 Operation in Wait Mode
The BDM cannot be used in wait mode if the system disables the clocks to the BDM.
There is a clearing mechanism associated with the WAIT instruction when the clocks to the BDM (CPU
core platform) are disabled. As the clocks restart from wait mode, the BDM receives a soft reset (clearing
any command in progress) and the ACK function will be disabled. This is a change from previous BDM
modules.
15.4.14 Operation in Stop Mode
The BDM is completely shutdown in stop mode.
There is a clearing mechanism associated with the ST OP instruction. ST OP must be enabled and the part
must go into stop mode for this to occur. As the clocks restart from stop mode, the BDM receives a soft
reset (clearing any command in progress) and the ACK function will be disabled. This is a change from
previous BDM modules.
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 469
Chapter 16
Debug Module (DBGV1)
16.1 Introduction
This section describes the functionality of the debug (DBG) sub-block of the HCS12 core platform.
The DBG module is designed to be fully compatible with the existing BKP_HCS12_A module (BKP
mode) and furthermore provides an on-chip trace buffer with flexible triggering capability (DBG mode).
The DBG module provides for non-intrusive debug of application software. The DBG module is optimized
for the HCS12 16-bit architecture.
16.1.1 Features
The DBG module in BKP mode includes these distinctive features:
• Full or dual breakpoint mode
— Compare on address and data (full)
— Compare on either of two addresses (dual)
• BDM or SWI breakpoint
— Enter BDM on breakpoint (BDM)
— Execute SWI on breakpoint (SWI)
• Tagged or forced breakpoint
— Break just before a specific instruction will begin execution (TAG)
— Break on the first instruction boundary after a match occurs (Force)
• Single, range, or page address compares
— Compare on address (single)
— Compare on address 256 byte (range)
— Compare on any 16K page (page)
• At forced breakpoints compare address on read or write
• High and/or low byte data compares
• Comparator C can provide an additional tag or force breakpoint (enhancement for BKP mode)
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
470 Freescale Semiconductor
The DBG in DBG mode includes these distinctive features:
• Three comparators (A, B, and C)
— Dual mode, comparators A and B used to compare addresses
— Full mode, comparator A compares address and comparator B compares data
— Can be used as trigger and/or breakpoint
— Comparator C used in LOOP1 capture mode or as additional breakpoint
• Four capture modes
— Normal mode, change-of-flow information is captured based on trigger specification
— Loop1 mode, comparator C is dynamically updated to prevent redundant change-of-flow
storage.
— Detail mode, address and data for all cycles except program fetch (P) and free (f) cycles are
stored in trace buffer
— Profile mode, last instruction address executed by CPU is returned when trace buffer address
is read
• Two types of breakpoint or debug triggers
— Break just before a specific instruction will begin execution (tag)
— Break on the first instruction boundary after a match occurs (force)
• BDM or SWI breakpoint
— Enter BDM on breakpoint (BDM)
— Execute SWI on breakpoint (SWI)
• Nine trigger modes for comparators A and B
—A
— A or B
— A then B
— A and B, where B is data (full mode)
— A and not B, where B is data (full mode)
— Event only B, store data
— A then event only B, store data
— Inside range, A ≤ address ≤ B
— Outside range, address < Α or address > B
• Comparator C provides an additional tag or force breakpoint when capture mode is not configured
in LOOP1 mode.
• Sixty-four word (16 bits wide) trace buffer for storing change-of-flow information, event only data
and other bus information.
— Source address of taken conditional branches (long, short, bit-conditional, and loop constructs)
— Destination address of indexed JMP, JSR, and CALL instruction.
— Destination address of RTI, RTS, and RTC instructions
— Vector address of interrupts, except for SWI and BDM vectors
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 471
— Data associated with event B trigger modes
— Detail report mode stores address and data for all cycles except program (P) and free (f) cycles
— Current instruction address when in profiling mode
— BGND is not considered a change-of-flow (cof) by the debugger
16.1.2 Modes of Operation
There are two main modes of operation: breakpoint mode and debug mode. Each one is mutually exclusive
of the other and selected via a software programmable control bit.
In the breakpoint mode there are two sub-modes of operation:
• Dual address mode, where a match on either of two addresses will cause the system to enter
background debug mode (BDM) or initiate a software interrupt (SWI).
• Full breakpoint mode, where a match on address and data will cause the system to enter
background debug mode (BDM) or initiate a software interrupt (SWI).
In debug mode, there are several sub-modes of operation.
• Trigger modes
There are many ways to create a logical trigger . The trigger can be used to capture bus information
either starting from the trigger or ending at the trigger. Types of triggers (A and B are registers):
— A only
— A or B
— A then B
— Event only B (data capture)
— A then event only B (data capture)
— A and B, full mode
— A and not B, full mode
— Inside range
— Outside range
• Capture modes
There are several capture modes. These determine which bus information is saved and which is
ignored.
— Normal: save change-of-flow program fetches
— Loop1: save change-of-flow program fetches, ignoring duplicates
— Detail: save all bus operations except program and free cycles
— Profile: poll target from external device
16.1.3 Block Diagram
Figure 16-1 is a block diagram of this module in breakpoint mode. Figure 16-2 is a block diagram of this
module in debug mode.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
472 Freescale Semiconductor
Figure 16-1. DBG Block Diagram in BKP Mode
COMPARATOR
COMPARE BLOCK
REGISTER BLOCK
COMPARATOR
COMPARATOR
COMPARATOR
COMPARATOR
COMPARATOR
EXPANSION ADDRESSES
EXPANSION ADDRESSES
ADDRESS HIGH
ADDRESS LOW
DATA HIGH
DATA LOW
ADDRESS HIGH
ADDRESS LOW
COMPARATOR
COMPARATOR
READ DATA HIGH
READ DATA LOW
. . . . . . . . . . . .
CLOCKS AND BKP CONTROL
CONTROL SIGNALS SIGNALS
CONTROL BLOCK
BREAKPOINT MODES
AND GENERATION OF SWI,
FORCE BDM, AND TAGS
EXPANSION ADDRESS
ADDRESS
WRITE DATA
READ DATA
READ/WRITE
CONTROL
CONTROL BITS
CONTROL SIGNALS
RESULTS SIGNALS
BKP0H
BKP0L
BKP0X
BKPCT0
BKP1X
BKPCT1
BKP1L
BKP1H
WRITE
BKP READ
DATA BUS
DATA BUS
DATA/ADDRESS
HIGH MUX
DATA/ADDRESS
LOW MUX
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 473
Figure 16-2. DBG Block Diagram in DBG Mode
16.2 External Signal Description
The DBG sub-module relies on the external bus interface (generally the MEBI) when the DBG is matching
on the external bus.
The tag pins in Table 16-1 (part of the MEBI) may also be a part of the breakpoint operation.
Table 16-1. External System Pins Associated with DBG and MEBI
Pin Name Pin Functions Description
BKGD/MODC/
TAG H I
TAGHI When instruction tagging is on, a 0 at the falling edge of E tags the high half of the
instruction word being read into the instruction queue.
PE3/LSTRB/ TAGLO TAGL O In expanded wide mode or emulation narrow modes, when instruction tagging is on
and low strobe is enabled, a 0 at the falling edge of E tags the low half of the
instruction word being read into the instruction queue.
TAG
FORCE
ADDRESS BUS
MATCH_A
CONTROL
READ DATA BUS
READ/WRITE
STORE
MCU IN BDM
M
U
X
POINTER
REGISTER
MATCH_B
M
U
X
EVENT ONLY
WRITE DATA BUS
TRACE BUFFER
DBG READ DATA BUS
DBG MODE ENABLE
M
U
X
WRITE DATA BUS
READ DATA BUS
READ/WRITE
MATCH_C
LOOP1
DETAIL
M
U
X
PROFILE CAPTURE MODE
CPU PROGRAM COUNTER
CONTROL
COMPARATOR A
ADDRESS/DATA/CONTROL
COMPARATOR B
COMPARATOR C
REGISTERS
TRACER
BUFFER
CONTROL
LOGIC
CHANGE-OF-FLOW
INDICATORS
OR PROFILING DATA
64 x 16 BIT
WORD
TRACE
BUFFER
PROFILE
CAPTURE
REGISTER
LAST
INSTRUCTION
ADDRESS
BUS CLOCK
INSTRUCTION
LAST CYCLE
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
474 Freescale Semiconductor
16.3 Memory Map and Register Definition
A summary of the registers associated with the DBG sub-block is shown in Figure 16-3. Detailed
descriptions of the registers and bits are given in the subsections that follow.
16.3.1 Module Memory Map
16.3.2 Register Descriptions
This section consists of the DBG register descriptions in address order. Most of the register bits can be
written to in either BKP or DBG mode, although they may not have any effect in one of the modes.
However , the only bits in the DBG module that can be written while the debugger is armed (ARM = 1) are
DBGEN and ARM
Table 16-2. DBGV1 Memory Map
Address
Offset Use Access
Debug Control Register (DBGC1) R/W
Debug Status and Control Register (DBGSC) R/W
Debug Trace Buffer Register High (DBGTBH) R
Debug Trace Buffer Register Low (DBGTBL) R
4 Debug Count Register (DBGCNT) R
5 Debug Comparator C Extended Register (DBGCCX) R/W
6 Debug Comparator C Register High (DBGCCH) R/W
Debug Comparator C Register Low (DBGCCL) R/W
8 Debug Control Register 2 (DBGC2) / (BKPCT0) R/W
9 Debug Control Register 3 (DBGC3) / (BKPCT1) R/W
A Debug Comparator A Extended Register (DBGCAX) / (/BKP0X) R/W
B Debug Comparator A Register High (DBGCAH) / (BKP0H) R/W
Debug Comparator A Register Low (DBGCAL) / (BKP0L) R/W
Debug Comparator B Extended Register (DBGCBX) / (BKP1X) R/W
E Debug Comparator B Register High (DBGCBH) / (BKP1H) R/W
F Debug Comparator B Register Low (DBGCBL) / (BKP1L) R/W
Name1Bit 7654321Bit 0
DBGC1 RDBGEN ARM TRGSEL BEGIN DBGBRK 0CAPMOD
W
DBGSC RAF BF CF 0 TRG
W
= Unimplemented or Reserved
Figure 16-3. DBG Register Summary
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 475
DBGTBH R Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
DBGTBL RBit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
W
DBGCNT RTBF 0 CNT
W
DBGCCX(2)RPAGSEL EXTCMP
W
DBGCCH(2) RBit 15 14 13 12 11 10 9 Bit 8
W
DBGCCL(2) RBit 7654321Bit 0
W
DBGC2
BKPCT0
RBKABEN FULL BDM TAGAB BKCEN TAGC RWCEN RWC
W
DBGC3
BKPCT1
RBKAMBH BKAMBL BKBMBH BKBMBL RWAEN RWA RWBEN RWB
W
DBGCAX
BKP0X
RPAGSEL EXTCMP
W
DBGCAH
BKP0H
RBit 15 14 13 12 11 10 9 Bit 8
W
DBGCAL
BKP0L
RBit 7654321Bit 0
W
DBGCBX
BKP1X
RPAGSEL EXTCMP
W
DBGCBH
BKP1H
RBit 15 14 13 12 11 10 9 Bit 8
W
DBGCBL
BKP1L
RBit 7654321Bit 0
W
1The DBG module is designed for backwards compatibility to existing BKP modules. Register and bit names have changed from
the BKP module. This column shows the DBG register name, as well as the BKP register name for reference.
2Comparator C can be used to enhance the BKP mode by providing a third breakpoint.
Name1Bit 7654321Bit 0
= Unimplemented or Reserved
Figure 16-3. DBG Register Summary (continued)
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
476 Freescale Semiconductor
16.3.2.1 Debug Control Register 1 (DBGC1)
NOTE
All bits are used in DBG mode only.
NOTE
This register cannot be written if BKP mode is enabled (BKABEN in
DBGC2 is set).
76543210
R
DBGEN ARM TRGSEL BEGIN DBGBRK
0
CAPMOD
W
Reset00000000
= Unimplemented or Reserved
Figure 16-4. Debug Control Register (DBGC1)
Table 16-3. DBGC1 Field Descriptions
Field Description
7
DBGEN
DBG Mode Enable Bit — The DBGEN bit enables the DBG module for use in DBG mode. This bit cannot be set
if the MCU is in secure mode.
0 DBG mode disabled
1 DBG mode enabled
6
ARM
Arm Bit — The ARM bit controls whether the debugger is comparing and storing data in the trace buffer. See
Section 16.4.2.4, “Arming the DBG Module,” for more information.
0 Debugger unarmed
1 Debugger armed
Note: This bit cannot be set if the DBGEN bit is not also being set at the same time. For example, a write of 01
to DBGEN[7:6] will be interpreted as a write of 00.
5
TRGSEL
Trigger Selection Bit — The TRGSEL bit controls the triggering condition for comparators A and B in DBG
mode. It serves essentially the same function as the TAGAB bit in the DBGC2 register does in BKP mode. See
Section 16.4.2.1.2, “Trigger Selection,” for more information. TRGSEL may also determine the type of breakpoint
based on comparator A and B if enabled in DBG mode (DBGBRK = 1). Please refer to Section 16.4.3.1,
“Breakpoint Based on Comparator A and B.”
0 Trigger on any compare address match
1 Trigger before opcode at compare address gets executed (tagged-type)
4
BEGIN
Begin/End Trigger Bit — The BEGIN bit controls whether the trigger begins or ends storing of data in the trace
buffer. See Section 16.4.2.8.1, “Storing with Begin-Trigger,” and Section 16.4.2.8.2, “Storing with End-Trigger,”
for more details.
0 Trigger at end of stored data
1 Trigger before storing data
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 477
3
DBGBRK
DBG Breakpoint Enable Bit — The DBGBRK bit controls whether the debugger will request a breakpoint based
on comparator A and B to the CPU upon completion of a tracing session. Please refer to Section 16.4.3,
“Breakpoints,” for further details.
0 CPU break request not enabled
1 CPU break request enabled
1:0
CAPMOD
Capture Mode Field — See Ta ble 16-4 for capture mode field definitions. In LOOP1 mode, the debugger will
automatically inhibit redundant entries into capture memory. In detail mode, the debugger is storing address and
data for all cycles except program fetch (P) and free (f) cycles. In profile mode, the debugger is returning the
address of the last instruction executed by the CPU on each access of trace buffer address. Refer to
Section 16.4.2.6, “Capture Modes,” for more information.
Table 16-4. CAPMOD Encoding
CAPMOD Description
00 Normal
01 LOOP1
10 DETAIL
11 PROFILE
Table 16-3. DBGC1 Field Descriptions (continued)
Field Description
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
478 Freescale Semiconductor
16.3.2.2 Debug Status and Control Register (DBGSC)
76543210
RAF BF CF 0
TRG
W
Reset00000000
= Unimplemented or Reserved
Figure 16-5. Debug Status and Control Register (DBGSC)
Table 16-5. DBGSC Field Descriptions
Field Description
7
AF
Trigger A Match Flag — The AF bit indicates if trigger A match condition was met since arming. This bit is
cleared when ARM in DBGC1 is written to a 1 or on any write to this register.
0 Trigger A did not match
1 Trigger A match
6
BF
Trigger B Match Flag — The BF bit indicates if trigger B match condition was met since arming.This bit is cleared
when ARM in DBGC1 is written to a 1 or on any write to this register.
0 Trigger B did not match
1 Trigger B match
5
CF
Comparator C Match Flag — The CF bit indicates if comparator C match condition was met since arming.This
bit is cleared when ARM in DBGC1 is written to a 1 or on any write to this register.
0 Comparator C did not match
1 Comparator C match
3:0
TRG
Trigger Mode Bits — The TRG bits select the trigger mode of the DBG module as shown Ta b l e 1 6 - 6 . See
Section 16.4.2.5, “Trigger Modes,” for more detail.
Table 16-6. Trigger Mode Encoding
TRG Value Meaning
0000 A only
0001 A or B
0010 A then B
0011 Event only B
0100 A then event only B
0101 A and B (full mode)
0110 A and Not B (full mode)
0111 Inside range
1000 Outside range
1001
↓
1111
Reserved
(Defaults to A only)
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 479
16.3.2.3 Debug Trace Buffer Register (DBGTB)
15 14 13 12 11 10 9 8
R Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
Resetuuuuuuuu
= Unimplemented or Reserved
Figure 16-6. Debug Trace Buffer Register High (DBGTBH)
76543210
RBit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
W
Resetuuuuuuuu
= Unimplemented or Reserved
Figure 16-7. Debug Trace Buffer Register Low (DBGTBL)
Table 16-7. DBGTB Field Descriptions
Field Description
15:0 Trace Buffer Data Bits — The trace buffer data bits contain the data of the trace buffer. This register can be read
only as a word read. Any byte reads or misaligned access of these registers will return 0 and will not cause the
trace buffer pointer to increment to the next trace buffer address. The same is true for word reads while the
debugger is armed. In addition, this register may appear to contain incorrect data if it is not read with the same
capture mode bit settings as when the trace buffer data was recorded (See Section 16.4.2.9, “Reading Data from
Trace Buffer”). Because reads will reflect the contents of the trace buffer RAM, the reset state is undefined.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
480 Freescale Semiconductor
16.3.2.4 Debug Count Register (DBGCNT)
76543210
R TBF 0 CNT
W
Reset00000000
= Unimplemented or Reserved
Figure 16-8. Debug Count Register (DBGCNT)
Table 16-8. DBGCNT Field Descriptions
Field Description
7
TBF
Trace Buffer Full — The TBF bit indicates that the trace buffer has stored 64 or more words of data since it was
last armed. If this bit is set, then all 64 words will be valid data, regardless of the value in CNT[5:0]. The TBF bit
is cleared when ARM in DBGC1 is written to a 1.
5:0
CNT
Count Value — The CNT bits indicate the number of valid data words stored in the trace buffer. Table 16-9 shows
the correlation between the CNT bits and the number of valid data words in the trace buffer. When the CNT rolls
over to 0, the TBF bit will be set and incrementing of CNT will continue if DBG is in end-trigger mode. The
DBGCNT register is cleared when ARM in DBGC1 is written to a 1.
Table 16-9. CNT Decoding Table
TBF CNT Description
0 000000 No data valid
0 000001 1 word valid
0 000010
..
..
111110
2 words valid
..
..
62 words valid
0 111111 63 words valid
1 000000 64 words valid; if BEGIN = 1, the
ARM bit will be cleared. A
breakpoint will be generated if
DBGBRK = 1
1 000001
..
..
111111
64 words valid,
oldest data has been overwritten
by most recent data
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 481
16.3.2.5 Debug Comparator C Extended Register (DBGCCX)
76543210
R
PAGSEL EXTCMP
W
Reset00000000
Figure 16-9. Debug Comparator C Extended Register (DBGCCX)
Table 16-10. DBGCCX Field Descriptions
Field Description
7:6
PAGSEL
Page Selector Field — In both BKP and DBG mode, PAGSEL selects the type of paging as shown in
Ta b le 1 6 - 1 1 .
DPAGE and EPAGE are not yet implemented so the value in bit 7 will be ignored (i.e., PAGSEL values of 10 and
11 will be interpreted as values of 00 and 01, respectively).
5:0
EXTCMP
Comparator C Extended Compare Bits — The EXTCMP bits are used as comparison address bits as shown
in Table 16-11 along with the appropriate PPAGE, DPAGE, or EPAGE signal from the core.
Note: Comparator C can be used when the DBG module is configured for BKP mode. Extended addressing
comparisons for comparator C use PAGSEL and will operate differently to the way that comparator A and
B operate in BKP mode.
Table 16-11. PAGSEL Decoding1
1See Figure 16-10.
PAGSEL Description EXTCMP Comment
00 Normal (64k) Not used No paged memory
01 PPAGE
(256 — 16K pages)
EXTCMP[5:0] is compared to
address bits [21:16]2
2Current HCS12 implementations have PPAGE limited to 6 bits. Therefore, EXTCMP[5:4] should be set to 00.
PPAGE[7:0] / XAB[21:14] becomes
address bits [21:14]1
103
3Data page (DPAGE) and Extra page (EPAGE) are reserved for implementation on devices that support paged data and extra
space.
DPAGE (reserved)
(256 — 4K pages)
EXTCMP[3:0] is compared to
address bits [19:16]
DPAGE / XAB[21:14] becomes address
bits [19:12]
112EPAGE (reserved)
(256 — 1K pages)
EXTCMP[1:0] is compared to
address bits [17:16]
EPAGE / XAB[21:14] becomes address
bits [17:10]
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
482 Freescale Semiconductor
16.3.2.6 Debug Comparator C Register (DBGCC)
DBGCXX DBGCXH[15:12]
PAGSEL EXTCMP
BIT 15 BIT 14 BIT 13 BIT 12
76
0
5
0
43 2 1 BIT 0
SEE NOTE 1
PORTK/XAB XAB21 XAB20 XAB19 XAB18 XAB17 XAB16 XAB15 XAB14
PPAGE PIX7 PIX6 PIX5 PIX4 PIX3 PIX2 PIX1 PIX0
SEE NOTE 2
NOTES:
1. In BKP and DBG mode, PAGSEL selects the type of paging as shown in Table 16-11.
2. Current HCS12 implementations are limited to six PPAGE bits, PIX[5:0]. Therefore, EXTCMP[5:4] = 00.
Figure 16-10. Comparator C Extended Comparison in BKP/DBG Mode
15 14 13 12 11 10 9 8
R Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
Reset00000000
= Unimplemented or Reserved
Figure 16-11. Debug Comparator C Register High (DBGCCH)
76543210
RBit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
W
Reset00000000
= Unimplemented or Reserved
Figure 16-12. Debug Comparator C Register Low (DBGCCL)
Table 16-12. DBGCC Field Descriptions
Field Description
15:0 Comparator C Compare Bits — The comparator C compare bits control whether comparator C will compare
the address bus bits [15:0] to a logic 1 or logic 0. See Table 16-13.
0 Compare corresponding address bit to a logic 0
1 Compare corresponding address bit to a logic 1
Note: This register will be cleared automatically when the DBG module is armed in LOOP1 mode.
BKP/DBG MODE
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 483
16.3.2.7 Debug Control Register 2 (DBGC2)
Figure 16-13. Debug Control Register 2 (DBGC2)
Table 16-13. Comparator C Compares
PAGSEL EXTCMP Compare High-Byte Compare
x0 No compare DBGCCH[7:0] = AB[15:8]
x1 EXTCMP[5:0] = XAB[21:16] DBGCCH[7:0] = XAB[15:14],AB[13:8]
76543210
R
BKABEN1
1When BKABEN is set (BKP mode), all bits in DBGC2 are available. When BKABEN is cleared and DBG is used in DBG mode,
bits FULL and TAGAB have no meaning.
FULL BDM TAGAB BKCEN2
2These bits can be used in BKP mode and DBG mode (when capture mode is not set in LOOP1) to provide a third breakpoint.
TAG C 2RWCEN2RWC2
W
Reset00000000
Table 16-14. DBGC2 Field Descriptions
Field Description
7
BKABEN
Breakpoint Using Comparator A and B Enable — This bit enables the breakpoint capability using comparator
A and B, when set (BKP mode) the DBGEN bit in DBGC1 cannot be set.
0 Breakpoint module off
1 Breakpoint module on
6
FULL
Full Breakpoint Mode Enable — This bit controls whether the breakpoint module is in dual mode or full mode.
In full mode, comparator A is used to match address and comparator B is used to match data. See
Section 16.4.1.2, “Full Breakpoint Mode,” for more details.
0 Dual address mode enabled
1 Full breakpoint mode enabled
5
BDM
Background Debug Mode Enable — This bit determines if the breakpoint causes the system to enter
background debug mode (BDM) or initiate a software interrupt (SWI).
0 Go to software interrupt on a break request
1 Go to BDM on a break request
4
TAG A B
Comparator A/B Tag Select — This bit controls whether the breakpoint will cause a break on the next instruction
boundary (force) or on a match that will be an executable opcode (tagged). Non-executed opcodes cannot cause
a tagged breakpoint.
0 On match, break at the next instruction boundary (force)
1 On match, break if/when the instruction is about to be executed (tagged)
3
BKCEN
Breakpoint Comparator C Enable Bit — This bit enables the breakpoint capability using comparator C.
0 Comparator C disabled for breakpoint
1 Comparator C enabled for breakpoint
Note: This bit will be cleared automatically when the DBG module is armed in loop1 mode.
2
TAG C
Comparator C Tag Select — This bit controls whether the breakpoint will cause a break on the next instruction
boundary (force) or on a match that will be an executable opcode (tagged). Non-executed opcodes cannot cause
a tagged breakpoint.
0 On match, break at the next instruction boundary (force)
1 On match, break if/when the instruction is about to be executed (tagged)
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
484 Freescale Semiconductor
16.3.2.8 Debug Control Register 3 (DBGC3)
Figure 16-14. Debug Control Register 3 (DBGC3)
1
RWCEN
Read/Write Comparator C Enable Bit — The RWCEN bit controls whether read or write comparison is enabled
for comparator C. RWCEN is not useful for tagged breakpoints.
0 Read/Write is not used in comparison
1 Read/Write is used in comparison
0
RWC
Read/Write Comparator C Value Bit — The RWC bit controls whether read or write is used in compare for
comparator C. The RWC bit is not used if RWCEN = 0.
0 Write cycle will be matched
1 Read cycle will be matched
76543210
R
BKAMBH1
1In DBG mode, BKAMBH:BKAMBL has no meaning and are forced to 0’s.
BKAMBL1BKBMBH2
2In DBG mode, BKBMBH:BKBMBL are used in full mode to qualify data.
BKBMBL2RWAEN RWA RWBEN RWB
W
Reset00000000
Table 16-15. DBGC3 Field Descriptions
Field Description
7:6
BKAMB[H:L]
Breakpoint Mask High Byte for First Address — In dual or full mode, these bits may be used to mask (disable)
the comparison of the high and/or low bytes of the first address breakpoint. The functionality is as given in
Ta b le 1 6 - 1 6 .
The x:0 case is for a full address compare. When a program page is selected, the full address compare will be
based on bits for a 20-bit compare. The registers used for the compare are {DBGCAX[5:0], DBGCAH[5:0],
DBGCAL[7:0]}, where DBGAX[5:0] corresponds to PPAGE[5:0] or extended address bits [19:14] and CPU
address [13:0]. When a program page is not selected, the full address compare will be based on bits for a 16-bit
compare. The registers used for the compare are {DBGCAH[7:0], DBGCAL[7:0]} which corresponds to CPU
address [15:0].
Note: This extended address compare scheme causes an aliasing problem in BKP mode in which several
physical addresses may match with a single logical address. This problem may be avoided by using DBG
mode to generate breakpoints.
The 1:0 case is not sensible because it would ignore the high order address and compare the low order and
expansion addresses. Logic forces this case to compare all address lines (effectively ignoring the BKAMBH
control bit).
The 1:1 case is useful for triggering a breakpoint on any access to a particular expansion page. This only makes
sense if a program page is being accessed so that the breakpoint trigger will occur only if DBGCAX compares.
Table 16-14. DBGC2 Field Descriptions (continued)
Field Description
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 485
5:4
BKBMB[H:L]
Breakpoint Mask High Byte and Low Byte of Data (Second Address) — In dual mode, these bits may be
used to mask (disable) the comparison of the high and/or low bytes of the second address breakpoint. The
functionality is as given in Table 16-17.
The x:0 case is for a full address compare. When a program page is selected, the full address compare will be
based on bits for a 20-bit compare. The registers used for the compare are {DBGCBX[5:0], DBGCBH[5:0],
DBGCBL[7:0]} where DBGCBX[5:0] corresponds to PPAGE[5:0] or extended address bits [19:14] and CPU
address [13:0]. When a program page is not selected, the full address compare will be based on bits for a 16-bit
compare. The registers used for the compare are {DBGCBH[7:0], DBGCBL[7:0]} which corresponds to CPU
address [15:0].
Note: This extended address compare scheme causes an aliasing problem in BKP mode in which several
physical addresses may match with a single logical address. This problem may be avoided by using DBG
mode to generate breakpoints.
The 1:0 case is not sensible because it would ignore the high order address and compare the low order and
expansion addresses. Logic forces this case to compare all address lines (effectively ignoring the BKBMBH
control bit).
The 1:1 case is useful for triggering a breakpoint on any access to a particular expansion page. This only makes
sense if a program page is being accessed so that the breakpoint trigger will occur only if DBGCBX compares.
In full mode, these bits may be used to mask (disable) the comparison of the high and/or low bytes of the data
breakpoint. The functionality is as given in Table 16-18.
3
RWAEN
Read/Write Comparator A Enable Bit — The RWAEN bit controls whether read or write comparison is enabled
for comparator A. See Section 16.4.2.1.1, “Read or Write Comparison,” for more information. This bit is not useful
for tagged operations.
0 Read/Write is not used in comparison
1 Read/Write is used in comparison
2
RWA
Read/Write Comparator A Value Bit — The RWA bit controls whether read or write is used in compare for
comparator A. The RWA bit is not used if RWAEN = 0.
0 Write cycle will be matched
1 Read cycle will be matched
1
RWBEN
Read/Write Comparator B Enable Bit — The RWBEN bit controls whether read or write comparison is enabled
for comparator B. See Section 16.4.2.1.1, “Read or Write Comparison,” for more information. This bit is not useful
for tagged operations.
0 Read/Write is not used in comparison
1 Read/Write is used in comparison
0
RWB
Read/Write Comparator B Value Bit — The RWB bit controls whether read or write is used in compare for
comparator B. The RWB bit is not used if RWBEN = 0.
0 Write cycle will be matched
1 Read cycle will be matched
Note: RWB and RWBEN are not used in full mode.
Table 16-16. Breakpoint Mask Bits for First Address
BKAMBH:BKAMBL Address Compare DBGCAX DBGCAH DBGCAL
x:0 Full address compare Yes1
1If PPAGE is selected.
Ye s Ye s
0:1 256 byte address range Yes1Ye s N o
1:1 16K byte address range Yes1No No
Table 16-15. DBGC3 Field Descriptions (continued)
Field Description
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
486 Freescale Semiconductor
Table 16-17. Breakpoint Mask Bits for Second Address (Dual Mode)
BKBMBH:BKBMBL Address Compare DBGCBX DBGCBH DBGCBL
x:0 Full address compare Yes1
1If PPAGE is selected.
Ye s Ye s
0:1 256 byte address range Yes1Ye s N o
1:1 16K byte address range Yes1No No
Table 16-18. Breakpoint Mask Bits for Data Breakpoints (Full Mode)
BKBMBH:BKBMBL Data Compare DBGCBX DBGCBH DBGCBL
0:0 High and low byte compare No1
1Expansion addresses for breakpoint B are not applicable in this mode.
Ye s Ye s
0:1 High byte No1Ye s N o
1:0 Low byte No1No Yes
1:1 No compare No1No No
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 487
16.3.2.9 Debug Comparator A Extended Register (DBGCAX)
76543210
R
PAGSEL EXTCMP
W
Reset00000000
Figure 16-15. Debug Comparator A Extended Register (DBGCAX)
Table 16-19. DBGCAX Field Descriptions
Field Description
7:6
PAGSEL
Page Selector Field — If DBGEN is set in DBGC1, then PAGSEL selects the type of paging as shown in
Ta b le 1 6 - 2 0 .
DPAGE and EPAGE are not yet implemented so the value in bit 7 will be ignored (i.e., PAGSEL values of 10 and
11 will be interpreted as values of 00 and 01, respectively).
In BKP mode, PAGSEL has no meaning and EXTCMP[5:0] are compared to address bits [19:14] if the address
is in the FLASH/ROM memory space.
5:0
EXTCMP
Comparator A Extended Compare Bits — The EXTCMP bits are used as comparison address bits as shown
in Table 16-20 along with the appropriate PPAGE, DPAGE, or EPAGE signal from the core.
Table 16-20. Comparator A or B Compares
Mode EXTCMP Compare High-Byte Compare
BKP1
1See Figure 16-16.
Not FLASH/ROM access No compare DBGCxH[7:0] = AB[15:8]
FLASH/ROM access EXTCMP[5:0] = XAB[19:14] DBGCxH[5:0] = AB[13:8]
DBG2
2See Figure 16-10 (note that while this figure provides extended comparisons for comparator C, the figure also pertains to
comparators A and B in DBG mode only).
PAGSEL = 00 No compare DBGCxH[7:0] = AB[15:8]
PAGSEL = 01 EXTCMP[5:0] = XAB[21:16] DBGCxH[7:0] = XAB[15:14], AB[13:8]
PAGSEL EXTCMP
DBGCXX 0 0 54321BIT 0
SEE NOTE 1
PORTK/XAB XAB21 XAB20 XAB19 XAB18 XAB17 XAB16 XAB15 XAB14
PPAGE PIX7 PIX6 PIX5 PIX4 PIX3 PIX2 PIX1 PIX0
SEE NOTE 2
NOTES:
1. In BKP mode, PAGSEL has no functionality. Therefore, set PAGSEL to 00 (reset state).
2. Current HCS12 implementations are limited to six PPAGE bits, PIX[5:0].
Figure 16-16. Comparators A and B Extended Comparison in BKP Mode
BKP MODE
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
488 Freescale Semiconductor
16.3.2.10 Debug Comparator A Register (DBGCA)
16.3.2.11 Debug Comparator B Extended Register (DBGCBX)
15 14 13 12 11 10 9 8
R
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
Reset00000000
Figure 16-17. Debug Comparator A Register High (DBGCAH)
76543210
R
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
W
Reset00000000
Figure 16-18. Debug Comparator A Register Low (DBGCAL)
Table 16-21. DBGCA Field Descriptions
Field Description
15:0
15:0
Comparator A Compare Bits — The comparator A compare bits control whether comparator A compares the
address bus bits [15:0] to a logic 1 or logic 0. See Ta bl e 1 6 - 2 0 .
0 Compare corresponding address bit to a logic 0
1 Compare corresponding address bit to a logic 1
76543210
R
PAGSEL EXTCMP
W
Reset00000000
Figure 16-19. Debug Comparator B Extended Register (DBGCBX)
Table 16-22. DBGCBX Field Descriptions
Field Description
7:6
PAGSEL
Page Selector Field — If DBGEN is set in DBGC1, then PAGSEL selects the type of paging as shown in
Ta b le 1 6 - 1 1 .
DPAGE and EPAGE are not yet implemented so the value in bit 7 will be ignored (i.e., PAGSEL values of 10 and
11 will be interpreted as values of 00 and 01, respectively.)
In BKP mode, PAGSEL has no meaning and EXTCMP[5:0] are compared to address bits [19:14] if the address
is in the FLASH/ROM memory space.
5:0
EXTCMP
Comparator B Extended Compare Bits — The EXTCMP bits are used as comparison address bits as shown
in Table 16-11 along with the appropriate PPAGE, DPAGE, or EPAGE signal from the core. Also see Table 16-20.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 489
16.3.2.12 Debug Comparator B Register (DBGCB)
16.4 Functional Description
This section provides a complete functional description of the DBG module. The DBG module can be
configured to run in either of two modes, BKP or DBG. BKP mode is enabled by setting BKABEN in
DBGC2. DBG mode is enabled by setting DBGEN in DBGC1. Setting BKABEN in DBGC2 overrides the
DBGEN in DBGC1 and prevents DBG mode. If the part is in secure mode, DBG mode cannot be enabled.
16.4.1 DBG Operating in BKP Mode
In BKP mode, the DBG will be fully backwards compatible with the existing BKP_ST12_A module. The
DBGC2 register has four additional bits that were not available on existing BKP_ST12_A modules. As
long as these bits are written to either all 1s or all 0s, they should be transparent to the user. All 1s would
enable comparator C to be used as a breakpoint, but tagging would be enabled. Th e match address register
would be all 0s if not modified by the user. Therefore, code executing at address 0x0000 would have to
occur before a breakpoint based on comparator C would happen.
The DBG module in BKP mode supports two modes of operation: dual address mode and full breakpoint
mode. Within each of these modes, forced or tagged breakpoint types can be used. Forced breakpoints
occur at the next instruction boundary if a match occurs and tagged breakpoints allow for breaking just
before the tagged instruction executes. The action taken upon a successful match can be to either place the
CPU in background debug mode or to initiate a software interrupt.
15 14 13 12 11 10 9 8
R
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
W
Reset00000000
Figure 16-20. Debug Comparator B Register High (DBGCBH)
76543210
R
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
W
Reset00000000
Figure 16-21. Debug Comparator B Register Low (DBGCBL)
Table 16-23. DBGCB Field Descriptions
Field Description
15:0
15:0
Comparator B Compare Bits — The comparator B compare bits control whether comparator B compares the
address bus bits [15:0] or data bus bits [15:0] to a logic 1 or logic 0. See Table 16-20.
0 Compare corresponding address bit to a logic 0, compares to data if in Full mode
1 Compare corresponding address bit to a logic 1, compares to data if in Full mode
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
490 Freescale Semiconductor
The breakpoint can operate in dual address mode or full breakpoint mode. Each of these modes is
discussed in the subsections below.
16.4.1.1 Dual Address Mode
When dual address mode is enabled, two address breakpoints can be set. Each breakpoint can cause the
system to enter background debug mode or to initiate a software interrupt based upon the state of BDM in
DBGC2 being logic 1 or logic 0, respectively . BDM requests have a higher priority than SWI requests. No
data breakpoints are allowed in this mode.
TAGAB in DBGC2 selects whether the breakpoint mode is forced or tagged. The BKxMBH:L bits in
DBGC3 select whether or not the breakpoint is matched exactly or is a range breakpoint. They also select
whether the address is matched on the high byte, low byte, both bytes, and/or memory expansion. The
RWx and RWxEN bits in DBGC3 select whether the type of bus cycle to match is a read, write, or
read/write when performing forced breakpoints.
16.4.1.2 Full Breakpoint Mode
Full breakpoint mode requires a match on address and data for a breakpoint to occur. Upon a successful
match, the system will enter background debug mode or initiate a software interrupt based upon the state
of BDM in DBGC2 being logic 1 or logic 0, respectively. BDM requests have a higher priority than SWI
requests. R/W matches are also allowed in this mode.
TAGAB in DBGC2 selects whether the breakpoint mode is forced or tagged. When TAGAB is set in
DBGC2, only addresses are compared and data is ignored. The BKAMBH:L bits in DBGC3 select
whether or not the breakpoint is matched exactly, is a range breakpoint, or is in page space. The
BKBMBH:L bits in DBGC3 select whether the data is matched on the high byte, low byte, or both bytes.
RWA and RWAEN bits in DBGC2 select whether the type of bus cycle to match is a read or a write when
performing forced breakpoints. RWB and RWBEN bits in DBGC2 are not used in full breakpoint mode.
NOTE
The full trigger mode is designed to be used for either a word access or a
byte access, but not both at the same time. Confusing trigger operation
(seemingly false triggers or no trigger) can occur if the trigger address
occurs in the user program as both byte and word accesses.
16.4.1.3 Breakpoint Priority
Breakpoint operation is first determined by the state of the BDM module. If the BDM module is already
active, meaning the CPU is executing out of BDM firmware, breakpoints are not allowed. In addition,
while executing a BDM TRACE command, tagging into BDM is not allowed. If BDM is not active, the
breakpoint will give priority to BDM requests over SWI requests. This condition applies to both forced
and tagged breakpoints.
In all cases, BDM related breakpoints will have priority over those generated by the Breakpoint sub-block.
This priority includes breakpoints enabled by the TAGLO and TAGHI external pins of the system that
interface with the BDM directly and whose signal information passes through and is used by the
breakpoint sub-block.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 491
NOTE
BDM should not be entered from a breakpoint unless the ENABLE bit is set
in the BDM. Even if the ENABLE bit in the BDM is cleared, the CPU
actually executes the BDM firmware code. It checks the ENABLE and
returns if ENABLE is not set. If the BDM is not serviced by the monitor then
the breakpoint would be re-asserted when the BDM returns to normal CPU
flow.
There is no hardware to enforce restriction of breakpoint operation if the
BDM is not enabled.
When program control returns from a tagged breakpoint through an RTI or
a BDM GO command, it will return to the instruction whose tag generated
the breakpoint. Unless breakpoints are disabled or modified in the service
routine or active BDM session, the instruction will be tagged again and the
breakpoint will be repeated. In the case of BDM breakpoints, this situation
can also be avoided by executing a TRACE1 command before the GO to
increment the program flow past the tagged instruction.
16.4.1.4 Using Comparator C in BKP Mode
The original BKP_ST12_A module supports two breakpoints. The DBG_ST12_A module can be used in
BKP mode and allow a third breakpoint using comparator C. Four additional bits, BKCEN, TAGC,
R WCEN, and RWC in DBGC2 in conjunction with additional comparator C address registers, DBGCCX,
DBGCCH, and DBGCCL allow the user to set up a third breakpoint. Using PAGSEL in DBGCCX for
expanded memory will work diff erently than the way paged memory is done using comparator A and B in
BKP mode. See Section 16.3.2.5, “Debug Comparator C Extended Register (DBGCCX),” for more
information on using comparator C.
16.4.2 DBG Operating in DBG Mode
Enabling the DBG module in DBG mode, allows the arming, triggering, and storing of data in the trace
buffer and can be used to cause CPU breakpoints. The DBG module is made up of three main blocks, the
comparators, trace buffer control logic, and the trace buffer.
NOTE
In general, there is a latency between the triggering event appearing on the
bus and being detected by the DBG circuitry . In general, tagged triggers will
be more predictable than forced triggers.
16.4.2.1 Comparators
The DBG contains three comparators, A, B, and C. Comparator A compares the core address bus with the
address stored in DBGCAH and DBGCAL. Comparator B compares the core address bus with the address
stored in DBGCBH and DBGCBL except in full mode, where it compares the data buses to the data stored
in DBGCBH and DBGCBL. Comparator C can be used as a breakpoint generator or as the address
comparison unit in the loop1 mode. Matches on comparator A, B, and C are signaled to the trace buffer
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
492 Freescale Semiconductor
control (TBC) block. When PAGSEL = 01, registers DBGCAX, DBGCBX, and DBGCCX are used to
match the upper addresses as shown in Table 16-11.
NOTE
If a tagged-type C breakpoint is set at the same address as an A/B
tagged-type trigger (including the initial entry in an inside or outside range
trigger), the C breakpoint will have priority and the trigger will not be
recognized.
16.4.2.1.1 Read or Write Comparison
Read or write comparisons are useful only with TRGSEL = 0, because only opcodes should be tagged as
they are “read” from memory. RWAEN and RWBEN are ignored when TRGSEL = 1.
In full modes (“A and B” and “A and not B”) RWAEN and RWA are used to select re ad or write
comparisons for both comparators A and B. Table 16-24 shows the ef fect for RWAEN, RWA, and RW on
the DBGCB comparison conditions. The RWBEN and RWB bits are not used and are ignored in full
modes.
16.4.2.1.2 Trigger Selection
The TRGSEL bit in DBGC1 is used to determine the triggering condition in DBG mode. TRGSEL applies
to both trigger A and B except in the event only trigger modes. By setting TRGSEL, the comparators A
and B will qualify a match with the output of opcode tracking logic and a trigger occurs before the tagged
instruction executes (tagged-type trigger). With the TRGSEL bit cleared, a comparator match forces a
trigger when the matching condition occurs (force-type trigger).
NOTE
If the TRGSEL is set, the address stored in the comparator match address
registers must be an opcode address for the trigger to occur.
16.4.2.2 Trace Buffer Control (TBC)
The TBC is the main controller for the DBG module. Its function is to decide whether data should be stored
in the trace buffer based on the trigger mode and the match signals from the comparator. The TBC also
determines whether a request to break the CPU should occur.
Table 16-24. Read or Write Comparison Logic Table
RWAEN bit RWA bit RW signal Comment
0 x 0 Write data bus
0 x 1 Read data bus
1 0 0 Write data bus
1 0 1 No data bus compare since RW=1
1 1 0 No data bus compare since RW=0
1 1 1 Read data bus
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 493
16.4.2.3 Begin- and End-Trigger
The definitions of begin- and end-trigger as used in the DBG module are as follows:
• Begin-trigger: Sto rage in trace buffer occurs after the trigger and continues until 64 locations are
filled.
• End-trigger: S torage in trace buffer occurs until th e trigger , with the least recent data falling out of
the trace buffer if more than 64 words are collected.
16.4.2.4 Arming the DBG Module
In DBG mode, arming occurs by setting DBGEN and ARM in DBGC1. The ARM bit in DBGC1 is cleared
when the trigger condition is met in end-trigger mode or when the Trace Buffer is filled in begin-trigger
mode. The TBC logic determines whether a trigger condition has been met based on the trigger mode and
the trigger selection.
16.4.2.5 Trigger Modes
The DBG module supports nine trigger modes. The trigger modes are encoded as shown in Table 16-6.
The trigger mode is used as a qualifier for either starting or ending the storing of data in the trace buffer.
When the match condition is met, the appropriate flag A or B is set in DBGSC. Arming the DBG module
clears the A, B, and C flags in DBGSC. In all trigger modes except for the event-only modes and DETAIL
capture mode, change-of-flow addresses are stored in the trace buffer. In the event-only modes only the
value on the data bus at the trigger event B will be stored. In DETAIL capture mode address and data for
all cycles except program fetch (P) and free (f) cycles are stored in trace buffer.
16.4.2.5.1 A Only
In the A only trigger mode, if the match condition for A is met, the A flag in DBGSC is set and a trigger
occurs.
16.4.2.5.2 A or B
In the A or B trigger mode, if the match condition for A or B is met, the corresponding flag in DBGSC is
set and a trigger occurs.
16.4.2.5.3 A then B
In the A then B trigger mode, the match condition for A must be met before the match condition for B is
compared. When the match condition for A or B is met, the corresponding flag in DBGSC is set. The
trigger occurs only after A then B have matched.
NOTE
When tagging and using A then B, if addresses A and B are close together ,
then B may not complete the trigger sequence. This occurs when A and B
are in the instruction queue at the same time. Basically the A trigge r has not
yet occurred, so the B instruction is not tagged. Generally, if address B is at
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
494 Freescale Semiconductor
least six addresses higher than address A (or B is lower than A) and there
are not changes of flow to put these in the queue at the same time, then this
operation should trigger properly.
16.4.2.5.4 Event-Only B (Store Data)
In the event-only B trigger mode, if the match condition for B is met, the B flag in DBGSC is set and a
trigger occurs. The event-only B trigger mode is considered a begin-trigger type and the BEGIN bit in
DBGC1 is ignored. Event-only B is incompatible with instruction tagging (TRGSEL = 1), and thus the
value of TRGSEL is ignored. Please refer to Section 16.4.2.7, “Storage Memory,” for more information.
This trigger mode is incompatible with the detail capture mode so the detail capture mode will have
priority. TRGSEL and BEGIN will not be ignored and this trigger mode will behave as if it were “B only”.
16.4.2.5.5 A then Event-Only B (Store Data)
In the A then event-only B trigger mode, the match condition for A must be met before the match condition
for B is compared, after the A match has occurred, a trigger occurs each time B matches. When the match
condition for A or B is met, the corresponding flag in DBGSC is set. The A then event-only B trigger mode
is considered a begin-trigger type and BEGIN in DBGC1 is ignored. TRGSEL in DBGC1 applies only to
the match condition for A. Please refer to Section 16.4.2.7, “Storage Memory,” for more information.
This trigger mode is incompatible with the detail capture mode so the detail capture mode will have
priority. TRGSEL and BEGIN will not be ignored and this trigger mode will be the same as A then B.
16.4.2.5.6 A and B (Full Mode)
In the A and B trigger mode, comparator A compares to the address bus and comparator B compares to
the data bus. In the A and B trigger mode, if the match condition for A and B happen on the same bus cycle,
both the A and B flags in the DBGSC register are set and a trigger occurs.
If TRGSEL = 1, only matches from comparator A are used to determine if the trigger condition is met and
comparator B matches are ignored. If TRGSEL = 0, full-word data matches on an odd address boundary
(misaligned access) do not work unless the access is to a RAM that manages misaligned accesses in a
single clock cycle (which is typical of RAM modules used in HCS12 MCUs).
16.4.2.5.7 A and Not B (Full Mode)
In the A and not B trigger mode, comparator A compares to the address bus and comparator B compares
to the data bus. In the A and not B trigger mode, if the match condition for A and not B happen on the same
bus cycle, both the A and B flags in DBGSC are set and a trigger occurs.
If TRGSEL = 1, only matches from comparator A are used to determine if the trigger condition is met and
comparator B matches are ignored. As described in Section 16.4.2.5.6, “A and B (Full Mode),” full-word
data compares on misaligned accesses will not match expected data (and thus will cause a trigger in this
mode) unless the access is to a RAM that manages misaligned accesses in a single clock cycle.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 495
16.4.2.5.8 Inside Range (A ≤ address ≤ B)
In the inside range trigger mode, if the match condition for A and B happen on the same bus cycle, both
the A and B flags in DBGSC are set and a trigger occurs. If a match condition on only A or only B occurs
no flags are set. If TRGSEL = 1, the inside range is accurate only to word boundaries. If TRGSEL = 0, an
aligned word access which straddles the range boundary will cause a trigger only if the aligned address is
within the range.
16.4.2.5.9 Outside Range (address < A or address > B)
In the outside range trigger mode, if the match condition for A or B is met, the corresponding flag in
DBGSC is set and a trigger occurs. If TRGSEL = 1, the outside range is accurate only to word boundaries.
If TRGSEL = 0, an aligned word access which straddles the range boundary will cause a trigger only if the
aligned address is outside the range.
16.4.2.5.10 Control Bit Priorities
The definitions of some of the control bits are incompatible with each other. Table 16-25 and the notes
associated with it summarize how these incompatibilities are managed:
• Read/write comparisons are not compatible with TRGSEL = 1. Therefore, RWAEN and RWBEN
are ignored.
• Event-only trigger modes are always considered a begin-type trigger. See Section 16.4.2.8.1,
“Storing with Begin-Trigger,” and Section 16.4.2.8.2, “Storing with End-Trigger.”
• Detail capture mode has priority over the event-only trigger/capture modes. Therefore, even t-only
modes have no meaning in detail mode and their functions default to similar trigger modes.
Table 16-25. Resolution of Mode Conflicts
Mode
Normal / Loop1 Detail
Tag Force Tag Force
A only
A or B
A then B
Event-only B 1 1, 3 3
A then event-only B 2 4 4
A and B (full mode) 5 5
A and not B (full mode) 5 5
Inside range 6 6
Outside range 6 6
1 — Ignored — same as force
2 — Ignored for comparator B
3 — Reduces to effectively “B only”
4 — Works same as A then B
5 — Reduces to effectively “A only” — B not compared
6 — Only accurate to word boundaries
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
496 Freescale Semiconductor
16.4.2.6 Capture Modes
The DBG in DBG mode can operate in four capture modes. These modes are described in the following
subsections.
16.4.2.6.1 Normal Mode
In normal mode, the DBG module uses comparator A and B as triggering devices. Change-of-flow
information or data will be stored depending on TRG in DBGSC.
16.4.2.6.2 Loop1 Mode
The intent of loop1 mode is to prevent the trace buffer from being filled entirely with duplicate information
from a looping construct such as delays using the DBNE instruction or polling loops using
BRSET/BRCLR instructions. Immediately after address information is placed in the trace buffer, the DBG
module writes this value into the C comparator and the C comparator is placed in ignore address mode.
This will prevent duplicate address entries in the trace buffer resulting from repeated bit-conditional
branches. Comparator C will be cleared when the ARM bit is set in loop1 mode to prevent the previous
contents of the register from interfering with loop1 mode operation. Breakpoints based on comparator C
are disabled.
Loop1 mode only inhibits duplicate source address entries that would typically be stored in most tight
looping constructs. It will not inhibit repeated entries of destination addresses or vector addresses, because
repeated entries of these would most likely indicate a bug in the user’s code that the DBG module is
designed to help find.
NOTE
In certain very tight loops, the source address will have already been fetched
again before the C comparator is updated. This results in the source address
being stored twice before further duplicate entries are suppressed. This
condition occurs with branch-on-bit instructions when the branch is fetched
by the first P-cycle of the branch or with loop-construct instructions in
which the branch is fetched with the first or second P cycle. See examples
below:
LOOP INCX ; 1-byte instruction fetched by 1st P-cycle of BRCLR
BRCLR CMPTMP,#$0c,LOOP ; the BRCLR instruction also will be fetched by 1st P-cycle of BRCLR
LOOP2 BRN * ; 2-byte instruction fetched by 1st P-cycle of DBNE
NOP ; 1-byte instruction fetched by 2nd P-cycle of DBNE
DBNE A,LOOP2 ; this instruction also fetched by 2nd P-cycle of DBNE
NOTE
Loop1 mode does not support paged memory, and inhibits duplicate entries
in the trace buffer based solely on the CPU address. There is a remote
possibility of an erroneous address match if program flow alternates
between paged and unpaged memory space.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 497
16.4.2.6.3 Detail Mode
In the detail mode, address and data for all cycles except program fetch (P) and free (f) cycles are stored
in trace buffer. This mode is intended to supply additional information on indexed, indirect addressing
modes where storing only the destination address would not provide all information required for a user to
determine where his code was in error.
16.4.2.6.4 Profile Mode
This mode is intended to allow a host computer to poll a running target and provide a histogram of program
execution. Each read of the trace buffer address will return the address of the last instruction executed. The
DBGCNT register is not incremented and the trace buf fer does not get filled. The ARM bit is not used and
all breakpoints and all other debug functions will be disabled.
16.4.2.7 Storage Memory
The storage memory is a 64 words deep by 16-bits wide dual port RAM array . The CPU accesses the RAM
array through a single memory location window (DBGTBH:DBGTBL). The DBG module stores trace
information in the RAM array in a circular buffer format. As data is read via the CPU, a pointer into the
RAM will increment so that the next CPU read will receive fresh information. In all trigger modes except
for event-only and detail capture mode, the data stored in the trace buffer will be change-of-flow addresses.
change-of-flow addresses are defined as follows:
• Source address of conditional branches (long, short, BRSET, and loop constructs) taken
• Destination address of indexed JMP, JSR, and CALL instruction
• Destination address of RTI, RTS, and RTC instructions
• Vector address of interrupts except for SWI and BDM vectors
In the event-only trigger modes only the 16-bit data bus value corresponding to the event is store d. In the
detail capture mode, address and then data are stored for all cycles except program fetch (P) and free (f)
cycles.
16.4.2.8 Storing Data in Memory Storage Buffer
16.4.2.8.1 Storing with Begin-Trigger
S toring with begin-trigger can be used in all trigger modes. When DBG mode is enabled and armed in the
begin-trigger mode, data is not stored in the trace buffer until the trigger condition is met. As soon as the
trigger condition is met, the DBG module will remain armed until 64 words are stored in the trace buf fer.
If the trigger is at the address of the change-of-flow instruction the change-of-flow associated with the
trigger event will be stored in the trace buffer.
16.4.2.8.2 Storing with End-Trigger
Storing with end-trigger cannot be used in event-only trigger modes. When DBG mode is enabled and
armed in the end-trigger mode, data is stored in the trace buffer until the trigger condition is met. When
the trigger condition is met, the DBG module will become de-armed and no more data will be stored. If
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
498 Freescale Semiconductor
the trigger is at the address of a change-of-flow address the trigger event will not be stored in the trace
buffer.
16.4.2.9 Reading Data from Trace Buffer
The data stored in the trace buffer can be read using either the background debug module (BDM) module
or the CPU provided the DBG module is enabled and not armed. The trace buffer data is read out first-in
first-out. By reading CNT in DBGCNT the number of valid words can be determined. CNT will not
decrement as data is read from DBGTBH:DBGTBL. The trace buffer data is read by reading
DBGTBH:DBGTBL with a 16-bit read. Each time DBGTBH:DBGTBL is read, a pointer in the DBG will
be incremented to allow reading of the next word.
Reading the trace buffer while the DBG module is armed will return invalid data and no shifting of the
RAM pointer will occur.
NOTE
The trace buffer should be read with the DBG module enabled and in the
same capture mode that the data was recorded. The contents of the trace
buffer counter register (DBGCNT) are resolved differently in detail mode
verses the other modes and may lead to incorrect interpreta tion of the tr ace
buffer data.
16.4.3 Breakpoints
There are two ways of getting a breakpoint in DBG mode. One is based on the trigger condition of the
trigger mode using comparator A and/or B, and the other is using comparator C. External breakpoints
generated using the TAGHI and TAGLO external pins are disabled in DBG mode.
16.4.3.1 Breakpoint Based on Comparator A and B
A breakpoint request to the CPU can be enabled by setting DBGBRK in DBGC1. The value of BEGIN in
DBGC1 determines when the breakpoint request to the CPU will occur. When BEGIN in DBGC1 is set,
begin-trigger is selected and the breakpoint request will not occur until the trace buffer is filled with
64 words. When BEGIN in DBGC1 is cleared, end-trigger is selected and the breakpoint request will occur
immediately at the trigger cycle.
There are two types of breakpoint requests supported by the DBG module, tagged and forced. Tagged
breakpoints are associated with opcode addresses and allow breaking just before a specific instruction
executes. Forced breakpoints are not associated with opcode addresses and allow breaking at the next
instruction boundary. The type of breakpoint based on comparators A an d B is determined by TRGSEL in
the DBGC1 register (TRGSEL = 1 for tagged breakpoint, TRGSEL = 0 for forced breakpoint).
Table 16-26 illustrates the type of breakpoint that will occur based on the debug run.
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 499
16.4.3.2 Breakpoint Based on Comparator C
A breakpoint request to the CPU can be created if BKCEN in DBGC2 is set. Breakpoints based on a
successful comparator C match can be accomplished regardless of the mode of operation for comparator
A or B, and do not affect the status of the ARM bit. TAGC in DBGC2 is used to select either tagged or
forced breakpoint requests for comparator C. Breakpoints based on comparator C are disabled in LOOP1
mode.
NOTE
Because breakpoints cannot be disabled when the DBG is armed, one must
be careful to avoid an “infinite breakpoint loop” when using tagged-type C
breakpoints while the DBG is armed. If BDM breakpoints are selected,
executing a TRACE1 instruction before the GO instruction is the
recommended way to avoid re-triggering a breakpoint if one does not wish
to de-arm the DBG. If SWI breakpoints are selected, disarming the DBG in
the SWI interrupt service routine is the recommended way to avoid
re-triggering a breakpoint.
16.5 Resets
The DBG module is disabled after reset.
The DBG module cannot cause a MCU reset.
16.6 Interrupts
The DBG contains one interrupt source. If a breakpoint is requested and BDM in DBGC2 is cleared, an
SWI interrupt will be generated.
Table 16-26. Breakpoint Setup
BEGIN TRGSEL DBGBRK Type of Debug Run
0 0 0 Fill trace buffer until trigger address
(no CPU breakpoint — keep running)
0 0 1 Fill trace buffer until trigger address, then a forced breakpoint
request occurs
0 1 0 Fill trace buffer until trigger opcode is about to execute
(no CPU breakpoint — keep running)
0 1 1 Fill trace buffer until trigger opcode about to execute, then a
tagged breakpoint request occurs
1 0 0 Start trace buffer at trigger address
(no CPU breakpoint — keep running)
1 0 1 Start trace buffer at trigger address, a forced breakpoint
request occurs when trace buffer is full
1 1 0 Start trace buffer at trigger opcode
(no CPU breakpoint — keep running)
1 1 1 Start trace buffer at trigger opcode, a forced breakpoint request
occurs when trace buffer is full
Chapter 16 Debug Module (DBGV1)
MC9S12E256 Data Sheet, Rev. 1.08
500 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 501
Chapter 17
Interrupt (INTV1)
17.1 Introduction
This section describes the functionality of the interrupt (INT) sub-block of the S12 core platform.
A block diagram of the interrupt sub-block is shown in Figure 17-1.
Figure 17-1. INTV1 Block Diagram
HPRIO (OPTIONAL)
INT
PRIORITY DECODER
VECTOR REQUEST
INTERRUPTS
RESET FLAGS
WRITE DATA BUS
HPRIO VECTOR
XMASK
IMASK
QUALIFIED
INTERRUPT INPUT REGISTERS
INTERRUPTS
AND CONTROL REGISTERS
HIGHEST PRIORITY
I-INTERRUPT
READ DATA BUS
WAKEUP
VECTOR ADDRESS
INTERRUPT PENDING
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
502 Freescale Semiconductor
The interrupt sub-block decodes the priority of all system exception requests and provides the applicable
vector for processing the exception. The INT supports I-bit maskable and X-bit maskable interrupts, a
non-maskable unimplemented opcode trap, a non-maskable software interrupt (SWI) or background
debug mode request, and three system reset vector requests. All interrupt related exception requests are
managed by the interrupt sub-block (INT).
17.1.1 Features
The INT includes these features:
• Provides two to 122 I-bit maskable interrupt vectors (0xFF00–0xFFF2)
• Provides one X-bit maskable interrupt vector (0xFFF4)
• Provides a non-maskable software interrupt (SWI) or background debug mode request vector
(0xFFF6)
• Provides a non-maskable unimplemented opcode trap (TRAP) vector (0xFFF8)
• Provides three system reset vectors (0xFFFA–0xFFFE) (reset, CMR, and COP)
• Determines the appropriate vector and drives it onto the address bus at the appropriate time
• Signals the CPU that interrupts are pending
• Provides control registers which allow testing of interrupts
• Provides additional input signals which prevents requests for servicing I and X interrupts
• Wakes the system from stop or wait mode when an appropriate interrupt occurs or whenever XIRQ
is active, even if XIRQ is masked
• Provides asynchronous path for all I and X interrupts, (0xFF00–0xFFF4)
• (Optional) selects and stores the highest priority I interrupt based on the value written into the
HPRIO register
17.1.2 Modes of Operation
The functionality of the INT sub-block in various modes of operation is discussed in the subsections that
follow.
• Normal operation
The INT operates the same in all normal modes of operation.
• Special operation
Interrupts may be tested in special modes through the use of the interrupt test registers.
• Emulation modes
The INT operates the same in emulation modes as in normal modes.
• Low power modes
See Section 17.4.1, “Low-Power Modes,” for details
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 503
17.2 External Signal Description
Most interfacing with the interrupt sub-block is done within the core. However , the interrupt does receive
direct input from the multiplexed external bus interface (MEBI) sub-block of the core for the IRQ and
XIRQ pin data.
17.3 Memory Map and Register Definition
Detailed descriptions of the registers and associated bits are given in the subsections that follow.
17.3.1 Module Memory Map
17.3.2 Register Descriptions
Table 17-1. INT Memory Map
Address
Offset Use Access
0x0015 Interrupt Test Control Register (ITCR) R/W
0x0016 Interrupt Test Registers (ITEST) R/W
0x001F Highest Priority Interrupt (Optional) (HPRIO) R/W
Address Name Bit 7 6 5 4 3 2 1 Bit 0
0x0015 ITCR R0 0 0WRTINT ADR3 ADR2 ADR1 ADR0
W
0x0016 ITEST RINTE INTC INTA INT8 INT6 INT4 INT2 INT0
W
0x001F HPRIO
(OPTIONAL)
RPSEL7 PSEL6 PSEL5 PSEL4 PSEL3 PSEL2 PSEL1 0
W
= Unimplemented or Reserved
Figure 17-2. INT Register Summary
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
504 Freescale Semiconductor
17.3.2.1 Interrupt Test Control Register
Read: See individual bit descriptions
Write: See individual bit descriptions
76543210
R0 0 0
WRTINT ADR3 ADR2 ADR1 ADR0
W
Reset00001111
= Unimplemented or Reserved
Figure 17-3. Interrupt Test Control Register (ITCR)
Table 17-2. ITCR Field Descriptions
Field Description
4
WRTINT
Write to the Interrupt Test Registers
Read: anytime
Write: only in special modes and with I-bit mask and X-bit mask set.
0 Disables writes to the test registers; reads of the test registers will return the state of the interrupt inputs.
1 Disconnect the interrupt inputs from the priority decoder and use the values written into the ITEST registers
instead.
Note: Any interrupts which are pending at the time that WRTINT is set will remain until they are overwritten.
3:0
ADR[3:0]
Test Register Select Bits
Read: anytime
Write: anytime
These bits determine which test register is selected on a read or write. The hexadecimal value written here will
be the same as the upper nibble of the lower byte of the vector selects. That is, an “F” written into ADR[3:0] will
select vectors 0xFFFE–0xFFF0 while a “7” written to ADR[3:0] will select vectors 0xFF7E–0xFF70.
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 505
17.3.2.2 Interrupt Test Registers
Read: Only in special modes. Reads will return either the state of the interrupt inputs of the interrupt
sub-block (WRTINT = 0) or the values written into the TEST registers (WRTINT = 1). Reads will always
return 0s in normal modes.
Write: Only in special modes and with WRTINT = 1 and CCR I mask = 1.
76543210
R
INTE INTC INTA INT8 INT6 INT4 INT2 INT0
W
Reset00000000
Figure 17-4. Interrupt TEST Registers (ITEST)
Table 17-3. ITEST Field Descriptions
Field Description
7:0
INT[E:0]
Interrupt TEST Bits — These registers are used in special modes for testing the interrupt logic and priority
independent of the system configuration. Each bit is used to force a specific interrupt vector by writing it to a
logic 1 state. Bits are named INTE through INT0 to indicate vectors 0xFFxE through 0xFFx0. These bits can be
written only in special modes and only with the WRTINT bit set (logic 1) in the interrupt test control register
(ITCR). In addition, I interrupts must be masked using the I bit in the CCR. In this state, the interrupt input lines
to the interrupt sub-block will be disconnected and interrupt requests will be generated only by this register.
These bits can also be read in special modes to view that an interrupt requested by a system block (such as a
peripheral block) has reached the INT module.
There is a test register implemented for every eight interrupts in the overall system. All of the test registers share
the same address and are individually selected using the value stored in the ADR[3:0] bits of the interrupt test
control register (ITCR).
Note: When ADR[3:0] have the value of 0x000F, only bits 2:0 in the ITEST register will be accessible. That is,
vectors higher than 0xFFF4 cannot be tested using the test registers and bits 7:3 will always read as a
logic 0. If ADR[3:0] point to an unimplemented test register, writes will have no effect and reads will always
return a logic 0 value.
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
506 Freescale Semiconductor
17.3.2.3 Highest Priority I Interrupt (Optional)
Read: Anytime
Write: Only if I mask in CCR = 1
17.4 Functional Description
The interrupt sub-block processes all exception requests made by the CPU. These exceptions include
interrupt vector requests and reset vector requests. Each of these exception types and their overall priority
level is discussed in the subsections below.
17.4.1 Low-Power Modes
The INT does not contain any user-controlled options for reducing power consumption. The operation of
the INT in low-power modes is discussed in the following subsections.
17.4.1.1 Operation in Run Mode
The INT does not contain any options for reducing power in run mode.
17.4.1.2 Operation in Wait Mode
Clocks to the INT can be shut off during system wait mode and the asynchronous interrupt path will be
used to generate the wake-up signal upon recognition of a valid interrupt or any XIRQ request.
17.4.1.3 Operation in Stop Mode
Clocks to the INT can be shut off during system stop mode and the asynchronous interrupt path will be
used to generate the wake-up signal upon recognition of a valid interrupt or any XIRQ request.
76543210
R
PSEL7 PSEL6 PSEL5 PSEL4 PSEL3 PSEL2 PSEL1
0
W
Reset11110010
= Unimplemented or Reserved
Figure 17-5. Highest Priority I Interrupt Register (HPRIO)
Table 17-4. HPRIO Field Descriptions
Field Description
7:1
PSEL[7:1]
Highest Priority I Interrupt Select Bits — The state of these bits determines which I-bit maskable interrupt will
be promoted to highest priority (of the I-bit maskable interrupts). To promote an interrupt, the user writes the least
significant byte of the associated interrupt vector address to this register. If an unimplemented vector address or
a non I-bit masked vector address (value higher than 0x00F2) is written, IRQ (0xFFF2) will be the default highest
priority interrupt.
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 507
17.5 Resets
The INT supports three system reset exception request types: normal system reset or power-on-reset
request, crystal monitor reset request, and COP watchdog reset request. The type of reset exception request
must be decoded by the system and the proper request made to the core. The INT will then provide the
service routine address for the type of reset requested.
17.6 Interrupts
As shown in the block diagram in Figure 17-1, the INT contains a register block to provide interrupt status
and control, an optional highest priority I interrupt (HPRIO) block, and a priority decoder to evaluate
whether pending interrupts are valid and assess their priority.
17.6.1 Interrupt Registers
The INT registers are accessible only in special modes of operation and function as described in
Section 17.3.2.1, “Interrupt Test Control Register,” and Section 17.3.2.2, “Interrupt Test Registers,”
previously.
17.6.2 Highest Priority I-Bit Maskable Interrupt
When the optional HPRIO block is implemented, the user is allowed to promote a single I-bit maskable
interrupt to be the highest priority I interrupt. The HPRIO evaluates all interrupt exception requests and
passes the HPRIO vector to the priority decoder if the highest priority I interrupt is active. RTI replaces
the promoted interrupt source.
17.6.3 Interrupt Priority Decoder
The priority decoder evaluates all interrupts pending and determines their validity and priority. When the
CPU requests an interrupt vector, the decoder will provide the vector for the highest priority interrupt
request. Because the vector is not supplied until the CPU requests it, it is possible that a higher priority
interrupt request could override the original exception that caused the CPU to request the vector. In this
case, the CPU will receive the highest pr iority vector and the system will process this exception instead of
the original request.
NOTE
Care must be taken to ensure that all exception requests remain active until
the system begins execution of the applicable service routine; otherwise, the
exception request may not be processed.
If for any reason the interrupt source is unknown (e.g., an interrupt request becomes inactive after the
interrupt has been recognized but prior to the vector request), the vector address will default to that of the
last valid interrupt that existed during the particular interrupt sequence. If the CPU requests an interrupt
vector when there has never been a pending interrupt request, the INT will provide the software interrupt
(SWI) vector address.
Chapter 17 Interrupt (INTV1)
MC9S12E256 Data Sheet, Rev. 1.08
508 Freescale Semiconductor
17.7 Exception Priority
The priority (from highest to lowest) and address of all exception vectors issued by the INT upon request
by the CPU is shown in Table 17-5.
Table 17-5. Exception Vector Map and Priority
Vector Address Source
0xFFFE–0xFFFF System reset
0xFFFC–0xFFFD Crystal monitor reset
0xFFFA–0xFFFB COP reset
0xFFF8–0xFFF9 Unimplemented opcode trap
0xFFF6–0xFFF7 Software interrupt instruction (SWI) or BDM vector request
0xFFF4–0xFFF5 XIRQ signal
0xFFF2–0xFFF3 IRQ signal
0xFFF0–0xFF00 Device-specific I-bit maskable interrupt sources (priority in descending order)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 509
Chapter 18
Multiplexed External Bus Interface (MEBIV3)
18.1 Introduction
This section describes the functionality of the multiplexed external bus interface (MEBI) sub-block of the
S12 core platform. The functionality of the module is closely coupled with the S12 CPU and the memory
map controller (MMC) sub-blocks.
Figure 18-1 is a block diagram of the MEBI. In Figure 18-1, the signals on the right hand side represent
pins that are accessible externally. On some chips, these may not all be bonded out.
The MEBI sub-block of the core serves to provide access and/or visibility to internal core data
manipulation operations including timing reference information at the external boundary of the core and/or
system. Depending upon the system operating mode and the state of bits within the control registers of the
MEBI, the internal 16-bit read and write data operations will be represented in 8-bit or 16-bit accesses
externally. Using control information from other blocks within the system, the MEBI will determine the
appropriate type of data access to be generated.
18.1.1 Features
The block name includes these distinctive features:
• External bus controller with four 8-bit ports A,B, E, and K
• Data and data direction registers for ports A, B, E, and K when used as general-purpose I/O
• Control register to enable/disable alternate functions on ports E and K
• Mode control register
• Control register to enable/disable pull resistors on ports A, B, E, and K
• Control register to enable/disable reduced output drive on ports A, B, E, and K
• Control register to configure external clock behavior
• Control register to configure IRQ pin operation
• Logic to capture and synchronize external interrupt pin inputs
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
510 Freescale Semiconductor
Figure 18-1. MEBI Block Diagram
PE[7:2]/NOACC/
PE1/IRQ
PE0/XIRQ
BKGD/MODC/TAGHI
PK[7:0]/ECS/XCS/X[19:14]
PA[7:0]/A[15:8]/
D[15:8]/D[7:0]
Port KPort A
PB[7:0]/A[7:0]/
D[7:0]
Port BPort E
BKGD
REGS
EXT
BUS
I/F
CTL
Addr[19:0]
Data[15:0]
(Control)
Internal Bus
ECLK CTL
IRQ CTL
ADDR
ADDR
DATA
ADDR
DATA
PIPE CTL
CPU pipe info
IRQ interrupt
XIRQ interrupt
BDM tag info
IPIPE1/MODB/CLKTO
IPIPE0/MODA/
ECLK/
LSTRB/TAGLO
R/W
TAG CT L
Control signal(s)
Data signal (unidirectional)
Data bus (unidirectional)
Data bus (bidirectional)
Data signal (bidirectional)
mode
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 511
18.1.2 Modes of Operation
• Normal expanded wide mode
Ports A and B are configured as a 16-bit multiplexed address and data bus and port E provides bus
control and status signals. This mode allows 16-bit external memory and peripheral devices to be
interfaced to the system.
• Normal expanded narrow mode
Ports A and B are configured as a 16-bit address bus and port A is multiplexed with 8-bit data.
Port E provides bus control and status signals. This mode allows 8-bit external memory and
peripheral devices to be interfaced to the system.
• Normal single-chip mode
There is no external expansion bus in this mode. The processor program is executed from internal
memory. Ports A, B, K, and most of E are available as general-purpose I/O.
• Special single-chip mode
This mode is generally used for debugging single-chip operation, boot-strapping, or security
related operations. The active background mode is in control of CPU execution and BDM firmware
is waiting for additional serial commands through the BKGD pin. There is no external expansion
bus after reset in this mode.
• Emulation expanded wide mode
Developers use this mode for emulation systems in which the users target application is normal
expanded wide mode.
• Emulation expanded narrow mode
Developers use this mode for emulation systems in which the users target application is normal
expanded narrow mode.
• Special test mode
Ports A and B are configured as a 16-bit multiplexed address and data bus and port E provides bus
control and status signals. In special test mode, the write protection of many control bits is lifted
so that they can be thoroughly tested without needing to go through reset.
• Special peripheral mode
This mode is intended for Freescale Semiconductor factory testing of the system. The CPU is
inactive and an external (tester) bus master drives address, data, and bus control signals.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
512 Freescale Semiconductor
18.2 External Signal Description
In typical implementations, the MEBI sub-block of the core interfaces directly with external system pins.
Some pins may not be bonded out in all implementations.
Table 18-1 outlines the pin names and functions and gives a brief description of their operation reset state
of these pins and associated pull-ups or pull-downs is dependent on the mode of operation and on the
integration of this block at the chip level (chip dependent).
.Table 18-1. External System Pins Associated With MEBI
Pin Name Pin Functions Description
BKGD/MODC/
TAGHI
MODC At the rising edge on RESET, the state of this pin is registered into the MODC
bit to set the mode. (This pin always has an internal pullup.)
BKGD Pseudo open-drain communication pin for the single-wire background debug
mode. There is an internal pull-up resistor on this pin.
TAGHI When instruction tagging is on, a 0 at the falling edge of E tags the high half of
the instruction word being read into the instruction queue.
PA7/A15/D15/D7
thru
PA0/A8/D8/D0
PA7–PA0 General-purpose I/O pins, see PORTA and DDRA registers.
A15–A8 High-order address lines multiplexed during ECLK low. Outputs except in
special peripheral mode where they are inputs from an external tester system.
D15–D8 High-order bidirectional data lines multiplexed during ECLK high in expanded
wide modes, special peripheral mode, and visible internal accesses (IVIS = 1)
in emulation expanded narrow mode. Direction of data transfer is generally
indicated by R/W.
D15/D7
thru
D8/D0
Alternate high-order and low-order bytes of the bidirectional data lines
multiplexed during ECLK high in expanded narrow modes and narrow accesses
in wide modes. Direction of data transfer is generally indicated by R/W.
PB7/A7/D7
thru
PB0/A0/D0
PB7–PB0 General-purpose I/O pins, see PORTB and DDRB registers.
A7–A0 Low-order address lines multiplexed during ECLK low. Outputs except in
special peripheral mode where they are inputs from an external tester system.
D7–D0 Low-order bidirectional data lines multiplexed during ECLK high in expanded
wide modes, special peripheral mode, and visible internal accesses (with
IVIS = 1) in emulation expanded narrow mode. Direction of data transfer is
generally indicated by R/W.
PE7/NOACC PE7 General-purpose I/O pin, see PORTE and DDRE registers.
NOACC CPU No Access output. Indicates whether the current cycle is a free cycle. Only
available in expanded modes.
PE6/IPIPE1/
MODB/CLKTO
MODB At the rising edge of RESET, the state of this pin is registered into the MODB
bit to set the mode.
PE6 General-purpose I/O pin, see PORTE and DDRE registers.
IPIPE1 Instruction pipe status bit 1, enabled by PIPOE bit in PEAR.
CLKTO System clock test output. Only available in special modes. PIPOE = 1 overrides
this function. The enable for this function is in the clock module.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 513
Detailed descriptions of these pins can be found in Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)”.
PE5/IPIPE0/MODA MODA At the rising edge on RESET, the state of this pin is registered into the MODA
bit to set the mode.
PE5 General-purpose I/O pin, see PORTE and DDRE registers.
IPIPE0 Instruction pipe status bit 0, enabled by PIPOE bit in PEAR.
PE4/ECLK PE4 General-purpose I/O pin, see PORTE and DDRE registers.
ECLK Bus timing reference clock, can operate as a free-running clock at the system
clock rate or to produce one low-high clock per visible access, with the high
period stretched for slow accesses. ECLK is controlled by the NECLK bit in
PEAR, the IVIS bit in MODE, and the ESTR bit in EBICTL.
PE3/LSTRB/ TAGLO PE3 General-purpose I/O pin, see PORTE and DDRE registers.
LSTRB Low strobe bar, 0 indicates valid data on D7–D0.
SZ8 In special peripheral mode, this pin is an input indicating the size of the data
transfer (0 = 16-bit; 1 = 8-bit).
TAGLO In expanded wide mode or emulation narrow modes, when instruction tagging
is on and low strobe is enabled, a 0 at the falling edge of E tags the low half of
the instruction word being read into the instruction queue.
PE2/R/W PE2 General-purpose I/O pin, see PORTE and DDRE registers.
R/W Read/write, indicates the direction of internal data transfers. This is an output
except in special peripheral mode where it is an input.
PE1/IRQ PE1 General-purpose input-only pin, can be read even if IRQ enabled.
IRQ Maskable interrupt request, can be level sensitive or edge sensitive.
PE0/XIRQ PE0 General-purpose input-only pin.
XIRQ Non-maskable interrupt input.
PK7/ECS PK7 General-purpose I/O pin, see PORTK and DDRK registers.
ECS Emulation chip select
PK6/XCS PK6 General-purpose I/O pin, see PORTK and DDRK registers.
XCS External data chip select
PK5/X19
thru
PK0/X14
PK5–PK0 General-purpose I/O pins, see PORTK and DDRK registers.
X19–X14 Memory expansion addresses
Table 18-1. External System Pins Associated With MEBI (continued)
Pin Name Pin Functions Description
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
514 Freescale Semiconductor
18.3 Memory Map and Register Definition
A summary of the registers associated with the MEBI sub-block is shown in Table 18-2. Detailed
descriptions of the registers and bits are given in the subsections that follow. On most chips the registers
are mappable. Therefore, the upper bits may not be all 0s as shown in the table and descriptions.
18.3.1 Module Memory Map
Table 18-2. MEBI Memory Map
Address
Offset Use Access
0x0000 Port A Data Register (PORTA) R/W
0x0001 Port B Data Register (PORTB) R/W
0x0002 Data Direction Register A (DDRA) R/W
0x0003 Data Direction Register B (DDRB) R/W
0x0004 Reserved R
0x0005 Reserved R
0x0006 Reserved R
0x0007 Reserved R
0x0008 Port E Data Register (PORTE) R/W
0x0009 Data Direction Register E (DDRE) R/W
0x000A Port E Assignment Register (PEAR) R/W
0x000B Mode Register (MODE) R/W
0x000C Pull Control Register (PUCR) R/W
0x000D Reduced Drive Register (RDRIV) R/W
0x000E External Bus Interface Control Register (EBICTL) R/W
0x000F Reserved R
0x001E IRQ Control Register (IRQCR) R/W
0x00032 Port K Data Register (PORTK) R/W
0x00033 Data Direction Register K (DDRK) R/W
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 515
18.3.2 Register Descriptions
AddressName Bit 765432 1Bit 0
0x0000 PORTA RBit 765432 1Bit 0
W
0x0001 PORTB RBit 765432 1Bit 0
W
0x0002 DDRA RBit 765432 1Bit 0
W
0x0003 DDRB RBit 765432 1Bit 0
W
0x0004 Reserved R0 00000 0 0
W
0x0005 Reserved R0 00000 0 0
W
0x0006 Reserved R0 00000 0 0
W
0x0007 Reserved R0 00000 0 0
W
0x0008 PORTE RBit 765432
Bit 1 Bit 0
W
0x0009 DDRE RBit 76543Bit 2
00
W
0x000A PEAR RNOACCE 0PIPOE NECLK LSTRE RDWE 00
W
0x000B MODE RMODC MODB MODA 0IVIS 0EMK EME
W
0x000C PUCR RPUPKE 00
PUPEE 00
PUPBE PUPAE
W
0x000D RDRIV RRDRK 00
RDPE 00
RDPB RDPA
W
0x000E EBICTL R0 00000 0
ESTR
W
0x000F Reserved R0 00000 0 0
W
0x001E IRQCR RIRQE IRQEN 0000 0 0
W
0x0032 PORTK RBit 765432 1Bit 0
W
0x0033 DDRK RBit 765432 1Bit 0
W
= Unimplemented or Reserved
Figure 18-2. MEBI Register Summary
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
516 Freescale Semiconductor
18.3.2.1 Port A Data Register (PORTA)
Read: Anytime when register is in the map
Write: Anytime when register is in the map
Port A bits 7 through 0 are associated with address lines A15 through A8 respectively and data lines
D15/D7 through D8/D0 respectively. When this port is not used for external addresses such as in
single-chip mode, these pins can be used as general-purpose I/O. Data direction register A (DDRA)
determines the primary direction of each pin. DDRA also determines the source of data for a read of
PORTA.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
NOTE
To ensure that you read the value present on the PORTA pins, always wait
at least one cycle after writing to the DDRA register before reading from the
PORTA register.
76543210
R
Bit 7654321Bit 0
W
Reset00000000
Singl e C h i p PA7 PA 6 PA5 PA 4 PA3 PA2 PA 1 PA0
Expanded Wide,
Emulation Narrow with
IVIS, and Peripheral
AB/DB15 AB/DB14 AB/DB13 AB/DB12 AB/DB11 AB/DB10 AB/DB9 AB/DB8
Expanded Narrow AB15 and
DB15/DB7
AB14 and
DB14/DB6
AB13 and
DB13/DB5
AB12 and
DB12/DB4
AB11 and
DB11/DB3
AB10 and
DB10/DB2
AB9 and
DB9/DB1
AB8 and
DB8/DB0
Figure 18-3. Port A Data Register (PORTA)
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 517
18.3.2.2 Port B Data Register (PORTB)
Read: Anytime when register is in the map
Write: Anytime when register is in the map
Port B bits 7 through 0 are associated with address lines A7 through A0 respectively and data lines D7
through D0 respectively. When this port is not used for external addresses, such as in single-chip mode,
these pins can be used as general-purpose I/O. Data direction register B (DDRB) determines the primary
direction of each pin. DDRB also determines the source of data for a read of PORTB.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
NOTE
To ensure that you read the value present on the PORTB pins, always wait
at least one cycle after writing to the DDRB register before reading from the
PORTB register.
76543210
R
Bit 7654321Bit 0
W
Reset00000000
Single Chip PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0
Expanded Wide,
Emulation Narrow with
IVIS, and Peripheral
AB/DB7 AB/DB6 AB/DB5 AB/DB4 AB/DB3 AB/DB2 AB/DB1 AB/DB0
Expanded Narrow AB7 AB6 AB5 AB4 AB3 AB2 AB1 AB0
Figure 18-4. Port A Data Register (PORTB)
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
518 Freescale Semiconductor
18.3.2.3 Data Direction Register A (DDRA)
Read: Anytime when register is in the map
Write: Anytime when register is in the map
This register controls the data direction for port A. When port A is operating as a general-purpose I/O port,
DDRA determines the primary direction for each port A pin. A 1 causes the associated port pin to be an
output and a 0 causes the associated pin to be a high-impedance input. The value in a DDR bit also af fects
the source of data for reads of the corresponding PORTA register. If the DDR bit is 0 (input) the buffered
pin input state is read. If the DDR bit is 1 (output) the associated port data register bit state is read.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally. It is reset to 0x00 so the DDR does not override the three-state control
signals.
76543210
R
Bit 7654321Bit 0
W
Reset00000000
Figure 18-5. Data Direction Register A (DDRA)
Table 18-3. DDRA Field Descriptions
Field Description
7:0
DDRA
Data Direction Port A
0 Configure the corresponding I/O pin as an input
1 Configure the corresponding I/O pin as an output
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 519
18.3.2.4 Data Direction Register B (DDRB)
Read: Anytime when register is in the map
Write: Anytime when register is in the map
This register controls the data direction for port B. When port B is operating as a general-purpose I/O port,
DDRB determines the primary direction for each port B pin. A 1 causes the associated port pin to be an
output and a 0 causes the associated pin to be a high-impedance input. The value in a DDR bit also af fects
the source of data for reads of the corresponding PORTB register. If the DDR bit is 0 (input) the buffered
pin input state is read. If the DDR bit is 1 (output) the associated port data register bit state is read.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally. It is reset to 0x00 so the DDR does not override the three-state control
signals.
76543210
R
Bit 7654321Bit 0
W
Reset00000000
Figure 18-6. Data Direction Register B (DDRB)
Table 18-4. DDRB Field Descriptions
Field Description
7:0
DDRB
Data Direction Port B
0 Configure the corresponding I/O pin as an input
1 Configure the corresponding I/O pin as an output
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
520 Freescale Semiconductor
18.3.2.5 Reserved Registers
These register locations are not used (reserved). All unused registers and bits in this block return logic 0s
when read. Writes to these registers have no effect.
These registers are not in the on-chip map in special peripheral mode.
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 18-7. Reserved Register
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 18-8. Reserved Register
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 18-9. Reserved Register
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 18-10. Reserved Register
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 521
18.3.2.6 Port E Data Register (PORTE)
Read: Anytime when register is in the map
Write: Anytime when register is in the map
Port E is associated with external bus control signals and interrupt inputs. These include mode select
(MODB/IPIPE1, MODA/IPIPE0), E clock, size (LSTRB/TAGLO), read/write (R/W), IRQ, and XIRQ.
When not used for one of these specific functions, port E pins 7:2 can be used as general-purpose I/O and
pins 1:0 can be used as general-purpose input. The port E assignment register (PEAR) selects the function
of each pin and DDRE determines whether each pin is an input or output when it is configured to be
general-purpose I/O. DDRE also determines the source of data for a read of PORTE.
Some of these pins have software selectable pull resistors. IRQ and XIRQ can only be pulled up whereas
the polarity of the PE7, PE4, PE3, and PE2 pull resistors are determined by chip integration. Please refer
to Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)” (Section 1.3.2, “Signal Properties
Summary”) to determine the polarity of these resistors. A single control bit enables the pull devices for all
of these pins when they are configured as inputs.
This register is not in the on-chip map in special peripheral mode or in expanded modes when the EME
bit is set. Therefore, these accesses will be echoed externally.
NOTE
It is unwise to write PORTE and DDRE as a word access. If you are
changing port E pins from being inputs to outputs, the data may have extra
transitions during the write. It is best to initialize POR TE before enabling as
outputs.
NOTE
To ensure that you read the value present on the PORTE pins, always wait
at least one cycle after writing to the DDRE register before reading from the
PORTE register.
76543210
R
Bit 765432
Bit 1 Bit 0
W
Reset000000uu
Alternate
Pin Function NOACC
MODB
or IPIPE1
or CLKTO
MODA
or IPIPE0 ECLK LSTRB
or TAGLO R/W IRQ XIRQ
= Unimplemented or Reserved u = Unaffected by reset
Figure 18-11. Port E Data Register (PORTE)
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
522 Freescale Semiconductor
18.3.2.7 Data Direction Register E (DDRE)
Read: Anytime when register is in the map
Write: Anytime when register is in the map
Data direction register E is associated with port E. For bits in port E that are configured as general-purpose
I/O lines, DDRE determines the primary direction of each of these pins. A 1 causes the associated bit to
be an output and a 0 causes the associated bit to be an input. Port E bit 1 (associated with IRQ) and bit 0
(associated with XIRQ) cannot be configured as outputs. Port E, bits 1 and 0, can be read regardless of
whether the alternate interrupt function is enabled. The value in a DDR bit also af fects the source of data
for reads of the corresponding PORTE register. If the DDR bit is 0 (input) the buffered pin input state is
read. If the DDR bit is 1 (output) the associated port data register bit state is read.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally. Also, it is not in the map in expanded modes while the EME control
bit is set.
76543210
R
Bit 76 5 4 3Bit 2
00
W
Reset00000000
= Unimplemented or Reserved
Figure 18-12. Data Direction Register E (DDRE)
Table 18-5. DDRE Field Descriptions
Field Description
7:2
DDRE
Data Direction Port E
0 Configure the corresponding I/O pin as an input
1 Configure the corresponding I/O pin as an output
Note: It is unwise to write PORTE and DDRE as a word access. If you are changing port E pins from inputs to
outputs, the data may have extra transitions during the write. It is best to initialize PORTE before enabling
as outputs.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 523
18.3.2.8 Port E Assignment Register (PEAR)
Read: Anytime (provided this register is in the map).
Write: Each bit has specific write conditions. Please refer to the descriptions of each bit on the following
pages.
Port E serves as general-purpose I/O or as system and bus control signals. The PEAR register is used to
choose between the general-purpose I/O function and the alternate control functions. When an alternate
control function is selected, the associated DDRE bits are overridden.
The reset condition of this register depends on the mode of operation because bus control signals are
needed immediately after reset in some modes. In normal single-chip mode, no external bus control signals
are needed so all of port E is configured for general-purpose I/O. In normal expanded modes, only the E
clock is configured for its alternate bus control function and the other bits of port E are configured for
general-purpose I/O. As the reset vector is located in external memory, the E clock is required for this
access. R/W is only needed by the system when there are external writable resources. If the normal
expanded system needs any other bus control signals, PEAR would need to be written before any access
that needed the additional signals. In special test and emulation modes, IPIPE1, IPIPE0, E, LSTRB, and
R/W are configured out of reset as bus control signals.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
76543210
R
NOACCE
0
PIPOE NECLK LSTRE RDWE
00
W
Reset
Special Single Chip00000000
Special Test00101100
Peripheral0 0000000
Emulation Expanded
Narrow 1 0101100
Emulation Expanded
Wide 10101100
Normal Single Chip00010000
Normal Expanded
Narrow 00000000
Normal Expanded Wide00000000
= Unimplemented or Reserved
Figure 18-13. Port E Assignment Register (PEAR)
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
524 Freescale Semiconductor
Table 18-6. PEAR Field Descriptions
Field Description
7
NOACCE
CPU No Access Output Enable
Normal: write once
Emulation: write never
Special: write anytime
1 The associated pin (port E, bit 7) is general-purpose I/O.
0 The associated pin (port E, bit 7) is output and indicates whether the cycle is a CPU free cycle.
This bit has no effect in single-chip or special peripheral modes.
5
PIPOE
Pipe Status Signal Output Enable
Normal: write once
Emulation: write never
Special: write anytime.
0 The associated pins (port E, bits 6:5) are general-purpose I/O.
1 The associated pins (port E, bits 6:5) are outputs and indicate the state of the instruction queue
This bit has no effect in single-chip or special peripheral modes.
4
NECLK
No External E Clock
Normal and special: write anytime
Emulation: write never
0 The associated pin (port E, bit 4) is the external E clock pin. External E clock is free-running if ESTR = 0
1 The associated pin (port E, bit 4) is a general-purpose I/O pin.
External E clock is available as an output in all modes.
3
LSTRE
Low Strobe (LSTRB) Enable
Normal: write once
Emulation: write never
Special: write anytime.
0 The associated pin (port E, bit 3) is a general-purpose I/O pin.
1 The associated pin (port E, bit 3) is configured as the LSTRB bus control output. If BDM tagging is enabled,
TAGL O is multiplexed in on the rising edge of ECLK and LSTRB is driven out on the falling edge of ECLK.
This bit has no effect in single-chip, peripheral, or normal expanded narrow modes.
Note: LSTRB is used during external writes. After reset in normal expanded mode, LSTRB is disabled to provide
an extra I/O pin. If LSTRB is needed, it should be enabled before any external writes. External reads do
not normally need LSTRB because all 16 data bits can be driven even if the system only needs 8 bits of
data.
2
RDWE
Read/Write Enable
Normal: write once
Emulation: write never
Special: write anytime
0 The associated pin (port E, bit 2) is a general-purpose I/O pin.
1 The associated pin (port E, bit 2) is configured as the R/W pin
This bit has no effect in single-chip or special peripheral modes.
Note: R/W is used for external writes. After reset in normal expanded mode, R/W is disabled to provide an extra
I/O pin. If R/W is needed it should be enabled before any external writes.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 525
18.3.2.9 Mode Register (MODE)
Read: Anytime (provided this register is in the map).
Write: Each bit has specific write conditions. Please refer to the descriptions of each bit on the fo llowing
pages.
The MODE register is used to establish the operating mode and other miscellaneous functions (i.e.,
internal visibility and emulation of port E and K).
In special peripheral mode, this register is not accessible but it is reset as shown to system configuration
features. Changes to bits in the MODE register are delayed one cycle after the write.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
76543210
R
MODC MODB MODA
0
IVIS
0
EMK EME
W
Reset
Special Single Chip00000000
Emulation Expanded
Narrow 00101011
Special Test01001000
Emulation Expanded
Wide 01101011
Normal Single Chip10000000
Normal Expanded
Narrow 10100000
Peripheral11000000
Normal Expanded Wide11100000
= Unimplemented or Reserved
Figure 18-14. Mode Register (MODE)
Table 18-7. MODE Field Descriptions
Field Description
7:5
MOD[C:A]
Mode Select Bits — These bits indicate the current operating mode.
If MODA = 1, then MODC, MODB, and MODA are write never.
If MODC = MODA = 0, then MODC, MODB, and MODA are writable with the exception that you cannot change
to or from special peripheral mode
If MODC = 1, MODB = 0, and MODA = 0, then MODC is write never. MODB and MODA are write once, except
that you cannot change to special peripheral mode. From normal single-chip, only normal expanded narrow and
normal expanded wide modes are available.
See Tabl e 1 8-8 and Table 18-16.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
526 Freescale Semiconductor
3
IVIS
Internal Visibility (for both read and write accesses) — This bit determines whether internal accesses
generate a bus cycle that is visible on the external bus.
Normal: write once
Emulation: write never
Special: write anytime
0 No visibility of internal bus operations on external bus.
1 Internal bus operations are visible on external bus.
1
EMK
Emulate Port K
Normal: write once
Emulation: write never
Special: write anytime
0 PORTK and DDRK are in the memory map so port K can be used for general-purpose I/O.
1 If in any expanded mode, PORTK and DDRK are removed from the memory map.
In single-chip modes, PORTK and DDRK are always in the map regardless of the state of this bit.
In special peripheral mode, PORTK and DDRK are never in the map regardless of the state of this bit.
0
EME
Emulate Port E
Normal and Emulation: write never
Special: write anytime
0 PORTE and DDRE are in the memory map so port E can be used for general-purpose I/O.
1 If in any expanded mode or special peripheral mode, PORTE and DDRE are removed from the memory map.
Removing the registers from the map allows the user to emulate the function of these registers externally.
In single-chip modes, PORTE and DDRE are always in the map regardless of the state of this bit.
Table 18-8. MODC, MODB, and MODA Write Capabilitya
aNo writes to the MOD bits are allowed while operating in a secure mode. For more details, refer to Chapter 1, “MC9S12E256
Device Overview (MC9S12E256DGV1)”.
MODC MODB MODA Mode MODx Write Capability
0 0 0 Special single chip MODC, MODB, and MODA
write anytime but not to 110b
bIf you are in a special single-chip or special test mode and you write to this register, changing to normal single-chip mode, then
one allowed write to this register remains. If you write to normal expanded or emulation mode, then no writes remain.
0 0 1 Emulation narrow No write
0 1 0 Special test MODC, MODB, and MODA
write anytime but not to 1102
0 1 1 Emulation wide No write
1 0 0 Normal single chip MODC write never,
MODB and MODA write once
but not to 110
1 0 1 Normal expanded narrow No write
1 1 0 Special peripheral No write
1 1 1 Normal expanded wide No write
Table 18-7. MODE Field Descriptions (continued)
Field Description
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 527
18.3.2.10 Pull Control Register (PUCR)
Read: Anytime (provided this register is in the map).
Write: Anytime (provided this register is in the map).
This register is used to select pull resistors for the pins associated with the core ports. Pull resistors are
assigned on a per-port basis and apply to any pin in the corresponding port that is currently configured as
an input. The polarity of these pull resistors is determined by chip integration. Please refer to Chapter 1,
“MC9S12E256 Device Overview (MC9S12E256DGV1)” to determine the polarity of these resistors.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
NOTE
These bits have no effect when the associated pin(s) are outputs. (The pull
resistors are inactive.)
76543210
R
PUPKE
00
PUPEE
00
PUPBE PUPAE
W
Reset110010000
1. The default value of this parameter is shown. Please refer to Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)” to determine the actual reset state of this register.
= Unimplemented or Reserved
Figure 18-15. Pull Control Register (PUCR)
Table 18-9. PUCR Field Descriptions
Field Description
7
PUPKE
Pull resistors Port K Enable
0 Port K pull resistors are disabled.
1 Enable pull resistors for port K input pins.
4
PUPEE
Pull resistors Port E Enable
0 Port E pull resistors on bits 7, 4:0 are disabled.
1 Enable pull resistors for port E input pins bits 7, 4:0.
Note: Pins 5 and 6 of port E have pull resistors which are only enabled during reset. This bit has no effect on
these pins.
1
PUPBE
Pull resistors Port B Enable
0 Port B pull resistors are disabled.
1 Enable pull resistors for all port B input pins.
0
PUPAE
Pull resistors Port A Enable
0 Port A pull resistors are disabled.
1 Enable pull resistors for all port A input pins.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
528 Freescale Semiconductor
18.3.2.11 Reduced Drive Register (RDRIV)
Read: Anytime (provided this register is in the map)
Write: Anytime (provided this register is in the map)
This register is used to select reduced drive for the pins associated with the core ports. This gives reduced
power consumption and reduced RFI with a slight increase in transition time (depending on loading). This
feature would be used on ports which have a light loading. The reduced drive function is independent of
which function is being used on a particular port.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
76543210
R
RDRK
00
RDPE
00
RDPB RDPA
W
Reset00000000
= Unimplemented or Reserved
Figure 18-16. Reduced Drive Register (RDRIV)
Table 18-10. RDRIV Field Descriptions
Field Description
7
RDRK
Reduced Drive of Port K
0 All port K output pins have full drive enabled.
1 All port K output pins have reduced drive enabled.
4
RDPE
Reduced Drive of Port E
0 All port E output pins have full drive enabled.
1 All port E output pins have reduced drive enabled.
1
RDPB
Reduced Drive of Port B
0 All port B output pins have full drive enabled.
1 All port B output pins have reduced drive enabled.
0
RDPA
Reduced Drive of Ports A
0 All port A output pins have full drive enabled.
1 All port A output pins have reduced drive enabled.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 529
18.3.2.12 External Bus Interface Control Register (EBICTL)
Read: Anytime (provided this register is in the map)
Write: Refer to individual bit descriptions below
The EBICTL register is used to control miscellaneous functions (i.e., stretching of external E clock).
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
76543210
R0000000
ESTR
W
Reset:
Peripheral
All other modes
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
= Unimplemented or Reserved
Figure 18-17. External Bus Interface Control Register (EBICTL)
Table 18-11. EBICTL Field Descriptions
Field Description
0
ESTR
E Clock Stretches — This control bit determines whether the E clock behaves as a simple free-running clock or
as a bus control signal that is active only for external bus cycles.
Normal and Emulation: write once
Special: write anytime
0 E never stretches (always free running).
1 E stretches high during stretched external accesses and remains low during non-visible internal accesses.
This bit has no effect in single-chip modes.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
530 Freescale Semiconductor
18.3.2.13 Reserved Register
This register location is not used (reserved). All bits in this register return logic 0s when read. Writes to
this register have no effect.
This register is not in the on-chip memory map in expanded and special peripheral modes. Therefore, these
accesses will be echoed externally.
18.3.2.14 IRQ Control Register (IRQCR)
Read: See individual bit descriptions below
Write: See individual bit descriptions below
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 18-18. Reserved Register
76543210
R
IRQE IRQEN
000000
W
Reset01000000
= Unimplemented or Reserved
Figure 18-19. IRQ Control Register (IRQCR)
Table 18-12. IRQCR Field Descriptions
Field Description
7
IRQE
IRQ Select Edge Sensitive Only
Special modes: read or write anytime
Normal and Emulation modes: read anytime, write once
0 IRQ configured for low level recognition.
1 IRQ configured to respond only to falling edges. Falling edges on the IRQ pin will be detected anytime
IRQE = 1 and will be cleared only upon a reset or the servicing of the IRQ interrupt.
6
IRQEN
External IRQ Enable
Normal, emulation, and special modes: read or write anytime
0 External IRQ pin is disconnected from interrupt logic.
1 External IRQ pin is connected to interrupt logic.
Note: When IRQEN = 0, the edge detect latch is disabled.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 531
18.3.2.15 Port K Data Register (PORTK)
Read: Anytime
Write: Anytime
This port is associated with the internal memory expansion emulation pins. When the port is not enabled
to emulate the internal memory expansion, the port pins are used as general-purpose I/O. When port K is
operating as a general-purpose I/O port, DDRK determines the primary direction for each port K pin. A 1
causes the associated port pin to be an output and a 0 causes the associated pin to be a high-impedance
input. The value in a DDR bit also affects the source of data for reads of the corresponding PORTK
register. If the DDR bit is 0 (input) the buf fered pin input is read. If the DDR bit is 1 (output) the output of
the port data register is read.
This register is not in the map in peripheral or expanded modes while the EMK control bit in MODE
register is set. Therefore, these accesses will be echoed externally.
When inputs, these pins can be selected to be high impedance or pulled up, based upon the state of the
PUPKE bit in the PUCR register.
76543210
R
Bit 7654321Bit 0
W
Reset00000000
Alternate
Pin Function ECS XCS XAB19 XAB18 XAB17 XAB16 XAB15 XAB14
Figure 18-20. Port K Data Register (PORTK)
Table 18-13. PORTK Field Descriptions
Field Description
7
Port K, Bit 7
Port K, Bit 7 — This bit is used as an emulation chip select signal for the emulation of the internal memory
expansion, or as general-purpose I/O, depending upon the state of the EMK bit in the MODE register. While
this bit is used as a chip select, the external bit will return to its de-asserted state (VDD) for approximately 1/4
cycle just after the negative edge of ECLK, unless the external access is stretched and ECLK is free-running
(ESTR bit in EBICTL = 0). See Chapter 19, “Module Mapping Control (MMCV4)” for additional details on when
this signal will be active.
6
Port K, Bit 6
Port K, Bit 6 — This bit is used as an external chip select signal for most external accesses that are not
selected by ECS (see Chapter 19, “Module Mapping Control (MMCV4)”for more details), depending upon the
state the of the EMK bit in the MODE register. While this bit is used as a chip select, the external pin will return
to its de-asserted state (VDD) for approximately 1/4 cycle just after the negative edge of ECLK, unless the
external access is stretched and ECLK is free-running (ESTR bit in EBICTL = 0).
5:0
Port K, Bits 5:0
Port K, Bits 5:0 — These six bits are used to determine which FLASH/ROM or external memory array page
is being accessed. They can be viewed as expanded addresses XAB19–XAB14 of the 20-bit address used to
access up to1M byte internal FLASH/ROM or external memory array. Alternatively, these bits can be used for
general-purpose I/O depending upon the state of the EMK bit in the MODE register.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
532 Freescale Semiconductor
18.3.2.16 Port K Data Direction Register (DDRK)
Read: Anytime
Write: Anytime
This register determines the pr imary direction for each port K pin configured as general-purpose I/O. This
register is not in the map in peripheral or expanded modes while the EMK control bit in MODE register is
set. Therefore, these accesses will be echoed externally.
76543210
R
Bit 7654321Bit 0
W
Reset00000000
Figure 18-21. Port K Data Direction Register (DDRK)
Table 18-14. DDRK Field Descriptions
Field Description
7:0
DDRK
Data Direction Port K Bits
0 Associated pin is a high-impedance input
1 Associated pin is an output
Note: It is unwise to write PORTK and DDRK as a word access. If you are changing port K pins from inputs to
outputs, the data may have extra transitions during the write. It is best to initialize PORTK before enabling
as outputs.
Note: To ensure that you read the correct value from the PORTK pins, always wait at least one cycle after writing
to the DDRK register before reading from the PORTK register.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 533
18.4 Functional Description
18.4.1 Detecting Access Type from External Signals
The external signals LSTRB, R/W, and AB0 indicate the type of bus access that is taking place. Accesses
to the internal RAM module are the only type of access that would produce LSTRB = AB0 = 1, because
the internal RAM is specifically designed to allow misaligned 16-bit accesses in a single cycle. In these
cases the data for the address that was accessed is on the low half of the data bus and the data for
address + 1 is on the high half of the data bus. This is summarized in Table 18-15.
18.4.2 Stretched Bus Cycles
In order to allow fast internal bus cycles to coexist in a system with slower external memory resources, the
HCS12 supports the concept of stretched bus cycles (module timing reference clocks for timers and baud
rate generators are not affected by this stretching). Control bits in the MISC register in the MMC sub-block
of the core specify the amount of stretch (0, 1, 2, or 3 periods of the internal bus-rate clock). While
stretching, the CPU state machines are all held in their current state. At this point in the CPU bus cycle,
write data would already be driven onto the data bus so the length of time write data is valid is extended
in the case of a stretched bus cycle. Read data would not be captured by the system until the E clock falling
edge. In the case of a stretched bus cycle, read data is not required until the spec ified setup time before the
falling edge of the stretched E clock. The chip selects, and R/W signals remain valid during the period of
stretching (throughout the stretched E high time).
NOTE
The address portion of the bus cycle is not stretched.
Table 18-15. Access Type vs. Bus Control Pins
LSTRB AB0 R/W Type of Access
1 0 1 8-bit read of an even address
0 1 1 8-bit read of an odd address
1 0 0 8-bit write of an even address
0 1 0 8-bit write of an odd address
0 0 1 16-bit read of an even address
1 1 1 16-bit read of an odd address
(low/high data swapped)
0 0 0 16-bit write to an even address
1 1 0 16-bit write to an odd address
(low/high data swapped)
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
534 Freescale Semiconductor
18.4.3 Modes of Operation
The operating mode out of reset is determined by the states of the MODC, MODB, and MODA pins during
reset (Table 18-16). The MODC, MODB, and MODA bits in the MODE register show the current
operating mode and provide limited mode switching during operation. The states of the MODC, MODB,
and MODA pins are latched into these bits on the rising edge of the reset signal.
There are two basic types of operating modes:
1. Normal modes: Some registers and bits are protected against accidental changes.
2. Special modes: Allow greater access to protected control registers and bits for special purposes
such as testing.
A system development and debug feature, background debug mode (BDM), is available in all modes. In
special single-chip mode, BDM is active immediately after reset.
Some aspects of Port E are not mode dependent. Bit 1 of Port E is a general purpose input or the IRQ
interrupt input. IRQ can be enabled by bits in the CPU’s condition codes register but it is inhibited at reset
so this pin is initially configured as a simple input with a pull-up. Bit 0 of Port E is a general purpose input
or the XIRQ interrupt input. XIRQ can be enabled by bits in the CPU’s condition codes register but it is
inhibited at reset so this pin is initially configured as a simple input with a pull-up. The ESTR bit in the
EBICTL register is set to one by reset in any user mode. This assures that the reset vector can be fetched
even if it is located in an external slow memory device. The PE6/MODB/IPIPE1 and PE5/MODA/IPIPE0
pins act as high-impedance mode select inputs during reset.
The following paragraphs discuss the default bus setup and describe which aspects of the bus can be
changed after reset on a per mode basis.
Table 18-16. Mode Selection
MODC MODB MODA Mode Description
0 0 0 Special Single Chip, BDM allowed and ACTIVE. BDM is allowed in all
other modes but a serial command is required to make BDM active.
0 0 1 Emulation Expanded Narrow, BDM allowed
0 1 0 Special Test (Expanded Wide), BDM allowed
0 1 1 Emulation Expanded Wide, BDM allowed
1 0 0 Normal Single Chip, BDM allowed
1 0 1 Normal Expanded Narrow, BDM allowed
1 1 0 Peripheral; BDM allowed but bus operations would cause bus conflicts
(must not be used)
1 1 1 Normal Expanded Wide, BDM allowed
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 535
18.4.3.1 Normal Operating Modes
These modes provide three operating configurations. Background debug is available in all three modes,
but must first be enabled for some operations by means of a BDM background command, then activated.
18.4.3.1.1 Normal Single-Chip Mode
There is no external expansion bus in this mode. All pins of Ports A, B and E are configured as general
purpose I/O pins Port E bits 1 and 0 are available as general purpose input only pins with internal pull
resistors enabled. All other pins of Port E are bidirectional I/O pins that are initially configured as
high-impedance inputs with internal pull resistors enabled. Ports A and B are configured as
high-impedance inputs with their internal pull resistors disabled.
The pins associated with Port E bits 6, 5, 3, and 2 cannot be configured for their alternate functions IPIPE1,
IPIPE0, LSTRB, and R/W while the MCU is in single chip modes. In single chip modes, the associated
control bits PIPOE, LSTRE, and RDWE are reset to zero. Writing the opposite state into them in single
chip mode does not change the operation of the associated Port E pins.
In normal single chip mode, the MODE register is writable one time. This allows a user program to change
the bus mode to narrow or wide expanded mode and/or turn on visibility of internal accesses.
Port E, bit 4 can be configured for a free-running E clock output by clearing NECLK=0. T ypically the only
use for an E clock output while the MCU is in single chip modes would be to get a constant speed clock
for use in the external application system.
18.4.3.1.2 Normal Expanded Wide Mode
In expanded wide modes, Ports A and B are configured as a 16-bit multiplexed address and data bus and
Port E bit 4 is configured as the E clock output signal. These signals allow external memory and peripheral
devices to be interfaced to the MCU.
Port E pins other than PE4/ECLK are configured as general purpose I/O pins (initially high-impedance
inputs with internal pull resistors enabled). Control bits PIPOE, NECLK, LSTRE, and RDWE in the
PEAR register can be used to configure Port E pins to act as bus control outputs instead of general purpose
I/O pins.
It is possible to enable the pipe status signals on Port E bits 6 and 5 by setting the PIPOE bit in PEAR, but
it would be unusual to do so in this mode. Development systems where pipe status signals are monitored
would typically use the special variation of this mode.
The Port E bit 2 pin can be reconfigured as the R/W bus control signal by writing “1” to the RDWE bit in
PEAR. If the expanded system includes external devices that can be written, such as RAM, the RDWE bit
would need to be set before any attempt to write to an external location. If there are no writable resources
in the external system, PE2 can be left as a general purpose I/O pin.
The Port E bit 3 pin can be reconfigured as the LSTRB bus control signal by writing “1” to the LSTRE bit
in PEAR. The default condition of this pin is a general purpose input because the LSTRB function is not
needed in all expanded wide applications.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
536 Freescale Semiconductor
The Port E bit 4 pin is initially configured as ECLK output with stretch. The E clock output function
depends upon the settings of the NECLK bit in the PEAR register, the IVIS bit in the MODE register and
the ESTR bit in the EBICTL register. The E clock is available for use in external select decode logic or as
a constant speed clock for use in the external application system.
18.4.3.1.3 Normal Expanded Narrow Mode
This mode is used for lower cost production systems that use 8-bit wide external EPROMs or RAMs. Such
systems take extra bus cycles to access 16-bit locations but this may be preferred over the extra cost of
additional external memory devices.
Ports A and B are configured as a 16-bit address bus and Port A is multiplexed with data. Internal visibility
is not available in this mode because the internal cycles would need to be split into two 8-bit cycles.
Since the PEAR register can only be written one time in this mode, use care to set all bits to the desired
states during the single allowed write.
The PE3/LSTRB pin is always a general purpose I/O pin in normal expanded narrow mode. Although it
is possible to write the LSTRE bit in PEAR to “1” in this mode, the state of LSTRE is overridden and Port
E bit 3 cannot be reconfigured as the LSTRB output.
It is possible to enable the pipe status signals on Port E bits 6 and 5 by setting the PIPOE bit in PEAR, but
it would be unusual to do so in this mode. LSTRB would also be needed to fully understand system
activity. Development systems where pipe status signals are monitored would typically use special
expanded wide mode or occasionally special expanded narrow mode.
The PE4/ECLK pin is initially configured as ECLK output with stretch. The E clock output function
depends upon the settings of the NECLK bit in the PEAR register, the IVIS bit in the MODE register and
the ESTR bit in the EBICTL register. In normal expanded narrow mode, the E clock is available for use in
external select decode logic or as a constant speed clock for use in the external application system.
The PE2/R/W pin is initially configured as a general purpose input with an internal pull resistor enabled
but this pin can be reconfigured as the R/W bus control signal by writing “1” to the RDWE bit in PEAR.
If the expanded narrow system includes external devices that can be written such as RAM, the RDWE bit
would need to be set before any attempt to write to an external location. If there are no writable resources
in the external system, PE2 can be left as a general purpose I/O pin.
18.4.3.1.4 Emulation Expanded Wide Mode
In expanded wide modes, Ports A and B are configured as a 16-bit multiplexed address and data bus and
Port E provides bus control and status signals. These signals allow external memory and peripheral devices
to be interfaced to the MCU. These signals can also be used by a logic analyzer to monitor the progress of
application programs.
The bus control related pins in Port E (PE7/NOACC, PE6/MODB/IPIPE1, PE5/MODA/IPIPE0,
PE4/ECLK, PE3/LSTRB/TAGLO, and PE2/R/W) are all configured to serve their bus control output
functions rather than general purpose I/O. Notice that writes to the bus control enable bits in the PEAR
register in emulation mode are restricted.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 537
18.4.3.1.5 Emulation Expanded Narrow Mode
Expanded narrow modes are intended to allow connection of single 8-bit external memory devices for
lower cost systems that do not need the performance of a full 16-bit external data bus. Accesses to internal
resources that have been mapped external (i.e., PORTA, PORTB, DDRA, DDRB, PORTE, DDRE, PEAR,
PUCR, RDRIV) will be accessed with a 16-bit data bus on Ports A and B. Accesses of 16-bit external
words to addresses which are normally mapped external will be broken into two separate 8-bit accesses
using Port A as an 8-bit data bus. Internal operations continue to use full 16-bit data paths. They are only
visible externally as 16-bit information if IVIS=1.
Ports A and B are configured as multiplexed address and data output ports. During external accesses,
address A15, data D15 and D7 are associated with PA7, address A0 is associated with PB0 and data D8
and D0 are associated with PA0. During internal visible accesses and accesses to internal resources that
have been mapped external, address A15 and data D15 is associated with PA7 and address A0 and data
D0 is associated with PB0.
The bus control related pins in Port E (PE7/NOACC, PE6/MODB/IPIPE1, PE5/MODA/IPIPE0,
PE4/ECLK, PE3/LSTRB/TAGLO, and PE2/R/W) are all configured to serve their bus control output
functions rather than general purpose I/O. Notice that writes to the bus control enable bits in the PEAR
register in emulation mode are restricted.
The main difference between special modes and normal modes is that some of the bus control and system
control signals cannot be written in emulation modes.
18.4.3.2 Special Operating Modes
There are two special operating modes that correspond to normal operating modes. These operating modes
are commonly used in factory testing and system development.
18.4.3.2.1 Special Single-Chip Mode
When the MCU is reset in this mode, the background debug mode is enabled and active. The MCU does
not fetch the reset vector and execute application code as it would in other modes. Instead the active
background mode is in control of CPU execution and BDM firmware is waiting for additional serial
commands through the BKGD pin. When a serial command instructs the MCU to return to normal
execution, the system will be configured as described below unless the reset states of internal control
registers have been changed through background commands after the MCU was reset.
There is no external expansion bus after reset in this mode. Ports A and B are initially simple bidirectional
I/O pins that are configured as high-impedance inputs with internal pull resistors disabled; however,
writing to the mode select bits in the M ODE register (which is allowed in sp ecial modes) can change this
after reset. All of the Port E pins (except PE4/ECLK) are initially configured as general purpose
high-impedance inputs with internal pull resistors enabled. PE4/ECLK is configured as the E clock output
in this mode.
The pins associated with Port E bits 6, 5, 3, and 2 cannot be configured for their alternate functions IPIPE1,
IPIPE0, LSTRB, and R/W while the MCU is in single chip modes. In single chip modes, the associated
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
538 Freescale Semiconductor
control bits PIPOE, LSTRE and RDWE are reset to zero. Writing the opposite value into these bits in
single chip mode does not change the operation of the associated Port E pins.
Port E, bit 4 can be configured for a free-running E clock output by clearing NECLK=0. Typically the only
use for an E clock output while the MCU is in single chip modes would be to get a constant speed clock
for use in the external application system.
18.4.3.2.2 Special Test Mode
In expanded wide modes, Ports A and B are configured as a 16-bit multiplexed address and data bus and
Port E provides bus control and status signals. In special test mode, the write protection of many control
bits is lifted so that they can be thoroughly tested without needing to go through reset.
18.4.3.3 Test Operating Mode
There is a test operating mode in which an external master, such as an I.C. tester, can control the on-chip
peripherals.
18.4.3.3.1 Peripheral Mode
This mode is intended for factory testing of the MCU. In this mode, the CPU is inactive and an external
(tester) bus master drives address, data and bus control signals in through Ports A, B and E. In effect, the
whole MCU acts as if it was a peripheral under control of an external CPU. This allows faster testing of
on-chip memory and peripherals than previous testing methods. Since the mode control register is not
accessible in peripheral mode, the only way to change to another mode is to reset the MCU into a different
mode. Background debugging should not be used while the MCU is in special peripheral mode as internal
bus conflicts between BDM and the external master can cause improper operation of both functions.
18.4.4 Internal Visibility
Internal visibility is available when the MCU is operating in expanded wide modes or emulation narrow
mode. It is not available in single-chip, peripheral or normal expanded narrow modes. Internal visibility is
enabled by setting the IVIS bit in the MODE register.
If an internal access is made while E, R/W, and LSTRB are configured as bus control outputs and internal
visibility is off (IVI S=0), E will remain low for the cycle, R/W will remain high, and address, data and the
LSTRB pins will remain at their previous state.
When internal visibility is enabled (IVIS=1), certain internal cycles will be blocked from going external.
During cycles when the BDM is selected, R/W will remain high, data will maintain its previous state, and
address and LSTRB pins will be updated with the internal value. During CPU no access cycles when the
BDM is not driving, R/W will remain high, and address, data and the LSTRB pins will remain at their
previous state.
NOTE
When the system is operating in a secure mode, internal visibility is not
available (i.e., IVIS = 1 has no effect). Also, the IPIPE signals will not be
visible, regardless of operating mode. IPIPE1–IPIPE0 will display 0es if
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 539
they are enabled. In addition, the MOD bits in the MODE control register
cannot be written.
18.4.5 Low-Power Options
The MEBI does not contain any user-controlled options for reducing power consumption. The operation
of the MEBI in low-power modes is discussed in the following subsections.
18.4.5.1 Operation in Run Mode
The MEBI does not contain any options for reducing power in run mode; however, the external addresses
are conditioned to reduce power in single-chip modes. Expanded bus modes will increase power
consumption.
18.4.5.2 Operation in Wait Mode
The MEBI does not contain any options for reducing power in wait mode.
18.4.5.3 Operation in Stop Mode
The MEBI will cease to function after execution of a CPU STOP instruction.
Chapter 18 Multiplexed External Bus Interface (MEBIV3)
MC9S12E256 Data Sheet, Rev. 1.08
540 Freescale Semiconductor
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 541
Chapter 19
Module Mapping Control (MMCV4)
19.1 Introduction
This section describes the functionality of the module mapping control (MMC) sub-block of the S12 core
platform.
The block diagram of the MMC is shown in Figure 19-1.
Figure 19-1. MMC Block Diagram
The MMC is the sub-module which controls memory map assignment and selection of internal resources
and external space. Internal buses between the core and memories and between the co re and peripherals is
controlled in this module. The memory expansion is generated in this module.
MMC
MODE INFORMATION
REGISTERS
CPU WRITE DATA BUS
CPU ADDRESS BUS
CPU CONTROL
STOP, WAIT
ADDRESS DECODE
CPU READ DATA BUS
EBI ALTERNATE ADDRESS BUS
EBI ALTERNATE WRITE DATA BUS
EBI ALTERNATE READ DATA BUS
SECURITY
CLOCKS, RESET
READ & WRITE ENABLES
ALTERNATE ADDRESS BUS (BDM)
ALTERNATE WRITE DATA BUS (BDM)
ALTERNATE READ DATA BUS (BDM)
CORE SELECT (S)
PORT K INTERFACE
MEMORY SPACE SELECT(S)
PERIPHERAL SELECT
BUS CONTROL
SECURE
BDM_UNSECURE
MMC_SECURE
INTERNAL MEMORY
EXPANSION
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
542 Freescale Semiconductor
19.1.1 Features
• Registers for mapping of address space for on-chip RAM, EEPROM, and FLASH (or ROM)
memory blocks and associated registers
• Memory mapping control and selection based upon address decode and system operating mode
• Core address bus control
• Core data bus control and multiplexing
• Core security state decoding
• Emulation chip select signal generation (ECS)
• External chip select signal generation (XCS)
• Internal memory expansion
• External stretch and ROM mapping control functions via the MISC register
• Reserved registers for test purposes
• Configurable system memory options defined at integration of core into the system-on-a-chip
(SoC).
19.1.2 Modes of Operation
Some of the registers operate differently depending on the mode of operation (i.e., normal expanded wide,
special single chip, etc.). This is best understood from the register descriptions.
19.2 External Signal Description
All interfacing with the MMC sub-block is done within the core, it has no external signals.
19.3 Memory Map and Register Definition
A summary of the registers associated with the MMC sub-block is shown in Figure 19-2. Detailed
descriptions of the registers and bits are given in the subsections that follow.
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 543
19.3.1 Module Memory Map
Table 19-1. MMC Memory Map
Address
Offset Register Access
0x0010 Initialization of Internal RAM Position Register (INITRM) R/W
0x0011 Initialization of Internal Registers Position Register (INITRG) R/W
0x0012 Initialization of Internal EEPROM Position Register (INITEE) R/W
0x0013 Miscellaneous System Control Register (MISC) R/W
Reserved —
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Reserved —
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0x001C Memory Size Register 0 (MEMSIZ0) R
0x001D Memory Size Register 1 (MEMSIZ1) R
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0x0030 Program Page Index Register (PPAGE) R/W
Reserved —
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
544 Freescale Semiconductor
19.3.2 Register Descriptions
Name Bit 7654321Bit 0
INITRM R RAM15 RAM14 RAM13 RAM12 RAM11 00
RAMHAL
W
INITRG R 0 REG14 REG13 REG12 REG11 000
W
INITEE R EE15 EE14 EE13 EE12 EE11 00
EEON
W
MISCR0000
EXSTR1 EXSTR0 ROMHM ROMON
W
MTSTORBit 7654321Bit 0
W
MTST1RBit 7654321Bit 0
W
MEMSIZ0 R REG_SW0 0 EEP_SW1 EEP_SW0 0 RAM_SW2 RAM_SW1 RAM_SW0
W
MEMSIZ1 R ROM_SW1 ROM_SW0 0 0 0 0 PAG_SW1 PAG_SW0
W
PPAGE R 0 0 PIX5 PIX4 PIX3 PIX2 PIX1 PIX0
W
ReservedR00000000
W
= Unimplemented
Figure 19-2. MMC Register Summary
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 545
19.3.2.1 Initialization of Internal RAM Position Register (INITRM)
Read: Anytime
Write: Once in normal and emulation modes, anytime in special modes
NOTE
Writes to this register take one cycle to go into effect.
This register initializes the position of the internal RAM within the on-chip system memory map.
19.3.2.2 Initialization of Internal Registers Position Register (INITRG)
Read: Anytime
Write: Once in normal and emulation modes and anytime in special modes
This register initializes the position of the internal registers within the on-chip system memory map. The
registers occupy either a 1K byte or 2K byte space and can be mapped to any 2K byte space within the first
32K bytes of the system’s address space.
76543210
RRAM15 RAM14 RAM13 RAM12 RAM11 00
RAMHAL
W
Reset00001001
= Unimplemented or Reserved
Figure 19-3. Initialization of Internal RAM Position Register (INITRM)
Table 19-2. INITRM Field Descriptions
Field Description
7:3
RAM[15:11]
Internal RAM Map Position — These bits determine the upper five bits of the base address for the system’s
internal RAM array.
0
RAMHAL
RAM High-Align — RAMHAL specifies the alignment of the internal RAM array.
0 Aligns the RAM to the lowest address (0x0000) of the mappable space
1 Aligns the RAM to the higher address (0xFFFF) of the mappable space
76543210
R0 REG14 REG13 REG12 REG11 000
W
Reset00000000
= Unimplemented or Reserved
Figure 19-4. Initialization of Internal Registers Position Register (INITRG)
Table 19-3. INITRG Field Descriptions
Field Description
6:3
REG[14:11]
Internal Register Map Position — These four bits in combination with the leading zero supplied by bit 7 of
INITRG determine the upper five bits of the base address for the system’s internal registers (i.e., the minimum
base address is 0x0000 and the maximum is 0x7FFF).
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
546 Freescale Semiconductor
19.3.2.3 Initialization of Internal EEPROM Position Register (INITEE)
Read: Anytime
Write: The EEON bit can be written to any time on all devices. Bits E[11:15] are “write anytime in all
modes” on most devices. On some devices, bits E[1 1 :15] are “write once in normal and emulation modes
and write anytime in special modes”. See Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)” to determine the actual write access rights.
NOTE
Writes to this register take one cycle to go into effect.
This register initializes the position of the internal EEPROM within the on-chip system memory map.
76543210
R
EE15 EE14 EE13 EE12 EE11
00
EEON
W
Reset1————————
1. The reset state of this register is controlled at chip integration. Please refer to Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)” to determine the actual reset state of this register.
= Unimplemented or Reserved
Figure 19-5. Initialization of Internal EEPROM Position Register (INITEE)
Table 19-4. INITEE Field Descriptions
Field Description
7:3
EE[15:11]
Internal EEPROM Map Position — These bits determine the upper five bits of the base address for the system’s
internal EEPROM array.
0
EEON
Enable EEPROM — This bit is used to enable the EEPROM memory in the memory map.
0 Disables the EEPROM from the memory map.
1 Enables the EEPROM in the memory map at the address selected by EE[15:11].
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 547
19.3.2.4 Miscellaneous System Control Register (MISC)
Read: Anytime
Write: As stated in each bit description
NOTE
Writes to this register take one cycle to go into effect.
This register initializes miscellaneous control functions.
76543210
R0000
EXSTR1 EXSTR0 ROMHM ROMON
W
Reset: Expanded
or Emulation 0000110—
1
Reset: Peripheral
or Single Chip 00001101
Reset: Special Test00001100
1. The reset state of this bit is determined at the chip integration level.
= Unimplemented or Reserved
Figure 19-6. Miscellaneous System Control Register (MISC)
Table 19-5. MISC Field Descriptions
Field Description
3:2
EXSTR[1:0]
External Access Stretch Bits 1 and 0
Write: once in normal and emulation modes and anytime in special modes
This two-bit field determines the amount of clock stretch on accesses to the external address space as shown in
Ta b le 1 9 - 6 . In single chip and peripheral modes these bits have no meaning or effect.
1
ROMHM
FLASH EEPROM or ROM Only in Second Half of Memory Map
Write: once in normal and emulation modes and anytime in special modes
0 The fixed page(s) of FLASH EEPROM or ROM in the lower half of the memory map can be accessed.
1 Disables direct access to the FLASH EEPROM or ROM in the lower half of the memory map. These physical
locations of the FLASH EEPROM or ROM remain accessible through the program page window.
0
ROMON
ROMON — Enable FLASH EEPROM or ROM
Write: once in normal and emulation modes and anytime in special modes
This bit is used to enable the FLASH EEPROM or ROM memory in the memory map.
0 Disables the FLASH EEPROM or ROM from the memory map.
1 Enables the FLASH EEPROM or ROM in the memory map.
Table 19-6. External Stretch Bit Definition
Stretch Bit EXSTR1 Stretch Bit EXSTR0 Number of E Clocks Stretched
00 0
01 1
10 2
11 3
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
548 Freescale Semiconductor
19.3.2.5 Reserved Test Register 0 (MTST0)
Read: Anytime
Write: No effect — this register location is used for internal test purposes.
19.3.2.6 Reserved Test Register 1 (MTST1)
Read: Anytime
Write: No effect — this register location is used for internal test purposes.
76543210
R00000000
W
Reset00000000
= Unimplemented or Reserved
Figure 19-7. Reserved Test Register 0 (MTST0)
76543210
R00000000
W
Reset00010000
= Unimplemented or Reserved
Figure 19-8. Reserved Test Register 1 (MTST1)
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 549
19.3.2.7 Memory Size Register 0 (MEMSIZ0)
Read: Anytime
Write: Writes have no effect
Reset: Defined at chip integration, see Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)”.
The MEMSIZ0 register reflects the state of the register , EEPROM and RAM memory space configuration
switches at the core boundary which are configured at system integration. This register allows read
visibility to the state of these switches.
76543210
R REG_SW0 0 EEP_SW1 EEP_SW0 0 RAM_SW2 RAM_SW1 RAM_SW0
W
Reset————————
= Unimplemented or Reserved
Figure 19-9. Memory Size Register 0 (MEMSIZ0)
Table 19-7. MEMSIZ0 Field Descriptions
Field Description
7
REG_SW0
Allocated System Register Space
0 Allocated system register space size is 1K byte
1 Allocated system register space size is 2K byte
5:4
EEP_SW[1:0]
Allocated System EEPROM Memory Space — The allocated system EEPROM memory space size is as
given in Table 1 9-8.
2
RAM_SW[2:0]
Allocated System RAM Memory Space — The allocated system RAM memory space size is as given in
Ta b le 1 9 - 9 .
Table 19-8. Allocated EEPROM Memory Space
eep_sw1:eep_sw0 Allocated EEPROM Space
00 0K byte
01 2K bytes
10 4K bytes
11 8K bytes
Table 19-9. Allocated RAM Memory Space
ram_sw2:ram_sw0 Allocated
RAM Space
RAM
Mappable Region
INITRM
Bits Used
RAM Reset
Base Address1
000 2K bytes 2K bytes RAM[15:11] 0x0800
001 4K bytes 4K bytes RAM[15:12] 0x0000
010 6K bytes 8K bytes2RAM[15:13] 0x0800
011 8K bytes 8K bytes RAM[15:13] 0x0000
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
550 Freescale Semiconductor
NOTE
As stated, the bits in this register provide read visibility to the system
physical memory space allocations defined at system integration. The actual
array size for any given type of memory block may differ from the allocated
size. Please refer to Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)” for actual sizes.
19.3.2.8 Memory Size Register 1 (MEMSIZ1)
Read: Anytime
Write: Writes have no effect
Reset: Defined at chip integration, see Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)”.
The MEMSIZ1 register reflects the state of the FLASH or ROM physical memory space and paging
switches at the core boundary which are configured at system integration. This register allows read
visibility to the state of these switches.
100 10K bytes 16K bytes 2RAM[15:14] 0x1800
101 12K bytes 16K bytes 2RAM[15:14] 0x1000
110 14K bytes 16K bytes 2RAM[15:14] 0x0800
111 16K bytes 16K bytes RAM[15:14] 0x0000
1The RAM Reset BASE Address is based on the reset value of the INITRM register, 0x0009.
2Alignment of the Allocated RAM space within the RAM mappable region is dependent on the value of RAMHAL.
76543210
R ROM_SW1 ROM_SW0 0 0 0 0 PAG_SW1 PAG_SW0
W
Reset————————
= Unimplemented or Reserved
Figure 19-10. Memory Size Register 1 (MEMSIZ1)
Table 19-10. MEMSIZ1 Field Descriptions
Field Description
7:6
ROM_SW[1:0]
Allocated System FLASH or ROM Physical Memory Space — The allocated system FLASH or ROM
physical memory space is as given in Table 19-11.
1:0
PAG_SW[1:0]
Allocated Off-Chip FLASH or ROM Memory Space — The allocated off-chip FLASH or ROM memory space
size is as given in Table 19-12.
Table 19-9. Allocated RAM Memory Space (continued)
ram_sw2:ram_sw0 Allocated
RAM Space
RAM
Mappable Region
INITRM
Bits Used
RAM Reset
Base Address1
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 551
NOTE
As stated, the bits in this register provide read visibility to the system
memory space and on-chip/off-chip partitioning allocations defined at
system integration. The actual array size for any given type of memory
block may differ from the allocated size. Please refer to Chapter 1,
“MC9S12E256 Device Overview (MC9S12E256DGV1)” for actual sizes.
19.3.2.9 Program Page Index Register (PPAGE)
Read: Anytime
W rite: Determined at chip integration. Generally it’ s: “write anytime in all modes;” on some devices it will
be: “write only in special modes.” Check specific device documentation to determine which applies.
Reset: Defined at chip integration as either 0x00 (paired with write in any mode) or 0x3C (paired with
write only in special modes), see Chapter 1, “MC9S12E256 Device Overview (MC9S12E256DGV1)”.
Table 19-11. Allocated FLASH/ROM Physical Memory Space
rom_sw1:rom_sw0 Allocated FLASH
or ROM Space
00 0K byte
01 16K bytes
10 48K bytes(1)
11 64K bytes(1)
NOTES:
1. The ROMHM software bit in the MISC register determines the accessibility of the
FLASH/ROM memory space. Please refer to Section 19.3.2.8, “Memory Size Register
1 (MEMSIZ1),” for a detailed functional description of the ROMHM bit.
Table 19-12. Allocated Off-Chip Memory Options
pag_sw1:pag_sw0 Off-Chip Space On-Chip Space
00 876K bytes 128K bytes
01 768K bytes 256K bytes
10 512K bytes 512K bytes
11 0K byte 1M byte
76543210
R0 0
PIX5 PIX4 PIX3 PIX2 PIX1 PIX0
W
Reset1————————
1. The reset state of this register is controlled at chip integration. Please refer to Chapter 1, “MC9S12E256 Device Overview
(MC9S12E256DGV1)” to determine the actual reset state of this register.
= Unimplemented or Reserved
Figure 19-11. Program Page Index Register (PPAGE)
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
552 Freescale Semiconductor
The HCS12 core architecture limits the physical address space available to 64K bytes. The program page
index register allows for integrating up to 1M byte of FLASH or ROM into the system by using the six
page index bits to page 16K byte blocks into the program page window located from 0x8000 to 0xBFFF
as defined in Table 19-14. CALL and RTC instructions have special access to read and write this register
without using the address bus.
NOTE
Normal writes to this register take on e cycle to go into effect. Writes to this
register using the special access o f th e CALL and RTC instructions will be
complete before the end of the associated instruction.
19.4 Functional Description
The MMC sub-block performs four basic functions of the core operation: bus control, address decoding
and select signal generation, memory expansion, and security decoding for the system. Each aspect is
described in the following subsections.
19.4.1 Bus Control
The MMC controls the address bus and data buses that interface the core with the rest of the system. This
includes the multiplexing of the input data buses to the core onto the main CPU read data bus and control
Table 19-13. PPAGE Field Descriptions
Field Description
5:0
PIX[5:0]
Program Page Index Bits 5:0 — These page index bits are used to select which of the 64 FLASH or ROM
array pages is to be accessed in the program page window as shown in Ta bl e 1 9 - 1 4 .
Table 19-14. Program Page Index Register Bits
PIX5 PIX4 PIX3 PIX2 PIX1 PIX0 Program Space
Selected
000000 16K page 0
000001 16K page 1
000010 16K page 2
000011 16K page 3
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1 1 1 1 0 0 16K page 60
1 1 1 1 0 1 16K page 61
1 1 1 1 1 0 16K page 62
1 1 1 1 1 1 16K page 63
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 553
of data flow from the CPU to the output address and data buses of the core. In addition, the MMC manages
all CPU read data bus swapping operations.
19.4.2 Address Decoding
As data flows on the core address bus, the MMC decodes the address information, determines whether the
internal core register or firmware space, the peripheral space or a memory regis ter or array space is being
addressed and generates the correct select signal. This decoding operation also interprets the mode of
operation of the system and the state of the mapping control registers in order to generate the proper select.
The MMC also generates two external chip select signals, emulation chip select (ECS) and external chip
select (XCS).
19.4.2.1 Select Priority and Mode Considerations
Although internal resources such as control registers and on-chip memory have default addresses, each can
be relocated by changing the default values in control registers. Normally, I/O addresses, control registers,
vector spaces, expansion windows, and on-chip memory are mapped so that their address ranges do not
overlap. The MMC will make only one select signal active at any given time. This activation is based upon
the priority outlined in Table 19-15. If two or more blocks share the same address space, only the select
signal for the block with the highest priority will become active. An example of this is if the registers and
the RAM are mapped to the same space, the registers will have priority over the RAM and the portion of
RAM mapped in this shared space will not be accessible. The expansion windows have the lowest priority .
This means that registers, vectors, and on-chip memory are always visible to a program regardless of the
values in the page select registers.
In expanded modes, all address space not used by internal resources is by default external memory space.
The data registers and data direction registers for ports A and B are removed from the on-chip memory
map and become external accesses. If the EME bit in the MODE register (see Chapter 18, “Multiplexed
External Bus Interface (MEBIV3)”) is set, the data and data direction registers for port E are also removed
from the on-chip memory map and become external accesses.
In special peripheral mode, the first 16 registers associated with bus expansion are removed from the
on-chip memory map (PORTA, PORTB, DDRA, DDRB, PORTE, DDRE, PEAR, MODE, PUCR,
RDRIV, and the EBI reserved registers).
Table 19-15. Select Signal Priority
Priority Address Space
Highest BDM (internal to core) firmware or register space
... Internal register space
... RAM memory block
... EEPROM memory block
... On-chip FLASH or ROM
Lowest Remaining external space
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
554 Freescale Semiconductor
In emulation modes, if the EMK bit in the MODE register (see Chapter 18, “Multiplexed External Bus
Interface (MEBIV3)”) is set, the data and data direction registers for port K are removed from the on-chip
memory map and become external accesses.
19.4.2.2 Emulation Chip Select Signal
When the EMK bit in the MODE register (see Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”) is set, port K bit 7 is used as an active-low emulation chip select signal, ECS. This signal is
active when the system is in emulation mode, the EMK bit is set and the FLASH or ROM space is being
addressed subject to the conditions outlined in Section 19.4.3.2, “Extended Address (XAB19:14) and ECS
Signal Functionality.” When the EMK bit is clear, this pin is used for general purpose I/O.
19.4.2.3 External Chip Select Signal
When the EMK bit in the MODE register (see Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”) is set, port K bit 6 is used as an active-low external chip select signal, XCS. This signal is
active only when the ECS signal described above is not active and when the system is addressing the
external address space. Accesses to unimplemente d locations within the register space or to locations that
are removed from the map (i.e., ports A and B in expanded modes) will not cause this signal to become
active. When the EMK bit is clear, this pin is used for general purpose I/O.
19.4.3 Memory Expansion
The HCS12 core architecture limits the physical address space available to 64K bytes. The program page
index register allows for integrating up to 1M byte of FLASH or ROM into the system by using the six
page index bits to page 16K byte blocks into the program page window located from 0x8000 to 0xBFFF
in the physical memory space. The paged memory space can consist of solely on-chip memory or a
combination of on-chip and off-chip memory . This partitioning is configured at system integration through
the use of the paging configuration switches (pag_sw1:pag_sw0) at the core boundary. The options
available to the integrator are as given in Table 19-16 (this table matches Table 19-12 but is repeated here
for easy reference).
Based upon the system configuration, the program page window will consider its access to be either
internal or external as defined in Table 19-17.
Table 19-16. Allocated Off-Chip Memory Options
pag_sw1:pag_sw0 Off-Chip Space On-Chip Space
00 876K bytes 128K bytes
01 768K bytes 256K bytes
10 512K bytes 512K bytes
11 0K byte 1M byte
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 555
NOTE
The partitioning as defined in Table 19-17 applies only to the allocated
memory space and the actual on-chip memory sizes implemented in the
system may differ. Please refer to Chapter 1, “MC9S12E256 Device
Overview (MC9S12E256DGV1)” for actual sizes.
The PPAGE register holds the page select value for the program page window. The value of the PPAGE
register can be manipulated by normal read and write (some devices don’t allow writes in some modes)
instructions as well as the CALL and RTC instructions.
Control registers, vector spaces, and a portion of on-chip memory are located in unpaged portions of the
64K byte physical address space. The stack and I/O addresses should also be in unpaged memory to make
them accessible from any page.
The starting address of a service routine must be located in unpaged memory because the 16-bit exception
vectors cannot point to addresses in paged memory. However , a service routine can call other routines that
are in paged memory. The upper 16K byte block of memory space (0xC000–0xFFFF) is unpaged. It is
recommended that all reset and interrupt vectors point to locations in this area.
19.4.3.1 CALL and Return from Call Instructions
CALL and RTC are uninterruptable instructions that automate page switching in the program expansion
window. CALL is similar to a JSR instruction, but the subroutine that is called can be located anywhere in
the normal 64K byte address space or on any page of program expansion memory. CALL calculates and
stacks a return address, stacks the current PPAGE value, and writes a new instruction-supplied value to
PPAGE. The PPAGE value controls which of the 64 possible pages is visible through the 16K byte
expansion window in the 64K byte memory map. Execution then begins at the address of the called
subroutine.
Table 19-17. External/Internal Page Window Access
pag_sw1:pag_sw0 Partitioning PIX5:0 Value Page Window
Access
00 876K off-Chip,
128K on-Chip
0x0000–0x0037 External
0x0038–0x003F Internal
01 768K off-chip,
256K on-chip
0x0000–0x002F External
0x0030–0x003F Internal
10 512K off-chip,
512K on-chip
0x0000–0x001F External
0x0020–0x003F Internal
11 0K off-chip,
1M on-chip
N/A External
0x0000–0x003F Internal
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
556 Freescale Semiconductor
During the execution of a CALL instruction, the CPU:
• Writes the old PPAGE value into an internal temporary register and writes the new
instruction-supplied PPAGE value into the PPAGE register.
• Calculates the address of the next instruction after the CALL instruction (the return address), and
pushes this 16-bit value onto the stack.
• Pushes the old PPAGE value onto the stack.
• Calculates the effective address of the subroutine, refills the queue, and begins execution at the new
address on the selected page of the expansion window.
This sequence is uninterruptable; there is no need to inhibit interrupts during CALL execution. A CALL
can be performed from any address in memory to any other address.
The PPAGE value supplied by the instruction is part of the effective address. For all addressing mode
variations except indexed-indirect modes, the new page value is provided by an immediate operand in the
instruction. In indexed-indirect variations of CALL, a pointer specifies memory locations where the new
page value and the address of the called subroutine are stored. Using indirect addressing for both the new
page value and the address within the page allows values calculated at run time rather than immediate
values that must be known at the time of assembly.
The RTC instruction terminates subroutines invoked by a CALL instruction. RTC unstacks the PPAGE
value and the return address and refills the queue. Execution resumes with the next instruction after the
CALL.
During the execution of an RTC instruction, the CPU:
• Pulls the old PPAGE value from the stack
• Pulls the 16-bit return address from the stack and loads it into the PC
• Writes the old PPAGE value into the PPAGE register
• Refills the queue and resumes execution at the return address
This sequence is uninterruptable; an RTC can be executed from anywhere in memory, even from a
different page of extended memory in the expansion window.
The CALL and RTC instructions behave like JSR and RTS, except they use more execution cycles.
Therefore, routinely substituting CALL/RTC for JSR/R TS is not recommended. JSR and RTS can be used
to access subroutines that are on the same page in expanded memory. However , a subroutine in expanded
memory that can be called from other pages must be terminated with an RTC. And the RTC unstacks a
PPAGE value. So any access to the subroutine, even from the same page, must use a CALL instruction so
that the correct PPAGE value is in the stack.
19.4.3.2 Extended Address (XAB19:14) and ECS Signal Functionality
If the EMK bit in the MODE register is set (see Chapter 18, “Multiplexed External Bus Interface
(MEBIV3)”) the PIX5:0 values will be output on XAB19:14 respectively (port K bits 5:0) when the system
is addressing within the physical program page window address space (0x8000–0xBFFF) and is in an
expanded mode. When addressing anywhere else within the physical address space (outside of the paging
space), the XAB19:14 signals will be assigned a constant value based upon the physical address space
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 557
selected. In addition, the active-low emulation chip select signal, ECS, will likewise function based upon
the assigned memory allocation. In the cases of 48K byte and 64K byte allocated physical FLASH/ROM
space, the operation of the ECS signal will additionally depend upon the state of the ROMHM bit (see
Section 19.3.2.4, “Miscellaneous System Control Register (MISC)”) in the MISC register. Table 19-18,
Table 19-19, Table 19-20, and Table 19-21 summarize the functionality of these signals based upon the
allocated memory configuration. Again, this signal information is only available externally when the EMK
bit is set and the system is in an expanded mode.
Table 19-18. 0K Byte Physical FLASH/ROM Allocated
Address Space Page Window Access ROMHM ECS XAB19:14
0x0000–0x3FFF N/A N/A 1 0x3D
0x4000–0x7FFF N/A N/A 1 0x3E
0x8000–0xBFFF N/A N/A 0 PIX[5:0]
0xC000–0xFFFF N/A N/A 0 0x3F
Table 19-19. 16K Byte Physical FLASH/ROM Allocated
Address Space Page Window Access ROMHM ECS XAB19:14
0x0000–0x3FFF N/A N/A 1 0x3D
0x4000–0x7FFF N/A N/A 1 0x3E
0x8000–0xBFFF N/A N/A 1 PIX[5:0]
0xC000–0xFFFF N/A N/A 0 0x3F
Table 19-20. 48K Byte Physical FLASH/ROM Allocated
Address Space Page Window Access ROMHM ECS XAB19:14
0x0000–0x3FFF N/A N/A 1 0x3D
0x4000–0x7FFF N/A 0 0 0x3E
N/A 1 1
0x8000–0xBFFF External N/A 1 PIX[5:0]
Internal N/A 0
0xC000–0xFFFF N/A N/A 0 0x3F
Table 19-21. 64K Byte Physical FLASH/ROM Allocated
Address Space Page Window Access ROMHM ECS XAB19:14
0x0000–0x3FFF N/A 0 0 0x3D
N/A 1 1
0x4000–0x7FFF N/A 0 0 0x3E
N/A 1 1
0x8000–0xBFFF External N/A 1 PIX[5:0]
Internal N/A 0
0xC000–0xFFFF N/A N/A 0 0x3F
Chapter 19 Module Mapping Control (MMCV4)
MC9S12E256 Data Sheet, Rev. 1.08
558 Freescale Semiconductor
A graphical example of a memory paging for a system configured as 1M byte on-chip FLASH/ROM with
64K allocated physical space is given in Figure 19-12.
Figure 19-12. Memory Paging Example: 1M Byte On-Chip FLASH/ROM, 64K Allocation
These 16K FLASH/ROM pages accessible from 0x0000 to 0x7FFF if selected
by the ROMHM bit in the MISC register.
NORMAL
SINGLE CHIP
ONE 16K FLASH/ROM PAGE ACCESSIBLE AT A TIME
(SELECTED BY PPAGE = 0 TO 63)
0x0000
0x8000
0xFF00
0xFFFF
0x4000
0xC000
59
62
63
60 61 62 630123
61
16K FLASH
(UNPAGED)
16K FLASH
(UNPAGED)
16K FLASH
(PAGED)
16K FLASH
(UNPAGED)
VECTORS
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 559
Appendix A
Electrical Characteristics
A.1 General
NOTE
The electrical characteristics given in this section are preliminary and
should be used as a guide only. Values cannot be guaranteed by Freescale
and are subject to change without notice.
The part is specified and tested over the 5V and 3.3V ranges. For the
intermediate range, generally the electrical specifications for the 3.3V range
apply, but the part is not tested in production test in the intermediate range.
This supplement contains the most accurate electrical information for the MC9S12E-Family
microcontroller available at the time of publication. The information should be considered
PRELIMINARY and is subject to change.
This introduction is intended to give an overview on several common topics like power supply, current
injection etc.
A.1.1 Parameter Classification
The electrical parameters shown in this supplement are guaranteed by various methods. To give the
customer a better understanding the following classification is used and the parameters are tagged
accordingly in the tables where appropriate.
NOTE
This classification will be added at a later release of the specification
P: Those parameters are guaranteed during production testing on each individual device.
C: Those parameters are achieved by the design characterization by measuring a statistically relevant
sample size across process variations. They are regularly verified by production monitors.
T : Those parameters are achieved by design characterization on a small sample size from typical devices.
All values shown in the typical column are within this category.
D: Those parameters are derived mainly from simulations.
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
560 Freescale Semiconductor
A.1.2 Power Supply
The MC9S12E-Family utilizes several pins to supply power to the I/O ports, A/D converter, oscillator,
PLL and internal logic.
The VDDA, VSSA pair supplies the A/D converter and D/A converter.
The VDDX, VSSX pair supplies the I/O pins
The VDDR, VSSR pair supplies the internal voltage regulator.
VDD1, VSS1, VDD2 and VSS2 are the supply pins for the internal logic.
VDDPLL, VSSPLL supply the oscillator and the PLL.
VSS1 and VSS2 are internally connected by metal.
VDD1 and VDD2 are internally connected by metal.
VDDA, VDDX, VDDR as well as VSSA, VSSX, VSSR are connected by anti-parallel diodes for
ESD protection.
NOTE
In the following context VDD5 is used for either VDDA, VDDR and
VDDX; VSS5 is used for either VSSA, VSSR and VSSX unless otherwise
noted.
IDD5 denotes the sum of the currents flowing into the VDDA, VDDX and
VDDR pins.
VDD is used for VDD1, VDD2 and VDDPLL, VSS is used for VSS1, VSS2
and VSSPLL.
IDD is used for the sum of the currents flowing into VDD1 and VDD2.
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 561
A.1.3 Pins
There are four groups of functional pins.
A.1.3.1 3.3V/5V I/O Pins
Those I/O pins have a nominal level of 3.3V or 5V depending on the application operating point. This
group of pins is comprised of all port I/O pins, the analog inputs, BKGD pin and the RESET inputs.The
internal structure of all those pins is identical, however some of the functionality may be disabled.
A.1.3.2 Analog Reference
This group of pins is comprised of the VRH and VRL pins.
A.1.3.3 Oscillator
The pins XFC, EXTAL, XT AL dedicated to the oscillator have a nominal 2.5V level. They are supplied by
VDDPLL.
A.1.3.4 TEST
This pin is used for production testing only.
A.1.4 Current Injection
Power supply must maintain regulation within operating VDD5 or VDD range during instantaneous and
operating maximum current conditions. If positive injection current (Vin > VDD5) is greater than IDD5, the
injection current ma y flow out of VDD5 and could result in external power supply going out of regulation.
Insure external VDD5 load will shunt current greater than maximum injection current. This will be the
greatest risk when the MCU is not consuming power; e.g. if no system clock is present, or if clock rate is
very low which would reduce overall power consumption.
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
562 Freescale Semiconductor
A.1.5 Absolute Maximum Ratings
Absolute maximum ratings are stress ratings only. A functional operation under or outside those maxima
is not guaranteed. S tress beyond those limits may affect the reliability or cause permanent damage of the
device.
This device contains circuitry protecting against damage due to high static voltage or electrical fields;
however, it is advised that normal precautions be taken to avoid application of any voltages higher than
maximum-rated voltages to this high-impedance circuit. Reliability of operation is enhanced if unused
inputs are tied to an appropriate logic voltage level (e.g., either VSS5 or VDD5).
Table A-1. Absolute Maximum Ratings
Num Rating Symbol Min Max Unit
1 I/O, Regulator and Analog Supply Voltage VDD5 –0.3 6.5 V
2 Internal Logic Supply Voltage1
1The device contains an internal voltage regulator to generate the logic and PLL supply out of the I/O supply. The absolute
maximum ratings apply when the device is powered from an external source.
VDD –0.3 3.0 V
3 PLL Supply Voltage 1VDDPLL –0.3 3.0 V
4 Voltage difference VDDX to VDDR and VDDA ∆VDDX –0.3 0.3 V
5 Voltage difference VSSX to VSSR and VSSA ∆VSSX –0.3 0.3 V
6 Digital I/O Input Voltage VIN –0.3 6.5 V
7 Analog Reference VRH, VRL –0.3 6.5 V
8 XFC, EXTAL, XTAL inputs VILV –0.3 3.0 V
9 TEST input VTEST –0.3 10.0 V
10 Instantaneous Maximum Current
Single pin limit for all digital I/O pins 2
2All digital I/O pins are internally clamped to VSSX and VDDX, VSSR and VDDR or VSSA and VDDA.
ID–25 +25 mA
11 Instantaneous Maximum Current
Single pin limit for XFC, EXTAL, XTAL3
3These pins are internally clamped to VSSPLL and VDDPLL
IDL –25 +25 mA
12 Instantaneous Maximum Current
Single pin limit for TEST4
4This pin is clamped low to VSSR, but not clamped high. This pin must be tied low in applications.
IDT –0.25 0 mA
13 Operating Temperature Range (packaged) TA– 40 125 °C
14 Operating Temperature Range (junction) TJ– 40 140 °C
15 Storage Temperature Range Tstg – 65 155 °C
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 563
A.1.6 ESD Protection and Latch-up Immunity
All ESD testing is in conformity with CDF-AEC-Q100 Stress test qualification for Automotive Grade
Integrated Circuits. During the device qualification ESD stresses were performed for the Human Body
Model (HBM), the Machine Model (MM) and the Charge Device Model.
A device will be defined as a failure if after exposure to ESD pulses the device no longer meets the device
specification. Complete DC parametric and functional testing is performed per the applicable device
specification at room temperature followed by hot temperature, unless specified otherwise in the device
specification.
Table A-2. ESD and Latch-up Test Conditions
Model Description Symbol Value Unit
Human Body Series Resistance R1 1500 Ohm
Storage Capacitance C 100 pF
Number of Pulse per pin
positive
negative
—
—
3
3
Machine Series Resistance R1 0 Ohm
Storage Capacitance C 200 pF
Number of Pulse per pin
positive
negative
—
—
3
3
Latch-up Minimum input voltage limit — –2.5 V
Maximum input voltage limit — 7.5 V
Table A-3. ESD and Latch-Up Protection Characteristics
Num C Rating Symbol Min Max Unit
1 C Human Body Model (HBM) VHBM 2000 — V
2 C Machine Model (MM) VMM 200 — V
3 C Charge Device Model (CDM) VCDM 500 — V
4 C Latch-up Current at 125°C
positive
negative
ILAT
+100
-100
—
—
mA
5 C Latch-up Current at 27°C
positive
negative
ILAT
+200
-200
—
—
mA
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
564 Freescale Semiconductor
A.1.7 Operating Conditions
This chapter describes the operating conditions of the device. Unless otherwise noted those conditions
apply to all the following data.
NOTE
Instead of specifying ambient temperature all parameters are specified for
the more meaningful silicon junction temperature. For power dissipation
calculations refer to Section A.1.8, “Power Dissipation and Thermal
Characteristics”.
A.1.8 Power Dissipation and Thermal Characteristics
Power dissipation and thermal characteristics are closely related. The user must assure that the maximum
operating junction temperature is not exceeded. The average chip-junction temperature (TJ) in °C can be
obtained from:
The total power dissipation can be calculated from:
Table A-4. Operating Conditions
Rating Symbol Min Typ Max Unit
I/O, Regulator and Analog Supply Voltage VDD5 2.97 3.3/5 5.5 V
Internal Logic Supply Voltage1
1The device contains an internal voltage regulator to generate the logic and PLL supply out of the I/O supply. The given
operating range applies when this regulator is disabled and the device is powered from an external source.
VDD 2.35 2.5 2.75 V
PLL Supply Voltage 1VDDPLL 2.35 2.5 2.75 V
Voltage Difference VDDX to VDDA ∆VDDX –0.1 0 0.1 V
Voltage Difference VSSX to VSSR and VSSA ∆VSSX –0.1 0 0.1 V
Oscillator fosc 0.5 — 16 MHz
Bus Frequency2
2Some blocks e.g. ATD (conversion) and NVMs (program/erase) require higher bus frequencies for proper operation.
fbus 0.25 — 25 MHz
Operating Junction Temperature Range TJ–40 — 140 °C
TJTAPDΘJA
•()+=
TJJunction Temperature, [°C]=
TAAmbient Temperature, [°C]=
PDTotal Chip Power Dissipation, [W]=
ΘJA Package Thermal Resistance, [ °C/W]=
PDPINT PIO
+=
PINT Chip Internal Power Dissipation, [W]=
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 565
Two cases with internal voltage regulator enabled and disabled must be considered:
1. Internal Voltage Regulator disabled
Which is the sum of all output currents on I/O ports associated with VDDX and VDDM.
For RDSON is valid:
respectively
2. Internal voltage regulator enabled
IDDR is the current shown in Table A-8 and not the overall current flowing into VDDR, which
additionally contains the current flowing into the external loads with output high.
Which is the sum of all output currents on I/O ports associated with VDDX and VDDR.
Table A-5. Thermal Package Characteristics1
1The values for thermal resistance are achieved by package simulations
Num C Rating Symbol Min Typ Max Unit
1 T Thermal Resistance LQFP112, single sided PCB2
2PC Board according to EIA/JEDEC Standard 51-3
θJA ——54°
oC/W
2 T Thermal Resistance LQFP112, double sided PCB
with 2 internal planes3
3PC Board according to EIA/JEDEC Standard 51-7
θJA ——41
oC/W
3 T Junction to Board LQFP112 θJB ——31°
oC/W
4 T Junction to Case LQFP112 θJC ——11
oC/W
5 T Junction to Package Top LQFP112 ΨJT —— 2
oC/W
6 T Thermal Resistance QFP 80, single sided PCB θJA ——51°
oC/W
7 T Thermal Resistance QFP 80, double sided PCB
with 2 internal planes
θJA ——41
oC/W
8 T Junction to Board QFP80 θJB ——27°
oC/W
9 T Junction to Case QFP80 θJC ——14
oC/W
10 T Junction to Package Top QFP80 ΨJT —— 3
oC/W
PINT IDD VDD
⋅IDDPLL VDDPLL
⋅IDDA
+V
DDA
⋅+=
PIO RDSON
i
∑IIOi2
⋅=
RDSON VOL
IOL
------------ for outputs driven low;=
RDSON VDD5 VOH
–
IOH
------------------------------------ for outputs driven high;=
PINT IDDR VDDR
⋅IDDA VDDA
⋅+=
PIO RDSON
i
∑IIOi
2
⋅=
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
566 Freescale Semiconductor
A.1.9 I/O Characteristics
This section describes the characteristics of all 3.3V/5V I/O pins. All parameters are not always applicable,
e.g., not all pins feature pull up/down resistances.
Table A-6. 5V I/O Characteristics
Conditions are shown in Ta b l e A - 4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 P Input High Voltage VIH 0.65*VDD5 ——V
T Input High Voltage VIH ——V
DD5 + 0.3 V
2 P Input Low Voltage VIL — — 0.35*VDD5 V
T Input Low Voltage VIL VSS5 – 0.3 — — V
3 C Input Hysteresis VHYS —250—mV
4 P Input Leakage Current (pins in high ohmic input
mode)1
Vin = VDD5 or VSS5
1Maximum leakage current occurs at maximum operating temperature. Current decreases by approximately one-half for each
8°C to 12°C in the temperature range from 50°C to 125°C.
Iin –1.0 — 1.0 µA
5 C Output High Voltage (pins in output mode)
Partial Drive IOH = –2mA
VOH VDD5 – 0.8 — — V
6 P Output High Voltage (pins in output mode)
Full Drive IOH = –10mA
VOH VDD5 – 0.8 — — V
7 C Output Low Voltage (pins in output mode)
Partial Drive IOL = +2mA
VOL ——0.8V
8 P Output Low Voltage (pins in output mode)
Full Drive IOL = +10mA
VOL ——0.8V
9 P Internal Pull Up Device Current, tested at VIL Max. IPUL — — –130 µA
10 C Internal Pull Up Device Current, tested at VIH Min. IPUH –10 — — µA
11 P Internal Pull Down Device Current, tested at VIH
Min.
IPDH ——130µA
12 C Internal Pull Down Device Current, tested at VIL
Max.
IPDL 10 — — µA
13 D Input Capacitance Cin —6—pF
14 T Injection current2
Single Pin limit
Total Device Limit. Sum of all injected currents
2Refer to Section A.1.4, “Current Injection” for more details
IICS
IICP
–2.5
–25
—
—
2.5
25
mA
15 P Port AD Interrupt Input Pulse filtered3
3Parameter only applies in STOP or Pseudo STOP mode.
tPIGN —— 3µs
16 P Port AD Interrupt Input Pulse passed3tPVAL 10 — — µs
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 567
A.1.10 Supply Currents
This section describes the current consumption characteristics of the device as well as the conditions for
the measurements.
Table A-7. Preliminary 3.3V I/O Characteristics
Conditions are shown in Ta b l e A - 4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 P Input High Voltage VIH 0.65*VDD5 ——V
T Input High Voltage VIH ——V
DD5 + 0.3 V
2 P Input Low Voltage VIL — — 0.35*VDD5 V
T Input Low Voltage VIL VSS5 – 0.3 — — V
3 C Input Hysteresis VHYS 250 mV
4 P Input Leakage Current (pins in high ohmic input
mode)1
Vin = VDD5 or VSS5
1Maximum leakage current occurs at maximum operating temperature. Current decreases by approximately one-half for each
8°C to 12°C in the temperature range from 50°C to 125°C.
Iin –1.0 — 1.0 µA
5 C Output High Voltage (pins in output mode)
Partial Drive IOH = –0.75mA
VOH VDD5 – 0.4 — — V
6 P Output High Voltage (pins in output mode)
Full Drive IOH = –4mA
VOH VDD5 – 0.4 — — V
7 C Output Low Voltage (pins in output mode)
Partial Drive IOL = +0.9mA
VOL ——0.4V
8 P Output Low Voltage (pins in output mode)
Full Drive IOL = +4.75mA
VOL ——0.4V
9 P Internal Pull Up Device Current, tested at VIL Max. IPUL — — –60 µA
10 C Internal Pull Up Device Current, tested at VIH Min. IPUH –6 — — µA
11 P Internal Pull Down Device Current, tested at VIH
Min.
IPDH ——60µA
12 C Internal Pull Down Device Current, tested at VIL
Max.
IPDL 6——µA
13 D Input Capacitance Cin —6—pF
14 T Injection current2
Single Pin limit
Total Device Limit. Sum of all injected currents
2Refer to Section A.1.4, “Current Injection”, for more details
IICS
IICP
–2.5
–25
—
—
2.5
25
mA
15 P Port AD Interrupt Input Pulse filtered3
3Parameter only applies in STOP or Pseudo STOP mode.
tPIGN —— 3µs
16 P Port AD Interrupt Input Pulse passed3tPVAL 10 — — µs
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
568 Freescale Semiconductor
A.1.10.1 Measurement Conditions
All measurements are without output loads. Unless otherwise noted the currents are measured in single
chip mode, internal voltage regulator enabled and at 25MHz bus frequency using a 4MHz oscillator.
A.1.10.2 Additional Remarks
In expanded modes the currents flowing in the system are highly dependent on the load at the address, data
and control signals as well as on the duty cycle of those signals. No generally applicable numbers can be
given. A very good estimate is to take the single chip currents and add the currents due to the external loads.
Table A-8. Supply Current Characteristics
Conditions are shown in Ta b l e A - 4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 P Run supply currents
Single Chip, Internal regulator enabled IDD5 ——65
mA
2
P
P
Wait Supply current
All modules enabled
only RTI enabled
IDDW
—
—
—
—
40
5
mA
3
C
C
C
C
C
C
C
Pseudo Stop Current (RTI and COP enabled) 1, 2
–40°C
27°C
70°C
85°C
105°C
125°C
140°C
1PLL off
2At those low power dissipation levels TJ = TA can be assumed
IDDPS
—
—
—
—
—
—
—
570
600
650
750
850
1200
1500
—
—
—
—
—
—
—
µA
4
C
P
C
C
P
C
P
C
P
Pseudo Stop Current (RTI and COP disabled) 1,2
-40°C
27°C
70°C
85°C
"C" Temp Option 100°C
105°C
"V" Temp Option 120°C
125°C
"M" Temp Option 140°C
IDDPS
—
—
—
—
—
—
—
—
—
370
400
450
550
600
650
800
850
1200
—
500
—
—
1600
—
2100
—
5000
µA
5
C
P
C
C
P
C
P
C
P
Stop Current 2
-40°C
27°C
70°C
85°C
"C" Temp Option 100°C
105°C
"V" Temp Option 120°C
125°C
"M" Temp Option 140°C
IDDS
—
—
—
—
—
—
—
—
—
12
30
100
130
160
200
350
400
600
—
100
—
—
1200
—
1700
—
5000
µA
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 569
A.2 Voltage Regulator
This section describes the characteristics of the on chip voltage regulator.
Table A-9. Voltage Regulator Electrical Parameters
Num C Characteristic Symbol Min Typ Max Unit
1 P Input Voltages VVDDR,A 2.97 — 5.5 V
3 P Output Voltage Core
Full Performance Mode VDD 2.35 2.5 2.75 V
4 P Output Voltage PLL
Full Performance Mode VDDPLL 2.35 2.5 2.75 V
5 P Low Voltage Interrupt1
Assert Level
Deassert Level
1Monitors VDDA, active only in Full Performance Mode. Indicates I/O & ADC performance degradation due to low supply voltage.
VLVI A
VLVI D
4.0
4.15
4.37
4.52
4.66
4.77
V
V
6 P Low Voltage Reset2
Assert Level
Deassert Level
2Monitors VDD, active only in Full Performance Mode. VLV RA and VPORD must overlap
VLVRA
VLVR D
2.25
—
—
—
—
2.55
V
V
7 C Power-on Reset3
Assert Level
Deassert Level
3Monitors VDD. Active in all modes.
VPORA
VPORD
0.97
—
---
---
—
2.05
V
V
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
570 Freescale Semiconductor
A.2.1 Chip Power-up and LVI/LVR Graphical Explanation
Voltage regulator sub modules LVI (low voltage interrupt), POR (power-on reset) and LVR (low voltage
reset) handle chip power-up or drops of the supply voltage. Their function is described in Figure A-1.
Figure A-1. Voltage Regulator — Chip Power-up and Voltage Drops (not scaled)
VLVID
VLVIA
VLVRD
VLVRA
VPORD
LVI
POR
LVR
t
VVDDA
VDD
LVI enable d LVI disabled due to LVR
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 571
A.2.2 Output Loads
A.2.2.1 Resistive Loads
The on-chip voltage regulator is intended to supply the internal logic and oscillator circuits allows no
external DC loads.
A.2.2.2 Capacitive Loads
The capacitive loads are specif ied in Table A-10. Ceramic capacitors with X7R dielectricum are required.
A.3 Startup, Oscillator, and PLL
A.3.1 Startup
Table A-11 summarizes several startup characteristics explained in this section.
Table A-10. Voltage Regulator — Capacitive Loads
Num Characteristic Symbol Min Typ Max Unit
1V
DD external capacitive load CDDext 200 440 12000 nF
2V
DDPLL external capacitive load CDDPLLext 90 220 5000 nF
Table A-11. Startup Characteristics
Conditions are shown in Table A-4 unless otherwise note d
Num C Rating Symbol Min Typ Max Unit
1 T POR release level VPORR — — 2.07 V
2 T POR assert level VPORA 0.97 — — V
3 D Reset input pulse width, minimum input time PWRSTL 2 — — tosc
4 D Startup from Reset nRST 192 — 196 nosc
5 D Interrupt pulse width, IRQ edge-sensitive mode PWIRQ 20 — — ns
6 D Wait recovery startup time tWRS — 14 tcyc
7 P LVR release level VLVR R 2.25 — — V
8 P LVR assert level VLVRA — — 2.55 V
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
572 Freescale Semiconductor
A.3.1.1 POR
The release level V PORR and the assert level VPORA are derived from the VDD Supply . They are also valid
if the device is powered externally . After releasing the POR reset the oscillator and the clock quality check
are started. If after a time tCQOUT no valid oscillation is detected, the MCU will start using the internal self
clock. The fastest startup time possible is given by nuposc.
A.3.1.2 LVR
The release level VLVRR and the assert level VLVRA are derived from the VDD Supply. They are also valid
if the device is powered externally. After releasing the LVR reset the oscillator and the clock quality check
are started. If after a time tCQOUT no valid oscillation is detected, the MCU will start using the internal self
clock. The fastest startup time possible is given by nuposc.
A.3.1.3 SRAM Data Retention
Provided an appropriate external reset signal is applied to the MCU, preventing the CPU from executing
code when VDD5 is out of specification limits, the SRAM contents integrity is guaranteed if after the reset
the PORF bit in the CRG Flags Register has not been set.
A.3.1.4 External Reset
When external reset is asserted for a time greater than PWRSTL the CRG module generates an internal
reset, and the CPU starts fetching the reset vector without doing a clock quality check, if there was an
oscillation before reset.
A.3.1.5 Stop Recovery
Out of STOP the controller can be woken up by an external interrupt. A clock quality check as after POR
is performed before releasing the clocks to the system.
A.3.1.6 Pseudo Stop and Wait Recovery
The recovery from Pseudo STOP and Wait are essentially the same since the oscillator was not stopped in
both modes. The controller can be woken up by internal or external interrupts. After twrs the CPU starts
fetching the interrupt vector.
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 573
A.3.2 Oscillator
The device features an internal Colpitts and Pierce oscillator. The selection of Colpitts oscillator or Pierce
oscillator/external clock depends on the XCLKS signal which is sampled during reset. Pierce
oscillator/external clock mode allows the input of a square wave. Before asserting the oscillator to the
internal system clocks the quality of the oscillation is checked for each start from either power-on, STOP
or oscillator fail. tCQOUT specifies the maximum time before switching to the internal self clock mode after
POR or STOP if a proper oscillation is not detected. The quality check also determines the minimum
oscillator start-up time tUPOSC. The device also features a clock monitor. A Clock Monitor Failure is
asserted if the frequency of the incoming clock signal is below the Assert Frequency fCMFA.
Table A-12. Oscillator Characteristics
Conditions are shown in Table A-4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1a C Crystal oscillator range (Colpitts) fOSC 0.5 — 16 MHz
1b C Crystal oscillator range (Pierce) 1
1Depending on the crystal a damping series resistor might be necessary
fOSC 0.5 — 40 MHz
2 P Startup Current iOSC 100 — — µA
3 C Oscillator start-up time (Colpitts) tUPOSC — 82
2fosc = 4MHz, C = 22pF.
1003
3Maximum value is for extreme cases using high Q, low frequency crystals
ms
4 D Clock Quality check time-out tCQOUT 0.45 2.5 s
5 P Clock Monitor Failure Assert Frequency fCMFA 50 100 200 KHz
6 P External square wave input frequency 4
4Only valid if Pierce oscillator/external clock mode is selected
fEXT 0.5 — 50 MHz
7 D External square wave pulse width low4tEXTL 9.5 — — ns
8 D External square wave pulse width high4tEXTH 9.5 — — ns
9 D External square wave rise time4tEXTR — — 1 ns
10 D External square wave fall time4tEXTF — — 1 ns
11 D Input Capacitance (EXTAL, XTAL pins) CIN — 7 pF
12 C DC Operating Bias in Colpitts Configuration on
EXTAL Pin
VDCBIAS — 1.1 — V
13 P EXTAL Pin Input High Voltage4VIH,EXTAL 0.75*VDDPLL — — V
T EXTAL Pin Input High Voltage4VIH,EXTAL — — VDDPLL + 0.3 V
14 P EXTAL Pin Input Low Voltage4VIL,EXTAL — — 0.25*VDDPLL V
T EXTAL Pin Input Low Voltage4VIL,EXTAL VSSPLL – 0.3 — — V
15 C EXTAL Pin Input Hysteresis4VHYS,EXTAL — 250 — mV
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
574 Freescale Semiconductor
A.3.3 Phase Locked Loop
The oscillator provides the reference clock for the PLL. The PLL´s Voltage Controlled Oscillator (VCO)
is also the system clock source in self clock mode.
A.3.3.1 XFC Component Selection
This section describes the selection of the XFC components to achieve a good filter characteristics.
Figure A-2. Basic PLL Functional Diagram
The following procedure can be used to calculate the resistance and capacitance values using typical values
for K1, f1 and ich from Table A-13.
The grey boxes show the calculation for fVCO = 50MHz and fref = 1MHz. E.g., these frequencies are used
for fOSC = 4MHz and a 25MHz bus clock.
The VCO Gain at the desired VCO frequency is approximated by:
The phase detector relationship is given by:
ich is the current in tracking mode.
fosc 1
refdv+1
fref
Phase
Detector
VCO
KV
1
synr+1
fvco
Loop Divider
KΦ
1
2
∆
fcmp
CsR
Cp
VDDPLL
XFC Pin
KVK1e
f1fvco
–()
K11V⋅
----------------------------
⋅=100–e
60 50–()
100–
------------------------
⋅== -90.48MHz/V
KΦich
–KV
⋅== 316.7Hz/Ω
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 575
The loop bandwidth fC should be chosen to fulfill the Gardner’s stability criteria by at least a factor of 10,
typical values are 50. ζ = 0.9 ensures a good transient response.
And finally the frequency relationship is defined as
With the above values the resistance can be calculated. The example is shown for a loop bandwidth
fC=10kHz:
The capacitance Cs can now be calculated as:
The capacitance Cp should be chosen in the range of:
A.3.3.2 Jitter Information
The basic functionality of the PLL is shown in Figure A-2. With each transition of the clock fcmp, the
deviation from the reference clock fref is measured and input voltage to the VCO is adjusted
accordingly.The adjustment is done continuously with no abrupt changes in the clock output frequency.
Noise, voltage, temperature and other factors cause slight variations in the control loop resulting in a clock
jitter. This jitter affects the real minimum and maximum clock periods as illustrated in Figure A-3.
fC
2ζfref
⋅⋅
πζ 1ζ2
++
⎝⎠
⎛⎞
⋅
-------------------------------------------1
10
------ fC
fref
410⋅
-------------- ζ0.9=();<→⋅<
fC < 25kHz
n
fVCO
fref
--------------- 2 s y n r 1+()⋅== = 50
R2πnf
C
⋅⋅⋅
KΦ
-----------------------------== 2*π*50*10kHz/(316.7Hz/Ω)=9.9kΩ=~10kΩ
Cs
2ζ2
⋅
πfCR⋅⋅
---------------------- 0.516
fCR⋅
---------------ζ0.9=();≈== 5.19nF =~ 4.7nF
Cs20⁄CpCs10⁄≤≤ Cp = 470pF
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
576 Freescale Semiconductor
Figure A-3. Jitter Definitions
The relative deviation of tnom is at its maximum for one clock period, and decreases towards zero for larger
number of clock periods (N).
Defining the jitter as:
For N < 100, the following equation is a good fit for the maximum jitter:
This is very important to notice with respect to timers, serial modules where a prescaler will eliminate the
effect of the jitter to a large extent.
23 N-1N1
0
tnom
tmax1
tmin1
tmaxN
tminN
JN() max 1 tmax N()
Nt
nom
⋅
-----------------------
–1tmin N()
Nt
nom
⋅
-----------------------
–,
⎝⎠
⎜⎟
⎛⎞
=
JN() j1
N
-------- j2
+=
1 5 10 20 N
J(N)
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 577
Table A-13. PLL Characteristics
Conditions are shown in Table A-4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 P Self Clock Mode frequency fSCM 1—5.5MHz
2 D VCO locking range fVCO 8—50MHz
3 D Lock Detector transition from Acquisition to
Tracking mode
|∆trk|3 — 4%
1
1% deviation from target frequency
4 D Lock Detection |∆Lock|0 — 1.5%
1
5 D Un-Lock Detection |∆unl|0.5 — 2.5%
1
6 D Lock Detector transition from Tracking to
Acquisition mode
|∆unt|6 — 8%
1
7 C PLLON Total Stabilization delay (Auto Mode) 2
2fOSC = 4MHz, fBUS = 25MHz equivalent fVCO = 50MHz: REFDV = #$03, SYNR = #$018, Cs = 4.7nF, Cp = 470pF, Rs = 10KΩ.
tstab —0.5 —ms
8 D PLLON Acquisition mode stabilization delay 2tacq —0.3 —ms
9 D PLLON Tracking mode stabilization delay 2tal —0.2 —ms
10 D Fitting parameter VCO loop gain K1— -100 — MHz/V
11 D Fitting parameter VCO loop frequency f1—60 —MHz
12 D Charge pump current acquisition mode | ich |—38.5—µA
13 D Charge pump current tracking mode | ich |—3.5 —µA
14 C Jitter fit parameter 12j1——1.1%
15 C Jitter fit parameter 22j2— — 0.13 %
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
578 Freescale Semiconductor
A.4 Flash NVM
A.4.1 NVM Timing
The time base for all NVM program or erase operations is derived from the oscillator. A minimum
oscillator frequency fNVMOSC is required for performing program or erase operations. The NVM modules
do not have any means to monitor the frequency and will not prevent program or erase operation at
frequencies above or below the specified minimum. Attempting to program or erase the NVM modules at
a lower frequency a full program or erase transition is not assured.
The Flash program and erase operations are timed using a clock derived from the oscillator using the
FCLKDIV register. The frequency of this clock must be set within the limits specified as fNVMOP.
The minimum program and erase times shown in Table A-14 are calculated for maximum fNVMOP and
maximum fbus. The maximum times are calculated for minimum fNVMOP and a fbus of 2MHz.
A.4.1.1 Single Word Programming
The programming time for single word programming is dependent on the bus frequency as a well as on the
frequency f¨NVMOP and can be calculated according to the following formula.
A.4.1.2 Row Programming
Flash programming where up to 64 words in a row can be programmed consecutively by keeping the
command pipeline filled. The time to program a consecutive word can be calculated as:
The time to program a whole row is:
Row programming is more than 2 times faster than single word programming.
A.4.1.3 Sector Erase
Erasing a 1024 byte Flash sector takes:
The setup times can be ignored for this operation.
tswpgm 91
fNVMOP
-------------------------
⋅25 1
fbus
------------
⋅+=
tbwpgm 41
fNVMOP
-------------------------
⋅91
fbus
------------
⋅+=
tbrpgm tswpgm 63 tbwpgm
⋅+=
tera 4000 1
fNVMOP
-------------------------
⋅≈
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 579
A.4.1.4 Mass Erase
Erasing a NVM block takes:
The setup times can be ignored for this operation.
A.4.1.5 Blank Check
The time it takes to perform a blank check on the Flash is dependant on the location of the first non-blank
word starting at relative address zero. It takes one bus cycle per word to verify plus a setup of the command.
Table A-14. NVM Timing Characteristics
Conditions are shown in Ta b l e A - 4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 D External Oscillator Clock fNVMOSC 0.5 — 501
1Restrictions for oscillator in crystal mode apply!
MHz
2 D Bus frequency for Programming or Erase Operations fNVMBUS 1——MHz
3 D Operating Frequency fNVMOP 150 — 200 kHz
4 P Single Word Programming Time tswpgm 462
2Minimum Programming times are achieved under maximum NVM operating frequency fNVMOP and maximum bus frequency
fbus.
—74.5
3
3Maximum Erase and Programming times are achieved under particular combinations of fNVMOP and bus frequency f bus. Refer
to formulae in Section A.4.1.1, “Single Word Programming” through Section A.4.1.4, “Mass Erase” for guidance.
µs
5 D Flash Burst Programming consecutive word tbwpgm 20.42—31
3µs
6 D Flash Burst Programming Time for 64 Word row tbrpgm 1331.22— 2027.53µs
7 P Sector Erase Time tera 204
4Minimum Erase times are achieved under maximum NVM operating frequency fNVMOP
.
—26.7
3ms
8 P Mass Erase Time tmass 1004—133
3ms
9 D Blank Check Time Flash per block t check 115
5Minimum time, if first word in the array is not blank
— 655466
6Maximum time to complete check on an erased block
7tcyc
7Where tcyc is the system bus clock period.
tmass 20000 1
fNVMOP
-------------------------
⋅≈
tcheck location tcyc 10 tcyc
⋅+⋅≈
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
580 Freescale Semiconductor
A.4.2 NVM Reliability
The reliability of the NVM blocks is guaranteed by stress test during qualification, constant process
monitors and burn-in to screen early life failures. The program/erase cycle count on the sector is
incremented every time a sector or mass erase event is executed.
Figure A-4. Typical Endurance
Table A-15. NVM Reliability Characteristics1
1TJavg will not exeed 85°C considering a typical temperature profile over the lifetime of a consumer, industrial or automotive
application.
Conditions are shown in Ta b l e A - 4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
Flash Reliability Characteristics
1 C Data retention after 10,000 program/erase cycles at an
average junction temperature of TJavg ≤ 85°C
tFLRET 15 1002
2Typical data retention values are based on intrinsic capability of the technology measured at high temperature and de-rated to
25°C using the Arrhenius equation. For additional information on how Freescale defines Typical Data Retention, please refer
to Engineering Bulletin EB618.
— Years
2 C Data retention with <100 program/erase cycles at an
average junction temperature TJavg ≤ 85°C
20 1002—
3 C Number of program/erase cycles
(–40°C ≤ TJ ≤ 0°C)
nFL 10,000 — — Cycles
4 C Number of program/erase cycles
(0°C ≤ TJ ≤ 140°C)
10,000 100,0003
3Spec table quotes typical endurance evaluated at 25°C for this product family, typical endurance at various temperature can
be estimated using the graph below. For additional information on how Freescale defines Typical Endurance, please refer to
Engineering Bulletin EB619.
—
Typical Endurance [103 Cycles]
Operating Temperature TJ [°C]
0
50
100
150
200
250
300
350
400
450
500
–40 –20 0 20 40 60 80 100 120 140
------ Flash
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 581
A.5 SPI Characteristics
This section provides electrical parametrics and ratings for the SPI.
In Table A-16 the measurement conditions are listed.
A.5.1 Master Mode
In Figure A-5 the timing diagram for master mode with transmission format CPHA=0 is depicted.
Figure A-5. SPI Master Timing (CPHA = 0)
Table A-16. Measurement Conditions
Description Value Unit
Drive mode full drive mode —
Load capacitance CLOAD, on all outputs 50 pF
Thresholds for delay measurement points (20% / 80%) VDDX V
SCK
(OUTPUT)
SCK
(OUTPUT)
MISO
(INPUT)
MOSI
(OUTPUT)
SS1
(OUTPUT)
1
9
5 6
MSB IN2
BIT 6 . . . 1
LSB IN
MSB OUT2LSB OUT
BIT 6 . . . 1
11
4
4
2
10
(CPOL = 0)
(CPOL = 1)
3
13
13
1.If configured as an output.
2. LSBF = 0. For LSBF = 1, bit order is LSB, bit 1, ..., bit 6, MSB.
12
12
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
582 Freescale Semiconductor
In Figure A-6 the timing diagram for master mode with transmission format CPHA=1 is depicted.
Figure A-6. SPI Master Timing (CPHA=1)
In Table A-17 the timing characteristics for master mode are listed.
Table A-17. SPI Master Mode Timing Characteristics
Num C Characteristic Symbol Min Typ Max Unit
1 P SCK Frequency fsck 1/2048 — 1/2f
bus
1 P SCK Period tsck 2 — 2048 tbus
2 D Enable Lead Time tlead —1/2— t
sck
3 D Enable Lag Time tlag —1/2— t
sck
4 D Clock (SCK) High or Low Time twsck —1/2— t
sck
5 D Data Setup Time (Inputs) tsu 8——ns
6 D Data Hold Time (Inputs) thi 8——ns
9 D Data Valid after SCK Edge tvsck — — 30 ns
10 D Data Valid after SS fall (CPHA = 0) tvss — — 15 ns
11 D Data Hold Time (Outputs) tho 20 — — ns
12 D Rise and Fall Time Inputs trfi —— 8 ns
13 D Rise and Fall Time Outputs trfo —— 8 ns
SCK
(OUTPUT)
SCK
(OUTPUT)
MISO
(INPUT)
MOSI
(OUTPUT)
1
5 6
MSB IN2
BIT 6 . . . 1
LSB IN
MASTER MSB OUT2MASTER LSB OUT
BIT 6 . . . 1
4
4
9
12 13
11
PORT DATA
(CPOL = 0)
(CPOL = 1)
PORT DATA
SS1
(OUTPUT)
212 13 3
1.If configured as output
2. LSBF = 0. For LSBF = 1, bit order is LSB, bit 1, ..., bit 6, MSB.
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 583
A.5.2 Slave Mode
In Figure A-7 the timing diagram for slave mode with transmission format CPHA = 0 is depicted.
Figure A-7. SPI Slave Timing (CPHA = 0)
In Figure A-8 the timing diagram for slave mode with transmission format CPHA = 1 is depicted.
Figure A-8. SPI Slave Timing (CPHA = 1)
SCK
(INPUT)
SCK
(INPUT)
MOSI
(INPUT)
MISO
(OUTPUT)
SS
(INPUT)
1
9
5 6
MSB IN
BIT 6 . . . 1
LSB IN
SLAVE MSB SLAVE LSB OUT
BIT 6 . . . 1
11
4
4
2
7
(CPOL = 0)
(CPOL = 1)
3
13
NOTE: Not defined!
12
12
11
SEE
13
NOTE
8
10
see
note
SCK
(INPUT)
SCK
(INPUT)
MOSI
(INPUT)
MISO
(OUTPUT)
1
5 6
MSB IN
BIT 6 . . . 1
LSB IN
MSB OUT SLAVE LSB OUT
BIT 6 . . . 1
4
4
9
12 13
11
(CPOL = 0)
(CPOL = 1)
SS
(INPUT)
212 13
3
NOTE: Not defined!
SLAVE
7
8
see
note
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
584 Freescale Semiconductor
In Table A-18 the timing characteristics for slave mode are listed.
Table A-18. SPI Slave Mode Timing Characteristics
Num C Characteristic Symbol Min Typ Max Unit
1 P SCK Frequency fsck DC — 1/4f
bus
1 P SCK Period tsck 4— t
bus
2 D Enable Lead Time tlead 4——t
bus
3 D Enable Lag Time tlag 4——t
bus
4 D Clock (SCK) High or Low Time twsck 4——t
bus
5 D Data Setup Time (Inputs) tsu 8——ns
6 D Data Hold Time (Inputs) thi 8——ns
7 D Slave Access Time (time to data active) ta— — 20 ns
8 D Slave MISO Disable Time tdis — — 22 ns
9 D Data Valid after SCK Edge tvsck — — 30 + tbus1
1tbus added due to internal synchronization delay
ns
10 D Data Valid after SS fall tvss — — 30 + tbus1ns
11 D Data Hold Time (Outputs) tho 20 — — ns
12 D Rise and Fall Time Inputs trfi —— 8 ns
13 D Rise and Fall Time Outputs trfo —— 8 ns
∞
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 585
A.6 ATD Characteristics
This section describes the characteristics of the analog to digital converter.
The ATD is specified and tested for both the 3.3V and 5V range. For ranges between 3.3V and 5V the ATD
accuracy is generally the same as in the 3.3V range but is not tested in this range in production test.
A.6.1 ATD Operating Characteristics — 5V Range
The Table A-19 shows conditions under which the ATD operates.
The following constraints exist to obtain full-scale, full range results:
VSSA ≤ VRL ≤ VIN ≤ VRH ≤ VDDA. This constraint exists since the sample buffer amplifier can not
drive beyond the power supply levels that it ties to. If the input level goes outside of this range it will
effectively be clipped.
A.6.2 ATD Operating Characteristics — 3.3V Range
The Table A-20 shows conditions under which the ATD operates.
The following constraints exist to obtain full-scale, full range results:
VSSA ≤ VRL ≤ VIN ≤ VRH ≤ VDDA. This constraint exists since the sample buffer amplifier can not
drive beyond the power supply levels that it ties to. If the input level goes outside of this range it will
effectively be clipped.
Table A-19. 5V ATD Operating Characteristics
Conditions are shown in Ta ble A-4 unless otherwise noted. Supply Voltage 5V-10% <= VDDA <=5V+10%
Num C Rating Symbol Min Typ Max Unit
1 D Reference Potential
Low
High
VRL
VRH
VSSA
VDDA/2
—
—
VDDA/2
VDDA
V
V
2 C Differential Reference Voltage1
1Full accuracy is not guaranteed when differential voltage is less than 4.75V
VRH–VRL 4.75 5.0 5.25 V
3 D ATD Clock Frequency fAT DC LK 0.5 — 2.0 MHz
4DATD 10-Bit Conversion Period Clock Cycles2
Conv, Time at 2.0MHz ATD Clock fATDCLK
Conv, Time at 4.0MHz3 ATD Clock fATD CL K
2The minimum time assumes a final sample period of 2 ATD clocks cycles while the maximum time assumes a final sample
period of 16 ATD clocks.
3Reduced accuracy see Ta b l e A - 2 2 and Ta b l e A - 2 3 .
NCONV10
TCONV10
TCONV10
14
7
3.5
—
—
—
28
14
7
Cycles
µs
µs
5 D ATD 8-Bit Conversion Period
Clock Cycles1
Conv, Time at 2.0MHz ATD Clock fATDCLK
NCONV8
TCONV8
12
6
—
—
26
13
Cycles
µs
6 D Stop Recovery Time (VDDA = 5.0 Volts) tSR ——20µs
7 P Reference Supply current IREF — — 0.375 mA
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
586 Freescale Semiconductor
A.6.3 Factors Influencing Accuracy
Three factors — source resistance, source capacitance and current injection — have an influence on the
accuracy of the ATD.
A.6.3.1 Source Resistance
Due to the input pin leakage current as specified in Table A-6 and Table A-7 in conjunction with the source
resistance there will be a voltage drop from the signal source to the ATD input. The maximum source
resistance RS specifies results in an error of less than 1/2 LSB (2.5mV) at the maximum leakage current.
If device or operating conditions are less than worst case or leakage-induced error is acceptable, larger
values of source resistance are allowed.
A.6.3.2 Source Capacitance
When sampling an additional internal capacitor is switched to the input. This can cause a voltage drop due
to charge sharing with the external and the pin capacitance. For a maximum sampling error of the input
voltage ≤ 1LSB, then the external filter capacitor, Cf ≥ 1024 * (CINS- CINN).
A.6.3.3 Current Injection
There are two cases to consider.
1. A current is injected into the channel being converted. The channel being stressed has conversion
values of 0x3FF (0xFF in 8-bit mode) for analog inputs greater than VRH and 0x000 for values
less than VRL unless the current is higher than specified as disruptive conditions.
Table A-20. 3.3V ATD Operating Characteristics
Conditions are shown in Ta b l e A - 4 unless otherwise noted; Supply Voltage 3.3V-10% <= VDDA <= 3.3V+10%
Num C Rating Symbol Min Typ Max Unit
1 D Reference Potential
Low
High
VRL
VRH
VSSA
VDDA/2
—
—
VDDA/2
VDDA
V
V
2 C Differential Reference Voltage VRH-VRL 3.0 3.3 3.6 V
3 D ATD Clock Frequency fAT D C L K 0.5 — 2.0 MHz
4 D ATD 10-Bit Conversion Period
Clock Cycles1
Conv, Time at 2.0MHz ATD Clock fATD CL K
Conv, Time at 4.0MHz2 ATD Clock fATDC LK
1The minimum time assumes a final sample period of 2 ATD clocks cycles while the maximum time assumes a final sample
period of 16 ATD clocks.
2Reduced accuracy see Table A-22 and Tabl e A - 2 3 .
NCONV10
TCONV10
TCONV10
14
7
3.5
—
—
—
28
14
7
Cycles
µs
µs
5 D ATD 8-Bit Conversion Period
Clock Cycles1
Conv, Time at 2.0MHz ATD Clock fATD CL K
NCONV8
TCONV8
12
6
—
—
26
13
Cycles
µs
6 D Recovery Time (VDDA=3.3 Volts) tREC ——20µs
7 P Reference Supply current IREF — — 0.250 mA
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 587
2. Current is injected into pins in the neighborhood of the channel being converted. A portion of this
current is picked up by the channel (coupling ratio K), This additional current impacts the accuracy
of the conversion depending on the source resistance.
The additional input voltage error on the converted channel can be calculated as
VERR = K * RS * IINJ, with IINJ being the sum of the currents injected into the two pins adjacent
to the converted channel.
A.6.4 ATD Accuracy — 5V Range
Table A-22 specifies the ATD conversion performance excluding any errors due to current injection, input
capacitance and source resistance.
Table A-21. ATD Electrical Characteristics
Conditions are shown in Ta b l e A - 4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 C Max input Source Resistance RS—— 1 KΩ
2 T Total Input Capacitance
Non Sampling
Sampling
CINN
CINS
—
—
—
—
10
15
pF
3 C Disruptive Analog Input Current INA –2.5 — 2.5 mA
4 C Coupling Ratio positive current injection Kp——10
-4 A/A
5 C Coupling Ratio negative current injection Kn——10
-2 A/A
Table A-22. 5V ATD Conversion Performance
Conditions are shown in Tabl e A-4 unless otherwise noted
VREF = VRH - VRL = 5.12V. Resulting to one 8 bit count = 20mV and one 10 bit count = 5mV
fATD CL K = 2.0MHz
Num C Rating Symbol Min Typ Max Unit
1 P 10-Bit Resolution LSB — 5 — mV
2 P 10-Bit Differential Nonlinearity DNL –1 — 1 Counts
3 P 10-Bit Integral Nonlinearity INL –2.0 — 2.0 Counts
4 P 10-Bit Absolute Error1
1These values include quantization error which is inherently 1/2 count for any A/D converter.
AE –2.5 — 2.5 Counts
5 C 10-Bit Absolute Error at fATDCLK= 4MHz AE — ±7.0 — Counts
6 P 8-Bit Resolution LSB — 20 — mV
7 P 8-Bit Differential Nonlinearity DNL –0.5 — 0.5 Counts
8 P 8-Bit Integral Nonlinearity INL –1.0 ±0.5 1.0 Counts
9 P 8-Bit Absolute Error1AE –1.5 ±1.0 1.5 Counts
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
588 Freescale Semiconductor
A.6.5 ATD Accuracy — 3.3V Range
Table A-23 specifies the ATD conversion performance excluding any errors due to current injection, input
capacitance and source resistance.
For the following definitions see also Figure A-9.
Differential Non-Linearity (DNL) is defined as the difference between two adjacent switching steps.
The Integral Non-Linearity (INL) is defined as the sum of all DNLs:
Table A-23. 3.3V ATD Conversion Performance
Conditions are shown in Ta b l e A - 4 unless otherwise noted
VREF = VRH - VRL = 3.328V. Resulting to one 8 bit count = 13mV and one 10 bit count = 3.25mV
fATDCLK = 2.0MHz
Num C Rating Symbol Min Typ Max Unit
1 P 10-Bit Resolution LSB — 3.25 — mV
2 P 10-Bit Differential Nonlinearity DNL –1.5 1.5 Counts
3 P 10-Bit Integral Nonlinearity INL –3.5 ±1.5 3.5 Counts
4 P 10-Bit Absolute Error1
1These values include the quantization error which is inherently 1/2 count for any A/D converter.
AE –5 ±2.5 5 Counts
5 C 10-Bit Absolute Error at fATDCLK= 4MHz AE — ±7.0 — Counts
6 P 8-Bit Resolution LSB — 13 — mV
7 P 8-Bit Differential Nonlinearity DNL –0.5 — 0.5 Counts
8 P 8-Bit Integral Nonlinearity INL –1.5 ±1.0 1.5 Counts
9 P 8-Bit Absolute Error1AE –2.0 ±1.5 2.0 Counts
DNL i() ViVi1–
–
1LSB
--------------------------- 1–=
INL n() DNL i()
i1=
n
∑VnV0
–
1LSB
---------------------n–==
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 589
Figure A-9. ATD Accuracy Definitions
NOTE
Figure A-9 shows only definitions, for specification values refer to
Table A-22 and Table A-23.
1
5Vin
mV
10 15 20 25 30 35 40 5085 5090 5095 5100 5105 5110 5115 51205065 5070 5075 50805060
0
3
2
5
4
7
6
50
0x3F7
0x3F9
0x3F8
0x3FB
0x3FA
0x3FD
0x3FC
0x3FE
0x3FF
0x3F4
0x3F6
0x3F5
8
9
1
2
0xFF
0xFE
0xFD
0x3F3
10-Bit Resolution
8-Bit Resolution
Ideal Transfer Curve
10-Bit Transfer Curve
8-Bit Transfer Curve
5055
10-Bit Absolute Error Boundary
8-Bit Absolute Error Boundary
LSB
Vi-1 Vi
DNL
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
590 Freescale Semiconductor
A.7 DAC Characteristics
This section describes the characteristics of the digital to analog converter.
A.7.1 DAC Operating Characteristics
A.8 External Bus Timing
A timing diagram of the external multiplexed-bus is illustrated in Figure A-10 with the actual timing
values shown on table Table A-26 and Table A-27. All major bus signals are included in the diagram.
While both a data write and data read cycle are shown, only one or the other would occur on a particular
bus cycle.
The expanded bus timings are highly dependent on the load conditions. The timing parameters shown
assume a balanced load across all outputs.
Table A-24. DAC Electrical Characteristics (Operating)
Num C Characteristic Condition Symbol Min Typ Max Unit
1 D DAC Supply VDDA 2.97 — 5.5 V
2 D DAC Supply Current Running IDDArun ——3.5mA
DStop
(low power)
IDDstop ——1.0mA
3 D Reference Potential Low VSSA VSSA —V
SSA V
D High VREF VDDA/2 — VDDA V
4 D Reference Supply Current VREF to VSSA IREF ——400mA
5 D Input Current, Channel Off1IOFF –200 — 1 µA
6 D Operating Temperature Range T –40 — 125 °C
Table A-25. DAC Timing/Performance Characteristics
Num C Parameters Symbol Min Typ Max Unit
1 D DAC Operating Frequency fBUS ——25MHz
2 D Integral Non-Linearity INL — 0.25 — Count
3 D Differential Non-Linearity DNL — 0.10 — Count
4 D Resolution RES — — 8 Bit
5 D Settling Time TS5—10 µs
6 P Absolute Accuracy ABSACC –1 — 1 Count
7 D Offset Error ERR — +/-2.5 — mV
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 591
Figure A-10. General External Bus Timing
Addr/Data
(read)
Addr/Data
(write)
addr data
data
510 11
8
166
ECLK
1, 2
3 4
addr data
data
12
159
7
14 13
ECS
2120 22 23
Non-Multiplexed
17
19
LSTRB
29
NOACC
32
IPIPO0
IPIPO1, PE6,5
35
18
27
28
30
33 36
31
34
R/W
24
26
25
Addresses
PE4
PA, PB
PA, PB
PK5:0
PK7
PE2
PE3
PE7
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
592 Freescale Semiconductor
Table A-26. Expanded Bus Timing Characteristics (5V Range)
Conditions are 4.75V < VDDX < 5.25V, Junction Temperature -40°C to +140°C, CLOAD = 50pF
Num C Rating Symbol Min Typ Max Unit
1 P Frequency of operation (E-clock) fo0—25.0MHz
2 P Cycle time tcyc 40 — — ns
3 D Pulse width, E low PWEL 19 — — ns
4 D Pulse width, E high1
1Affected by clock stretch: add N x tcyc where N=0,1,2 or 3, depending on the number of clock stretches.
PWEH 19 — — ns
5 D Address delay time tAD —— 8ns
6 D Address valid time to E rise (PWEL–tAD)t
AV 11 — — ns
7 D Muxed address hold time tMAH 2——ns
8 D Address hold to data valid tAHDS 7——ns
9 D Data hold to address tDHA 2——ns
10 D Read data setup time tDSR 13 — — ns
11 D Read data hold time tDHR 0——ns
12 D Write data delay time tDDW —— 7ns
13 D Write data hold time tDHW 2——ns
14 D Write data setup time1 (PWEH–tDDW)t
DSW 12 — — ns
15 D Address access time1 (tcyc–tAD–tDSR)t
ACCA 19 — — ns
16 D E high access time1 (PWEH–tDSR)t
ACCE 6——ns
17 D Non-multiplexed address delay time tNAD —— 6ns
18 D Non-muxed address valid to E rise (PWEL–tNAD)t
NAV 14 — — ns
19 D Non-multiplexed address hold time tNAH 2——ns
20 D Chip select delay time tCSD — — 16 ns
21 D Chip select access time1 (tcyc–tCSD–tDSR)t
ACCS 11 — — ns
22 D Chip select hold time tCSH 2——ns
23 D Chip select negated time tCSN 8——ns
24 D Read/write delay time tRWD —— 7ns
25 D Read/write valid time to E rise (PWEL–tRWD)t
RWV 14 — — ns
26 D Read/write hold time tRWH 2——ns
27 D Low strobe delay time tLSD —— 7ns
28 D Low strobe valid time to E rise (PWEL–tLSD)t
LSV 14 — — ns
29 D Low strobe hold time tLSH 2——ns
30 D NOACC strobe delay time tNOD —— 7ns
31 D NOACC valid time to E rise (PWEL–tNOD)t
NOV 14 — — ns
32 D NOACC hold time tNOH 2——
ns
33 D IPIPO[1:0] delay time tP0D 2—7ns
34 D IPIPO[1:0] valid time to E rise (PWEL–tP0D)tP0V 11 ——
ns
35 D IPIPO[1:0] delay time1 (PWEH-tP1V)tP1D 2—25 ns
36 D IPIPO[1:0] valid time to E fall tP1V 11 ——
ns
Appendix A Electrical Characteristics
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 593
Table A-27. Expanded Bus Timing Characteristics (3.3V Range)
Conditions are VDDX=3.3V+/-10%, Junction Temperature -40°C to +140°C, CLOAD = 50pF
Num C Rating Symbol Min Typ Max Unit
1 P Frequency of operation (E-clock) fo0 — 16.0 MHz
2 P Cycle time tcyc 62.5 — — ns
3 D Pulse width, E low PWEL 30 — — ns
4 D Pulse width, E high1
1Affected by clock stretch: add N x tcyc where N=0,1,2 or 3, depending on the number of clock stretches.
PWEH 30 — — ns
5 D Address delay time tAD — — 16 ns
6 D Address valid time to E rise (PWEL–tAD)t
AV 16 — — ns
7 D Muxed address hold time tMAH 2——ns
8 D Address hold to data valid tAHDS 7——ns
9 D Data hold to address tDHA 2——ns
10 D Read data setup time tDSR 15 — — ns
11 D Read data hold time tDHR 0——ns
12 D Write data delay time tDDW — — 15 ns
13 D Write data hold time tDHW 2——ns
14 D Write data setup time1 (PWEH–tDDW)t
DSW 15 — — ns
15 D Address access time1 (tcyc–tAD–tDSR)t
ACCA 29 — — ns
16 D E high access time1 (PWEH–tDSR)t
ACCE 15 — — ns
17 D Non-multiplexed address delay time tNAD — — 14 ns
18 D Non-muxed address valid to E rise (PWEL–tNAD)t
NAV 16 — — ns
19 D Non-multiplexed address hold time tNAH 2——ns
20 D Chip select delay time tCSD — — 25 ns
21 D Chip select access time1 (tcyc–tCSD–tDSR)t
ACCS 22.5 — — ns
22 D Chip select hold time tCSH 2——ns
23 D Chip select negated time tCSN 8——ns
24 D Read/write delay time tRWD — — 14 ns
25 D Read/write valid time to E rise (PWEL–tRWD)t
RWV 16 — — ns
26 D Read/write hold time tRWH 2——ns
27 D Low strobe delay time tLSD — — 14 ns
28 D Low strobe valid time to E rise (PWEL–tLSD)t
LSV 16 — — ns
29 D Low strobe hold time tLSH 2——ns
30 D NOACC strobe delay time tNOD — — 14 ns
31 D NOACC valid time to E rise (PWEL–tNOD)t
NOV 16 — — ns
32 D NOACC hold time tNOH 2——ns
33 D IPIPO[1:0] delay time tP0D 2 — 14 ns
34 D IPIPO[1:0] valid time to E rise (PWEL–tP0D)t
P0V 16 — — ns
35 D IPIPO[1:0] delay time1 (PWEH-tP1V)t
P1D 2—25ns
36 D IPIPO[1:0] valid time to E fall tP1V 11 — — ns
MC9S12E256 Data Sheet, Rev. 1.08
Freescale Semiconductor 594
Appendix B
Ordering Information and Mechanical Drawings
Figure B-1. Order Part Number Coding
Table B-1 lists the part number coding based on the package and temperature.
Table B-2 summarizes the package option and size configuration.
Table B-1. Part Number Coding
Part Number Temperature Package
MC9S12E256CFU -40°C, 85°C 80 QFP
MC9S12E256CPV -40°C, 85°C 112 LQFP
MC9S12E256MFU -40°C, 125°C 80 QFP
MC9S12E256MPV -40°C, 125°C 112 LQFP
Table B-2. Package Option Summary
Part
Number Package Temp.1
Options
1C: TA = 85¯C, f = 25MHz. M: TA= 125¯C, f = 25MHz
Flash RAM MEBI TIM SCI SPI IIC A/D D/A PWM PMF KWU I/O2
2I/O is the sum of ports capable to act as digital input or output.
TIM is the number of channels.
A/D is the number of A/D channels.
D/A is the number of D/A channels.
PWM is the number of channels.
PMF is the number of channels.
KWU is the number of key wake up interrupt pins.
I/O is the sum of ports capable to act as digital input or output.
MC9S12E256 112LQFP M, C 256K 16K 112 3 1 1 16 2 6 6 16 92
80QFP 0 60
MC9S12 E256 C FU
Package Option
Temperature Option
Device Title
Controller Family
Temperature Options
Package Options
FU = 80 QFP
PV = 112 LQFP
C = –40°C to 85°C
V = –40°C to 105°C
M = –40°C to 125°C
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MC9S12E256
Rev. 1.08, 01/2006
