Doc. No. 102199B
July 22, 2004
CX81801-7x/8x
SmartV.XX Modem
V.92/V.34/V.32bis Modem in 128-Pin TQFP
with CX20493 SmartDAA® and Optional
CX20442 Voice Codec
Data Sheet
CX81801-7x/8x SmartV.XX Modem Data Sheet
ii Conexant 102199B
Revision Record
Revision Date Comments
A 6/2/2003 Initial release.
B 7/22/2004 Rev. B release.
© 2003, 2004 Conexant Systems, Inc.
All Rights Reserved.
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CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant iii
Contents
1. Introduction..........................................................................................................................................1-1
1.1 Overview ......................................................................................................................................................................... 1-1
1.2 Applications .................................................................................................................................................................... 1-2
1.3 Features .......................................................................................................................................................................... 1-4
1.3.1 General Modem Features................................................................................................................................ 1-4
1.3.2 SmartDAA Features ........................................................................................................................................ 1-5
1.3.3 Applications.................................................................................................................................................... 1-5
1.4 Technical Overview......................................................................................................................................................... 1-6
1.4.1 General Description ........................................................................................................................................ 1-6
1.4.2 MCU Firmware................................................................................................................................................ 1-6
1.4.3 Operating Modes ............................................................................................................................................ 1-6
1.4.3.1 Data/Fax Modes.......................................................................................................................... 1-6
1.4.3.2 V.44 Data Compression.............................................................................................................. 1-7
1.4.3.3 Worldwide Operation.................................................................................................................. 1-7
1.4.3.4 TAM Mode.................................................................................................................................. 1-8
1.4.3.5 Speakerphone Mode (S Models)................................................................................................ 1-9
1.4.4 Reference Designs.......................................................................................................................................... 1-9
1.5 Hardware Description ..................................................................................................................................................... 1-9
1.5.1 CX81801 Modem Device ................................................................................................................................ 1-9
1.5.2 Digital Isolation Barrier................................................................................................................................. 1-10
1.5.3 CX20493 SmartDAA Line Side Device.......................................................................................................... 1-10
1.5.4 CX20442 Voice Codec .................................................................................................................................. 1-10
1.6 AT Commands .............................................................................................................................................................. 1-10
2. Technical Specifications .......................................................................................................................2-1
2.1 Serial DTE Interface Operation........................................................................................................................................ 2-1
2.1.1 Automatic Speed/Format Sensing .................................................................................................................. 2-1
2.2 Parallel Host Bus Interface Operation............................................................................................................................. 2-2
2.3 Establishing Data Modem Connections .......................................................................................................................... 2-2
2.3.1 Dialing ............................................................................................................................................................ 2-2
2.3.2 Telephone Number Directory.......................................................................................................................... 2-2
2.3.3 Modem Handshaking Protocol ....................................................................................................................... 2-2
2.3.4 Call Progress Tone Detection ......................................................................................................................... 2-2
2.3.5 Answer Tone Detection................................................................................................................................... 2-2
2.3.6 Ring Detection................................................................................................................................................ 2-2
2.3.7 Billing Protection ............................................................................................................................................ 2-3
2.3.8 Connection Speeds......................................................................................................................................... 2-3
2.3.9 Automode ....................................................................................................................................................... 2-3
2.4 Data Mode ...................................................................................................................................................................... 2-4
CX81801-7x/8x SmartV.XX Modem Data Sheet
iv Conexant 102199B
2.4.1 Speed Buffering (Normal Mode) .................................................................................................................... 2-4
2.4.2 Flow Control ................................................................................................................................................... 2-4
2.4.3 Escape Sequence Detection............................................................................................................................ 2-4
2.4.4 BREAK Detection ............................................................................................................................................ 2-4
2.4.5 Telephone Line Monitoring............................................................................................................................. 2-4
2.4.6 Fall Forward/Fallback (V.92/V.90/V.34/V.32 bis/V.32) ................................................................................... 2-4
2.4.7 Retrain............................................................................................................................................................ 2-5
2.4.8 Programmable Inactivity Timer ...................................................................................................................... 2-5
2.4.9 DTE Signal Monitoring (Serial DTE Interface Only)........................................................................................ 2-5
2.5 V.92 Features.................................................................................................................................................................. 2-5
2.5.1 Modem-on-Hold ............................................................................................................................................. 2-5
2.5.2 Quick Connect ................................................................................................................................................ 2-6
2.5.3 PCM Upstream ............................................................................................................................................... 2-6
2.6 Error Correction and Data Compression......................................................................................................................... 2-6
2.6.1 V.42 Error Correction ..................................................................................................................................... 2-6
2.6.2 MNP 2-4 Error Correction .............................................................................................................................. 2-6
2.6.3 V.44 Data Compression.................................................................................................................................. 2-6
2.6.4 V.42 bis Data Compression ............................................................................................................................ 2-6
2.6.5 MNP 5 Data Compression .............................................................................................................................. 2-7
2.7 Telephony Extensions..................................................................................................................................................... 2-7
2.7.1 Line In Use Detection ..................................................................................................................................... 2-7
2.7.2 Extension Pickup Detection............................................................................................................................ 2-7
2.7.3 Remote Hangup Detection.............................................................................................................................. 2-8
2.8 Fax Class 1 and Fax Class 1.0 Operation ........................................................................................................................ 2-8
2.9 Point-of-Sales Support ................................................................................................................................................... 2-8
2.10 Voice/Audio Mode .......................................................................................................................................................... 2-8
2.10.1 Online Voice Command Mode ........................................................................................................................ 2-8
2.10.2 Voice Receive Mode ....................................................................................................................................... 2-8
2.10.3 Voice Transmit Mode ..................................................................................................................................... 2-9
2.10.4 Full-Duplex Receive and Transmit Mode........................................................................................................ 2-9
2.10.5 Audio Mode .................................................................................................................................................... 2-9
2.10.6 Tone Detectors ............................................................................................................................................... 2-9
2.10.7 Speakerphone Mode....................................................................................................................................... 2-9
2.11 V.80 Synchronous Access Mode (SAM) - Video Conferencing...................................................................................... 2-9
2.12 Full-Duplex Speakerphone (FDSP) Mode (S Models)................................................................................................... 2-10
2.13 Caller ID ........................................................................................................................................................................ 2-10
2.14 Worldwide Country Support ......................................................................................................................................... 2-10
2.15 Diagnostics................................................................................................................................................................... 2-11
2.15.1 Commanded Tests........................................................................................................................................ 2-11
2.15.2 Power On Reset Tests .................................................................................................................................. 2-11
2.16 Low Power Sleep Mode ................................................................................................................................................ 2-12
3. Hardware Interface ...............................................................................................................................3-1
3.1 CX81801 Modem Hardware Pins and Signals ................................................................................................................ 3-1
3.1.1 Common to Parallel and Serial Interface Configurations................................................................................ 3-1
3.1.1.1 LSD Interface (Through DIB)...................................................................................................... 3-1
3.1.1.2 Call Progress Speaker Interface .................................................................................................3-1
3.1.1.3 Voice Relay Interface (S Models) ............................................................................................... 3-1
3.1.1.4 Serial EEPROM Interface............................................................................................................ 3-1
3.1.1.5 External Bus Interface ................................................................................................................ 3-2
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant v
3.1.2 Serial Interface Configuration Only................................................................................................................. 3-2
3.1.2.1 Serial DTE Interface and Indicator Outputs (PARIF = Low)........................................................ 3-2
3.1.3 Parallel Interface Configuration Only (PARIF = High)..................................................................................... 3-3
3.1.3.1 Parallel Host Bus Interface ......................................................................................................... 3-3
3.1.4 CX81801 Modem Interface Signals................................................................................................................ 3-3
3.2 CX20493 LSD Hardware Pins and Signals ................................................................................................................... 3-22
3.2.1 CX20493 LSD Signal Summary.................................................................................................................... 3-22
3.2.1.1 Smart Modem Interface (Through DIB) ................................................................................... 3-22
3.2.1.2 Telephone Line Interface .......................................................................................................... 3-22
3.2.1.3 Voltage References................................................................................................................... 3-22
3.2.1.4 General Purpose Input/Output.................................................................................................. 3-23
3.2.1.5 No Connects............................................................................................................................. 3-23
3.2.2 CX20493 LSD Pin Assignments and Signal Definitions ............................................................................... 3-23
3.3 CX20442 VC Hardware Pins and Signals (S Models)................................................................................................... 3-28
3.3.1 CX20442 VC Signal Summary...................................................................................................................... 3-28
3.3.1.1 Speakerphone Interface............................................................................................................ 3-28
3.3.1.2 Telephone Handset/Headset Interface...................................................................................... 3-28
3.3.1.3 CX81801 Modem Interface....................................................................................................... 3-28
3.3.1.4 Host Interface........................................................................................................................... 3-28
3.3.2 CX20442 VC Pin Assignments and Signal Definitions ................................................................................. 3-29
3.4 Electrical and Environmental Specifications ................................................................................................................. 3-35
3.4.1 Operating Conditions, Absolute Maximum Ratings, and Power Requirements ........................................... 3-35
3.4.2 Interface and Timing Waveforms ................................................................................................................. 3-37
3.4.2.1 External Memory Bus Timing ................................................................................................... 3-37
3.4.2.2 Parallel Host Bus Timing .......................................................................................................... 3-39
3.4.2.3 Serial DTE Interface.................................................................................................................. 3-41
3.5 Crystal Specifications ................................................................................................................................................... 3-42
4. Package Dimensions ............................................................................................................................4-1
5. Parallel Host Interface ..........................................................................................................................5-1
5.1 Overview ......................................................................................................................................................................... 5-1
5.2 Register Signal Definitions ............................................................................................................................................. 5-3
5.2.1 IER - Interrupt Enable Register (Addr = 1, DLAB = 0) .................................................................................... 5-3
5.2.2 FCR - FIFO Control Register (Addr = 2, Write Only) ....................................................................................... 5-4
5.2.3 IIR - Interrupt Identifier Register (Addr = 2) .................................................................................................. 5-5
5.2.4 LCR - Line Control Register (Addr = 3) .......................................................................................................... 5-6
5.2.5 MCR - Modem Control Register (Addr = 4).................................................................................................... 5-7
5.2.6 LSR - Line Status Register (Addr = 5)............................................................................................................ 5-7
5.2.7 MSR - Modem Status Register (Addr = 6) ..................................................................................................... 5-9
5.2.8 RBR - RX Buffer (Receiver Buffer Register) (Addr = 0, DLAB = 0) ................................................................ 5-9
5.2.9 THR - TX Buffer (Transmitter Holding Register) (Addr = 0, DLAB = 0).......................................................... 5-9
5.2.10 Divisor Registers (Addr = 0 and 1, DLAB = 1).............................................................................................. 5-10
5.3 Receiver FIFO Interrupt Operation ................................................................................................................................ 5-10
5.3.1 Receiver Data Available Interrupt ................................................................................................................. 5-10
5.3.2 Receiver Character Timeout Interrupts......................................................................................................... 5-11
5.4 Transmitter FIFO Interrupt Operation ........................................................................................................................... 5-11
5.4.1 Transmitter Empty Interrupt......................................................................................................................... 5-11
CX81801-7x/8x SmartV.XX Modem Data Sheet
vi Conexant 102199B
Figures
Figure 1-1. SmartV.XX Modem Simplified Interface Diagram ............................................................................................ 1-3
Figure 1-2. SmartV.XX Modem Major Interfaces................................................................................................................ 1-3
Figure 2-1. TMIND# Test Results Pulse Cycles ................................................................................................................ 2-12
Figure 3-1. CX81801 Modem Hardware Signals for Parallel Interface (PARIF = High) ...................................................... 3-4
Figure 3-2. CX81801 Modem 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High) ......................................... 3-5
Figure 3-3. CX81801 Modem Hardware Signals for Serial Interface (PARIF = Low)........................................................ 3-12
Figure 3-4. CX81801 Modem 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)...........................................3-13
Figure 3-5. CX20493 LSD Hardware Interface Signals ..................................................................................................... 3-23
Figure 3-6. CX20493 LSD 28-Pin QFN Pin Signals........................................................................................................... 3-24
Figure 3-7. CX20442 VC Hardware Interface Signals ....................................................................................................... 3-30
Figure 3-8. CX20442 VC 32-Pin TQFP Pin Signals ........................................................................................................... 3-30
Figure 3-9. Waveforms - External Memory Bus................................................................................................................ 3-38
Figure 3-10. Waveforms - Parallel Host Bus..................................................................................................................... 3-40
Figure 3-11. Waveforms - Serial DTE Interface ................................................................................................................ 3-41
Figure 4-1. Package Dimensions - 128-Pin TQFP............................................................................................................... 4-2
Figure 4-2. Package Dimensions - 32-pin TQFP ................................................................................................................. 4-3
Figure 4-3. Package Dimensions - 28-Pin QFN................................................................................................................... 4-4
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant vii
Tables
Table 1-1. SmartV.XX Modem Models and Functions ........................................................................................................ 1-2
Table 1-2. Default Countries Supported.............................................................................................................................. 1-8
Table 2-1. +MS Command Automode Connectivity............................................................................................................ 2-3
Table 3-1. CX81801 Modem 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High)........................................... 3-6
Table 3-2. CX81801 Modem Pin Signal Definitions for Parallel Interface (PARIF = High) ................................................. 3-8
Table 3-3. CX81801 Modem 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)............................................3-14
Table 3-4. CX81801 Modem Pin Signal Definitions for Serial Interface (PARIF = Low)................................................... 3-16
Table 3-5. CX81801 Modem I/O Type Definitions ............................................................................................................ 3-21
Table 3-6. CX81801 Modem DC Electrical Characteristics ............................................................................................... 3-21
Table 3-7. CX20493 LSD 28-Pin QFN Pin Signals ............................................................................................................ 3-24
Table 3-8. CX20493 LSD Hardware Signal Definitions ..................................................................................................... 3-25
Table 3-9. CX20493 LSD GPIO DC Electrical Characteristics ........................................................................................... 3-27
Table 3-10. CX20493 AVdd DC Electrical Characteristics................................................................................................. 3-27
Table 3-11. CX20442 VC 32-Pin TQFP Pin Signals........................................................................................................... 3-31
Table 3-12. CX20442 VC Pin Signal Definitions ............................................................................................................... 3-32
Table 3-13. CX20442 VC DC Electrical Characteristics..................................................................................................... 3-33
Table 3-14. CX20442 VC Analog Electrical Characteristics............................................................................................... 3-34
Table 3-15. Operating Conditions ..................................................................................................................................... 3-35
Table 3-16. CX81801 Absolute Maximum Ratings ........................................................................................................... 3-35
Table 3-17. CX20493 Absolute Maximum Ratings ........................................................................................................... 3-35
Table 3-18. CX20442 Absolute Maximum Ratings ........................................................................................................... 3-36
Table 3-19. Current and Power Requirements.................................................................................................................. 3-36
Table 3-20. Timing - External Memory Bus ...................................................................................................................... 3-37
Table 3-21. Timing - Parallel Host Bus ............................................................................................................................. 3-39
Table 3-22. Crystal Specifications..................................................................................................................................... 3-42
Table 5-1. Parallel Interface Registers ................................................................................................................................ 5-2
Table 5-2. Interrupt Sources and Reset Control ................................................................................................................. 5-5
Table 5-3. Programmable Baud Rates .............................................................................................................................. 5-10
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 1-1
1. Introduction
1.1 Overview
The Conexant® SmartV.XX Modem is a full-featured, wo r l dwi de, control l er-based
modem that integrates modem controller (MCU), modem data pump (MDP), 256 KB
ROM, 32 KB RAM, and SmartDAA system side device (SSD) functions onto a single
die.
The modem operates by executing firmware from internal ROM and RAM. Optional
customized firmware is supported with optional external flash ROM memory.
Additionally, added/modified country profiles are supported by internal SRAM patch
(maxim um of one pr ofi l e) or seri al EEPR OM. Downloadable ar chitecture supports
downloading of customized MCU firmware from the host/DTE to the SmartV.XX
modem.
The SmartV.XX Modem device set consists of a CX81801 modem device in a 128-pin
TQFP and a CX20493 SmartDAA Line Side Device (LSD) in a 28-pin QFN.
Conexant ’s SmartDAA® technology eliminates the need for a costly analog transformer,
relays and opto-isolations typically used in discrete DAA (Data Access Arrangement)
implementations. The SmartDAA architecture also simplifies product implementation by
eliminating the need for country-specific board conf ig urations enabling worldwide
homologation of a single modem board design and a single b ill of materials (BOM).
Low profile, small TQFP and QFN packages with reduced voltage operation and low
power consumption makes this device set an ideal solution for embedded and palmtop
application using parallel host o r serial DTE interface.
The SmartV.XX Modem supports data rates up to V.92, data compression, error
correction, fax rates up t o 14.4 kbps and speaker p ho ne m ode.
In V.92 and V.90 (V.92 models) data modes, the modem can receive data at speeds up to
56 kbps. In V.34 data mode (V.92 and V.34 models), the modem can receive data at
speeds up to 33.6 kbps. In V.32 bis data mode, the modem can receive data at speeds up
to 14.4 kbps.
Data compress (V.44/V.42bis/MNP5) and error correction (V.42/MNP 2-4) mod e s are
supported to max imize data throughput and data transfer integrity. Non-error-correction
mode is also supported.
Fax Group 3 send and receive rates are supported up to 14.4 kbps with T.30 protocol.
The SmartV.XX modem operates with PSTN telephone lines worldwide.
S models, using the optional CX20442 Voice Codec (VC) in a 32-pin TQFP, support
position independ en t, full-duplex speakerphone (FDSP) operation using microphone and
speaker, as well as other voice/TAM applications using handset or headset.
Table 1-1 lists the available models. A simplified device int erface drawing is shown in
Figure 1-1. A functional interface drawing showing optional memory is shown in
Figure 1-2.
CX81801-7x/8x SmartV.XX Modem Data Sheet
1-2 Conexant 102199B
1.2 Applications
• Set top boxes
• Gaming devices
• Point of sale terminals
• Remote monitoring and data collections systems
• Handheld computers
• Other embedded systems
Table 1-1. SmartV.XX Modem Models and Functions
Model/Order/Part Numbers Supported Functions
Marketing Name Device Set Order
No.
Modem Device
[128-Pin TQFP]
Part No.
Line Side
Device (LSD)
[28-Pin QFN]
Part No.
Voice Codec
(VC)
[32-Pin TQFP]
Part No.
V.90 Data,
QC, MOH
V.34 Data V.32 bis Data,
V.44 Data
Compression,
V.17 Fax, TAM,
Worldwide
Voice/
FDSP
SmartV.92 DS56-L147-203 CX81801-74 CX20493-21 — Y Y Y —
SmartV.92/S DS56-L147-204 CX81801-74 CX20493-21 CX20442-11 Y Y Y Y
SmartV.92/LF DS56-L147-206 CX81801-84 CX20493-31 — Y Y Y —
SmartV.34 DS28-L147-203 CX81801-72 CX20493-21 — — Y Y —
SmartV.34/S DS28-L147-204 CX81801-72 CX20493-21 CX20442-11 — Y Y Y
SmartV.34/LF DS28-L147-206 CX81801-82 CX20493-31 — — Y Y —
SmartV.32bis DS96-L147-203 CX81801-73 CX20493-21 — — — Y —
SmartV.32bis/S DS96-L147-204 CX81801-73 CX20493-21 CX20442-11 — — Y Y
SmartV.32bis/LF DS96-L147-206 CX81801-83 CX20493-31 — — — Y —
Notes:
1. Supported functions (Y = Supported; — = Not supported).
QC, MOH, PCM Quick connect, Modem-on-Hold, PCM upstream
TAM Telephone answering machine (Voice playback and record through telephone line)
FDSP Full-duplex speakerphone and voice playback and record through telephone line, handset, and mic/speaker
2. For ordering purposes, the CX prefix may not be included in the part number for some devices. Also, the CX prefix may not appear in the part number as
branded on some devices.
3. LF = Lead-free (Pb-free) devices.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 1-3
Figure 1-1. SmartV.XX Modem Simplified Interface Diagram
CX81801
Modem
128-Pin TQFP
CX20493
SmartDAA
Line Side
Device (LSD)
28-Pin QFN
CX20442
Voice Codec
(VC)
32-Pin TQFP
(Optional)
MIC
SPEAKER
TIP
RING
Telephone
Line
Interface
Discrete
Components
102199_001
Digital
Isolation
Barrier
(DIB)
TIP
RING HANDSET (OPTIONAL)
TELEPHONE LINE
(OPTIONAL)
PARALLEL
HOST BUS OR
SERIAL DTE
INTERFACE
Figure 1-2. SmartV.XX Modem Major Interfaces
CX81801 Modem
128-Pin TQFP
CX20442
Voice Codec (VC)
32-Pin TQFP
(Optional)
SmartDAA
Interface
Modem Data
Pump (MDP)
Digital Speaker
Circuit (Option al )
Paralle Host
or Serial DTE
Interface
MIC
SPEAKER
102199_002
SOUNDUCER
HS Hybrid
Components
(Optional)
RAM
(32K x 8)
ROM
(256k x 8)
Optional RAM
Up to 1M (128K x 8)
Optional Flash ROM
Up to 4M (512K x 8)
Microcontroller
Unit (MCU)
Serial EEPROM
2K (256 x 8) to
256K (32K x 8)
(Optional)
TIP
RING
Telephone
Line Interface
Discrete
Components
TIP
RING
Voice Relay,
HS Pickup
Detector
(Optional)
TELEPHONE
LINE
TELEPHONE
HANDSET
Digital
Isolation
Barrier (DIB)
Components
CX20493 SmartDAA
Line Side Device (LSD)
28-Pin QFN
Line
Side
DIB
Interface
(LSDI)
Codec Telephone
Line
Interface
DAA Hardware
Rectifier
and Filter
Components
(Mic/Speaker)
Interface
(Optional)
CX81801-7x/8x SmartV.XX Modem Data Sheet
1-4 Conexant 102199B
1.3 Features
1.3.1 General Modem Features
• Data modem
− Quick connect, Modem-on-Hold, and PCM upstream functions (V.92 models)
− ITU-T V.92/V.90 (V.92 models), V.34 (V.92 and V.34 models), V.32bis, V.32,
V.29, FastPOS (V.29), V.22 bis, V.22, V.22 Fast Connect, V.23, V.21,
Bell 212A, and Bell 103
− V.250 and V.251 commands
• Data compression and error correction
− V.44 data compression
− V.42 bis and MNP 5 data co mpression
− V.42 LAPM and MNP 2-4 error correction
• Fax modem send and receive rates up to 14.4 kbps
− V.17, V.29 , V. 27 ter, and V.21 channel 2
− EIA/TIA 578 Class 1 and T.31 Class 1.0
• V.80 synchronous access mode supports host-controlled communication protocols
with H.324 interface support
• Interfaces to optional external ROM/flash ROM, RAM, and/or optional serial
EEPROM
• Data/Fax/Voice call discrimination
• Hardware-based modem controller
• Hardware-based digital signal processor (DSP)
• Worldwide operation
− Complies to TBR21 and other country requirements
− On-hook and/or off-hook Caller ID detection for selected countries
− Call progress, blacklisting
− Internal ROM includes default values for 29 countries
− Additional and modified country profile can be stored in internal SRAM
• Caller waiting detection
• Caller ID detect
− On-hook Caller ID detection
− Off-hook Call Waiting Caller ID detection during data mode in V.92, V.90,
V.34, V.32bi s, and V. 3 2
• Distinctive ring detect
• Modem customization available through patch code that can be stored in optional
serial EEPROM or internal SRAM
• Telephony/TAM
− V.253 commands
− 2-bit and 4-bit Conexant ADPCM, 8-bit linear PCM, and 4-bit IMA coding
− 8 kHz sample rate
− Concurrent DTMF, ring, and Caller ID detection
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 1-5
• Full-duplex speakerphone (FDSP) mode using optional CX20442 Voice Codec
(S models)
− Microphone and speaker interface
− Telephone handset or headset interface
− Acoustic and line echo cancellation
− Microphone gain and muting
− Speaker volume control and muting
• Built-in host/DTE interface
− Parallel 16550A UART-compatible interface up to 230.4 kbps
− Serial ITU-T V.24 (EIA/TIA-232-E) logical interface up to 115.2 kbps
• Downloadable architecture
• Direct mode (serial DTE interface)
• Flow control and speed buffering
• Automatic format/speed sensing
• Serial async/sync data; parallel async data
• Thin packages support low profile designs (1.6 mm max. height)
− CX81801 Modem dev ice in 128-pin TQFP
− CX20493 LSD in 28-p in QFN
− CX20442 VC in 32-pin TQFP
• +3.3V operation with +5 V tolerant digital inputs
• Typical power use
− CX81801 and CX20493: 209 mW (Normal Mode); 59 mW (Sleep Mode)
− CX2044 2: 5 mW (Normal Mode)
1.3.2 SmartDAA Features
• System side powered DAA operates under poor line current supp ly conditions
• Modem Wake - on -R i n g
• Ring detection
• Line current loss detection
• Pulse dialing
• Line-in-use det ect i on du ri n g o n-h oo k operation
• Remote hang-up detection for efficient call termination
• Extension pickup detection
• Digital PBX line protection
• Meets worldwide DC Voltage/Current (VI) masks requirements
1.3.3 Applications
• Set top boxes
• Gaming devices
• Point of sale terminals
• Remote monitoring and data collections systems
• Handheld computers
• Other embedded systems
CX81801-7x/8x SmartV.XX Modem Data Sheet
1-6 Conexant 102199B
1.4 Technical Overview
1.4.1 General Description
Modem operation, including dialing, call progress, telepho ne line interface, telephone
handset interface, option a l voice/speakerphone interf ace, and host interface functions are
supported an d controlled through the V.250, V.25 1, and V.253-compatible command set.
The modem hardware connects to the host via a parallel or serial interface as selected by
the PARIF input. The OEM adds a crystal circuit, DIB components, telephone line
interface, telephone handset/telephony extension interface, voice/speakerphone interface,
optional external serial EEPROM, optional external ROM/flash ROM, optional external
RAM, and other supporting discrete components as supported by the modem model
(Table 1-1) and required by the application to complete the syste m.
Customized modem firmware can be supported by the use of external memory in various
combinations, e.g., either external ROM/flash ROM (up to 256 KB), or external serial
EEPROM (256 to 32 KB) and ex ternal RAM (up to 128 KB). To support country profile
addition or modification, external serial EEPROM (256 to 32 KB) can be installed.
Customized code can include OEM-defined commands, i.e., identification codes (I3),
identifier string (I4), manufacturer iden tification (+GMI), model identification (+GMM),
and revision identification (+GMR), as well as code modification.
Parallel interface operation is selected by PARIF input high.
Serial interface operation is selected by PARIF input low.
1.4.2 MCU Firmware
MCU firmware performs processing of general modem control, command sets, data
modem, error correction and data compression (ECC), fax class 1, fax class 1.0,
voice/audio/ TAM / spea kerphone, wo rl d wid e, V.8 0 , and serial DTE/parallel host interface
functions according to modem models (Table 1-1).
MCU firmware can be customized to include OEM-defined commands, i.e., identification
codes (I3), iden tifier string (I4), manufacturer identification (+GMI), model identificatio n
(+GMM), and revision identification (+GMR), as well as code modification.
The modem firmware is provided in object code form for the OEM to program into
external ROM/flash ROM. The modem firmware may also be provided in source code
form under a source code addendum license agreement. External ROM/Flash ROM and
RAM must be installed in order to operate the modem with customized firmware.
1.4.3 Operating Modes
1.4.3.1 Data/Fax Modes
Data modem modes perform complete handshake and data rate negotiations. Using
modem modulations to optimize modem configuration for line conditions, the modem
can connect at the highest data rate that the channel can support from 56 kbps down to
2400 bps with automatic fallback.
In V.92/V.90 data modem modes (V.92 models), the modem can receive data from a
digital source using a V.92-compatible central site modem at line speeds up to 56 kbps.
With PCM upstream enabled (V.92 only), data transmission supports sending data at line
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 1-7
speeds up to 48 kbps. When PCM upstream is disabled, data transmission supports
sending data at line speeds up to V.34 rates. This mode can fallback to V.34 mode and to
lower rates as dictated by line conditions.
The following modes are supp orted in V.92 models when connected to a V.92-
compatible server supporting the feature listed.
• Quick connect: Allows quicker subsequent connections to a server by using stored
line parameters obtained during the initial connection.
• Modem-on-Hold: Allows detection and reporting of incoming phone calls on the
PSTN with enabled Call Waiting. If the incoming call is accepted by the user, the
user has a pre-defined amount of time of holding the data connection for a brief
conversation. The data connection resumes upon incoming call termination .
• PCM upstream: Boosts the upstream data rates. A maximum of 48 kbps is supported
when connected to a V.92 server that supports PCM upstream.
In V.34 data modem mode (V.92 and V.34 models), the modem can operate in full-
duplex, asynchronous modes at line rates up to 33.6 kbps. Automode operation in V.34 is
provided in acco rdance with PN3320 and in V.32 bis in accordance with PN2330. All
tone and patter n detect i on fun ct i ons req uired by the applicable ITU or Bell standards are
supported.
In V.32 bis data modem mode, the modem can operate at line speeds up to 14.4 kbps.
In fax modem mode, the modem can operate in half-duplex, synchronous modes and can
support Group 3 facsimile send and receive speeds of 14400, 12000, 9600, 7200, 4800,
and 2400 bps. Fax data transmission and reception performed by the modem are
controlled and monitored through the EIA/TIA-578 Fax Class 1, or T.31 Fax Class 1.0
command interface. Full HDLC formatting, zero insertion/deletion, and CRC
generation/checking are provided.
1.4.3.2 V.44 Data Compression
V.44 provides efficient data compression that minimizes the download time for the types
of files associated with Internet use. This improvement is most noticeable when browsing
and searching the web since HTML text files are highly compressi ble. (T he improved
performance amount varies both with the actual format and with the content of individual
pages and files.)
1.4.3.3 Worldwide Operation
SmartDAA technology allows a single PCB design and single BOM to be homologated
worldwide. Adv anced features such as extension pickup detection, remote hang-up
detection, line-in-u se de tection, and digital PBX detection are supported.
Country-dependent modem parameters for functions such as dialing, carrier transmit
level, calling tone, call progress tone detectio n, answer tone detection, blacklisting, caller
ID, and re lay control are programmable.
Country code IDs are defined by ITU-T T.35.
Embedded ROM code includes default profiles for 29 countries. Additional co untry
profiles can be stored in internal SRAM or external serial EEPROM (request additional
country profiles from a Conexant Sales Office). Duplicate country profiles stored in
internal SRAM or external serial EEPROM will override the profiles in embedded ROM
code. The default countries supported are listed in Table 1-2. Country profiles for
CTR-21 countries are TBR-21 compliant.
CX81801-7x/8x SmartV.XX Modem Data Sheet
1-8 Conexant 102199B
Table 1-2. Default Countries Supported
Country Country
Code Call Waiting Tone
Detection (CW)
Supported
On-Hook Type 1
Caller ID (CID)
Supported
Off-Hook Type 2
Called ID (CID2)
Supported
Australia 09 X X
Austria 0A X X
Belgium 0F X
Brazil 16 X
China 26 X X
Denmark 31 X X
Finland 3C X X
France 3D X X X
Germany 42 X X
Hong Kong 50 X X X
India 53 X
Ireland 57 X
Italy 59 X X
Japan 00 X X X
Korea 61 X
Malaysia 6C X
Mexico 73
Netherlands 7B X
Norway 82 X X
Poland 8A X
Portugal 8B X
Singapore 9C X X X
South Africa 9F X
Spain A0 X X
Sweden A5 X X
Switzerland A6 X
Taiwan FE X X
United Kingdom B4 X X X
United States B5 X X X
Reserved FD X X X
1.4.3.4 TAM Mode
TAM Mode features include 8-bit linear coding at 8 kHz sample rate. Tone detection/
generation, call discrimination, and concurrent DTMF detection are also supported.
TAM Mode is supported by four submodes:
• Online Voice Command Mode supports connection to the telephone line or, for S
models, a microphone/speaker/handset/headset.
• Voice Receive Mode supports recording voice or audio data input from the telephone
line or, for S models, a microphone/handset/headset.
• Voice Transmit Mode suppor ts p layback of voice or audio data to th e telephone line
or, for S models, a speaker/handset/headset.
• Full-duplex Receive and Transmit Mode.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 1-9
1.4.3.5 Speakerphone Mode (S Models)
S models include additional telepho ne handset, external microphone, and external
speaker interfaces which support voice and full-duplex speakerphone (FDSP) operation.
Hands-free fu ll-duplex telephone operation is supported in Speakerphone Mode under
host control. Speakerphone Mode features an advanced proprietary speakerphone
algorithm which supports full-duplex voice conversation with acoustic, line, and handset
echo cancellation. Parameters are constantly adju sted to maintain stability with au tomatic
fallback from full-duplex to pseudo-duplex operation. The speakerphone algorithm
allows position independ ent place ment o f microphone and speaker. The host can
separately control volume, muting, and AGC in microphone and speaker channels.
1.4.4 Reference Designs
A data/fax/TAM/speakerphone reference design for external modems is available to
minimize application design time, reduce development cost, and accelerate market entry.
This designs is:
• For CX81801 and CX20493: RD01-D660-1xx
A design package is available in electronic form. This package includes schematics, bill
of materials (BOM), vendor part list (VPL), board layout files in Gerber format, and
complete documentation.
1.5 Hardware Description
SmartDAA technology eliminates the need for a costly analog transformer, relays, and
opto-isolators that are typically used in discrete DAA implementations. The
programmable SmartDAA architecture simplifies product implementation in worldwide
markets by eliminating the need for country-specific components.
1.5.1 CX81801 Modem Device
The CX81801 Modem, packaged in a 128-pin TQFP, includes a Microcontroller (MCU),
a Modem Data Pump (MDP), 256 KB internal ROM, 32 KB internal RAM, and
SmartDAA interface functions.
The CX81801 Modem connects to host via a parallel host (PARIF = high) or a logical
V.24 (EIA/TIA-232-E) serial DTE interface (PARIF = low).
The CX81801 Modem performs the command processing and host interface functions.
The crystal frequ en c y is 28.224 MHz ± 50 ppm.
The CX81801 Modem optionally connects to an external OEM-supplied serial EEPROM
over a dedicated 2-line serial interface. The capacity of the EEPROM can be 256 bytes up
to 32 KB. The EEPROM can hold information such as firmware configuration
customization, and country code parameters.
The CX81801 Modem performs telephone line signal modulation/demodulation in a
hardware digit al signal pr ocessor (DSP) which red uces co mputational lo ad on the host
processor.
The SmartDAA interface communicates with, and supplies power and clock to, the LSD
through the DIB.
CX81801-7x/8x SmartV.XX Modem Data Sheet
1-10 Conexant 102199B
The CX81801 optionally conn ects to external OEM-supplied ROM/flash ROM and RAM
over a non-multiplexed 19-b it address bus and 8-bit data bus.
1.5.2 Digital Isolation Barrier
The OEM-supplied Digital Isolation Barrier (DIB) electrically DC isolates the CX81801
from the LSD and telephone line. The modem is connected to a fixed digital ground and
operates with standard CMOS logic levels. The LSD is connected to a floating ground
and can tolerate high voltage input (compatible with telephone line and typical surg e
requirements).
The DIB transformer couples power and clock from the CX81801 to the LSD.
The DIB data channel supports bidirectional half-duplex serial transfer of data, control,
and status information between the CX81801 and the LSD over two lines.
1.5.3 CX20493 SmartDAA Line Side Device
The CX20493 SmartDAA Line Side Device (LSD) includes a Line Side DIB Interface
(LSDI), a coder/decoder (codec), and a Telephone Line Interface (TLI).
The LSDI communicates with, and receives power and clock from, the SmartDAA
interface in the CX81801 through the DIB.
LSD power is received from the MDP PWRCLKP and PWRCLKN pins via the DIB
through a full-wave rectified bridge and capacitive power filter circuit connected to the
DIB transformer secondary winding.
The CLK input is also accepted from the DIB transformer secondary winding through a
capacitor and a resistor in series.
Information is transferred between the LSD and the CX81801 through the DIB_P and
DIB_N pins. T hese pins connect to the CX8 18 0 1 DIB_DATAP and DIB_DATAN pi ns ,
respectively, through the DIB.
The TLI integrates DAA and direct telephone line interface functions and connects
directly to the line TIP and RING pins, as well as to external line protection components.
Direct LSD connection to TIP and RING allows real-time measurement of telephone line
parameters, such as the telephone central office (CO) battery voltage, individual
telephone line (co p per wi re ) resistance, and all ows dy namic regulation of the off-hook
TIP and RING voltage and total current drawn from the central office (CO). This allows
the modem to maintain compliance with U.S. and worldwide regulations and to actively
control the DAA po wer dissipation.
1.5.4 CX20442 Voice Codec
The optional CX20442 Voice Codec (VC), packaged in a 32-pin TQFP, supports
voice/full-duplex speakerphone (FDSP) opera tion with interfaces to a microphone and
speaker and to a telephone handset/headset.
1.6 AT Commands
The SmartV.XX Modem supports AT commands for data mode, fax class 1 or 1.0,
voice/audio, full-duplex speakerphone (FDSP), V.80 commands, and S Register. See
Doc. No. 102184 for a description of the commands.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 1-11
Data Mode Operation. Data functions operate in response to the AT commands when
+FCLASS=0. Default parameters support U.S./Canada operation.
Fax Mode Operati on. Facsimile functions operate in response to fax class 1 commands
when +FCLASS=1 or to fax class 1.0 commands when +FCLASS=1.0.
Voice/Audio Operation. Voice/audio functions operate in response to voice/audio
commands wh en +FCL AS S=8.
Speakerphone Operation. FDSP functions operate in response to speakerphone
commands when +FCLASS=8 and +VSP=1 is selected.
CX81801-7x/8x SmartV.XX Modem Data Sheet
1-12 Conexant 102199B
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CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 2-1
2. Technical Specifications
2.1 Serial DTE Interface Operation
2.1.1 Automatic Speed/Format Sensing
Command Mode and Data Mode. The modem can automatically determine the speed
and format of the data sent from the DTE. The modem can sense speeds of 300, 600,
1200, 2400, 4800, 7200, 9600, 12000, 14400, 16800, 19200, 21600, 24000, 26400,
28800, 38400, 57600, and 115200 bps and the following data formats:
Parity Data Length
(No. of Bits) No. of
Stop Bits Character Length
(No. of Bits)
None 7 2 10
Odd 7 1 10
Even 7 1 10
None 8 1 10
Odd 8 1 11*
Even 8 1 11*
*11-bit characters are sensed, but the parity bit is stripped off during
data transmission in Normal and Error Correction modes.
The modem can speed sense data with mark or space parity and configures itself as
follows:
DTE Configuration Modem Configuration
7 mark 7 none
7 space 8 none
8 mark 8 none
8 space 8 even
Fax Mode. In V.17 fax mode, the modem can sense speeds up to 115.2 kbps.
CX81801-7x/8x SmartV.XX Modem Data Sheet
2-2 Conexant 102199B
2.2 Parallel Host Bus Interface Operation
Command Mode and Data Mode. The modem can operate at rates up to 230.4 kbps by
programming the Divisor Latch in the parallel interface registers if supported b y
communications software and/or driver.
Fax Mode. In V.17 mode, the modem can operate at rates up to 230.4 kbps by
programming the Divisor Latch in the parallel interface registers if supported b y
communications software and/or driver.
2.3 Establishing Data Modem Connections
2.3.1 Dialing
DTMF Dialing. DTMF dialing using DTMF tone pairs is supported in accord ance with
ITU-T Q.23. The transmit tone level complies with Bell Publication 47001.
Pulse Dialing. Pulse dialing is supported in accordance with EIA/TIA-496-A.
Blind Dialing. The modem can blind dial in the absence of a dial tone if enabled by the
X0, X1, or X3 comm a nd.
2.3.2 Telephone Number Directory
The modem supports four telephone number entries in a directory that can be saved in a
serial EEPROM. Each telephone number can be up to 32 characters (including the
command line t erminating car ri age ret u rn ) i n length. A teleph o ne number can be saved
using the &Zn=x command, and a saved telephone number can be dialed using the DS=n
command.
2.3.3 Modem Handshaking Protocol
If a tone is not detected within the time specified in the S7 register after the last digit is
dialed, the modem aborts the call attempt.
2.3.4 Call Progress Tone Detection
Ringback, equipment busy, congested tone, warble tone, and progress tones can be
detected in accordance with the applicable standard.
2.3.5 Answer Tone Detection
Answer tone can be detect ed over the frequency ra n ge of 2 100 ± 4 0 Hz in ITU-T modes
and 2225 ± 40 Hz in Bell modes.
2.3.6 Ring Detection
A ring signal can be detected from a TTL-compatible 15.3 Hz to 68 Hz square wave
input.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 2-3
2.3.7 Billing Protection
When the modem goes off-hook to answer an incoming call, both transmission and
reception of data are prevented for 2 seconds (data modem) or 4 seconds (fax adaptive
answer) to allow transmission of the billing to ne signal.
2.3.8 Connection Speeds
The modem functions as a data modem when the +FCLASS=0 command is active.
Line connection can be selected using the +MS command. The +MS command selects
modulation, enables/disables automode, and selects minimum and maximum line speeds
(Table 2-1).
2.3.9 Automode
Automode detection can be enabled by the +MS command to allow the modem to
connect to a remote modem in accordance with draft PN-3320 for V.34 (Table 2-1).
Table 2-1. +MS Command A utomode Connectivity
Modulation <carrier> Possible (<min_rx_rate>, <min_rx_rate>, (<min_ tx_rate>),
and <max_tx_rate>) Rates (bps)
Bell 103 B103 300
Bell 212 B212 1200 Rx/75 Tx or 75 Rx/1200 Tx
V.21 V21 300
V.22 V22 1200
V.22 bis V22B 2400 or 1200
V.23 V23C 1200
V.32 V32 9600 or 4800
V.32 bis V32B 14400, 12000, 9600, 7200, or 4800
V.34 V34 33600, 31200, 28800, 26400, 24000, 21600, 19200, 16800,
14400, 12000, 9600, 7200, 4800, or 2400
V.90 V90 56000, 54667, 53333, 52000, 50667, 49333, 48000, 46667,
45333, 44000, 42667, 41333, 40000, 38667, 37333, 36000,
34667, 33333, 32000, 30667, 29333, 28000
V.92 downstream V92 56000, 54667, 53333, 52000, 50667, 49333, 48000, 46667,
45333, 44000, 42667, 41333, 40000, 38667, 37333, 36000,
34667, 33333, 32000, 30667, 29333, 28000
V.92 upstream V92 48000, 46667, 45333, 44000, 42667, 41333, 40000, 38667,
37333, 36000, 34667, 33333, 32000, 30667, 29333, 28000,
26667, 25333, 24000
CX81801-7x/8x SmartV.XX Modem Data Sheet
2-4 Conexant 102199B
2.4 Data Mode
The modem enters data mode when a telephone line connection has been established
between modems and all handshaking has been completed.
2.4.1 Speed Buffering (Normal Mode)
Speed buffering allows a DTE to send data to, and receive data from, a modem at a speed
different than the line speed. The modem supports speed buffering at all line speeds.
2.4.2 Flow Control
DTE-to-Modem Flow Control. If the modem-to-line speed is less than the DTE-to-
modem speed, the modem supports XOFF/XON or RTS/CTS flow control with the DTE
to ensure data integrity.
2.4.3 Escape Sequence Detection
The +++ escape sequence can be used to return control to the command mode from the
data mode. Escape sequence detection is disabled by an S2 Register value greater than
127.
2.4.4 BREAK Detection
The modem can detect a BREAK signal from either the DTE or the remote modem. The
\Kn command determines the modem response to a received BREAK signal.
2.4.5 Telephone Line Monitoring
GSTN Cleardow n (V. 90, V.34, V.32 bis, V. 32 ). Upon re ceiving GSTN Cleardown from
the remote modem in a non-error correcting mode, the modem cleanly terminates the call.
Loss of Carrier (V.22 bis and Below). If carrier is lost for a time greater than specified
by the S10 register, the modem disconnects.
2.4.6 Fall Forward/Fallback (V.92/V.90/V.34/V.32 bis/V.32)
During initial handshak e, the modem will fallback to the optimal line connection within
V.92/V.90/V.34/V.32 bis/V.32 mode depending upon signal quality if automode is
enabled by the +MS or N1 com mand.
When connected in V.92/V.90/V.34/V.32 bis/V.32 mode, the modem will fall forward or
fallback to the optimal line speed within the current modulation depending upon signal
quality if fall forward/fallback is enabled by the %E2 co mmand.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 2-5
2.4.7 Retrain
The modem may lose synchronization with the received line signal under poor or
changing line conditions. If this occurs, retraining may be initiated to attemp t recovery
depending on the type of connection.
The modem initiates a retrain if line quality becomes unacceptable if enabled by the %E
command. The modem continues to retrain until an acceptable connection is achieved, or
until 30 seconds elapse resulting in line disconnect.
2.4.8 Programmable Inactivity Timer
The modem disconnects from the line if data is not sent or received for a specified length
of time. In normal or error-correction mode, this inactivity timer is reset when data is
received from either the DTE or from the line. This timer can be set to a value between 0
and 255 seconds by using register S30. A v alue of 0 disables the inactivity timer.
2.4.9 DTE Signal Monitoring (Serial DTE Interface Only)
DTR#. When DTR# is asserted, the modem responds in accordance with the &Dn and
&Qn commands.
RTS#. RTS# is used for flow control if enabled by the &K command in normal or error-
correction mode.
2.5 V.92 Features
Modem-on-Hold, quick connect, and PCM upstream are only available in V.92 models
when connecting in V.92 data mode. V.92 features are only available when the server
called is a V.92 server that supports that particular feature.
2.5.1 Modem-on-Hold
The Modem-on-Hold (MOH) function enables the modem to place a data call to the
Internet on hold while using the same line to accept an incoming or place an outgoing
voice call. This feature is available only with a connection to a server supporting MOH.
MOH can be executed through either of two methods:
• One method is to enable MOH through the +PMH command. With Call Waiting
Detection (+PCW command) enabled, an incom i ng call can be detected while on-
line. Using a string of commands, the modem negotiates with the server to place the
data connection on hold while the line is released so that it can be used to conduct a
voice call. Once the voice call is completed, the modem can quickly renegotiate with
the server back to the original data call.
• An alternative method is to use communications software that utilizes the Conexant
Modem-on- Ho l d dri ve rs u nder Windows PC operating syst e ms. Using this m e t hod,
the software can detect an incoming call, place the data connection on hold, and
switch back to a data connection.
CX81801-7x/8x SmartV.XX Modem Data Sheet
2-6 Conexant 102199B
2.5.2 Quick Connect
The quick connect function enables the modem to shorten the connect time of subsequent
calls to a server supporting quick connect. The quick connect feature is supported by the
+PQC command.
2.5.3 PCM Upstream
PCM upstream boosts the upstream data rates between the user and ISP to reduce upload
times for large files and email attachments. A maximum of 48 kbps upstream rate is
supported with PCM upstream enabled, in contrast to a maximum of 32.2 kbps upstream
rate with PCM upstream not enabled. PCM upstream is supported by the +PIG command.
PCM upstream is disabled by default.
2.6 Error Correction and Data Compression
2.6.1 V.42 Error Correction
V.42 supports two methods of error correction: LAPM and, as a fallback, MNP 4. The
modem provides a detection and negotiation technique for determining and establishing
the best method of error correction between two modems.
2.6.2 MNP 2-4 Error Correction
MNP 2-4 is a data link protocol that uses error correction algorithms to ensure data
integrity. Supporting stream mode, the modem sends data frames in varying lengths
depending on the amount of time between characters coming from the DTE.
2.6.3 V.44 Data Compression
V.44 data compression mode, enabled by the +DS44 command, encodes pages and files
associated with Web pages. These files include WEB pages, graphics and image files,
and document files. V.44 can provid e an effective data throughput rate up to DTE rate for
a 56-kbps connection. The improved performance amount varies both with the actual
format and with the content of individual pages and files.
2.6.4 V.42 bis Data Compression
V.42 bis data compression mode, enabled by the %Cn command or S46 register, operates
when a LAPM connection is established.
The V.42 bis data compression employs a “string learning” algorithm in which a string of
characters from the DTE is encoded as a fixed length codeword. Two 2-KB dictionaries
are used to store the strings. These dictionaries are dynamically updated during normal
operation.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 2-7
2.6.5 MNP 5 Data Compression
MNP 5 data compression mode, enabled by the %Cn command, operates during an MNP
connection.
In MNP 5, the modem increases its throughput by compressing data into tokens before
transmitting it to the remote modem, and by decompressing encoded received data before
sending it to the DTE.
2.7 Telephony Extensions
The following telephony extension features are supported and are typically implemented
in designs for set-top box applications and TAM software applications to enhance end-
user experience:
• Line In Use detection
• Extension Pickup detection
• Remote Hang-up detection
The telephony extension features are enabled through the -STE command. The -TTE
command can be used to adjust the voltage thresholds fo r the telephony extension
features.
2.7.1 Line In Use Detection
The Line In Use Detection feature can stop the modem from disturbing the phone line
when the line is already being us ed. When an automated system tries to dial using ATDT
and the phone line is in use, the modem will not go off hook and will respond with the
message “LINE IN USE”. In the case where no phone line is connected to the modem,
the modem will respond with the message “NO LINE”.
2.7.2 Extension Pickup Detection
The Extension Pickup Detection feature (also commonly referred as PPD or Parallel
phone detection) allows the modem to detect when another telephony device (i.e., fax
machine, phone, satellite/cable box) is attempting to us e the phone line. When an
extension pickup has been detected, the modem will go on-hook and respond with the
message “OFF-HOOK INTRUSION”.
The Remote Hangup Detection feature will cause the modem to go back on-hook and
respond with the message “LINE REVERSAL DETECTED” during a data connection
when the remote modem is disconnected for abnormal termination reasons (remote phone
line unplugged, remote server/modem shutdown). For Voice applications, this method
can be used in addition to silence detectio n to determine when a remote caller has hung
up to terminate a voice recording.
This feature can be used to quickly drop a modem connection in the event when a user
picks up a extension phone line. For example, this feature allows set top boxes with an
integrated SmartV.XX modem to give normal voice users the highest priority over the
telephone line.
This feature can also be used in Telephone Answering Machine applications (TAM). Its
main use would be to stop the TAM operation when a phone is picked up.
CX81801-7x/8x SmartV.XX Modem Data Sheet
2-8 Conexant 102199B
2.7.3 Remote Hangup Detection
The Remote Hangup Detection feature will cause the modem to go back on-hook and
respond with the message “LINE REVERSAL DETECTED” during a data connection
when the remote modem is disconnected for abnormal termination reasons (remote phone
line unplugged, remote server/modem shutdown). For Voice applications, this method
can be used in addition to silence detectio n to determine when a remote caller has hung
up to terminate a voice recording.
2.8 Fax Class 1 and Fax Class 1.0 Operation
Facsimile functions operate in response to fax class 1 commands when +FCLASS=1 or to
fax class 1.0 commands when +FCLASS=1.0.
In the fax mode, the on-line behavior of the modem is different from the data (non-fax)
mode. After dialing, modem operation is controlled by fax commands. Some AT
commands are still valid bu t may operate differently than in data modem mode.
Calling tone is generated in accordance with T.30.
2.9 Point-of-Sales Support
Point-of-Sales (POS) terminals usually need to exchange a small amount of data in the
shortest amount of time. Low speed modulations such as Bell212A or V.22 are still
mainly used in POS applications. Add itionally, new non-standard sequences have been
developed to better support POS applications.
Industry standard and shortened answer tone B103 and V.21 are supported, as well as
FastPOS (V.29) and V.22 Fast Connect. POS terminal modulations are supported by the
$F command.
2.10 Voice/Audio Mode
Voice and audio functions are supported by the Voice Mode. Voice Mode includes four
submodes: Online Voice Command Mode, Voice Receive Mode, Voice Transmit Mode
and Full-Duplex Receive and Transmit Mode.
2.10.1 Online Voice Command Mode
This mode results from the connection to the telephone line or a voice/audio I/O device
(e.g., microphone, speaker, or handset) through the use of the +FCLASS=8 and +VLS
commands. After mode entry, AT commands can be entered without aborting the
connection.
2.10.2 Voice Receive Mode
This mode is entered when the +VRX command is active in order to record voice or
audio data input at the RIN pin, typically from a microphone/handset or the telephone
line.
Received analog voice samples are converted to digital form and compressed for reading
by the host. AT commands control the codec bits-per-sample rate.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 2-9
Received analog mono audio samples are converted to digital form and formatted into 8-
bit unsigned linear PCM format for reading by the host. AT commands control the bit
length and sampling rate. Concurrent DTMF/tone detection is available at the 8 kHz
sample rate.
2.10.3 Voice Transmit Mode
This mode is entered when the +VTX command is active in order to playback voice or
audio data to the TXA output, typically to a speaker/h andset or to the telephone line.
Digitized voice data is decompressed and converted to analog form at the original
compression quantization sample-per-bits rate then output to the TXA output.
Digitized audio data is converted to analog form then output to the TXA output.
2.10.4 Full-Duplex Receive and Transmit Mode
This mode is entered when the +VTR command is active in order to concurrently receive
and transmit voice.
2.10.5 Audio Mode
The audio mode enables the host to transmit and receive 8-bit audio signals. In this mode,
the modem directly accesses the internal analog-to-digital (A/D) converter (ADC) and the
digital-to-analog (D/A) converter (DAC). Incoming analog audio signals can then be
converted to digital format and digital signals can be converted to analog audio output.
2.10.6 Tone Detectors
The tone detector signal path is separate from the main received signal path thus enabling
tone detection to be independent of the configuration status. In Tone Mode, all three tone
detectors are operational.
2.10.7 Speakerphone Mode
Speakerphone mode is controlled in voice mode with the following commands:
Use Speakerphone After Dialing or Answering (+V SP=1). +VSP=1 selects
speakerphone mode while in +FCLASS=8 mode. Speakerphone operation is entered
during Voice Online Command mode after completing dialing or answering.
Speakerphone Settings. T he +VGM an d + V GS com mands can be used to control the
microphone gain and speaker volume, respectively. VGM and +VGS commands are valid
only after the modem has entered the Voice Online mode while in the +VSP=1 setting.
2.11 V.80 Synchronous Access Mode (SAM) - Video Conferencing
V.80 Synchronous Access Mode between the modem and the host/DTE is provided for
host-controlled communication protocols, e.g., H.324 video conferencing applications.
Voice-call-first (VCF) before switching to a videophone call is also supported.
CX81801-7x/8x SmartV.XX Modem Data Sheet
2-10 Conexant 102199B
2.12 Full-Duplex Speakerphone (FDSP) Mode (S Models)
The modem operates in FDSP mode when +FCLASS=8 and +VSP=1 (Section 2.10.7).
In FDSP Mode, speech from a microphone or handset is converted to digital form,
shaped, and output to the telephone line through the line interface circuit. Speech
received from the telephone line is shaped, converted to analog form, and output to the
speaker or handset. Shaping includes both acoustic and line echo cancellation.
2.13 Caller ID
Both Type I Caller ID (On-Hook Caller ID) and Type II Caller ID (Call Waiting Caller
ID) are supported for U.S. and many other countries (see Section 2.14). Both types of
Caller ID are enabled/disabled using the +VCID command. Call Waiting Tone detection
must be enabled using the +PCW command to detect and decode Call Waiting Caller ID.
When enabled, caller ID info rmation (date, time, caller code, and name) can be passed to
the DTE in formatted or unformatted form. Inquiry support allows the current caller ID
mode and mode capabilities of the modem to be retrieved from the modem.
Type II Caller ID (Call Waiting Caller ID) detection operates only during data mode in
V.92, V.90, V.34, V.32bi s, or V.32.
2.14 Worldwide Country Support
Internal modem firmware supports 29 country profiles (see Section 1.3.2). These country
profiles include the following country-dependent parameters:
• Dial tone detection levels and frequency ranges.
• DTMF dialing parameters: Transmit output level, DTMF signal duration, and DTMF
interdigit interval.
• Pulse dialing parameters: Make/break times, set/clear times, and dial codes are
programmable
• Ring detection frequency ran g e.
• Type I and Type II Caller ID detection are supported for many countries. Contact
your local Conexant sales office for additional coun try support.
• Blind diali ng enabl ed/disabl e.
• Carrier transmit level (through S91 for data and S92 for fax). The maximum,
minimum, and default values can be defined to match specific country and DAA
requirements.
• Calling tone is generated in acco rdance with V.25. Calling tone may be toggled
(enabled/disabled) by inclusion of a “^” character in a dial string. It may also be
disabled.
• Frequency and cadence of tones for busy, ringback, congested, warble, dial tone 1,
and dial tone 2.
• Answer tone det ect i on peri o d .
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 2-11
• Blacklist parameters. The modem can operate in accordance with requirements of
individual countries to preven t misuse of the network by limiting repeated calls to
the same number when previous call attempts have failed. Call failure can be
detected for reasons such as no dial tone, number busy, no answer, no ringback
detected, voice (rather than modem) detected, and key abort (dial attempt aborted by
user). Actions resulting from such failures can include specification of minimum
inter-call delay, extended delay between calls, and maximum numbers of retries
before the number is permanently forbidden ("blacklisted").
These country profiles may be altered or customized by modifying the country-dependent
parameters. Addition a l prof iles may also b e included. There are two ways to add or
modify profiles:
• Incorporating additional or modified profiles into extern al flash ROM co ntaining the
entire modem firmware code.
• Linking additional or modified profiles from an external serial EEPROM (needed
only if the external flash ROM capacity is exceeded.
Please contact an FAE at the local Conexant sales office if a country code customization
is required.
2.15 Diagnostics
2.15.1 Commanded Tests
Diagnostics are performed in response to test commands.
Analog Loopback (&T1 Command). Data from the local DTE is sent to the modem,
which loops the data back to the local DTE.
DTMF Generation (%TT0 Command). Continuous DTMF tones are generated by the
DSP and output thro ugh the DAA.
Tone Generation (%TT3 Command). Continuous tones are generated by the DSP and
output through the DAA.
2.15.2 Power On Reset Tests
Upon power on, the modem performs tests of the modem and internal RAM. If the
modem or internal RAM test fails, the TMIND# output is pulse d as foll ows (Figure 2- 1 ):
• Internal RAM test fails: One pulse cycle (pulse cycle = 0.5 sec. on, 0.5 sec. off)
every 1.5 seconds .
• Modem device test fails: Three pulse cycles every 1.5 seconds.
CX81801-7x/8x SmartV.XX Modem Data Sheet
2-12 Conexant 102199B
Figure 2-1. TMIND# Test Results Pulse Cycles
102179_004
0 .5 11.522.533.544.55
Internal RAM Fails
0 .5 11.522.533.544.55
Modem Device Fails
5.5
5.566.57
Pulse Cycle
Pulse Cycle 1.5 Sec
1.5 Sec
2.16 Low Power Sleep Mode
Sleep Mode Entry. The modem enters the low power sleep mode when no line
connection exists and no host activity occurs for the period of tim e specified in the S24
register. All modem circuits are turned off except the internal clock circuitry in order to
consume reduced power while being able to immediately wake up and resume normal
operation.
Wake-up. Wa ke-up occurs when a ring is detected on the telephone line, the host writes
to the modem (parallel interface), or the DTE sends a character to the modem (serial
interface).
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-1
3. Hardware Interface
3.1 CX81801 Modem Hardware Pins and Signals
3.1.1 Common to Parallel and Serial Interface Configurations
3.1.1.1 LSD Interface (Through DIB)
The DIB interface signals are:
• Clock and Power Positiv e (PWRCLKP); outpu t
• Clock and Power Negative (PWRCLKN); output
• Data Positive (DIB_DATAP); input/output
• Data Negative (DIB_DATAN); input/output
3.1.1.2 Call Progress Speaker Interface
The call progress speaker interface signal is:
• Digital speaker output (DSPKOUT); output
DSPKOUT is a square wave output in Data/Fax mode used for call progress or carrier
monitoring. This output can be optionally connected to a low-cost on-board speaker, e.g.,
a sounducer, or to an analog speaker circuit.
3.1.1.3 Voice Relay Interface (S Models)
The voice relay interface signal is:
• Voice Relay Control (VOICE#); output
3.1.1.4 Serial EEPROM Interface
A 2-line serial interface to an optional serial EEPROM is supported. The interface signals
are:
• Bidirectional Dat a input /output (NVMDATA)
• Clock output (NVM C LK)
The EEPROM can hold information such as firmware customization, and country code
parameters. Data stored in EEPROM takes precedence over the factory default settings.
Note: This information is usually stored in flash ROM; serial EEPROM is required only
if storage is required for more than 31 country profiles.
The EEPROM size can range from 2 Kb (256 x 8) to 256 Kb (32K x 8). A 2 Kb
EEPROM must be 100 kHz or 400 kHz; higher capacity EEPROMs must be 400 kHz.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-2 Conexant 102199B
3.1.1.5 External Bus Interface
The external bus optionally connects to OEM-supplied external memory:
• Up to 4 Mb (512K x 8) ROM/flash ROM
• Up to 1 Mb (128K x 8) RAM
The non-multiplexed external bus interface signals are:
• Eight bidirect ional Dat a lines (D0-D7)
• 19 Address output lines (A0-A18)
• Read Enable output (READ#)
• Write Enable output (WRITE#)
• ROM Chip Select output (ROMSEL#)
• RAM Chip Select output (RAMSEL#)
3.1.2 Serial Interface Configuration Only
3.1.2.1 Serial DTE Interface and Indicator Outputs (PARIF = Low)
A V.24/EIA/TIA-232-E logic-compatible serial DTE interface is selected when the
PARIF input is low.
The supported DTE interface signals are:
• Serial Transmit Data input (TXD#)
• Serial Receive Data output line (RXD#)
• Clear to Send output (CTS#)
• Data Set Ready output (DSR#)
• Received Line Signal Detector (RLSD#)
• Test Mode output (TM#)
• Ring Indicator (RI#)
• Data Terminal Ready control input (DTR#)
• Request to Send control input (RTS#)
Additional clo c k si gnal s p ro v i ded f or sy nchronous m ode ar e:
• Receive Data Clock (RXCLK#)
• Transmit Data Clock (TXCLK#)
• External Clock (XTCLK#)
The following i ndicat o r output lines are also supported:
• Auto Answer indicator output (AAIND#)
• Data Terminal Ready indicator output (DTRI ND #)
• Test Mode indicator output (TMIND#)
• Off-hook indicator output (OHIND#)
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-3
3.1.3 Parallel Interface Configuration Only (PARIF = High)
A 16550A UART-compatible parallel host bus interface is selected when the PARIF
input is high.
3.1.3.1 Parallel Host Bus Interface
The parallel host interface signals are:
• Host Reset control input line (RESET#)
• Host Chip Select control input (HCS#)
• Host Read control input (HRD#) and Host Write control input (HWT#)
• Host Interrupt output line (HINT)
• Three Host Address input lines (HA0-HA2)
• Eight Host Data lines (HD0-HD7)
3.1.4 CX81801 Modem Interface Signals
CX81801 Modem 128-pin TQFP hardware interface signals for parallel interface are
shown by major interface in Figure 3-1, are shown by pin number in Figure 3-2, and are
listed by pin number in Table 3-1. The Smart Modem hardware interface signals for
parallel interface are defined in Table 3-2.
CX81801 Modem 128-pin TQFP hardware interface signals for serial interface are shown
by major interface in Figure 3-3, are shown by pin number in Figure 3-4, and are listed
by pin number in Table 3-3. CX81801 Modem hardware interface signals for serial
interface are defined in Table 3-4.
I/O types are defined in Table 3-5.
DC electrical characteristics are listed in Table 3-6.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-4 Conexant 102199B
Figure 3-1. CX81801 Modem Hardware Signals for Parallel Interface (PARIF = High)
XTLI
XTLO
CLKIN
CLKOUT
XCLK
DV1TP
LPO
NOXYCK
PARIF
STPMODE# (PD3)
NMI#
RESET#
HCS# (PD4)
HRD# (PD6)
HWT# (PD5)
HINT (PB7)
HA0 (PD0)
HA1 (PD1)
HA2 (PD2)
HD0 (PC0)
HD1 (PC1)
HD2 (PC2)
HD3 (PC3)
HD4 (PC4)
HD5 (PC5)
HD6 (PC6)
HD7 (PC7)
RESERVED (PA0)
RESERVED (PE6)
RESERVED (PA1)
TESTP
PHS2
SR4IN
PD7
RESERVED (PA2)
RESERVED (PA6)
RESERVED (PB1)
RESERVED (P_PA00)
RESERVED (P_PA04)
RESERVED (P_PA05)
RESERVED (P_PB01)
RESERVED (BD2CLK)
RESERV ED (P_GP00)
P_PX00
P_PX02
P_PX03
VGG
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD_CORE
VDD_CORE
VDD_CORE
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
114
115
113
61
49
111
57
47
5
9
117
34
11
13
12
109
6
7
8
122
123
125
126
127
1
3
4
24
22
26
110
121
45
46
27
32
101
55
54
56
51
59
52
41
42
43
60
2
15
40
58
78
100
108
116
124
20
53
85
10
25
30
44
48
68
90
95
103
112
120
128
HOST
PARALLEL
BUS
LINE_SEL (PE7)
RESERVED (PA5)
RESERVED (PA4)
RESERVED (PE5)
RESERVED (PE2)
RESERVED (PA3)
RESERVED (PE0)
VOICE# (PE1)
HS_LCS (PE4)
DSPKOUT
PWRCLKP
PWRCLKN
DIB_DATAP
DIB_DATAN
IASLEEP (P_PF05)
M_CLK (P_PB00)
SR2CLK (P_PGP05)
SA2CLK (P_PX05)
SR3OUT
SR3IN (P_PX01)
SR2IO (P_PX06)
NVMCLK (PA7)
NVMDATA (PE3 )
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16 (PB0)
A17 (PB4)
A18 (PB5)
D0
D1
D2
D3
D4
D5
D6
D7
WRITE#
READ#
ROMSEL# (PB2 )
RAMSEL# (PB3)
EXT_RES# (PB6)
PLLVDD
PLLGND
23
31
29
21
17
28
14
16
19
98
96
97
93
94
50
37
92
38
35
36
39
33
18
71
72
73
74
75
76
77
79
80
81
84
86
87
88
89
91
99
105
106
62
63
64
65
66
67
69
70
118
119
102
104
107
82
83
EEPROM
(OPTIONAL)
102199_003
+3.3V
CX81801
Smart Modem
128-Pin TQFP
Parallel Interface
(PARIF = High)
+3.3V
DIGITAL ISOLATION
BARRIER (DIB)
0.1 uF
NC
+3.3V
NC
CRYSTAL
CIRCUIT
NC
EXTERNAL MEMORY
+3.3V
NC
SPEAKER CIRCUIT
NC
NC
+3.3V
CX20442
VOICE CODEC (VC)
(OPTIONAL)
SLEEP
M_CLKIN
M_SCK
M_STROBE
M_TXSIN
M_RXOUT
M_CNTRLSIN
+3.3V or +5V
VOICE#
HS_LCS
240K
NC
DAA
47K
47K
47K
NC
NC
NC
+3.3V
+3.3V
NC
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-5
Figure 3-2. CX81801 Modem 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High)
102199_004
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
57
58
59
60
61
62
63
64
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
GND
HD4 (PC4)
HD3 (PC3)
HD2 (PC2)
VDD
HD1 (PC1)
HD0 (PC0)
PHS2
GND
READ#
WRITE#
NMI#
VDD
XTLO
XTLI
CLKIN
GND
DV1TP
TESTP
HINT (PB7)
VDD
EXT_RES# (PB6)
A18 (PB5)
A17 (PB4)
RAMSEL# (PB3)
GND
SR2IO (P_PX06)
VDD
P_PX00
P_PX02
P_PX03
GND
SR4IN
PD7
NOXYCK
GND
XCLK
IASLEEP (P_PF05)
RXCLK (P_PB01)
XTCLK (GP00)
VDD_CORE
TXCLK (P_PA04)
RESERVED (P_PA00)
RESERVED (P_PA05)
LPO
VDD
RESERVED (BD2CLK)
VGG
CLKOUT
D0
D1
D2
ROMSEL# (PB2)
RESERVED (PB1)
VDD
A16 (PB0)
DSPKOUT
PWRCLKN
PWRCLKP
GND
DIB_DATAN
DIB_DATAP
SR2CLK (P_PGP05)
A15
GND
A14
A13
A12
A11
VDD_CORE
A10
PLLGND
PLLVDD
A9
A8
A7
VDD
A6
A5
A4
A3
A2
A1
A0
D7
D6
GND
D5
D4
D3
HD5 (PC5)
VDD
HD6 (PC6)
HD7 (PC7)
PARIF
HA0 (PD0)
HA1 (PD1)
HA2 (PD2)
STPMODE# (PD3)
GND
HCS# (PD4)
HWT# (PD5)
HRD# (PD6)
RESERVED (PE0)
VDD
VOICE# (PE1)
RESERVED (PE2)
NVMDATA (PE3)
HS_LCS (PE4)
VDD_CORE
RESERVED (PE5)
RESERVED (PE6)
LINE_SEL (PE7)
RESERVED (PA0)
GND
RESERVED (PA1)
RESERVED (PA2)
RESERVED (PA3)
RESERVED (PA4)
GND
RESERVED (PA5)
RESERVED (PA6)
NVMCLK (PA7)
RESET#
SR3OUT
SR3IN (P_PX01)
M_CLK (P_PB00)
SA2CLK (P_PX05)
CX81801
Parallel Interface
(PARIF Pin = High)
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-6 Conexant 102199B
Table 3-1. CX81801 Modem 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High)
Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface
1 HD5 (PC5) I/O Ith/Ot8 HB: HD5 65 D3 I/O Ith/Ot2 EB: D3
2 VDD P PWR +3.3V 66 D4 I/O Ith/Ot2 EB: D4
3 HD6 (PC6) I/O Ith/Ot8 HB: HD6 67 D5 I/O Ith/Ot2 EB: D5
4 HD7 (PC7) I/ O Ith/Ot8 HB: HD7 68 GND G GND GND
5 PARIF I Itpu NC (parallel interface) 69 D6 I/O Ith/Ot2 EB: D6
6 HA0 (PD0) I Ithpd/Ot2 HB: HA0 70 D7 I/O Ith/Ot2 EB: D7
7 HA1 (PD1) I Ithpd/Ot2 HB: HA1 71 A0 O It/Ot8 EB: A0
8 HA2 (PD2) I Ithpd/Ot2 HB: HA2 72 A1 O It/Ot8 EB: A1
9 STPMODE# (PD3) I Ith/Ot2 NC 73 A2 O It/Ot8 EB: A2
10 GND G GND GND 74 A3 O It/Ot8 EB: A3
11 HCS# (PD4) I It HB: CS# 75 A4 O It/Ot8 EB: A4
12 HWT# (PD5) I Ithpu HB: WT# 76 A5 O It/Ot8 EB: A5
13 HRD# (PD6) I Ithpu HB: RD# 77 A6 O It/Ot8 EB: A6
14 RESERVED (PE0) O It/Ot8 NC 78 VDD P PWR +3.3V
15 VDD P PW R +3.3V 79 A7 O It/Ot8 EB: A7
16 VOICE# (PE1) O It/Ot2 DAA: VOICE# 80 A8 O It/Ot8 EB: A8
17 RESERVED (PE2) O It/Ot2 RESERVED 81 A9 O It/Ot8 EB: A9
18 NVMDATA (PE3) I/O It/Ot2 NVRAM: SDA 82 PLLVDD P PWR +3.3V and to GND
through 0.1 µF
19 HS_LCS (PE4) I It/Ot2 GND through 47 KΩ 83 PLLGND G GND GND
20 VDD_CORE P PWR Internal core voltage 84 A10 O It/Ot8 EB: A10
21 CELDATA (PE5) I/O It/Ot2 +3.3V through 47 KΩ 85 VDD_CORE P PWR Internal core voltage
22 SSD_RING# (PE6) O It/Ot2 NC 86 A11 O It/Ot8 EB: A11
23 LINE_SEL (PE7) I It/Ot8 +3.3V through 47 KΩ 87 A12 O It/Ot8 EB: A12
24 RESERVED (PA0) O It/Ot2 NC 88 A13 O It/Ot8 EB: A13
25 GND G GND GND 89 A14 O It/Ot8 EB: A14
26 SSD_INT (PA1) O It/Ot2 NC 90 GND G GND GND
27 PA2 I/O It/Ot2 NC 91 A15 O It/Ot8 EB: A15
28 RESERVED (PA3) I Itpu/Ot2 RESERVED 92 SR2CLK (P_PGP05) I Itpu/Ot2 VC: M_SCK
29 RESERVED (PA4) I Itpu/Ot2 RESERVED 93 DIB_DATAP I/O Idd/Odd DIB: Data Pos.
Channel
30 GND G GND GND 94 DIB_DATAN I/O Idd/Odd DIB: Data Neg.
Channel
31 RESERVED (PA5) I It/Ot2 +3.3V through 47 KΩ 95 GND G GND GND
32 PA6 I/O It/Ot2 NC 96 PWRCLKP O Odpc DIB: Transformer
primary winding non-
dotted terminal
33 NVMCLK (PA7) O It/Ot2 NVRAM: SCL 97 PWRCLKN O Odpc DIB: Transformer
primary winding dotted
terminal
34 RESET# I It HB: RESET# 98 DSPKOUT O It/Ot2 Speaker Circuit
35 SR3OUT O Ot2 VC: M_TXSIN 99 A16 (PB0) O It/Ot2 EB: A16
36 SR3IN (P_PX01) I Itk/Ot2 VC: M_RXOUT 100 VDD P PWR +3.3V
37 M_CLK (P_PB00) O It/Ot2 VC: M_CLKIN 101 RESERVED (PB1) O It/Ot2 NC
38 SA2CLK (P_PX05) I Itpu/Ot2 VC: M_STROBE 102 ROMSEL# (PB2) O Ot2 EB: ROM CE#
39 SR2IO (P_PX06) O It/Ot2 VC: M_CNTRLSIN 103 GND G GND GND
40 VDD P PW R +3.3V 104 RAMSEL# (PB3) O It/Ot2 EB: RAM CS#
41 P_PX00 I/O It/Ot8 NC 105 A17 (PB4) O It/Ot2 EB: A17
42 P_PX02 I/O Itpu/Ot2 NC 106 A18 (PB5) O It/Ot2 EB: A18
43 P_PX03 I/O Itpu/Ot2 NC 107 EXT_RES# (PB6) O It/Ot2 NC
44 GND G GND GND 108 VDD P PWR +3.3V
45 SR4IN I Itk NC 109 HINT (PB7) O It/Ot8 HB: HINT
46 PD7 I/O It/Ot2 NC 110 TESTP I Itpu NC
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-7
Table 3-1. CX81801 Modem 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High) (Continued)
Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface
47 NOXYCK I Itpu GND 111 DV1TP I Itpu Clock Select
48 GND G GND GND 112 GND G GND GND
49 XCLK O It/Ot2 NC 113 CLKIN I It GND
50 IASLEEP (P_PF05) O Ot2 VC: SLEEP 114 XTLI I Ix Crystal Circuit
51 RESERVED
(P_PB01) I/O Itpu/Ot2 NC 115 XTLO O Ox Crystal Circuit
52 RESERVED (GP00) I/O It/Ot2 NC 116 VDD P PWR +3.3V
53 VDD_CORE P PWR Internal core voltage 117 NMI# I Ithpu +3.3V
54 RESERVED
(P_PA04) I/O Itpu/Ot2 NC 118 WRITE# O It/Ot2 EB: WRITE#
55 RESERVED
(P_PA00) I/O Itpu/Ot2 NC 119 READ# O It/Ot2 EB: READ#
56 RESERVED
(P_PA05) I/O Itk/Ot2 NC 120 GND G GND GND
57 LPO I Itpu/Ot2 +3.3V through 240 KΩ 121 PHS2 O Ot2 NC
58 VDD P PWR +3.3V 122 HD0 (PC0) I/O Ith/Ot8 HB: HD0
59 RESERVED
(BD2CLK) O Itpu/Ot2 NC 123 HD1 (PC1) I/O Ith/Ot8 HB: HD1
60 VGG P PWRG +3.3V or +5V 124 VDD P PWR +3.3V
61 CLKOUT O It/Ot2 NC 125 HD2 (PC2) I/O Ith/Ot8 HB: HD2
62 D0 I/O Ith/Ot2 EB: D0 126 HD3 (PC3) I/O Ith/Ot8 HB: HD3
63 D1 I/O IthOt2 EB: D1 127 HD4 (PC4) I/O Ith/Ot8 HB: HD4
64 D2 I/O Ith/Ot2 EB: D2 128 GND G GND GND
Notes:
1. I/O Types: See Table 3-5.
2. Interface Legend:
DIB Digital Isolation Barrier
EB Expansion Bus
HB Host Bus
NC No internal pin connection
VC Voice Codec
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-8 Conexant 102199B
Table 3-2. CX81801 Modem Pin Signal Definitions for Parallel Interface (PARIF = High)
Label Pin I/O I/O Type Signal Name/Description
System
XTLI,
XTLO 114,
115 I,
O Ix,
Ox Crystal In and Crystal Out. If an external 28.224 MHz crystal
circuit is used instead of an external clock circuit, connect XTLI
and XTLO to the external crystal circuit and connect CLKIN to
digital ground (GND).
CLKIN 113 I It Clock In. If an external 28.224 MHz clock circuit is used instead of
an external crystal circuit, connect CLKIN to the clock output and
leave XTLI and XTLO open.
CLKOUT 61 O It/Ot2 Clock Ou t. 28.224 MHz output clock. Leave open.
DV1TP 111 I Itpu Clock Input Select. This input is used to choose the clock input.
Connect to +3.3V or leave open to select XTLI as the clock input.
Connect to GND to select CLKIN as the clock input.
PARIF 5 I Itpu Parallel/Serial Interface Select. PARIF input high (open) selects
parallel host interface operation (see this table); PARIF low (GND)
selects serial DTE interface operation (see Table 3-4).
LINE_SEL (PE7) 23 I It/Ot8 Line Interface Select. Selects telephone line interface. Connect to
+3.3V though 47 KΩ.
STPMODE# (PD3) 9 I Ith/Ot2 Stop Mode. Not used. Leave open.
NMI# 117 I Ithpu Non-Maskable Interrupt. Not used. Connect to +3.3V.
RESET# 34 I It Reset. The active low RESET# input resets the Smart Modem
logic, and restores the saved configuration from serial EEPROM or
returns the modem to the factory default values if NVRAM is not
present.
RESET# low holds the modem in the reset state; RESET# going
high releases the modem from the reset state. After application of
VDD, RESET# must be held low for at least 15 ms after the VDD
power reaches operating range. The modem device set is ready to
use 25 ms after the low-to-high transition of RESET#.
For parallel Interface, connect RESET# input to the host bus
RESET line through an inverter.
VGG 60 P PWRG I/O Signaling Voltage Source. Connect to +3.3V for +3.3V inputs,
or to +5V for +5V inputs.
VDD 2, 15, 40, 58,
78, 100, 108,
116, 124
P PWR Digital Supply Voltage. Connect to VCC (+3.3V, filtered).
VDD_CORE 20, 53, 85 P PWR Core Voltage. Internal core voltage.
GND 10, 25, 30, 44,
48, 68, 90, 95,
103, 112, 120,
128
G GND Digital Ground. Connect to digital ground (GND).
LPO 57 I I/O
Low Power Oscillator. Connect to +3.3V through 240 KΩ.
NOXYCK 47 I Itpu Disable XCLK Output. When low, disables XCLK output (reduces
internal power consumption). When high, enables XCLK output.
Connect to GND.
PLLVDD 82 P PWR PLL Circuit Digital Supply Voltage. Connect to +3.3V and to
GND through 0.1 µF.
PLLGND 83 G GND PLL Circuit Digital Ground. Connect to GND.
Serial EEPROM (NVRAM) Interface
NVMCLK (PA7) 33 O It/Ot2 NVRAM Clock. NVMCLK output high enables the EEPROM.
Connect to EEPROM SCL pin.
NVMDATA (PE3) 18 I/O It/Ot2 NVRAM Data. The NVMDATA pin supplies a serial data interface
to the EEPROM. Connect to EEPROM SDA pin and to +3.3V
through 10 KΩ.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-9
Table 3-2. CX81801 Modem Pin Signal Definitions for Parallel Interface (PARIF = High) (Continued)
Label Pin I/O I/O Type Signal Name/Description
Speaker Interface
DSPKOUT 98 O It/Ot2 Modem Speaker Digital Output. The DSPKOUT digital output
reflects the received analog input signal digitized to TTL high or low
level by an internal comparator.
DIB Interface
PWRCLKP 96 O Odpc Clock and Power Positive. Provides clock and power to the LSD.
Connect to DIB transformer primary winding non -dotted terminal.
PWRCLKN 97 O Odpc Clock and Power Negative. Provides clock and power to the LSD.
Connect to DIB transformer primary winding dotted terminal.
DIB_DATAP 93 I/O Idd/Odd Data Positive. Transfers data, control, and status information
between the Smart Modem and the LSD. Connect to LSD through
DIB data positive channel components.
DIB_DATAN 94 I/0 Idd/Odd Data Negative. Transfers data, control, and status information
between the Smart Modem and the LSD. Connect to LSD through
DIB data negative channel components.
External Bus Interface
A0-A9,
A10-A15,
A16 (PB0),
A17 (PB4),
A18 (PB5)
71-77, 79-81,
84, 86-89, 91,
99,
105,
106
O,
O,
O,
O,
O
It/Ot8,
It/Ot8,
It/Ot2,
It/Ot2,
It/Ot2
Address Lines 0-18. A0-A18 are the address output lines used to
access external memory; up to 4 Mb (512 KB) ROM/flash ROM
using A0-A18 and up to 1 Mb (128 KB) RAM using A0-A16.
The 256 KB base modem ROM code is located in the 0-256 KB
address range.
D0-D7 62-67, 69-70 I/O Ith/Ot2 Data Line 0-7. D0-D7 are the bidirectional external memory bus
data lines.
READ# 119 O It/Ot2 Read Enable. READ# output low enables data transfer from the
selected device to the D0-D7 lines.
WRITE# 118 O It/Ot2 Write Enable. WRITE# output low enables data transfer from the
D0-D7 lines to the selected device.
ROMSEL# (PB2) 102 O Ot2 ROM Select. ROMSEL# (PB2, ES3) output low selects the external
ROM/flash ROM.
RAMSEL# (PB3) 104 O It/Ot2 RAM Select. RAMSEL# (PB3, ES2) output low selects the external
RAM.
RESERVED (PB1) 101 O It/Ot2 Reserved. PB1 (ES4) is used internally. Leave open.
EXT_RES# (PB6) 107 O It/Ot2 External Device Reset. Active low reset for external devices.
Leave open if not used.
CX20442 VC Interface
IASLEEP (P_PF05) 50 O Ot2 Modem Sleep. Connect to VC SLEEP pin.
M_CLK (P_PB00) 37 O It/Ot2 Master Clock Output. Connect to VC M_CLKIN pin.
SR2CLK (P_PGP05) 92 I Itpu/Ot2 Voice Serial Clock input. Connect to VC M_SCK pin.
SA2CLK (P_PX05) 38 I Itpu/Ot2 Voice Serial Frame Sync Input. Connect to VC M_STROBE pin.
SR3OUT 35 O Ot2 Voice Serial Transmit Data Output. Connect to VC M_TXSIN pin.
SR3IN (P_PX01) 36 I Itk/Ot2 Voice Serial Receive Data Input. Connect to VC M_RXOUT pin.
SR2IO (P_PX06) 39 O It/Ot2 Voice Control Output. Connect to VC M_CNTRLSIN pin.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-10 Conexant 102199B
Table 3-2. CX81801 Modem Pin Signal Definitions for Parallel Interface (PARIF = High) (Continued)
Label Pin I/O I/O Type Signal Name/Description
Parallel Host Interface
HCS# (PD4) 11 I It Host Bus Chip Select. HCS# input low enables the MCU host
bus interface.
HWT# (PD5) 12 I Ithpu Host Bus Write. HWT# is an active low, write control input. When
HCS# is low, HWT# low allows the host to write data or control
words into a selected MCU register.
HRD# (PD6) 13 I Ithpu Host Bus Read. HRD# is an active low, read control input. When
HCS# is low, HRD# low allows the host to read status information
or data from a selected MCU register.
HINT (PB7) 109 O It/Ot8 Host Bus Interrupt. HINT output is set high when the receiver
error flag, received data available, transmitter holding register
empty, or modem status interrupt is asserted. HINT is reset low
upon the appropriate interrupt service or master reset operation.
HA0-HA2
(PD0-PD2) 6-8 I Ithpd/Ot2 Host Bus Address Lines 0-2. During a host read or write
operation with HCS# low, HA0-HA2 select an internal MCU
16550A-compatible register.
HD0-HD7
(PC0-PC7) 122-123, 125-
127, 1, 3-4 I/O Ith/Ot8 Host Bus Data Lines 0-7. HD0-HD7 are three-state input/output
lines providing bidirectional communication between the host and
the MCU. Data, control words, and status information are
transferred over HD0-HD7.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-11
Table 3-2. CX81801 Modem Pin Signal Definitions for Parallel Interface (PARIF = High) (Continued)
Label Pin I/O I/O Type Signal Name/Description
DAA Interface
VOICE# (PE1) 16 O It/Ot2 Voice Rela y Control. This output (typically active low) used to
control the normally open voice relay.
HS_LCS (PE4) 19 I It/Ot2 Handset Line Current Sense. LCS is an active high input that
indicates a handset off-hook status. Not required for
data/fax/voice/speakerphone operation. If not used, connect to
GND through 47 KΩ.
Not Used
TESTP 110 I Itpu Test. Used for factory test only. L eave open.
XCLK 49 O It/Ot2 Not Used. Leave open.
PHS2 121 O Ot2 Not Used. Leave open.
SR4RIN 45 I Itk Not Used. Leave open.
PA2 27 I It/Ot2 Not Used. Leave open.
PA6 32 O It/Ot2 Not Used. Leave open.
PD7 46 I/O It/Ot2 Not Used. Leave open.
P_PX00 41 I/O It/Ot8 Not Used. Leave open.
P_PX02 42 I/O Itpu/Ot2 Not Used. Leave open.
P_PX03 43 I/O Itpu/Ot2 Not Used. Leave open.
RESERVED (PA0) 24 O It/Ot2 Not Used. Leave open.
RESERVED (PA1) 26 O It/Ot2 Not Used. Leave open.
RESERVED (PA3) 28 I Itpu/Ot2 Not Used. Leave open.
RESERVED (PA4) 29 I Itpu/Ot2 Not Used. Leave open.
RESERVED (PA5) 31 I It/Ot2 Reserved. Connect to +3.3V though 47 KΩ.
RESERVED (PE0) 14 O It/Ot8 Not Used. Leave open.
RESERVED (PE2) 17 O It/Ot2 Not Used. Leave open.
RESERVED (PE5) 21 I/O It/Ot2 Reserved. Connect to +3.3V though 47 KΩ.
RESERVED (PE6) 22 O It/Ot2 Not Used. Leave open.
RESERVED (GP00) 52 I/O It/Ot2 Not Used. Leave open.
RESERVED (P_PA00) 55 I/O Itpu/Ot2 Not Used. Leave open.
RESERVED (P_PA04) 54 I/O Itpu/Ot2 Not Used. Leave open.
RESERVED (P_PA05) 56 I/O Itk/Ot2 Not Used. Leave open.
RESERVED (P_PB01) 51 I/O Itpu/Ot2 Not Used. Leave open.
RESERVED
(P_BD2CLK) 59 I/O Itpu/Ot2 Not Used. Leave open.
Notes:
1. I/O Types: See Table 3-5.
2. Interface Legend:
DIB Digital Isolation Barrier
EB Expansion Bus
HB Host Bus
NC No internal pin connection
VC Voice Codec
RESERVED = No external connection allowed (may have internal connection).
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-12 Conexant 102199B
Figure 3-3. CX81801 Modem Hardware Signals for Serial Interface (PARIF = Low)
XTLI
XTLO
CLKIN
CLKOUT
XCLK
DV1TP
LPO
NOXYCK
PARIF
STPMODE# (PD3)
NMI#
RESET#
AAIND# (PC4)
TMIND# (PB7)
DTRIND# (PD0)
OHIND# (PE0)
TXD# (PA2)
RXD# (PA6)
CTS# (PC1)
DSR# (PC0)
RLSD# (PC2)
TM# (PC6)
RI# (PC5)
DTR# (PD4)
RTS# (PD6)
RXCLK# (P_PB01)
TXCLK# (P_PA05)
XTCL K # (P_GP00 )
RESERVED (PA0)
RESERVED (PE6)
RESERVED (PA1)
TESTP
PHS2
SR4IN
PC3
PD1
PD2
PD7
RESERVED (PB1)
RESERVED (PC7)
RESERVED (PD5)
RESERVED (P_PA00)
RESERVED (P_PA05)
RESERVED (BD2CLK)
P_PX00
P_PX02
P_PX03
VGG
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD_CORE
VDD_CORE
VDD_CORE
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
114
115
113
61
49
111
57
47
5
9
117
34
127
109
6
14
27
32
123
122
125
3
1
11
13
51
54
52
24
22
26
110
121
45
126
7
8
46
101
4
12
55
56
59
41
42
43
60
2
15
40
58
78
100
108
116
124
20
53
85
10
25
30
44
48
68
90
95
103
112
120
128
SERIAL DTE
INTERFACE
LINE_SEL (PE7)
RESERVED (PA5)
RESERVED (PA4)
RESERVED (PE5)
RESERVED (PE2)
RESERVED (PA3)
VOICE# (PE1)
HS_LCS (PE4)
DSPKOUT
PWRCLKP
PWRCLKN
DIB_DATAP
DIB_DATAN
IASLEEP (P_PF05)
M_CLK (P_PB00)
SR2CLK (P_PGP05)
SA2CLK (P_PX05)
SR3OUT
SR3IN (P_PX01)
SR2IO (P_PX06)
NVMCLK (PA7)
NVMDATA (PE3)
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16 (PB0)
A17 (PB4)
A18 (PB5)
D0
D1
D2
D3
D4
D5
D6
D7
WRITE#
READ#
ROMSEL# (PB2)
RAMSEL# (PB3)
EXT_RES# (PB6)
PLLVDD
PLLGND
23
31
29
21
17
28
16
19
98
96
97
93
94
50
37
92
38
35
36
39
33
18
71
72
73
74
75
76
77
79
80
81
84
86
87
88
89
91
99
105
106
62
63
64
65
66
67
69
70
118
119
102
104
107
82
83
EEPROM (OPTIONAL)
102199_005
+3.3V
CX81801
Smart Modem
128-Pin TQFP
Serial Interface
(PARIF = Low)
+3.3V
DIGITAL ISOLATION
BARRIER (DIB)
0.1 uF
NC
CRYSTAL
CIRCUIT
NC
EXTERNAL MEMORY
LED
INTERFACE
RESET CIRCUIT
SPEAKER CI R CUIT
SLEEP
M_CLKIN
M_SCK
M_STROBE
M_TXSIN
M_RXOUT
M_CNTRLSIN
NC
+3.3V
+3.3V or +5V
VOICE#
HS_LCS
CX20442
VOICE CODEC (VC)
(OPTIONAL)
SERIAL DTE
SYNCHRONOUS
CLOCKS
NC
NC
NC
+3.3V 240K
NC
+3.3V DAA
47K
+3.3V
47K
+3.3V
47K
NC
NC
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-13
Figure 3-4. CX81801 Modem 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)
102199_006
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
57
58
59
60
61
62
63
64
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
GND
AAIND# (PC4)
PC3
RLSD# (PC2)
VDD
CTS# (PC1)
DSR# (PC0)
PHS2
GND
READ#
WRITE#
NMI#
VDD
XTLO
XTLI
CLKIN
GND
DV1TP
TESTP
TMIND# (PB7)
VDD
EXT_RES# (PB6)
A18 (PB5)
A17 (PB4)
RAMSEL# (PB3)
GND
SR2IO (P_PX06)
VDD
P_PX00
P_PX02
P_PX03
GND
SR4IN
PD7
NOXYCK
GND
XCLK
IASLEEP (P_PF05)
RXCLK# (P_PB01)
XTCLK# (GP00)
VDD_CORE
TXCLK# (P_PA04)
RESERVED (P_PA00)
RESERVED (P_PA05)
LPO
VDD
RESERVED (BD2CLK)
VGG
CLKOUT
D0
D1
D2
ROMSEL# (PB2)
RESERVED (PB1)
VDD
A16 (PB0)
DSPKOUT
PWRCLKN
PWRCLKP
GND
DIB_DATAN
DIB_DATAP
SR2CLK (P_PGP05)
A15
GND
A14
A13
A12
A11
VDD_CORE
A10
PLLGND
PLLVDD
A9
A8
A7
VDD
A6
A5
A4
A3
A2
A1
A0
D7
D6
GND
D5
D4
D3
RI# (PC5)
VDD
TM# (PC6)
RESERVED (PC7)
PARIF
DTRIND# (PD0)
PD1
PD2
STPMODE# (PD3)
GND
DTR# (PD4)
RESERVED (PD5)
RTS# (PD6)
OHIND# (PE0)
VDD
VOICE# (PE1)
RESERVED (PE2)
NVMDATA (PE3)
HS_LCS (PE4)
VDD_CORE
RESERVED (PE5)
RESERVED (PE6)
LINE_SEL (PE7)
RESERVED (PA0)
GND
RESERVED (PA1)
TXD# (PA2)
RESERVED (PA3)
RESERVED (PA4)
GND
RESERVED (PA5)
RXD# (PA6)
NVMCLK (PA7)
RESET#
SR3OUT
SR3IN (P_PX01)
M_CLK (P_PB00)
SA2CLK (P_PX05)
CX81801
Serial Interface
(PARIF Pin = Low)
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-14 Conexant 102199B
Table 3-3. CX81801 Modem 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)
Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface
1 RI# (PC5) O Ith/Ot8 DTE IF: RI# 65 D3 I/O Ith/Ot2 EB: D3
2 VDD P PWR +3.3V 66 D4 I/O Ith/Ot2 EB: D4
3 TM# (PC6) O Ith/Ot8 DTE IF: TM# 67 D5 I/O Ith/Ot2 EB: D5
4 RESERVED (PC7) I Ith/Ot8 +3.3V through 47 KΩ 68 GND G GND GND
5 PARIF I Itpu GND (serial interface) 69 D6 I/O Ith/Ot2 EB: D6
6 DTRIND# (PD0) O Ithpd/Ot2 LED: DTRIND# 70 D7 I/O Ith/Ot2 EB: D7
7 PD1 I/O Ithpd/Ot2 NC 71 A0 O It/Ot8 EB: A0
8 PD2 I/O Ithpd/Ot2 NC 72 A1 O It/Ot8 EB: A1
9 STPMODE# (PD3) I Ith/Ot2 NC 73 A2 O It/Ot8 EB: A2
10 GND G GND GND 74 A3 O It/Ot8 EB: A3
11 DTR# (PD4) I It DTE IF: DTR# 75 A4 O It/Ot8 EB: A4
12 RESERVED (PD5) I Ithpu NC 76 A5 O It/Ot8 EB: A5
13 RTS# (PD6) I Ithpu DTE IF: RTS# 77 A6 O It/Ot8 EB: A6
14 OHIND# (PE0) O It/ Ot8 LED: OHIND# 78 VDD P PWR +3.3V
15 VDD P PWR +3.3V 79 A7 O It/Ot8 EB: A7
16 VOICE# (PE1) O It/Ot2 DAA: VOICE# 80 A8 O It/Ot8 EB: A8
17 RESERVED (PE2) O It/Ot2 NC 81 A9 O It/Ot8 EB: A9
18 NVMDATA (PE3) I/O It/Ot2 NVRAM: SDA 82 PLLVDD P PWR +3.3V and GND
through 0.1 µF
19 HS_LCS (PE4) I It/Ot2 GND through 47 KΩ 83 PLLGND G GND GND
20 VDD_CORE P PWR Internal core voltage 84 A10 O It/Ot8 EB: A10
21 RESERVED (PE5) I/O It/Ot2 +3.3V through 47 KΩ 85 VDD_CORE P PWR Internal core voltage
22 SSD_RING# (PE6) O It/Ot2 NC 86 A11 O It/Ot8 EB: A11
23 LINE_SEL (PE7) I It/Ot8 +3.3V through 47 KΩ 87 A12 O It/Ot8 EB: A12
24 RESERVED (PA0) O It/Ot2 NC 88 A13 O It/Ot8 EB: A13
25 GND G GND GND 89 A14 O It/Ot8 EB: A14
26 SSD_INT (PA1) O It/Ot2 NC 90 GND G GND GND
27 TXD# (PA2) I It/Ot2 DTE IF: TXD# 91 A15 O It/Ot8 EB: A15
28 RESERVED (PA3) I Itpu/Ot2 NC 92 SR2CLK (P_PGP05) I Itpu/Ot2 VC: M_SCK
29 RESERVED (PA4) I Itpu/Ot2 NC 93 DIB_DATAP I/O Idd/Odd DIB: Data Pos.
Channel
30 GND G GND GND 94 DIB_DATAN I/O Idd/Odd DIB: Data Neg.
Channel
31 RESERVED (PA5) I It/Ot2 +3.3V through 47 KΩ 95 GND G GND GND
32 RXD# (PA6) O It/Ot2 DTE IF: RXD# 96 PWRCLKP O Odpc DIB: Transformer
primary winding non-
dotted terminal
33 NVMCLK (PA7) O It/Ot2 NVRAM: SCL 97 PWRCLKN O Odpc DIB: Transformer
primary winding dotted
terminal
34 RESET# I It Reset Circuit 98 DSPKOUT O It/Ot2 Speaker Circuit
35 SR3OUT O Ot2 VC: M_TXSIN 99 A16 (PB0) O It/Ot2 EB: A16
36 SR3IN (P_PX01) I Itk/Ot2 VC: M_RXOUT 100 VDD P PWR +3.3V
37 M_CLK (P_PB00) O It/Ot2 VC: M_CLKIN 101 RESERVED (PB1) O It/Ot2 NC
38 SA2CLK (P_PX05) I Itpu/Ot2 VC: M_STROBE 102 ROMSEL# (PB2) O Ot2 EB: ROM CE#
39 SR2IO (P_PX06) O It/Ot2 VC: M_CNTRLSIN 103 GND G GND GND
40 VDD P PWR +3.3V 104 RAMSEL# (PB3) O It/Ot2 EB: RAM CS#
41 P_PX00 I/O It/Ot8 NC 105 A17 (PB4) O It/Ot2 EB: A17
42 P_PX02 I/O Itpu/Ot2 NC 106 A18 (PB5) O It/Ot2 EB: A18
43 P_PX03 I/O Itpu/Ot2 NC 107 EXT_RES# (PB6) O It/Ot2 NC
44 GND G GND GND 108 VDD P PWR +3.3V
45 SR4IN I Itk NC 109 TMIND# (PB7) O It/Ot8 LED: TMIND#
46 PD7 I/O It/Ot2 NC 110 TESTP I Itpu NC
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-15
Table 3-3. CX81801 Modem 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low) (Continued)
Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface
47 NOXYCK I Itpu GND 111 DV1TP I Itpu Clock Select
48 GND G GND GND 112 GND G GND GND
49 XCLK O It/Ot2 NC 113 CLKIN I It GND
50 IASLEEP (P_PF05) O Ot2 VC: SLEEP 114 XTLI I Ix Crystal Circuit
51 RX CLK# (P_PB01) O Itpu/Ot2 DTE: RXCLK 115 XTLO O Ox Crystal Circuit
52 X TCLK# (GP00) I It/Ot2 DTE: XTCLK 116 VDD P PWR +3.3V
53 VDD_CORE P PWR Internal core voltage 117 NMI# I Ithpu +3.3V
54 TX CLK# (P_PA04) O Itpu/Ot2 DTE: TXCLK 118 WRITE# O It/Ot2 EB: WRITE#
55 RESERVED
(P_PA00) I/O Itpu/Ot2 NC 119 READ# O It/Ot2 EB: READ#
56 RESERVED
(P_PA05) I/O Itk/Ot2 NC 120 GND G GND GND
57 LPO I Itpu/Ot2 +3.3V through 240 KΩ 121 PHS2 O Ot2 NC
58 VDD P PWR +3.3V 122 DSR# (PC0) I/O Ith/Ot8 DTE IF: DSR#
59 RESERVED
(BD2CLK) O Itpu/Ot2 NC 123 CTS# (PC1) I/O Ith/Ot8 DTE IF: CTS#
60 VGG P PWRG +3.3V or +5V 124 VDD P PWR +3.3V
61 CLKOUT O It/Ot2 NC 125 RLSD# (PC2) I/O Ith/Ot8 DTE IF: RLSD#
62 D0 I/O Ith/Ot2 EB: D0 126 PC3 I/O Ith/Ot8 NC
63 D1 I/O IthOt2 EB: D1 127 AAIND# (PC4) O Ith/Ot8 LED: AAIND#
64 D2 I/O Ith/Ot2 EB: D2 128 GND G GND GND
Notes:
1. I/O Types: See Table 3-5.
2. Interface Legend:
DIB Digital Isolation Barrier
EB Expansion Bus
HB Host Bus
NC No internal pin connection
VC Voice Codec
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-16 Conexant 102199B
Table 3-4. CX81801 Modem Pin Signal Definitions for Serial Interface (PARIF = Low)
Label Pin I/O I/O Type Signal Name/Description
System
XTLI,
XTLO 114,
115 I,
O Ix,
Ox Crystal In and Crystal Out. If an external 28.224 MHz crystal
circuit is used instead of an external clock circuit, connect XTLI
and XTLO to the external crystal circuit and connect CLKIN to
digital ground (GND).
CLKIN 113 I It Clock In. If an external 28.224 MHz clock circuit is used instead of
an external crystal circuit, connect CLKIN to the clock output and
leave XTLI and XTLO open.
CLKOUT 61 O It/Ot2 Clock Ou t. 28.224 MHz output clock. Leave open.
DV1TP 111 I Itpu Clock Input Select. This input is used to choose the clock input.
Connect to +3.3V or leave open to select XTLI as the clock input.
Connect to GND to select CLKIN as the clock input.
PARIF 5 I Itpu Parallel/Serial Interface Select. PARIF input high (open) selects
parallel host interface operation (see signal definitions in
Table 3-2); PARIF low (GND) selects serial DTE interface
operation (see signal definitions in this table).
LINE_SEL (PE7) 23 I It/Ot8 Line Interface Select. Selects telephone line interface. Connect to
+3.3V.
STPMODE# (PD3) 9 I Ith/Ot2 Stop Mode. Not used. Leave open.
NMI# 117 I Ithpu Non-Maskable Interrupt. Not used. Connect to +3.3V.
RESET# 34 I It Reset. The active low RESET# input resets the Smart Modem
logic, and restores the saved configuration from serial EEPROM or
returns the modem to the factory default values if NVRAM is not
present.
RESET# low holds the modem in the reset state; RESET# going
high releases the modem from the reset state. After application of
VDD, RESET# must be held low for at least 15 ms after the VDD
power reaches operating range. The modem device set is ready to
use 25 ms after the low-to-high transition of RESET#.
For serial Interface, the RESET# input is typically connected to a
reset switch circuit.
VGG 60 P PWRG I/O Signaling Voltage Source. Connect to +3.3V for +3.3V inputs,
or to +5V for +5V inputs.
VDD 2, 15, 40, 58,
78, 100, 108,
116, 124
P PWR Digital Supply Voltage. Connect to VCC (+3.3V, filtered).
VDD_CORE 20, 53, 85 P PWR Core Voltage. Internal core voltage.
GND 10, 25, 30, 44,
48, 68, 90, 95,
103, 112, 120,
128
G GND Digital Ground. Connect to digital ground (GND).
LPO 57 I I/O
Low Power Oscillator. Connect to +3.3V through 240 KΩ.
NOXYCK 47 I Itpu Disable XCLK Output. When low, disables XCLK output (reduces
internal power consumption). When high, enables XCLK output.
Connect to GND.
PLLVDD 82 P PWR PLL Circuit Digi tal Supply Voltage. Connect to +3.3V and to
GND through 0.1 µF.
PLLGND 83 G GND PLL Circuit Digital Ground. Connect to GND.
Serial EEPROM (NVRAM) Interface
NVMCLK (PA7) 33 O It/Ot2 NVRAM Clock. NVMCLK output high enables the EEPROM.
Connect to EEPROM SCL pin.
NVMDATA (PE3) 18 I/O It/Ot2 NVRAM Data. The NVMDATA pin supplies a serial data interface
to the EEPROM. Connect to EEPROM SDA pin and to +3.3V
through 10 KΩ.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-17
Table 3-4. CX81801 Modem Pin Signal Definitions for Serial Interface (PARIF = Low) (Continued)
Label Pin I/O I/O Type Signal Name/Description
Speaker Interface
DSPKOUT 98 O It/Ot2 Modem Speaker Digital O utput. The DSPKOUT digital output
reflects the received analog input signal digitized to TTL high or
low level by an internal comparator.
DIB Interface
PWRCLKP 96 O Odpc Clock and Power Positive. Provides clock and power to the LSD.
Connect to DIB transformer primary winding non -dotted terminal.
PWRCLKN 97 O Odpc Clock and Power Negative. Provides clock and power to the
LSD. Connect to DIB transformer primary winding dotted terminal.
DIB_DATAP 93 I/O Idd/Odd Data Positive. Transfers data, control, and status information
between the Smart Modem and the LSD. Connect to LSD through
DIB data positive channel components.
DIB_DATAN 94 I/0 Idd/Odd Data Negative. Transfers data, control, and status information
between the Smart Modem and the LSD. Connect to LSD through
DIB data negative channel components.
External Bus Interface
A0-A9,
A10-A15,
A16 (PB0),
A17 (PB4),
A18 (PB5)
71-77, 79-81,
84, 86-89, 91,
99,
105,
106
O,
O,
O,
O,
O
It/Ot8,
It/Ot8,
It/Ot2,
It/Ot2,
It/Ot2
Address Lines 0-18. A0-A18 are the address output lines used to
access external memory; up to 4 Mb (512 KB) ROM/flash ROM
using A0-A18 and up to 1 Mb (128 KB) RAM using A0-A16.
The 256 KB base modem ROM code is located in the 0-256 KB
address range.
D0-D7 62-67, 69-70 I/O Ith/Ot2 Data Line 0-7. D0-D7 are bidirectional external memory bus data
lines.
READ# 119 O It/Ot2 Read Enable. READ# output low enables data transfer from the
selected device to the D0-D7 lines.
WRITE# 118 O It/Ot2 Write Enable. WRITE# output low enables data transfer from the
D0-D7 lines to the selected device.
ROMSEL# (PB2) 102 O Ot2 ROM Select. ROMSEL# (PB2, ES3) output low sel ects the
external ROM.
RAMSEL# (PB3) 104 O It/Ot2 RAM Select. RAMSEL# (PB3, ES2) output low selects the
external RAM.
RESERVED (PB1) 101 O It/Ot2 Reserved. PB1 (ES4) is used internally. Leave open.
EXT_RES# (PB6) 107 O It/Ot2 External Device Reset. Active low reset for external devices.
Leave open if not used.
CX20442 VC Interface
IASLEEP (P_PF05) 50 O Ot2 Modem Sleep. Connect to VC SLEEP pin.
M_CLK (P_PB00) 37 O It/Ot2 Master Clock Output. Connect to VC M_CLKIN pin.
SR2CLK (P_PGP05) 92 I Itpu/Ot2 Voice Serial Clock input. Connect to VC M_SCK pin.
SA2CLK (P_PX05) 38 I Itpu/Ot2 Voice Serial Frame Sync Input. Connect to VC M_STROBE pin.
SR3OUT 35 O Ot2 Voice Serial Transmit Data Output. Connect to VC M_TXSIN
pin.
SR3IN (P_PX01) 36 I Itk/Ot2 Voice Serial Receive Data Input. Connect to VC M_RXOUT pin.
SR2IO (P_PX06) 39 O It/Ot2 Voice Control Output. Connect to VC M_CNTRLSIN pin.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-18 Conexant 102199B
Table 3-4. CX81801 Modem Pin Signal Definitions for Serial Interface (PARIF = Low) (Continued)
Label Pin I/O I/O Type Signal Name/Description
V.24 (EIA/TIA-232-E) DTE Serial Interface
TXD# (PA2) 27 I It/Ot2 Transmitted Data (EIA BA/ITU-T CT103). The DTE uses the
TXD# line to send data to the modem for transmission over the
telephone line or to transmit commands to the modem.
RXD# (PA6) 32 O It/Ot2 Received Data (EIA BB/ITU-T CT104). The modem uses the
RXD# line to send data received from the telephone line to the
DTE and to send modem responses to the DTE. During command
mode, RXD# data represents the modem responses to the DTE.
CTS# (PC1) 123 O Ith/Ot8 Clear To Send (EIA CB/ITU-T CT106). CTS# output ON (low)
indicates that the modem is ready to accept data from the DTE. In
asynchronous operation, in error correction or normal mode, CTS#
is always ON (low) unless RTS/CTS flow control is selected by the
&Kn command.
In synchronous operation, the modem also holds CTS# ON during
asynchronous command state. The modem turns CTS# OFF
immediately upon going off-hook and holds CTS# OFF until both
DSR# and RLSD# are ON and the modem is ready to transmit and
receive synchronous data. The modem can also be commanded
by the &Rn command to turn CTS# ON in response to an RTS#
OFF-to-ON transition.
DSR# (PC0) 122 O Ith/Ot8 Data Set Ready (EIA CC/ITU-T CT107). DSR# indicates modem
status to the DTE. DSR# OFF (high) indicates that the DTE is to
disregard all signals appearing on the interchange circuits except
Ring Indicator (RI#). DSR# output is controlled by the AT&Sn
command.
RLSD# (PC2) 125 O Ith/Ot8 Received Line Signal Detector (EIA CF/ITU-T CT109). When
AT&C0 command is not in effect, RLSD# output is ON when a
carrier is detected on the telephone line or OFF when carrier is not
detected.
TM# (PC6) 3 O Ith/Ot8 Test Mode (EIA TM/ITU-T CT142). The TM# output indicates the
modem is in test mode (low) or in any other mode (high).
RI# (PC5) 1 O Ith/Ot8 Ring I ndic ator (E IA CE/ITU-T CT125). RI# output ON (low)
indicates the presence of an ON segment of a ring signal on the
telephone line.
DTR# (PD4) 11 I It Data Terminal Ready (EIA CD/ITU-T CT108). The DTR# input is
turned ON (low) by the DTE when the DTE is ready to transmit or
receive data. DTR# ON prepares the modem to be connected to
the telephone line, and maintains the connection established by
the DTE (manual answering) or internally (automatic answering).
DTR# OFF places the modem in the disconnect state under
control of the &Dn and &Qn commands.
RTS# (PD6) 13 I Ithpu Request To Send (EIA C A/ITU-T CT105). RTS# input ON (low)
indicates that the DTE is ready to send data to the modem. In the
command state, the modem ignores RTS#.
In asynchronous operation, the modem ignores RTS# unless
RTS/CTS flow control is selected by the &Kn command. In
synchronous on-line operation, the modem can be commanded by
the &Rn command to ignore RTS# or to respond to RTS# by
turning on CTS# after the delay specified by Register S26.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-19
Table 3-4. CX81801 Modem Pin Signal Definitions for Serial Interface (PARIF = Low) (Continued)
Label Pin I/O I/O Type Signal Name/Description
V.24 (EIA/TIA-232-E) DTE Serial Interface (Continued)
RXCLK# (P_PB01) 51 O Itpu/Ot2 Receive Data Clock. A synchronous Receive Data Clock
(RXCLK) is output in synchronous modes. The RXCLK frequency
is the data rate (±0.01%) with a duty cycle of 50±1%. Leave open
if not used.
TXCLK# (P_PA04) 54 O Itpu/Ot2 Transmit Data Clock. A synchronous Transmit Data Clock
(TXCLK) is output in synchronous modes. The TXCLK frequency
is the data rate (±0.01%) with a duty cycle of 50±1%. Leave open
if not used.
XTCLK# (GP00) 52 I It/Ot2 External Data Clock. A synchronous External Transmit Data
Clock (XTCLK) is input in synchronous modes.
LED Indicator Interface
AAIND# (PC4) 127 O Ith/Ot8 Auto Answer Indicator. AAIND# output ON (low) corresponds to
the indicator on. AAIND# output is active when the modem is
configured to answer the ring automatically (ATS0 command ≠ 0).
TMIND# (PB7) 109 O It/Ot8 Test Mode Indicator. TMIND# output ON (low) corresponds to the
indicator on. TMIND# output pulses (indicator flashes) when the
modem is in test mode and if an error is detected.
DTRIND# (PD0) 6 O Ithpd/Ot2 DTR Indicator. DTRIND# output ON (low) corresponds to the
indicator on. The DTRIND# state reflects the DTR# output state
except when the &D0 command is active, in which case DTRIND#
is low.
OHIND# (PE0) 14 O It/Ot8 Off-Hook Indicator. OHIND# (PE 0) indicates the status of the off-
hook relay.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-20 Conexant 102199B
Table 3-4. CX81801 Modem Pin Signal Definitions for Serial Interface (PARIF = Low) (Continued)
Label Pin I/O I/O Type Signal Name/Description
DAA Interface
VOICE# (PE1) 16 O It/Ot2 Voice Relay Control. This output (typically active low) used to
control the normally open voice relay.
HS_LCS (PE4) 19 I It/Ot2 Handset Line Current Sense. LCS is an active high input that
indicates a handset off-hook status. Not required for
data/fax/voice/speakerphone operation. If not used, connect to
GND through 47 KΩ.
Not Used
TESTP 110 I Itpu Test. Used for factory test only. Leave open.
XCLK 49 O It/Ot2 Not Used. Leave open.
S4RIN 45 I Itk Not Used. Leave open.
PHS2 121 O Ot2 Not Used. Leave open.
PC3 126 I/O Ith/Ot8 Not Used. Leave open.
PD1 7 I/O Ithpd/Ot2 Not Used. Leave open.
PD2 8 I/O Ithpd/Ot2 Not Used. Leave open.
PD7 46 I/O It/Ot2 Not Used. Leave open.
P_PX00 41 I/O It/Ot8 Not Used. Leave open.
P_PX02 42 I/O Itpu/Ot2 Not Used. Leave open.
P_PX03 43 I/O Itpu/Ot2 Not Used. Leave open.
RESERVED (PA0) 24 O It/Ot2 Not Used. Leave open.
RESERVED (PA1) 26 O It/Ot2 Not Used. Leave open.
RESERVED (PA3) 28 I Itpu/Ot2 Not Used. Leave open.
RESERVED (PA4) 29 I Itpu/Ot2 Not Used. Leave open.
RESERVED (PA5) 31 I It/Ot2 Reserved. Connect to +3.3V though 47 KΩ.
RESERVED (PC7) 4 I Ith/Ot8 Reserved. Connect to +3.3V through 47 K Ω.
RESERVED (PD5) 12 I Ithpu Reserved. Leave open.
RESERVED (PE2) 17 O It/Ot2 Not Used. Leave open.
RESERVED (PE5) 21 I/O It/Ot2 Reserved. Connect to +3.3V though 47 KΩ.
RESERVED (PE6) 22 O It/Ot2 Not Used. Leave open.
RESERVED (P_PA00) 55 I/O Itpu/Ot2 Not Used. Leave open.
RESERVED (P_PA05) 56 I/O Itk/Ot2 Not Used. Leave open.
RESERVED
(P_BD2CLK) 59 I/O Itpu/Ot2 Not Used. Leave open.
Notes:
1. I/O Types: See Table 3-5.
2. Interface Legend:
DIB Digital Isolation Barrier
EB Expansion Bus
HB Host Bus
NC No internal pin connection
VC Voice Codec
RESERVED = No external connection allowed (may have internal connection).
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-21
Table 3-5. CX81801 Modem I/O Type Definitions
I/O Type Description
Idd/Odd Digital input/output, DIB data transceiver
Ix/Ox I/O, wire
It/Ot2 Digital input, +5V tolerant/ Digital output, 2 mA, ZINT = 120 Ω
Itk/Ot2 Digital input, +5V tolerant, keeper/ Digital output, 2 mA, ZINT = 120 Ω
Itpu/Ot2 Digital input, +5V tolerant, 75k Ω pull up/ Digital output, 2 mA, ZINT = 120 Ω
It/Ot8 Digital input, +5V tolerant,/ Digital output, 8 mA, ZINT = 50 Ω
Ithpd/Ot2 Digital input, +5V tolerant, hysteresis, 75k Ω pull down/ Digital output, 2 mA, ZINT = 120 Ω
Ith/Ot2 Digital input, +5V tolerant, hysteresis/Digital output, 2 mA, ZINT = 120 Ω
Ith/Ot8 Digital input, +5V tolerant, hysteresis/Digital output, 8 mA, ZINT = 50 Ω
It Digital input, +5V tolerant
Itk Digital input, +5V tolerant, keeper
Itkpu Digital input, +5V tolerant, keeper, 75k Ω pull up
Itpu Digital input, +5V tolerant, 75k Ω pull up
Ithpu Digital input, +5V tolerant, hysteresis, 75k Ω pull up
Odpc Digital output with adjustable drive, DIB clock and power
Ot2 Digital output, three-state, 2 mA, ZINT = 120 Ω
PWR VCC Power
PWRG VGG Power
GND Ground
NOTES:
1. See DC characteristics in Table 3-6.
2. I/O Type corresponds to the device Pad Type. The I/O column in signal interface tables refers to signal I/O direction used in
the application.
Table 3-6. CX81801 Modem DC Electrical Characteristics
Parameter Symbol Min. Typ. Max. Units Test Conditions
Input Voltage Low VIL
+5V tolerant 0 – 0.8 V
+5V tolerant hysteresis 0 – 0.3 * VGG V
Input Voltage High VIH – V
+5V tolerant 2 – 5.25 V
+5V tolerant hysteresis 0.7 * VDD – 5.25 V
Input Hysteresis VH – V
+3V hysteresis 0.5 – V
+5V tolerant, hysteresis 0.3 – V
Output Voltage Low VOL
Z
INT = 120 Ω 0 – 0.4 V IOL = 2 mA
Z
INT = 50 Ω 0 – 0.4 V IOL = 8 mA
Output Voltage High VOH – V
Z
INT = 120 Ω 2.4 – VDD V IOL = -2 mA
Z
INT = 50 Ω 2.4 – VDD V IOL = -8 mA
Pull-Up Resistance Rpu 50 – 200 kΩ
Pull-Down Resistance Rpd 50 – 200 kΩ
Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; TA = 0°C to 70°C; external load = 50 pF.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-22 Conexant 102199B
3.2 CX20493 LSD Hardware Pins and Signals
3.2.1 CX20493 LSD Signal Summary
3.2.1.1 Smart Modem Interface (Through DIB)
The DIB interface, power, and ground signals are:
• Clock (CLK, pi n 26 ); in put
• Digital Powe r (PWR+, pin 7); unregulat ed inp ut power
• Regulated Digital Voltage Supply (DVdd, pin 24)
• Digital Ground (DGnd, pin 23); digital ground
• Regulated Ana l og Voltage Suppl y (A Vd d, pin 2)
• Analog Ground (AGnd, pin 6); analog ground
• Data Positive (DIB_P, pin 27); input/o utput
• Data Negative (DIB_N, pin 28); input/output
3.2.1.2 Telephone Line Interface
The telephone line interface signals are:
• RING 1 AC Coupled (RAC1, pin 21); input
• TIP 1 AC Coupled (T AC 1, pin 20); input
• RING 2 AC Coupled (RAC2, pin 19); input
• TIP 2 AC Coupled (T AC 2, pin 18); input
• TIP and RING DC Measurement (TRDC, pin 12); input
• Electronic Inductor Capacitor (EIC, pin 11)
• Electronic Induct o r Output (EIO, pi n 1 7)
• Electronic Inductor Feedback (EIF, pin 16)
• Receive Analog Input (RXI, pin 9); input
• Transmit Output (TXO, pin 14); output
• Transmit Feedback (TXF, pin 13); input
• Virtual Im pedance 0 (VZ, pin 10); in p ut
• Electronic Induct o r Gr ou n d ( DC _ GN D, pin 15)
3.2.1.3 Voltage References
There are three reference voltage pins:
• Output Middle (Center) Reference Voltage (Vc, pin 3); output for decoupling
• Output Reference Voltage (V R e f, pi n 4 ); output for dec ou pling
• Bias Resistor (RBias, pin 5); input
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-23
3.2.1.4 General Purpose Input/Output
There is one unassigned general purpose input/output pin:
• General Purpose Input/Output 1 (GPIO1, pin 1); input/output
3.2.1.5 No Connects
Three pins are not used:
• No Connect 1 (NC1, pin 8); no internal connection
• No Connect 2 (NC2, pin 22); no internal connection
• No Connect 3 (NC3, pin 25); no internal connection
3.2.2 CX20493 LSD Pin Assignments and Signal Definitions
CX20493 LSD hardware interface signals are shown by major interface in Figure 3-5, are
shown by pin number in Figure 3-6, and are listed by pin number in Table 3-7.
CX20493 LSD hardware interface signals are defined in Table 3-8.
CX20493 LSD GPIO DC electrical characteristics are specified in Table 3-9.
CX20493 LSD AVdd DC electrical characteristics are listed in Table 3-10.
Figure 3-5. CX20493 LSD Hardware Interface Signals
RAC2
TAC2
RAC1
TAC1
EIC
TRDC
EIO
EIF
RXI
VZ
TXO
TXF
RBias
VRef
Vc
GPIO1
NC1
NC2
NC3
19
18
21
20
11
12
17
16
9
10
14
13
5
4
3
1
8
22
25
101701_006
CX20493
SmartDAA 3
Line Side
Device
(LSD)
28-Pin QFN
Electronic
Inductor,
Off-Hook,
Pulse Dial,
and TIP and
RING VI
Control
AGND_LSD
Safety
and EMI
Protection
Ring
Filter
AGND_LSD
C944
Receive
Coupling
Impedance
Matching
and
Transmitter
NC
NC
NC
NC
R954
AGND_LSD
DVdd
CLK
PWR+
AVdd
AGnd
DIB_P
DIB_N
PADDLE
DC_GND
DGND
24
26
7
2
6
27
28
29
15
23
C930 C928
AGND_LSD
DIGITAL
ISOLATION
BARRIER
(DIB)
PWRCLKN
PWRCLKP
DIB_DATAP
DIB_DATAN
DATA
CHANNEL
POWER AND
CLOCK
CHANNEL
R922
C922
C924
Telephone
Line
Connector
TIP
RING
C926
R932
Vdd
C952
C950
NOTE:
Consult applicable reference design for exact
component placement and values, and for layout guidelines.
C962
C974 C976
R990
C970
C978
DGND_LSD
Vdd
AGND_LSD DGND_LSD
GND_TIE
U908
C940
FB906
On-hook
Monitor
(Optional)
R950
R952
AGND_LSD
BR908
BR908 CC
BR908 AC1
PCLK2 CLK2
+-
R924
R926
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-24 Conexant 102199B
Figure 3-6. CX20493 LSD 28-Pin QFN Pin Signals
101701A_007
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
GPIO1
AVdd
Vc
Vref
RBias
AGnd
PWR+
RAC1
TAC1
RAC2
TAC2
EIO
EIF
DC_GND
NC1
RXI
VZ
EIC
TRDC
TXF
TXO
DIB_N
DIB_P
CLK
NC3
DVdd
DGnd
NC2
CX20493
Table 3-7. CX20493 LSD 28-Pin QFN Pin Signa ls
Pin Signal Label Pin Signal Label
1 GPIO1 15 DC_GND
2 AVdd 16 EIF
3 Vc 17 EIO
4 VRef 18 TAC2
5 RBias 19 RAC2
6 AGnd 20 TAC1
7 PWR+ 21 RAC1
8 NC1 22 NC2
9 RXI 23 DGnd
10 VZ 24 DVdd
11 EIC 25 NC3
12 TRDC 26 CLK
13 TXF 27 DIB_P
14 TXO 28 DIB_N
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-25
Table 3-8. CX20493 LSD Hardware Signal Definitions
Label Pin I/O I/O Type Signal Name/Description
System Signals
AVdd 2 PWR PWR Regulated Power Outp ut. Provides external power for LSD digital
circuits and a connection point for external decoupling. (AVdd is routed
internally to LSD analog circuits.) See PWR+ pin description. Connect to
LSD DVdd pin and connect to AGND_LSD throu gh C928 and C930 in
parallel. C928 and C930 must be placed close to pins 2 and 6. C930
must have ESR < 2 Ω.
AGnd 6 AGND_LSD AGND_LSD
Analog Ground. Connect to minus (-) terminal of full wave rectifier
(FWR). Connect FWR BR980 terminal to DIB transformer secondary
winding undotted terminal through R922.
VRef 4 REF REF Output Reference Voltage. Connect to AGND_LSD through C940 and
C976, which must be placed close to pin 4. Ensure a very close proximity
between C940 and the VRef pin. C940 must have a maximum ESR of
2 Ω.
VRef 4 REF REF Output Reference Voltage. Connect to AGND_LSD through C940 and
C976, which must be placed close to pin 4. Ensure a very close proximity
between C940 and the VRef pin. C940 must have a maximum ESR of
2 Ω.
Vc 3 REF REF Output Middle Reference Voltage. Connect to AGND_LSD through
C944 and C974, which must be placed close to pin 3. Ensure a very
close proximity between C944 and the Vc pin. Use a short path and a
wide trace to AGND_LSD pin.
PWR+ 7 PWR PWR Unregulated Power Input. Provides unregulated input power to the
LSD. PWR+ pin is an input which takes unregulated +3.2V to +4.5V from
the DIB power supply made up of the transformer, full-wave rectifier, and
filter capacitors. The PWR+ input is regulated by an internal linear
regulator to +3.3V ± 5% which is routed to the AVdd pin. If PWR+ is less
than +3.4V, then AVdd is equal to the unregulated PWR+ input value
minus 150 mV (Table 3-10).
Connect to plus (+) terminal of FWR. Connect terminal BR908 AC1 to
DIB transformer secondary winding dotted terminal through R990.
Connect transformer side of FB906 to AGND_LSD though C970. Place
FB906 and C970 close to pin 7 and pin 6 (AGnd).
DVdd 24 PWR PWR Digital Power Input. Input power for LSD digital circuits. Connect to LSD
AVdd pin and connect to DGND_LSD through C978. Place C978 near
pin 24.
DGnd 23 DGND_LSD DGND_LSD
LSD Digital Ground. Connect to DGND_LSD, and to AGND_LSD at the
DGND_LSD/AGND_LSD tie point (U908).
PADDLE — AGND_LSD AGND_LSD
Paddle Ground. Referred to as pin 29 in schematics. Connect to
AGND_LSD.
DIB Interface Signals
CLK 26 I I Clock. Provides input clock, AC coupled to the LSD. Connect to DIB
transformer secondary winding undotted terminal through C 926 (closest
to the CX20493), R932, then R922 in series. Connect the R932 and
R922 node to LSD AGND pin through full-wave rectifier BR908. Place
C926 near pin 26 and place R932 near C926.
DIB_P 27 I/O I/O Data and Control Positive. Connect to DIBDAT_P through R924 in
series with C922. DIB_P and DIB_N signals are differential and half-
duplex bidirectional.
DIB_N 28 I/O I/O Data and Control Negative. Connect to DIBDAT_N through R926 in
series with C924. DIB_P and DIB_N signals are differential and half-
duplex bidirectional.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-26 Conexant 102199B
Table 3-8. CX20493 LSD Hardware Signal Definitions (Continued)
Label Pin I/O I/O Type Signal Name/Description
TIP and RING Interface
RAC1
TAC1 21
20 I
I Ia
Ia RING1 AC Coupled and TIP1 AC Coupled. AC-coupled voltage from
telephone line used to detect ring.
Connect RAC1 to the diode bridge AC node (RING) through R902
(connects to pin 21) and C902 in series.
Connect TAC1 to the diode bridge AC node (TIP) through R904
(connects to pin 20) and C904 in series.
RAC2
TAC2 19
18 I
I Ia
Ia RING2 AC Coupled and TIP2 AC Coupled. AC-coupled voltage from
telephone line used to optionally detect signal while on-hook.
Connect RAC2 to the diode bridge AC node (RING) through R948
(connects to pin 19) and C948. Leave open if not used.
Connect TAC2 to the diode bridge AC node (TIP) through R946
(connects to pin 21) and C946. Leave open if not used.
EIC 11 O Oa Electronic Inductor Capacitor Switch. Internally switched to TRDC
when pulse dialing. Connect to AGND_LSD through C958.
TRDC 12 I Ia TIP and RING DC Measurement. Input on-hook voltage (from a resistive
divider). Used internally to extract TIP and RING DC voltage and Line
Polarity Reversal (LPR) information. R906 and C918 must be placed
very close to pin 12.
EIO 17 O Oa Electronic Inductor Output. Calculated voltage is applied to this output
to control off-hook and DC VI mask operation. Connect to base of Q902.
DC_GND 15 GND AGND_LSD LSD Electronic Inductor Ground. Connect to AGND_LSD and to the
GND_LSD/AGND_LSD tie point (U908).
EIF 16 I Ia Electronic Inductor Feedback. Connect to emitter of Q904 through
R968.
RXI 9 I Ia Recei ve Analog Input. Receiver operational amplifier inverting input.
AC coupled to the Bridge CC node through R910 (connects to pin 9) and
C912 in series. R910 and C912 must be placed very close to pin 9. The
length of the PCB trace connecting R910 to the RXI pin must be kept at
an absolute minimum.
RBias 5 I Ia Receiver Bias. Connect to AGND_LSD through R954, which must be
placed close to pin 5.
VZ 10 I Ia Virtual Impedance. Input signal used to provide line complex
impedance matching for worldwide countries. AC coupled to Bridge CC
node through R908 (connects to pin 10) and C910 in series. R908 and
C910 must be placed very close to pin 10. The length of the PCB trace
connecting R908 to the VZ pin must be kept at an absolute minimum.
TXO 14 O Oa Transmit Output. Outputs transmit signal and impedance matching
signal; connect to base of transmitter transistor Q906.
TXF 13 I Ia Trans mit Feedb ack. Connect to emitter of transmitter transistor Q906.
Not Used
GPIO1 1 I/O It/Ot12 General Purpose I/O 1. Leave open if not used.
NC1 8 No Connect. No internal connection. Leave open.
NC2 22 No Connect. No internal connection. Leave open.
NC3 25 No Connect. No internal connection. Leave open.
Notes:
1. I/O types*:
Ia Analog input
It Digital input, TTL-compatible
Oa Analog output
Ot12 Digital output, TTL-compatible, 12 mA, ZINTERNAL = 32 Ω
AGND_LSD Isolated LSD Analog Ground
GND_LSD Isolated LSD Digital Ground
*See CX20493 LSD GPIO DC Electrical Characteristics (Error! Reference source not found.).
2. Refer to applicable reference design for exact component placement and values.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-27
Table 3-9. CX20493 LSD GPIO DC Electrical Characteristics
Parameter Symbol Min. Typ. Max. Units Test Conditions
Input Voltage VIN -0.30 – 3.465 V DVdd = +3.465V
Input Voltage Low VIL – – 1.0 V
Input Voltage High VIH 1.6 – – V
Output Voltage Low VOL 0 – 0.33 V
Output Voltage High VOH 2.97 – – V
Input Leakage Current – -10 – 10 µA
Output Leakage Current (High Impedance) – -10 – 10 µA
GPIO Output Sink Current at 0.33 V maximum – 2.4 – - mA
GPIO Output Source Current at 2.97 V minimum – 2.4 – - mA
GPIO Rise Time/Fall Time 20 100 ns
Test Conditions unless otherwise stated: DVdd = +3.3V +5%; TA = 0°C to 70°C; ext ernal load = 50 pF
Table 3-10. CX20493 AVdd DC Electrical Characteristics
PWR+ Input AVdd O utp ut
+3.4V < PWR+ < +4.5V +3.3V ± 5%
+3.2V < PWR+ < +3.39V 3.05V < AVdd < 3.24V
See PWR+, AVdd, and DVdd descriptions in Table 3-8.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-28 Conexant 102199B
3.3 CX20442 VC Hardware Pins and Signals (S Models)
3.3.1 CX20442 VC Signal Summary
Microphone and analog speaker interface signals, as well as telephone handset/headset
interface signals are provided to suppor t functions such as speakerphone mod e, teleph one
emulation, microphone voice record, speaker voice playback, and call progress monitor.
3.3.1.1 Speakerphone Interface
The following signals are supported:
• Speaker Out (M_SPKR_OUT); analog output - Should be used in speakerphone
designs where sound quality is important
• Microphone (M_MIC_IN); analog input
3.3.1.2 Telephone Handset/Headset Interface
The following interface sign als are supported:
• Telephone Input (M_LINE_IN), inpu t (TELIN) - Optional connection to a telephone
handset interface circuit
• Telephone out put (M _ LINE_OUT P); o ut p ut (TELOUT) - Optional connection to a
telephone handset interface circuit
• Center Voltage (VC); output refere nce vol t age
3.3.1.3 CX81801 Modem Interface
The following interface sign als are supported:
• Sleep (SLEEP); input
• Master Clock (M_CLKIN); input
• Serial Clock (M_SCK); output
• Control (M _CNTRLSIN); input
• Serial Frame Sync (M_STROBE); output
• Serial Transmit Data (M_TXSIN); input
• Serial Receive Data (M_RXOUT); output
3.3.1.4 Host Interface
The following interface sign als are supported:
• Reset (POR); input
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-29
3.3.2 CX20442 VC Pin Assignments and Signal Definitions
VC 32-pin TQFP hardware interface signals are shown by major interface in Figure 3-7,
are shown by pin number in Figure 3-8, and are listed by pin number in Table 3-11.
VC hardware interface signals are defined in Table 3-12.
VC pin signal DC electrical characteristics are defined in Table 3-13.
VC pin signal analog electrical characteristics are defined in Table 3-14.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-30 Conexant 102199B
Figure 3-7. CX20442 VC Hardware Interface Signals
102199_009
CX20442
Voice Codec
(VC)
32-Pin TQFP
AUDIO
CIRCUIT
NC
SPKOUT
MIC
TELIN
TELOUT
CX81801
+3.3V
VAA (+3.3V)
1
4
19
21
23
20
22
18
17
25
5
28
26
6
27
IASLEEP
DRESET#
M_CLK
V_SCLK
V_STROBE
V_TXSIN
V_RXOUT
V_CTRL
SLEEP
POR
M_CLKIN
M_SCK
M_STROBE
M_TXSIN
M_RXOUT
M_CNTRLSIN
VDD
VDD
MAVDD
VSS
SET3V_BAR2
MAVSS
VSUB
M_DIG_SPEAKER
M_MIC_IN
M_SPKR_OUT
M_LINE_IN
M_LINE_OUTP
M_LINE_OUTM
VREF
VC
M_MIC_BIAS
M_RELAYA
M_RELAYB
M_ACT90
M_1BIT_OUT
D_LPBK_BAR
NC
NC
NC
2
13
3
14
9
10
11
12
15
24
16
29
30
31
7
8
32
AGND
0.1uF 10uF
HANDSET
INTERFACE
NC
AGND
GND
AGND
0.1uF 10uF
Figure 3-8. CX20442 VC 32-Pin TQFP Pin Signals
102199_010
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
SLEEP
M_DIG_SPEAKER
M_SPKR_OUT
POR
MAVDD
MAVSS
NC
NC
M_RELAYA
M_STROBE
M_RXOUT
M_SCK
M_TXSIN
M_CLKIN
M_CNTRLSIN
VDD
M_LINE_OUTP
M_LINE_OUTM
VREF
VC
M_MIC_IN
M_LINE_IN
M_MIC_BIAS
M_RELAYB
NC
D_LPBK_BAR
M_1BIT_OUT
M_ACT90
VSS
VSUB
SET3V_BAR2
VDD
CX20442
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-31
Table 3-11. CX20442 VC 32-Pin TQFP Pin Signals
Pin Signal Label I/O Interface
1 SLEEP I CX81801: IASLEEP
2 M_DIG_SPEAKER O NC
3 M_SPKR_OUT O Speaker interface circuit
4 POR I Host: RESET# or reset circuit
5 MAVDD P VAA (+3.3V)
6 MAVSS G AGND
7 NC NC
8 NC NC
9 M_LINE_OUTP O Handset interface circuit: TELOUT
10 M_LINE_OUTM O NC
11 VREF AGND through capacitors
12 VC AGND through capacitors
13 M_MIC_IN I Microphone interface circuit
14 M_LINE_IN I Handset interface circuit: TELIN
15 M_MIC_BIAS NC
16 M_RELAYB NC
17 VDD P +3.3V
18 M_CNTRLSIN I CX81801: V_CTRL
19 M_CLKIN I CX81801: M_CLK
20 M_TXSIN I CX81801: V_TXSIN
21 M_SCK O CX81801: V_SCLK
22 M_RXOUT O CX81801: V_RXOUT
23 M_STROBE O CX81801: V_STROBE
24 M_RELAYA O NC
25 VDD P +3.3V
26 M_SET3V_BAR2 I GND
27 VSUB G AGND
28 VSS G GND
29 M_ACT90 I NC
30 M_1BIT_OUT O NC
31 D_LPBK_BAR I NC
32 NC NC
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-32 Conexant 102199B
Table 3-12. CX20442 VC Pin Signal Definitions
Label Pin I/O I/O Type Signal Name/Description
System Signals
VDD 17, 25 P PWR Digital Power Suppl y. Connect to +3.3V and digital circuits power
supply filter.
MAVDD 5 P PWR Analog Power Supply. Connect to +3.3V and analog circuits
power supply filter.
VSS 28 G GND Digital Ground. Connect to GND.
MAVSS 6 G AGND Analog Ground. Connect to AGND.
VSUB 27 G GND Analog Ground. Connect to A GND.
POR 4 I Itpu Power-On Reset. Active low reset input. Connect to Host
RESET# or reset circuit.
SET3V_BAR2 26 I Itpu Set +3.3V Analog Reference. Connect to GND.
CX81801 Interconnect
SLEEP 1 I Itpd IA Sleep. Active high sleep input. Connect to CX81801 IASLEEP
pin.
M_CLKIN 19 I Itpd Master Clock Input. Connect to CX81801 M_CLK pin.
M_SCK 21 O Ot2 Serial Clock Output. Connect to CX81801 V_SCLK pin.
M_CNTRL_SIN 18 I Itpd Control Input. Connect to CX81801 V_CTRL pin.
M_STROBE 23 O Ot2 Serial Frame Sync. Connect to CX81801 V_STROBE pin.
M_TXSIN 20 I Itpd Serial Transmit Data. Connect to CX81801 V_TXSIN pin.
M_RXOUT 22 O Ot2 Serial Receive Data. Connect to CX81801 V_RXOUT pin.
Microphone/Speaker Interface
M_MIC_IN 13 I I(DA) Microphone Input. Single-ended analog input from the
microphone circuit.
M_SPKR_OUT 3 O O(DF) Modem Speaker Analog Output. The M_SPKR_OUT analog
output reflects the received analog input signal. The
M_SPKR_OUT on/off and three levels of attenuation are controlled
by bits in DSP RAM. When the speaker is turned off, the
M_SPKR_OUT output is clamped to the voltage at the VC pin. The
M_SPKR_OUT output can drive an impedance as low as 300 Ω. In
a typical application, the M_SPKR_OUT output is an input to an
external LM386 audio power amplifier.
Handset/Headset Interface
M_LINE_OUTP 9 O O(DF) Telephone Handset Out (TELOUT). Single-ended analog data
output to the telephone handset circuit. The output can drive a
300 Ω load.
M_LINE_IN 14 I I(DA) Telephone Handset Out (TELIN). Single-ended analog data input
from the telephone handset circuit.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-33
Table 3-15. CX20442 VC Pin Signal Definitions (Continued)
Label Pin I/O I/O Type Signal Name/Description
Reference Voltage
VREF 11 R REF High Voltage Reference. Connect to analog ground through
10 µF (polarized, + terminal to VREF) and 0.1 µF (ceramic) in
parallel. Ensure a very close proximity between these capacitors
and VREF pin.
VC 12 R REF Low Voltage Reference. Connect to analog ground through
10 µF (polarized, + terminal to VC) and 0.1 µF (ceramic) in
parallel. Ensure a very close proximity between these capacitors
and VC pin.
For handset interface, also connect to handset interface circuit
(VC_HAND).
Not Used
M_DIG_SPEAKER 2 O Ot2 Not Used. Leave open.
M_LINE_OUTM 10 O Oa Not Used. Leave open.
M_RELAYA 24 O Ot Not Used. Leave open.
M_RELAYB 16 O Ot Not Used. Leave open.
M_MIC_BIAS 15 O Oa Not Used. Leave open.
M_ACT90 29 I Itpu Not Used. Leave open.
M_1BIT_OUT 30 O Ot2 Not Used. Leave open.
D_LPBK_BAR 31 I It Not Used. Leave open.
NC 7, 8, 32 Internal No Connect. Leave open.
Notes:
1. I/O types*:
Ia Analog input
It Digital input, TTL-compatible
Itpd Digital input, TTL-compatible, internal 75k ± 25k Ω pull-down
Itpu Digital input, TTL-compatible, internal 75k ± 25k Ω pull-up
Oa Analog output
Ot2 Digital output, TTL-compatible, 2 mA, ZINTERNAL = 120 Ω
Ot2od Digital output, TTL-compatible, 2 mA, open drain, ZINTERNAL = 120 Ω
AGND Analog Ground
GND Digital Ground
Table 3-13. CX20442 VC DC Electrical Characteristics
Parameter Symbol Min. Typ. Max. Units Test Conditions
Input Voltage VIN -0.30 – VDD+0.3 V
Input Voltage Low VIL -0.30 – 0.2 *VDD V
Input Voltage High VIH 0.4*VDD – VDD+0.3 V
Output Voltage Low VOL 0 – 0.4 V
Output Voltage High VOH 0.8*VDD – VDD V
Input Leakage Current – -10 – 10 µA
Output Leakage Current (High
Impedance) – -10 – 10 µA
Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; TA = 0°C to 70°C; external load = 50 pF
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-34 Conexant 102199B
Table 3-14. CX20442 VC Analog Electrical Characteristics
Signal Name Type Characteristic Value
M_LINE_IN, I (DA) Input Impedance > 70K Ω
M_MIC_IN AC Input Voltage Range 1.1 VP-P
Reference Voltage +1.35 VDC
M_LINE_OUTP O (DD) Minimum Load 300 Ω
Maximum Capacitive Load 0 µF
Output Impedance
10 Ω
AC Output Voltage Range 1.4 VP-P (with reference to ground and a
600 Ω load)
Reference Voltage +1.35 VDC
DC Offset Voltage ± 200 mV
M_SPKR_OUT O (DF) Minimum Load 300 Ω
Maximum Capacitive Load 0.01 µF
Output Impedance
10 Ω
AC Output Voltage Range 1.4 VP-P
Reference Voltage +1.35 VDC
DC Offset Voltage ± 20 mV
Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; MAVDD = +3.3 ± 0.3 VDC, TA = 0°C to 70°C
Parameter Min Typ Max Units
DAC to Line Driver output (600Ω load, 3dB in SCF and CTF) SNR/SDR at:
4Vp-p differential
2Vp-p differential
-10dBm differential
88/85
82/95
72/100
dB
DAC to Speaker Driver output (150Ω load, 3dB in SCF and CTF, -6dB in
speaker driver) SNR/SDR at:
2Vp-p
1Vp-p
-10dBm
88/75
82/80
72/83
dB
Line Input to ADC (6dB in AAF) SNR/SDR at –10 dBm 80/95 dB
Input Leakage Current (analog inputs) -10 10 µA
Output Leakage Current (analog outputs) -10 10 µA
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-35
3.4 Electrical and Environmental Specifications
3.4.1 Operating Conditions, Absolute Maximum Ratings, and Power Requirements
The operating conditions are specified in Table 3-15.
The absolute maximum ratings are listed in Table 3-16 for the CX81801, Table 3-17 for
the CX20493, and Table 3-18 for the CX20442.
The current and power requirements are listed in Error! Reference source not found..
Table 3-15. Operating Conditions
Parameter Symbol Limits Units
Supply Voltage VDD +3.0 to +3.6 VDC
Operating Ambient Temperature TA 0 to +70 °C
Table 3-16. CX81801 Absolute Maximum Ratings
Parameter Symbol Limits Units
Supply Voltage VDD -0.5 to +4.0 VDC
Input Voltage VIN -0.5 to + (VGG + 0.5)* VDC
Storage Temperature Range TSTG -55 to +125 °C
Analog Inputs VIN -0.3 to (VAA + 0.5) VDC
Voltage Applied to Outputs in High
Impedance (Off) State VHZ -0.5 to + (VGG + 0.5)* VDC
DC Input Clamp Current IIK ±20 mA
DC Output Clamp Current IOK ±20 mA
Static Discharge Voltage (25°C) VESD ±2500 VDC
Latch-up Current (25°C) ITRIG ±400 mA
* VGG = +3.3V ± 0.3V, or +5V ± 0.25V
Table 3-17. CX20493 Absolute Maximum Ratings
Parameter Symbol Limits Units
Regulator Supply Voltage PWR+ -0.5 to +4.1 VDC
Supply Voltage DVdd, AVdd -0.5 to +3.6 VDC
Pin Voltage I/O -0.5 to DVdd + 0.5 VDC
Storage Temperature Range TSTG -55 to +125 °C
Voltage Applied to Outputs in High
Impedance (Off) State VHZ -0.5 to +5.5 VDC
Static Discharge Voltage (HBM) VESD ±2500 V
Latch-up Current (25°C) ITRIG ±250 mA
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-36 Conexant 102199B
Table 3-18. CX20442 Absolute Maximum Ratings
Parameter Symbol Limits Units
Analog Supply Voltage AVDD -0.3 to +4.6 V
Digital Supply Voltage VDD -0.3 to +4.6 V
Storage Temperature Range TSTG –55 to +150 °C
Digital Inputs VIN –0.3 to (VDD + 0.3) V
Analog Inputs VIN –0.3 to + (AVDD + 0.3) V
DC Input Clamp Current IIK ±10 mA
DC Output Clamp Current IOK ±10 mA
Static Discharge Voltage (25 °C) VESD ±2500 V
Latch-up Current (25 °C) ITRIG ±150 mA
Notes:
1. Ratings specified for +3.3 V operation.
2. Voltages referenced to ground (VSS).
Table 3-19. Current and Power Requirements
Mode Typical
Current
(Ityp)
(mA)
Maximum
Current
(Imax)
(mA)
Typical
Power
(Ptyp)
(mW)
Maximum
Power
(Pmax)
(mW)
Notes
CX81801 Modem and CX20493 LSD
Normal Mode: Off-hook, normal data connection 62 71 205 256 f = 28.224 MHz
Normal Mode: On-hook, idle, waiting for ring 60 69 198 248 f = 28.224 MHz
Sleep Mode 18 21 59 76 f = 0 MHz
CX20442 VC (Optional)
Normal Mode 1.5 2.0 5 7
Notes:
1. Operating voltage: VDD = +3.3V ± 0.3V.
2. Test conditions: VDD = +3.3V for typical values; VDD = +3.6V for maximum values.
3. Input Ripple ≤ 0.1 Vpeak-peak.
4. f = Internal frequency.
5. Typical power (Ptyp) computed from Ityp: Ptyp = Ityp * 3.3V;
Maximum power (Pmax) computed from Imax: Pmax = Imax * 3.6V.
Handling CMOS Devices
The device contains circuitry to protect the inputs against damage due to high static
voltages. However, it is advised that normal precautions be taken to avoid application of
any voltage higher than maximum rated voltage.
An unterminated input can acquire unpred ictable voltages through coup ling with stray
capacitance and internal cross talk. Both power dissipation and device noise immunity
degrades. Therefore, all inputs should be connected to an appropriate supply voltage.
Input signals should never exceed the voltage range from -0.5V to + (VGG + 0.5V). This
prevents forward biasing the input protection diodes and possibly entering a latch up
mode due to high current transients.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-37
3.4.2 Interface and Timing Waveforms
3.4.2.1 External Memory Bus Timing
The external memory bus timing is listed in Table 3-20 and illustrated in Figure 3-9.
Table 3-20. Timing - External Memory Bus
Symbol Parameter Min Typ. Max Units
tFI Internal Operating Frequency 28.224 – – MHz
tCYC Internal Operating Clock Cycle 30 – – ns
Read
tAS READ# High to Address Valid – 6.5 9 ns
tES READ# High to ES Valid – 8 11 ns
tRW READ# Pulse Width 15 – 105 ns
tRDS Read Data Valid to READ# High 6.1 – – ns
tRDH READ# High to Read Data Hold 0 0 – ns
Write
tAS WRITE# High to Address Valid – 6.5 8 ns
tES WRITE# High to ES Valid – 8 11 ns
tWW WRITE# to WRITE# Pulse Width 15 – 105 ns
tWTD WRITE# Low to Write Data Valid – 5 8.2 ns
tWTH WRITE# High to Write Data Hold 5.0 – – ns
Notes:
1. ES = RAMSEL# or ROMSEL#.
2. Read pulse width and write pulse width:
RAM: tRW, tWW = 0.5 tCYC = 15 for Non-Extended Cycle Timing
ROM: tRW, tWW = 3.5 tCYC = 105 for Extended Cycle Timing
3. Memory speed determination:
RAM: tACCESS = tCYC - tES - tRDS = 330 - 8 - 6.1 = 15.9 ns (i.e., use 15 ns memory)
ROM: tACCESS = 4(tCYC) - tES - tRDS = 4(30) - 8 - 6.1 = 105.9 ns (i.e., use 90 ns memory).
4. Output Enable to Output Delay Timing:
RAM: tOE = tRW - tRDS = 0.5(tCYC) - tRDS = 15 - 6.1 = 8.9 ns
ROM: tOE = tRW - tRDS = 3.5(tCYC) - tRDS = 105 - 6.1 = 98.9 ns.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-38 Conexant 102199B
Figure 3-9. Waveforms - External Memory Bus
Write Timing
Read Timing
tCYC
tAS
RDH
C2*
A[18:0]
tRW
tt
RDS
READ#
D[7:0]
ES#**
tES
* C2 = Internal Phase 2 clock.
** ES# = RAMSEL# or ROMSEL#.
100491 F3-09 WF EB
tCYC
tAS
tWW
ttWTH
WTD
ES
t
C2*
A[18:0]
WRITE#
D[7:0]
ES#**
* C2 = Internal Phase 2 clock.
** ES# = RAMSEL# or ROMSEL#.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-39
3.4.2.2 Parallel Host Bus Timing
The parallel host bus timing is listed in Table 3-21 and illustrated in Figure 3-10.
Table 3-21. Timing - Parallel Host Bus
Symbol Parameter Min Max Units
READ (See Notes 1, 2, 3, 4, and 5)
tAS Address Setup 5 – ns
tAH Address Hold 10 – ns
tCS Chip Select Setup 0 – ns
tCH Chip Select Hold 10 – ns
tRD HRD# Strobe Width 45 – ns
tDD Read Data Delay – 25 ns
tDRH Read Data Hold 5 – ns
WRITE (See Notes 1, 2, 3, 4, and 5)
tAS Address Setup 5 – ns
tAH Address Hold 15 – ns
tCS Chip Select Setup 0 – ns
tCH Chip Select Hold 10 – ns
tWT HWT# Strobe Width 75 – ns
tDS Write Data Setup (see Note 4) – 20 ns
tDWH Write Data Hold (see Note 5) 5 – ns
Notes:
1. When the host executes consecutive Rx FIFO reads, a minimum delay of 2 times the internal CPU clock cycle
plus 15 ns (85.86 ns at 28.224 MHz) is required from the falling edge of HRD# to the falling edge of the next Host
Rx FIFO HRD# clock.
2. When the Host executes consecutive Tx FIFO writes, a minimum delay of 2 times the internal CPU clock cycle
plus 15 ns (85.86 ns at 28.224 MHz) is required from the falling edge of HWT# to the falling edge of the next Host
Tx FIFO HWT# clock.
3. tDS is measured from the point at which both HCS# and HWT# are active.
4. tDWH is measured from the point at which either HCS# and HWT# become inactive.
5. Clock frequency = 28.224 MHz clock.
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-40 Conexant 102199B
Figure 3-10. Waveforms - Parallel Host Bus
tAS tAH
tCS tCH
tRD
tDD tDRH
HA[2-0]
HCS#
HRD#
HWT#
HD[7-0]
tAS tAH
tCS tCH
HA[2-0]
tWT
tDS tDWH
HCS#
HRD#
HWT#
HD[7-0]
100491 F3-10 WF-HB
a. Host Read
b. Host Write
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-41
3.4.2.3 Serial DTE Interface
The serial DTE interface waveforms for 4800 and 9600 bps are illustrated in Figure 3-11.
Figure 3-11. Waveforms - Serial DTE Interface
TXCLK
4800 BPS
TXD
4800 BPS
TXCLK
9600 BPS
TXD
9600 BPS
NOTE: THIS FIGURE IS VALID FOR SYNCHRONOUS MODE ONLY. THERE IS NO RELATIONSHIP BETWEEN
NOTE: TXD AND TXCLK IN ASYNCHRONOUS MODE.
RXCLK
4800 BPS
RXD
4800 BPS
RXCLK
9600 BPS
RXD
9600 BPS
NOTE: THIS FIGURE IS VALID FOR SYNCHRONOUS MODE ONLY. THERE IS NO RELATIONSHIP BETWEEN
NOTE: RXD AND RXCLK IN ASYNCHRONOUS MODE.
a. Transmit
b. Receive 1227F3-14 WF-Ser DTE
CX81801-7x/8x SmartV.XX Modem Data Sheet
3-42 Conexant 102199B
3.5 Crystal Specifications
Crystal specifications are listed in Table 3-22.
Table 3-22. Crystal Specifications
Characteristic Value
Frequency 28.224 MHz nominal
Calibration Tolerance ±50 ppm at 25°C (CL = 16.5 and 19.5 pF)
Frequency Stability vs. Temperature ±35 ppm (0°C to 70°C)
Frequency Stability vs. Aging ±20 ppm/5 years
Oscillation Mode Fundamental
Calibration Mode Parallel resonant
Load Capacitance, CL 18 pF nom.
Shunt Capacitance, CO 7 pF max.
Series Resistance, R1 35-60 Ω max. @20 nW drive level
Drive Level 100µW correlation; 500µW max.
Operating Temperature 0°C to 70°C
Storage Temperature –40°C to 85°C
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 3-43
This page is intentionally blank.
CX81801-7x/8x SmartV.XX Modem Data Sheet
4-2 Conexant 102199B
Figure 4-1. Package Dimensions - 128-Pin TQFP
eb
DD1
E1 DETAIL A
DETAIL A
A1
L1
c
L
A
E1
E2
E
D2
D1
A2
Millimeters
0.05
21.75
15.75
0.5
0.17
0.11
1.6 MAX
0.15
1.4 REF
22.25
20.0 REF
18.5 REF
16.25
14.0 REF
12.5 REF
0.75
1.0 REF
0.50 BSC
0.27
0.17
0.08 MAX
0.0020
0.8563
0.6201
0.0197
0.0067
0.0043
A
A1
A2
D
D1
D2
E
E1
E2
L
L1
e
b
c
Coplanarity
Min. Max. Min. Max.
Inches*
Dim.
Ref: 128-PIN TQFP (GP00-D264)
* Metric values (millimeters) should be used for
PCB layout. English values (inches) are
converted from metric values and may include
round-off errors.
0.0630 MAX
0.0059
0.0551 REF
0.8760
0.7874 REF
0.7283 REF
0.6398
0.5512 REF
0.4921 REF
0.0295
0.0394 REF
0.0197 BSC
0.0106
0.0067
0.0031 MAX
PD-TQFP-128 (040395)
PIN 1
REF
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 4-3
Figure 4-2. Package Dimensions - 32-pin TQFP
DETAIL A
A1
L1
c
L
A
D1
A2
Millimeters
0.05
8.75
0.5
0.30
0.13
1.6 MAX
0.15
1.4 REF
9.25
7.0 REF
5.6 REF
0.75
1.0 REF
0.80 BSC
0.40
0.19
0.10 MAX
0.0020
0.3445
0.0197
0.0118
0.0051
A
A1
A2
D
D1
D2
L
L1
e
b
c
Coplanarity
Min. Max. Min. Max.
Inches*
Dim.
Ref: 32-PIN TQFP (GP00-D262)
* Metric values (millimeters) should be used for
PCB layout. English values (inches) are
converted from metric values and may include
round-off errors.
0.0630 MAX
0.0059
0.0551 REF
0.3642
0.2756 REF
0.2205 REF
0.0295
0.0394 REF
0.0315 BSC
0.0157
0.0075
0.004 MAX
PD-TQFP-32 (040395)
DETAIL A
D1
eb
DD2
D1
D1
D
D2
PIN 1
REF
CX81801-7x/8x SmartV.XX Modem Data Sheet
4-4 Conexant 102199B
Figure 4-3. Package Dimensions - 28-Pin QFN
Max.
0.75
1.00
0.80
D
E
E1
D1
A
A1
A3
A2
-
-
0.00
5.00
5.00
4.75
4.75
0.20
0.65
0.01
0.85
0.05
L
b0.23
0.50
e
Min.
0.28
0.60
0.35
0.5 BSC
Nom.
D2
E2
2.95 3.10 3.25
2.95 3.10 3.25
PD_GP00-D682-001
Ref. GP00-D682-001
0.15
4.90
4.65
4.90
4.65
0.25
5.10
4.85
5.10
4.85
TERMINAL TIP
TOP VIEW
e
L
C
CC
D1
3
Pin 1 Identifier 1
2
28
E
E1
D
BOTTOM VIEW
10
A1
PLANE
SEATING
b
A2
A3
A1
A
L
e
NOTE 3
3
E2
2
D2
1
28
NOTE 1
NOTE 1
SCALE: NONE
SECTION "C-C"
b
Pin 1 Identifier
NOTES:
1. DIMENSION b APPLIES TO PLATED TERMINAL AND IS MEASURED
BETWEEN 0.20 AND 0.25mm FROM TERMINAL TIP.
2. PACKAGE WARPAGE MAX 0.05mm.
3. APPLIED FOR EXPOSED PAD AND TERMINALS. EXCLUDE EMBEDDING
PART OF EXPOSED PAD FROM MEASURING.
Symbol
Dimensions (Millimeters)
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 5-1
5. Parallel Host Interface
The modem supports a 16550A interface in parallel interface versions. The 16550A
interface can operate in FIFO mode or non-FIFO mode. Non-FIFO mode is the same as
16450 interface operation. FIFO mode unique operations are identified.
5.1 Overview
The parallel interface registers and the corresponding bit assignments are shown in
Table 5-1.
The modem emulates the 16450/16550A interface and includes both a 16-byte receiver
data first-in first-out buffer (RX FIFO) and a 16-byte transmit data first-in first-out buffer
(TX FIFO). When FIFO mode is selected in the FIFO Control Register (FCR0 = 1), both
FIFOs are operative. Furthermore, when FIFO mode is selected, DMA operation of the
FIFO can also be selected (FCR3 = 1). When FIFO mode is not selected, operation is
restricted to 16450 interface operation.
The received data is read by the host from the Receiver Buffer (RX Buffer). The RX
Buffer corresponds to the Receiver Buffer Register in a 16550A device. In FIFO mode,
the RX FIFO operates transparently behind the RX Buffer. Interface operation is
described with reference to the RX Buffer in both FIFO and non-FIFO modes.
The transmit data is loaded by the host into the Transmit Buffer (TX Buffer). The TX
Buffer corresponds to the Transmit Holding Register in a 16550A device. In FIFO mode,
the TX FIFO operates transparently behind the TX Buffer. Interface operation is
described with reference to the TX Buffer in both FIFO and non-FIFO modes.
CX81801-7x/8x SmartV.XX Modem Data Sheet
5-2 Conexant 102199B
Table 5-1. Parallel Interface Registers
Register Register Bit No.
No. Name 7 6 5 4 3 2 1 0
7 Scratch Register (SCR) Scratch Register
6 Modem Status Register (MSR) Data Carrier
Detect
(DCD)
Ring
Indicator (RI) Data Set
Ready
(DSR)
Clear to
Send
(CTS)
Delta Data
Carrier
Detect
(DDCD)
Trailing
Edge of Ring
Indicator
(TERI)
Delta Data
Set Ready
(DDSR)
Delta Clear
to Send
(DCTS)
5 Line Status Register (LSR) RX FIFO
Error Transmitter
Empty
(TEMT)
Transmitter
Buffer
Register
Empty
(THRE)
Break
Interrupt (BI) Framing
Error
(FE)
Parity
Error
(PE)
Overrun
Error
(OE)
Receiver
Data Ready
(DR)
4 Modem Control Register (MCR) 0 0 0 Local
Loopback Out 2 Out 1 Request to
Send
(RTS)
Data
Terminal
Ready
(DTR)
3 Line Control Register (LCR) Divisor Latch
Access Bit
(DLAB)
Set Break Stick Parity Even Parity
Select (EPS) Parity
Enable
(PEN)
Number of
Stop Bits
(STB)
Word Length
Select Bit 1
(WLS1)
Word Length
Select Bit 0
(WLS0)
2 Interrupt Identify Register (I IR )
(Read Only) FIFOs
Enabled FIFOs
Enabled 0 0 Pending
Interrupt ID
Bit 2
Pending
Interrupt ID
Bit 1
Pending
Interrupt ID
Bit 0
“0" if
Interrupt
Pending
2 FIFO Control Register (FCR)
(Write Only) Receiver
Trigger MSB Receiver
Trigger
LSB
Reserved Reserved DMA Mode
Select TX FIFO
Reset RX FIFO
Reset FIFO Enable
1
(DLAB = 0) Interrupt Enable Register (IER) 0 0 0 0 Enable
Modem
Status
Interrupt
(EDSSI)
Enable
Receiver
Line Status
Interrupt
(ELSI)
Enable
Transmitter
Holding
Register
Empty
Interrupt
(ETBEI)
Enable
Received
Data
Available
Interrupt
(ERBFI)
0
(DLAB = 0) Transmitter Buffer Register
(THR) Transmitter FIFO Buffer Register (Write Only)
0
(DLAB = 0) Receiver Buffer Register (RBR) Receiver FIFO Buffer Register (Read Only)
1
(DLAB = 1) Divisor Latch MSB Register
(DLM) Divisor Latch MSB
0
(DLAB = 1) Divisor Latch LSB Register
(DLL) Divisor Latch LSB
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 5-3
5.2 Register Signal Definitions
5.2.1 IER - Interrupt Enable Register (Addr = 1, DLAB = 0)
The IER enables five types of interrupts that can separately assert the HINT outpu t signal
(Table 5-2). A selected interrupt can be enabled by setting the corresponding enable bit to
a 1, or disabled by setting the corresponding enable bit to a 0. Disabling an interrupt in
the IER prohibits setting the corresp onding indication in the IIR and assertion of HINT.
Disabling all interrupts (resetting IER0 - IER3 to a 0) inhibits setting of any Interrupt
Identifier Register (IIR) bits and inhibits assertion of the HINT output. All other system
functions operate normally, including the setting of the Line Status Register (LSR) and
the Modem Status Register (MSR).
Bits 7-4 Not used.
Always 0.
Bit 3 Enable Modem Status Interrupt (EDSSI).
This bit, when a 1, enables assertio n of the HINT output whenever the Delta CTS
(MSR0), Delta DSR (MSR1), Delta TER (MSR2), or Delta DCD (MSR3) bit in the
Modem Status Register (MSR) is a 1. This bit, when a 0, disables assertion of HINT
due to setting of any of these four MSR bits.
Bit 2 Enable Receiver Line Status Interrupt (ELSI).
This bit, when a 1, enables assertion of the HINT output whenever the Overrun Error
(LSR1), Parity Error (LSR2), Framing Error (LSR3), or Break Interrupt (LSR4)
receiver status bit in the Line Status Register (LSR) changes state. This bit, when a 0,
disables assertion of HINT due to change of the receiver LSR bits 1-4.
Bit 1 Enable Transmitter Holding Register Empty Interrupt (ETBEI).
This bit, when a 1, enables assertion of the HINT output when the Transmitter Empty
bit in the Line Status Register (LSR5) is a 1. This bit, when a 0, disables assertion of
HINT due to LSR5.
Bit 0 Enable Receiver Data Available Interrupt (ERBFI) and Character
Timeout in FIFO Mode.
This bit, when a 1, enables assertion of the HINT output when the Receiver Data Ready
bit in the Line Status Register (LSR0) is a1 or character timeout occurs in the FIFO
mode. This bit, when a 0, disables assertion of HINT due to the LSR0 or character
timeout.
CX81801-7x/8x SmartV.XX Modem Data Sheet
5-4 Conexant 102199B
5.2.2 FCR - FIFO Control Register (Addr = 2, Write Only)
The FCR is a write-only register used to enable FIFO mode, clear the RX FIFO and TX
FIFO, enable DMA mode, and set the RX FIFO trigger level.
Bits 7-6 RX FIFO Trigger Level.
FCR7 and FCR6 set the trigger level for the RX FIFO (Receiver Data Available)
interrupt.
FCR7 FCR6 RX FIFO Trigger Level (Bytes)
0 0 01
0 1 04
1 0 08
1 1 14
Bits 5-4 Not used.
Bit 3 DMA Mode Select.
When FIFO mode is selected (FCR0 = 1), FCR3 selects non-DMA operation (FCR3 =
0) or DMA operation (FCR3 = 1). When FIFO mode is not selected (FCR0 = 0), this
bit is not used (the modem operates in non-DMA mode in 16450 operation).
DMA operation in FIFO mode.
RXRDY will be asserted when the number of characters in the RX FIFO is equal to or
greater than the value in the RX FIFO Trigger Level (IIR0-IIR3 = 4h) or the received
character timeout (IIR0-IIR3 = Ch) has occurred. RXRDY will go inactive when there
are no more characters in the RX FIFO.
TXRDY will be asserted when there are one or more empty (unfilled) locations in the
TX FIFO. TXRDY will go inactive when the TX FIFO is completely full.
Non-DMA operation in FIFO mode.
RXRDY will be asserted when there are one or more characters in the RX FIFO.
RXRDY will go inactive when there are no more characters in the RX FIFO.
TXRDY will be asserted when there are no characters in the TX FIFO. TXRDY will go
inactive when the first character is loaded into the TX FIFO Buffer.
Bit 2 TX FIFO Reset.
When FCR2 is a 1, all bytes in the TX FIFO are cleared. This bit is cleared
automatically by the modem.
Bit 1 RX FIFO Reset.
When FCR1 is a 1, all bytes in the RX FIFO are cleared. This bit is cleared
automatically by the modem.
Bit 0 FIFO Enable.
When FCR0 is a 0, 16450 mode is selected and all bits are cleared in both FIFOs.
When FCR0 is a 1, FIFO mode (16550A mode) is selected and both FIFOs are
enabled. FCR0 must be a 1 when other bits in the FCR are written or they will not be
acted upon.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 5-5
5.2.3 IIR - Interrupt Identifier Register (Addr = 2)
The Interrupt Identifier Register (IIR) id entifies the existence and type of up to five
prioritized pending interrupts. Four priority levels are set to assist interrupt processing in
the host. The four leve ls, in order of decreasing priority, are: Highest: Receiver Line
Status, 2: Receiver Data Available or Receiver Character Timeout, 3: TX Buffer Empty,
and 4: Modem Status.
When the IIR is accessed, the modem freezes all interrupts and indicates the highest
priority interrupt pending to the host. Any change occurring in interrupt conditions are
not indicated until this access is complete.
Bits 7-6 FIFO Mode.
These two bits copy FCR0.
Bits 5-4 Not Used.
Always 0.
Bits 3-1 Highest Priority Pending Interrupt.
These three bits identify the highest pr iority pending interrupt (Table 5-2). Bit 3 is
applicable only when FIFO mode is selected, otherwise bit 3 is a 0.
Bit 0 Interrupt Pending.
When this bit is a 0, an interrupt is pending; IIR bits 1-3 can be used to determine the
source of the interrupt. When this bit is a1, an interrupt is not pending .
Table 5-2. Interrupt Sources and Reset Control
Interrupt Identification Register Interrupt Set and Reset Functions
Bit
31 Bit 2 Bit 1 Bit 0 Priority
Level Interrupt Type Interrupt Sour ce Interrupt Reset Control
0 0 0 1 — None None —
0 1 1 0 Highest Receiver Line
Status Overrun Error OE (LSR1),
Parity Error (PE) (LSR2),
Framing Error (FE) (LSR3),
or Break Interrupt (BI) (LSR4)
Reading the LSR
0 1 0 0 2 Received Data
Available Received Data Available (LSR0) or
RX FIFO Trigger Level (FCR6-
FCR7) Reached1
Reading the RX Buffer or the RX
FIFO drops below the Trigger
Level
1 1 0 0 2 Character Time-out
Indication 1
The RX FIFO contains at least 1
character and no characters have
been removed from or input to the
RX FIFO during the last 4 character
times.
Reading the RX Buffer
0 0 1 0 3 TX Buffer Empty TX Buffer Empty Reading the IIR or writing to the
TX Buffer
0 0 0 0 4 Modem Status Delta CTS (DCTS) (MSR0),
Delta DSR (DDSR) (MSR1),
Trailing Edge Ring Indicator (TERI)
(MSR3), or Delta DCD (DCD)
(MSR4)
Reading the MSR
Notes:
1. FIFO Mode only.
CX81801-7x/8x SmartV.XX Modem Data Sheet
5-6 Conexant 102199B
5.2.4 LCR - Line Control Register (Addr = 3)
The Line Control Register (LCR) specifies the format of the asynchronous data
communications exchange.
Bit 7 Diviso r Latch Access Bit (DLAB).
This bit must be set to a 1 to access the Divisor latch registers during a read or write
operation. It must be reset to a 0 to access the Receiver Buffer, the Transmitter Buffer,
or the Interrupt Enable Register.
Bit 6 Set Break.
When bit 6 is a 1, the transmit data is forced to the break condition, i.e., space (0) is
sent. When bit 6 is a 0, break is not sent. The Set Break bit acts only on the transmit
data and has no effect on the serial in logic.
Bit 5 Stick Parity.
When parity is enabled (LCR3 = 1) and stick parity is selected (LCR5 = 1), the parity
bit is transmitted and checked by the receiver as a 0 if even parity is selected (LCR4 =
1) or as a 1 if odd parity is selected (LCR4 = 0). When stick parity is not selected
(LCR3 = 0), parity is transmit and checked as determined by the LCR3 an d LCR4 bits.
Bit 4 Even Parity Select (EPS).
When parity is enabled (LCR3 = 1) and stick parity is not selected (LCR5 = 0), the
number of 1s transmitted or checked by the receiver in the data word bits and parity bit
is either even (LCR4 = 1) or odd (LCR4 = 0).
Bit 3 Enable Parity (PEN).
When bit 3 is a 1, a parity bit is generated in the serial out (transmit) data stream and
checked in the serial in (receive) data stream as determined by the LCR 4 and LCR5
bits. The parity bit is located between the last data bit and the first stop bit.
Bit 2 Number of Stop Bits (STB).
This bit specifies the number of stop bits in each serial out character. If bit 2 is a 0, one
stop bit is generated regardless of word length. If bit 2 is a 1 and 5-bit word length is
selected, one and one-half stop bits are generated. If bit 2 is a 1 and a 6-, 7-, or 8-bit
word length is selected, two stop bits are generated. The serial in logic checks the first
stop bit only, regardless of the number of stop bits selected.
Bits 1-0 Word Length Select (WLS0 and WLS1).
These two bits specify the number of bits in each serial in or serial out character. The
encoding of bit s 0 and 1 is:
Bit 1 Bit 0 Word Length
0 0 5 Bits (Not supported)
0 1 6 Bits (Not supported)
1 0 7 Bits
1 1 8 Bits
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 5-7
5.2.5 MCR - Modem Control Register (Addr = 4)
The Modem Control Register (MCR) controls the interface with the modem or data set.
Bit 7-5 Not used.
Always 0.
Bit 4 Loca l Loopback.
When this bit is set to a 1, the diagno stic mod e is selected and the following occurs:
Data written to the Transmit Buffer is looped back to the Receiver Buffer.
The DTS (MCR0), RTS (MCR1), Out1 (MCR2), and Out2 (MCR3) modem control
register bits are internally connected to the DSR (MSR5), CTS (MSR4), RI (MSR6), and
DCD (MSR7) modem status regist er bi t s, re s pect i vely .
Bit 3 Output 2.
When this bit is a 1, HINT is enabled. When this bit is a 0, HINT is in the high
impedance state.
Bit 2 Output 1.
This bit is used in local loopback (see MCR4).
Bit 1 Request to Send (RTS).
This bit controls the Request to Send (RTS) function. When this bit is a 1, RTS is on.
When this bit is a 0, RTS is off.
Bit 0 Data Terminal Ready (DTR).
This bit controls the Data Terminal Ready (DTR) function. When this bit is a 1, DTR is
on. When this bit is a 0, DTR is off.
5.2.6 LSR - Line Status Register (Addr = 5)
This 8-bit register provides status information to the host concerning data transfer.
Bit 7 RX FIFO Error.
In the 16450 mode, this b it is not used and is always 0.
In the FIFO mode, this bit is set if there are one or more characters in the RX FIFO
with a parity error, frami ng er ro r, o r brea k indication detected. This bit is reset to a 0
when the host reads the LSR and none of the above conditions exist in the RX FIFO.
Bit 6 Transmitter Empty (TEMT).
This bit is set to a 1 whenever the TX Buffer (THR) and equivalent of the Transmitter
Shift Register (TSR) are both empty. It is reset to a 0 whenever either the THR or the
equivalent of the TSR contains a character.
In the FIFO mode, this bit is set to a 1 when ever the TX FIFO and the equivalent of
the TSR are both empty.
CX81801-7x/8x SmartV.XX Modem Data Sheet
5-8 Conexant 102199B
Bit 5 Transmitter Holding Register Empty (THRE) [TX Buffer Empty].
This bit, when set, indicates that the TX Buffer is empty and the modem can accept a
new character for transmission. In addition, this bit causes the modem to issue an
interrupt to the host when the Transmit Holding Register Empty Interrupt Enable bit
(IIR1) is set to 1. The THRE bit is set to a 1 when a character is transferred from the
TX Buffer. The bit is reset to 0 when a byte is written into the TX Buffer by the host.
In the FIFO mode, this bit is set when the TX FIFO is empty; it is cleared when at least
one byte is in the TX FIFO.
Bit 4 Break Interrupt (BI).
This bit is set to a 1 whenever the received data input is a space (logic 0) for longer
than two full word lengths plus 3 bits. The BI bit is reset when the host reads the LSR.
Bit 3 Framing Error (FE).
This bit indicates that the received character did not have a valid stop bit. The FE bit is
set to a 1 whenever the stop bit following the last data bit or parity bit is detected as a
logic o (space). The FE bit is reset to a 0 when the host reads the LSR.
In the FIFO mode, the error indication is associated with the particular character in the
FIFO it applies to; the FE bit is set to a 1 when this character is loaded into the RX
Buffer.
Bit 2 Parity Error (PE).
This bit indicates that the received data character in the RX Buffer does not have the
correct even or odd parity, as selected by the Even Parity Select bit (LCR4) and the
Stick Parity bit (LCR5). The PE bit is reset to a 0 when the host reads the LSR.
In the FIFO mode, the error indication is associated with the particular character in the
it applies to; the PE bit is set to a 1 when this character is loaded into the RX Buffer.
Bit 1 Overrun Error (OE).
This bit is set to a 1 whenever received data is loaded into the RX Buffer before the
host has read the previous data from the RX Buffer. The OE bit is reset to a 0 when the
host read s the LSR.
In the FIFO mode, if data continues to fill beyond the trigger level, an overrun
condition will occur only if the RX FIFO is full and the next character has been
completely received.
Bit 0 Receiver Data Ready (DR).
This bit is set to a 1 whenever a complete incoming character has been received and
has been transferred into the RX Buffer. The DR bit is reset to a 0 when the host reads
the RX Buffer.
In the FIFO mode, the DR bit is set when the number of received data bytes in the RX
FIFO equals or exceeds the trigger level specified in FCR0-FCR1.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 5-9
5.2.7 MSR - Modem Status Register (Addr = 6)
The Modem Status Register (MSR) reports current state and change information of the
modem. Bits 4-7 supply current state and bits 0-3 supply change information. The change
bits are set to a 1 whenever a control input from the modem changes state from the last
MSR read by the host. Bits 0-3 are reset to 0 when the host reads the MSR or upon reset.
Whenever bits 0, 1, 2, or 3 are set to a 1, a Modem Status Interrupt (IIR0-IIR3 = 0) is
generated.
Bit 7 Data Carrier Detect (DCD).
This bit indicates the logic state of the DCD# (RLSD# ) outp ut. If Loo pback is selected
(MCR4 = 1), this bit reflects the state of the Out2 bit in the MCR (MCR3).
Bit 6 Ring Indicator (RI).
This bit indicates the logic state of the RI# output. If Loopback is selected (MCR4 = 1),
this bit reflects the state of the Out1 bit in the MCR (MCR2).
Bit 5 Data Set Ready (DSR).
This bit indicates the logic state of the DSR# output. If Loopback is selected (MCR4 =
1), this bit reflects the state of the DTR bit in the MCR (MCR0).
Bit 4 Clear to Send (CTS).
This bit indicates the logic state of the CTS# output. If Loopback is selected (MCR4 =
1), this bit reflects the state of the RTS bit in the MCR (MCR1).
Bit 3 Delta Data Carrier Detect (DDCD).
This bit is set to a 1 when the DCD bit changes state since the MSR was last read by
the host.
Bit 2 Trailing Edge of Ring Indicator (TERI).
This bit is set to a 1 when the RI bit changes from a 1 to a 0 state since the MSR was
last read by the host.
Bit 1 Delta Data Set Ready (DDSR).
This bit is set to a 1 when the DSR bit has changed since the MSR was last read by the
host.
Bit 0 Delta Clear to Send (DCTS).
This bit is set to a 1 when the CTS bit has changed since the MSR was last read by the
host.
5.2.8 RBR - RX Buffer (Receiver Buffer Register) (Addr = 0, DLAB = 0)
The RX Buffer (RBR) is a read-only register at location 0 (with DLAB = 0). Bit 0 is the
least significant bit of the data, and is the first bit received.
5.2.9 THR - TX Buffer (Transmitter Holding Register) (Addr = 0, DLAB = 0)
The TX Buffer (THR) is a write-only register at address 0 when DLAB = 0. Bit 0 is the
least significant bit and the first bit sent.
CX81801-7x/8x SmartV.XX Modem Data Sheet
5-10 Conexant 102199B
5.2.10 Divisor Registers (Addr = 0 and 1, DLAB = 1)
The Divisor Latch LS (least significant byte) and Divisor Latch MS (most significant
byte) are two read-write registers at locations 0 and 1 when DLAB = 1, respect i vel y .
The baud rate is selected by loading each divisor latch with the appropriate hex value.
Programmable values corresponding to the desired baud rate are listed in Table 5-3.
1. SCR - Scratch Register (Addr = 7)
The Scratchpad Register is a read-write register at location 7. This register is not used by
the modem and can be use d by the host for t emporary storage.
Table 5-3. Programmable Baud Rates
Divisor Latch (Hex)
MS LS Divisor (Decimal) Baud Rate
06 00 1536 75
04 17 1047 110
03 00 768 150
01 80 384 300
00 C0 192 600
00 60 96 1200
00 30 48 2400
00 18 24 4800
00 0C 12 9600
00 06 6 19200
00 04 4 28800
00 03 3 38400
00 02 2 57600
00 01 1 115200
00 00 NA 230400
5.3 Receiver FIFO Interrupt Operation
5.3.1 Receiver Data Available Interrupt
When the FIFO mode is enabled (FCR0 = 1) and receiver interrupt (RX Data Available)
is enabled (IER0 = 1), receiver interrupt operation is as follows:
The Receiver Data Available Flag (LSR0) is set as soon as a received data character is
available in the RX FIFO. LSR0 is cleared when the RX FIFO is empty.
The Receiver Data Available interrupt code (IIR0-IIR4 = 4h) is set whenever the number
of received data bytes in the RX FIFO reaches the trigger level specified by FCR6-FCR7
bits; it is cleared whenever the number of received data bytes in the RX FIFO drops
below the trigger level specified by FCR6-FCR7 bits.
The HINT interrupt is asserted whenever the number of received data bytes in the RX
FIFO reaches the trigger level specified by FCR6-FCR7 bits. HINT interrupt is de-
asserted when the number of received data bytes in the RX FIFO drops below the trigger
level specified by FCR6-FCR7 bits.
CX81801-7x/8x SmartV.XX Modem Data Sheet
102199B Conexant 5-11
5.3.2 Receiver Character Timeout Interrupts
When the FIFO mode is enabled (FCR0 = 1) and receiver interrupt (Receiver Data
Available) is enabled (IER0 = 1), receiver character timeout interrupt operation is as
follows:
1. A Receiver character timeout interrupt code (IIR0-IIR3 = Ch) is set if at least one
received character is in the RX FIFO, the most recent received serial character was
longer than four continuous character times ago (if 2 stop bits are specified, the
second stop bit is included in this time period), and the most recent host read of the
RX FIFO was long er than four continuous character times ago.
5.4 Transmitter FIFO Interrupt Operation
5.4.1 Transmitter Empty Interrupt
When the FIFO mode is enabled (FCR0 = 1) and transmitter interrupt (TX Buffer Empty)
is enabled (IER0 = 1), transmitter in terrupt operation is as follows:
The TX Buffer Empty interrupt code (IIR0-IIR3 = 2h) will occur when the TX Buffer is
empty; it is cleared when the TX Buffer is written to (1 to 16 ch aracters) or the IIR is
read.
The TX Buffer Empty indications will be delayed 1 character time minus the last stop bit
time whenever the following occur: THRE = 1 and there have not been at least two bytes
at the same time in the TX FIFO Buffer since the last setting of THRE was set. The first
transmitter interrupt after setting FCR0 will be immediate.
CX81801-7x/8x SmartV.XX Modem Data Sheet
5-12 Conexant 102199B
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NOTES
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