CC2550RSTG3 - Texas Instruments

CC2550

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CC2550

Low-Cost Low-Power 2.4 GHz RF Transmitter

Applications

• 2400-2483.5 MHz ISM/SRD band systems

• Consumer electroni cs

• Wireless gam e controllers

• Wireless audi o

• RF enabled remote controls

Product Description

The

CC2550

is a low-cost 2.4 GHz transmitter

designed for very low-power wireless appli-

cations. The circuit is intended for the 2400-

2483.5 MHz ISM (Industrial, Scientific and

Medical) and SRD (Short Range Device) freq-

uency band.

The RF transmitter is integrated with a highly

configurable baseband modulator. The

modulator supports various modulation

formats and has a configurable data rate up to

500 kBaud.

The

CC2550

provides extensive hardware

support for packet handling, data buffering and

burst transmissions.

The main operating parameters and the 64-

byte transmit FIFO of

CC2550

can be controlled

via an SPI interface. In a typical system, the

CC2550

will be used together with a micro-

controller and a few passive components.

Key Features

RF Performance

• Programmable output power up to +1 dBm

• Programmable data rate from 1.2 to 500

kBaud

• Frequency range: 2400 – 2483.5 MHz

Analog Features

• OOK, 2-FSK, GFSK, and MSK supported

• Suitable for frequency hopping and multi-

channel systems due to a fast settling

frequency synthesizer with 90 us settling

time

• Integrated analog temperature sensor

Digital Features

• Flexible support for packet oriented

systems: On-chip support for sync word

insertion, flexible packet length, and

automatic CRC handling

• Efficient SPI interface: All registers can be

programmed with one “burst” transfer

• Optional automatic whitening of data

Low-Power Features

• 200 nA SLEEP mode current consumption

• Fast startup time: 240 us from SLEEP to

TX mode (measured on EM design [3])

• 64-byte TX data FIFO (enables burst

mode data transmission)

General

• Few external components: Complete on-

chip frequency synthesizer, no external

filters needed

• Green package: RoHS compliant and no

antimony or bromine

• Small size (QLP 4x4 mm package, 16

pins)

• Suited for systems compliant with EN 300

328 and EN 300 440 class 2 (Europe),

FCC CFR47 Part 15 (US), and ARIB STD-

T66 (Japan)

• Support for asynchronous and

synchronous serial transmit mode for

backwards compatibility with existing radio

communication protocols

CC2550

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Table of Contents

APPLICATIONS...........................................................................................................................................1

PRODUCT DESCRIPTION.........................................................................................................................1

KEY FEATURES..........................................................................................................................................1

RF PERFORMANCE ...................................................................................................................................1

ANALOG FEATURES .................................................................................................................................1

DIGITAL FEATURES..................................................................................................................................1

LOW-POWER FEATURES............................................................................................................. ............1

GENERAL .....................................................................................................................................................1

TABLE OF CONTENTS..............................................................................................................................2

ABBREVIATIONS........................................................................................................................................4

1 ABSOLUTE MAXIMU M RATINGS..............................................................................................4

2 OPERATING CONDITIONS ..........................................................................................................5

3 GENERAL CHARACTERI STICS..................................................................................................5

4 ELECTRICAL SPECIFICATIONS................................................................................................5

4.1 CURRENT CONSUMPTION .....................................................................................................................5

4.2 RF TRANSMIT SECTION........................................................................................................................6

4.3 CRYSTAL OSCILLATOR.........................................................................................................................7

4.4 FREQUENCY SYNTHESIZER CHARACTERISTICS.....................................................................................7

4.5 ANALOG TEMPERATURE SENSOR .........................................................................................................8

4.6 DC CHARACTERISTICS .........................................................................................................................8

4.7 POWER-ON RESET................................................................................................................................8

5 PIN CONFIGUR ATION...................................................................................................................9

6 CIRCUIT DESC RIPTIO N.............................................................................................................10

7 APPLICATION CI RC UIT.............................................................................................................10

8 CONFIGURATION OVERVIEW.................................................................................................13

9 CONFIGURATION SOFTWARE.................................................................................................14

10 4-WIRE SERIAL CONFIGURATION AND DATA IN TERFA CE...........................................14

10.1 CHIP STATUS BYTE ............................................................................................................................15

10.2 REGISTERS ACCESS ............................................................................................................................16

10.3 SPI READ ...........................................................................................................................................16

10.4 COMMAND STROBES ..........................................................................................................................17

10.5 FIFO ACCESS.....................................................................................................................................17

10.6 PATABLE ACCESS.............................................................................................................................17

11 MICROCONTROLLER INTERFACE AND PIN CONFIGURATION ...................................18

11.1 CONFIGURATION INTERFACE..............................................................................................................18

11.2 GENERAL CONTROL AND STATUS PINS ..............................................................................................18

12 DATA RATE PROGR A MMING...................................................................................................19

13 PACKET HANDLING HARDWARE SUPPORT.......................................................................19

13.1 DATA WHITENING...............................................................................................................................19

13.2 PACKET FORMAT................................................................................................................................20

13.3 PACKET HANDLING IN TRANSMIT MODE............................................................................................22

13.4 PACKET HANDLING IN FIRMWARE......................................................................................................22

14 MODULATION FORMATS..........................................................................................................22

14.1 FREQUENCY SHIFT KEYING................................................................................................................23

14.2 MINIMUM SHIFT KEYING....................................................................................................................23

14.3 AMPLITUDE MODULATION .................................................................................................................23

15 FORWARD ERRO R CORRECTION WITH INTERLEAVING..............................................23

15.1 FORWARD ERROR CORRECTION (FEC)...............................................................................................23

15.2 INTERLEAVING ...................................................................................................................................24

16 RADIO CONTROL.........................................................................................................................25

CC2550

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16.1 POWER-ON START-UP SEQUENCE......................................................................................................25

16.2 CRYSTAL CONTROL............................................................................................................................26

16.3 VOLTAGE REGULATOR CONTROL.......................................................................................................26

16.4 TX MODE...........................................................................................................................................27

16.5 TIMING ...............................................................................................................................................27

17 TX FIFO...........................................................................................................................................27

18 FREQUENCY PROGRAMMING.................................................................................................28

19 VCO..................................................................................................................................................29

19.1 VCO AND PLL SELF-CALIBRATION ...................................................................................................29

20 VOLTAGE REGULAT O R S ..........................................................................................................29

21 OUTPUT POWER PROGRAMMING.........................................................................................30

22 CRYSTAL OSCILLATOR.............................................................................................................32

22.1 REFERENCE SIGNAL ...........................................................................................................................32

23 EXTERNAL RF MATCH ..............................................................................................................32

24 PCB LAYOUT RECOMMENDATIONS......................................................................................33

25 GENERAL PURPOSE / TEST OUTPUT CONTROL PINS......................................................33

26 ASYNCHRONOUS AND SYNCH RO NO US SERI AL OPERATION.......................................34

26.1 ASYNCHRONOUS OPERATION.............................................................................................................34

26.2 SYNCHRONOUS SERIAL OPERATION ...................................................................................................35

27 SYSTEM CONSIDERATIONS AND GUIDELINES..................................................................35

27.1 SRD REGULATIONS............................................................................................................................35

27.2 FREQUENCY HOPPING AND MULTI-CHANNEL SYSTEMS.....................................................................35

27.3 WIDEBAND MODULATION NOT USING SPREAD SPECTRUM ................................................................36

27.4 DATA BURST TRANSMISSIONS............................................................................................................36

27.5 CONTINUOUS TRANSMISSIONS ...........................................................................................................36

27.6 SPECTRUM EFFICIENT MODULATION..................................................................................................36

27.7 LOW COST SYSTEMS ..........................................................................................................................36

27.8 BATTERY OPERATED SYSTEMS ..........................................................................................................36

27.9 INCREASING OUTPUT POWER .............................................................................................................37

28 CONFIGURATION REGISTERS.................................................................................................37

28.1 CONFIGURATION REGISTER DETAILS .................................................................................................41

28.2 STATUS REGISTER DETAILS................................................................................................................49

29 PACKAGE DE SCR IPTION (QLP 16)..........................................................................................52

29.1 RECOMMENDED PCB LAYOUT FOR PACKAGE (QLP 16)....................................................................53

29.2 PACKAGE THERMAL PROPERTIES .......................................................................................................53

29.3 SOLDERING INFORMATION .................................................................................................................53

29.4 TRAY SPECIFICATION .........................................................................................................................54

29.5 CARRIER TAPE AND REEL SPECIFICATION..........................................................................................54

30 ORDERING INFORMATION.......................................................................................................54

31 REFERENCES ................................................................................................................................54

32 GENERAL INFORMATION.........................................................................................................55

32.1 DOCUMENT HISTORY .........................................................................................................................55

32.2 PRODUCT STATUS DEFINITIONS .........................................................................................................56

33 ADDRESS INFOR M ATIO N..........................................................................................................57

34 TI WORLDWIDE TECHNICAL SUPPORT...............................................................................57

CC2550

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Abbreviations

Abbreviations used in this data sheet are described below.

ACP Adjacent Channel Power NA Not Applicable

ADC Analog to Digital Converter NRZ Non Return to Zero (coding)

AGC Automatic Gain Control LO Local Oscillator

AMR Automatic Meter Reading OBW Occupied Bandwidth

ARIB Association of Radio Industries and Businesses OOK On Off Keying

ASK Amplitude Shift Keying PA Power Amplifier

BER Bit Error Rate PCB Printed Circuit Board

BT Bandwidth-Time product PD Power Down

CFR Code of Federal Regulations PER Packet Error Rate

CRC Cyclic Redundancy Check PLL Phase Locked Loop

DC Direct Current POR Power-on Reset

ESR Equivalent Series Resistance QPSK Quadrature Phase Shift Keying

FCC Federal Communications Commission QLP Quad Leadless Package

FEC Forward Error Correction RF Radio Frequency

FHSS Frequency Hopping Spread Spectrum RX Receive, Receive Mode

FIFO First-In-First-Out SMD Surface Mount Device

2-FSK Frequency Shift Keying SNR Signal to Noise Ratio

GFSK Gaussian shaped Frequency Shift Keying SPI Serial Peripheral Interface

I/Q In-Phase/Quadrature SRD Short Range Device

ISM Industrial, Scientific and Medical TX Transmit, Transmit Mode

LC Inductor-Capacitor VCO Voltage Controlled Oscillator

LO Local Oscillator WLAN Wireless Local Area Networks

MCU Microcontroller Unit XOSC Crystal Oscillator

MSB Most Significant Bit XTAL Crystal

MSK Minimum Shift Keying

1 Absolute Maximum Ratings

Under no circumstances must the absolute maximum ratings given in Table 1 be violated. Stress

exceeding one or more of the limiting values may cause permanent damage to the device.

Caution! ESD sensitive device.

Precaution should be used when handling

the device in order to prevent permanent

damage.

Parameter Min Max Units Condition/Note

Supply voltage –0.3 3.9 V All supply pins must have the same voltage

Voltage on any digital pin –0.3 VDD+0.3,

max 3.9

V

Voltage on the pins RF_P, RF_N

and DCOUPL

–0.3 2.0 V

Storage temperature range –50 150 °C

Solder reflow temperature 260 °C According to IPC/JEDEC J-STD-020D

ESD <500 V According to JEDEC STD 22, method A114,

Human Body Model

Table 1: Abso lute Maximum Rati ngs

CC2550

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2 Operating Conditions

The

CC2550

operating conditions are listed in Table 2 below.

Parameter Min Max Unit Condition/Note

Operating temperature –40 85 °C

Operating supply voltage 1.8 3.6 V All supply pins must have the same voltage

Table 2: Op eratin g Condi tions

3 General Characteristics

Parameter Min Typ Max Unit Condition/Note

Frequency range 2400 2483.5 MHz

Data rate 1.2

1.2

26

500

250

500

kBaud

2-FSK

GFSK and OOK

(Shaped) MSK (also known as differential offset QPSK)

Optional Manchester encoding (the data rate in kbps will

be half the baud rate).

Table 3: General Characteristics

4 Electrical Specifications

4.1 Current Consumption

Tc = 25°C, VDD = 3.0 V if nothing else stated. All measurement results obtained using the CC2550EM reference design

([3]).

Parameter Min Typ Max Unit Condition/Note

200 nA

Voltage regulator to digital part off (SLEEP state). All GDO pins

programmed to 0x2F (HW to o)

Current consumption in power

down modes

160 µA Voltage regulator to digital part on, all other modules in power

down (XOFF state)

1.4 mA Only voltage regulator to digital part and crystal oscillator running

(IDLE state)

Current consumption

7.3 mA Only the frequency synthesizer is running (FSTXON state). This

current consumption is also representative for the other

intermediate states when going from IDLE to TX, including the

calibration state.

11.2 mA Transmit mode, –12 dBm output power

14.7 mA Transmit mode, -6 dBm output power

19.4 mA Transmit mode, 0 dBm output power

Current consumption, TX states

21.3 mA Transmit mode, +1 dBm output power

Table 4: Current Consumption

CC2550

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4.2 RF Transmit Section

Tc = 25°C, VDD = 3.0 V, 0 dBm if nothing else stated. All measurement results obtained using the CC2550EM reference

design ([3]).

Parameter Min Typ Max Unit Condition/Note

Differential load

impedance

80 + j74 Ω Differential impedance as seen from the RF-port (RF_P

and RF_N) towards the antenna. Follow the CC2550EM

reference design ([3]) available from the TI website.

Output power, highest

setting

+1

dBm Output power is programmable and full range is available

across the entire frequency band.

Delivered to 50 Ω single-ended load via CC2550EM

reference design ([3]) RF matching network.

Output power, lowest

setting

–30

dBm Output power is programmable and full range is available

across the entire frequency band.

Delivered to 50 Ω single-ended load via CC2550EM

reference design ([3]) RF matching network.

It is possible to program less than -30 dBm output power,

but this is not recommended due to large variation in

output power across operating conditions and processing

corners for these settings.

Adjacent channel

power (ACP) @2440

MHz

-25

-24

dBc

2.4 kBaud, 38.2 kHz deviation, 2-FSK, 250 kHz channel

spacing

10 kBaud, 38.2 kHz deviation, 2-FSK, 250 kHz channel

spacing

250 kBaud, MSK, 750 kHz channel spacing

500 kBaud, MSK, 1 MHz channel spacing

Spurious emissions

25 MHz – 1 GHz

47-74, 87.5-118, 174-

230, 470-862 MHz

1800-1900 MHz

At 2·RF and 3·RF

Otherwise above 1

GHz

–36

–54

–47

–41

–30

dBm

Restricted band in Europe

Restricted bands in USA

TX latency 8 bit Serial operation. Time from sampling the data on the

transmitter data input pin until it is observed on the RF

output ports.

Table 5: RF Transmit Parameters

CC2550

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4.3 Crystal Oscillator

Tc = 25°C, VDD = 3.0 V if nothing else stated. All measurement results obtained using the CC2550EM reference design

([3]).

Parameter Min Typ Max Unit Condition/Note

Crystal frequency 26 26 27 MHz

Tolerance ±40 ppm This is the total tolerance including a) initial tolerance, b) crystal

loading, c) aging and d) temperature dependence.

The acceptable crystal tolerance depends on RF frequency and

channel spacing / bandwidth.

ESR 100

Ω

Start-up time 150 µs Measured on CC2500EM reference design ([3]) using crystal

AT-41CD2 from NDK.

This parameter is to a large degree crystal dependent.

Table 6: Crystal Oscillator Parameters

4.4 Frequency Synthesizer Characteristics

Tc = 25°C, VDD = 3.0 V if nothing else stated. All measurement results obtained using the CC2550EM reference design

([3]). Min figures are given using a 27 MHz crystal. Typ and max figures are given using a 26 MHz crystal.

Parameter Min Typ Max Unit Condition/Note

Programmed

frequency resolution

397 FXOSC/

216

427 Hz 26-27 MHz crystal.

Synthesizer frequency

tolerance

±40 ppm Given by crystal used. Required accuracy (including

temperature and aging) depends on frequency band and

channel bandwidth / spacing.

–74 dBc/Hz @ 50 kHz offset from carrier

–74 dBc/Hz @ 100 kHz offset from carrier

–77 dBc/Hz @ 200 kHz offset from carrier

–97 dBc/Hz @ 1 MHz offset from carrier

–106 dBc/Hz @ 2 MHz offset from carrier

–114 dBc/Hz @ 5 MHz offset from carrier

RF carrier phase noise

@2440 MHz

–117 dBc/Hz @ 10 MHz offset from carrier

PLL turn-on / hop time 85.1 88.4 88.4 µs Time from leaving the IDLE state until arriving in the

FSTXON or TX state, when not performing calibration.

Crystal oscillator running.

PLL calibration time 694 721 721 µs Calibration can be initiated manually or automatically

before entering or after leaving RX/TX.

Table 7: Frequency Synthesizer Parameters

CC2550

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4.5 Analog Temperature Sensor

The characteristics of the analog temperature sensor at 3.0 V supply voltage are listed in Table 8

below. Note that it is necessary to write 0xBF to the PTEST register to use the analog temperature

sensor in the IDLE state.

Parameter Min Typ Max Unit Condition/Note

Output voltage at –40°C 0.660 V

Output voltage at 0°C 0.755 V

Output voltage at +40°C 0.859 V

Output voltage at +80°C 0.958 V

Temperature coefficient 2.54 mV/°C Fitted from –20°C to +80°C

Error in calculated

temperature, calibrated

-2 * 0 2

* °C From –20°C to +80°C when using 2.54 mV / °C,

after 1-point calibration at room temperature

* The indicated minimum and maximum error with 1-

point calibration is based on simulated values for

typical process parameters

Current consumption

increase when enabled

0.3 mA

Table 8: Analog Temperature Sensor Parameters

4.6 DC Characteristics

Tc = 25°C if nothing else stated.

Digital Inputs/Outputs Min Max Unit Condition/Note

Logic "0" input voltage 0 0.7 V

Logic "1" input voltage VDD-0.7 VDD V

Logic "0" output voltage 0 0.5 V For up to 4 mA output current

Logic "1" output voltage VDD-0.3 VDD V For up to 4 mA output current

Logic "0" input current NA -50 nA Input equals 0 V

Logic "1" input current NA 50 nA Input equals VDD

Table 9: DC Characteristics

4.7 Power-On Reset

When the power supply complies with the requirements in Table 10 below, proper Power-On-

Reset functionality is guaranteed. Otherwise, the chip should be assumed to have unknown state

until transmitting an SRES strobe over the SPI interface. See Section 16.1 on page 25 for further

details.

Parameter Min Typ Max Unit Condition/Note

Power-up ramp-up time 5 ms From 0 V until reaching 1.8 V

Power off time 1 ms Minimum time between power off and power-on.

Table 10: Power-on Reset Requirements

CC2550

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5 Pin Configuration

GND

Exposed die

attach pad

5

XOSC_Q1

6

AVDD

7

XOSC_Q2

8

GDO0 (ATEST)

9CSn

10 RF_P

11 RF_N

12 AVDD

13

AVDD

14

RBIAS

15

DGUARD

16

SI

1SCLK

2SO (GDO1)

3DVDD

4DCOUPL

Figure 1: Pinout Top View

Note: The exposed die attach pad must be connected to a solid ground plane as this is the main

ground connection for the chip.

Pin # Pin Name Pin Type Description

1 SCLK Digital Input Serial configuration interface, clock input

2 SO (GDO1) Digital Output Serial configuration interface, data output.

Optional general output pin when CSn is high

3 DVDD Power (Digital) 1.8 - 3.6 V digital power supply for digital I/O’s and for the digital core

voltage regulator

4 DCOUPL Power (Digital) 1.6 - 2.0 V digital power supply output for decoupling.

NOTE: This pin is intended for use with the

CC2550

only. It can not be

used to provide supply voltage to other devices.

5 XOSC_Q1 Analog I/O Crystal oscillator pin 1, or external clock input

6 AVDD Power (Analog) 1.8 - 3.6 V analog power supply connection

7 XOSC_Q2 Analog I/O Crystal oscillator pin 2

8 GDO0

(ATEST)

Digital I/O

Digital output pin for general use:

• Test signals

• FIFO status signals

• Clock output, down-divided from XOSC

• Serial input TX data

Also used as analog test I/O for prototype/production testing

9 CSn Digital Input Serial configuration interface, chip select

10 RF_P RF Output Positive RF output signal from PA

11 RF_N RF Output Negative RF output signal from PA

12 AVDD Power (Analog) 1.8 - 3.6 V analog power supply connection

13 AVDD Power (Analog) 1.8 - 3.6 V analog power supply connection

14 RBIAS Analog I/O External bias resistor for reference current

15 DGUARD Power (Digital) Power supply connection for digital noise isolation

16 SI Digital Input Serial configuration interface, data input

Table 11: Pinout Overview

CC2550

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6 Circuit Description

BIAS

XOSC_Q1 XOSC_Q2

XOSC

FREQ

SYNTH

RADIO CONTROL

RF_P

RF_N

CSn

SI

SO (GDO1)

SCLK

GDO0 (ATEST)

RBIAS

PA

FEC /

INTERLEAVER

PACKET

HANDLER

MODULATOR

TX FIFO

DIGITAL

INTERFACE

TO MCU

Figure 2:

CC2550

Simplifi ed Blo ck Dia gram

A simplified block diagram of

CC2550

is shown

in Figure 2.

The

CC2550

transmitter is based on direct

synthesis of the RF frequency.

The frequency synthesizer includes a

completely on-chip LC VCO.

A crystal is to be connected to XOSC_Q1 and

XOSC_Q2. The crystal oscillator generates the

reference frequency for the synthesizer, as

well as clocks for the digital part.

A 4-wire SPI serial interface is used for

configuration and data buffer access.

The digital baseband includes support for

channel configuration, packet handling and

data buffering.

7 Application Circuit

Only a few external components are required

for using the

CC2550

. The recommended

application circuit is shown in Figure 3. The

external components are described in Table

12, and typical values are given in Table 13.

Bias resistor

The bias resistor R141 is used to set an

accurate bias current.

Balun and RF matching

The components between the RF_N/RF_P pins

and the point where the two signals are joined

together (C102, C112, L101, and L111) form a

balun that converts the differential RF signal

on

CC2550

to a single-ended RF signal. C101

and C111 are needed for DC blocking.

Together with an appropriate LC network, the

balun components also transform the

impedance to match a 50 Ω antenna (or

cable). Suggested values are listed in Table

13.

The balun and LC filter component values and

their placement are important to keep the

performance optimized. It is highly

recommended to follow the CC2550EM

reference design ([3]).

Crystal

The crystal oscillator uses an external crystal

with two loading capacitors (C51 and C71).

See Section 22 on page 32 for details.

Power supply decoupling

The power supply must be properly decoupled

close to the supply pins. Note that decoupling

capacitors are not shown in the application

circuit. The placement and the size of the

decoupling capacitors are very important to

achieve the optimum performance. The

CC2550EM reference design ([3]) should be

followed closely.

CC2550

SWRS039B Page 11 of 58

Component Description

C41 Decoupling capacitor for on-chip voltage regulator to digital part

C51/C71 Crystal loading capacitors, see Section 22 on page 32 for details

C101/C111 RF balun DC blocking capacitors

C102/C112 RF balun/matching capacitors

C103/C104 RF LC filter/matching capacitors

L101/L111 RF balun/matching inductors (inexpensive multi-layer type)

L102 RF LC filter inductor (inexpensive multi-layer type)

R141 Resistor for internal bias current reference

XTAL 26-27 MHz crystal, see Section 22 on page 32 for details

Table 12: Overview of External Components (excluding supply decoupling capacitors)

Antenna

(50 Ohm)

Digital Inteface

1.8V-3.6V power supply

8 GDO0

5

6 AVDD

7 XOSC_Q2

SI 16

DGUARD 15

RBIAS 14

AVDD

13

1 SCLK

2 SO (GDO1)

3 DVDD

4

AVDD 12

RF_N 11

RF_P 10

CSn 9

XTAL

C102

C112

L111

L101 L102

C103 C104

R141

C51 C71

C41

CSn

GDO0

(optional)

SO

(GDO1)

SCLK

SI

CC2550

DIE ATTACH PAD:

C111

C101

DCOUPL

XOSC_Q1

Alternative:

Folded dipole PCB

antenna (no external

components needed)

Figure 3: Typical Application and Evaluation Circuit (excluding supply decoupling capacitors)

CC2550

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Component Value Manufacturer

C41 100 nF±10%, 0402 X5R Murata GRM15 series

C51 27 pF±5%, 0402 NP0 Murata GRM15 series

C71 27 pF±5%, 0402 NP0 Murata GRM15 series

C101 100 pF±5%, 0402 NP0 Murata GRM15 series

C102 1.0 pF±0.25pF, 0402 NP0 Murata GRM15 series

C103 1.8 pF±0.25pF, 0402 NP0 Murata GRM15 series

C104 1.5 pF±0.25pF, 0402 NP0 Murata GRM15 series

C111 100 pF±5%, 0402 NP0 Murata GRM15 series

C112 1.0 pF±0.25pF, 0402 NP0 Murata GRM15 series

L101 1.2 nH±0.3nH, 0402 monolithic Murata LQG15 series

L102 1.2 nH±0.3nH, 0402 monolithic Murata LQG15 series

L111 1.2 nH±0.3nH, 0402 monolithic Murata LQG15 series

R141 56 kΩ±1%, 0402 Koa RK73 series

XTAL 26.0 MHz surface mount crystal NDK, AT-41CD2

Table 13: Bill of Materials for the Applicati on Circuit

Measurements have been performed with

multi-layer inductors from other manufacturers

(e.g. Würth) and the measurement results

were the same as when using the Murata part.

The Gerber files for the CC2550EM reference

design ([3]) are available from the TI website.

CC2550

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8 Configuration Overview

CC2550

can be configured to achieve optimum

performance for many different applications.

Configuration is done using the SPI interface.

The following key parameters can be

programmed:

• Power-down / power up mode

• Crystal oscillator power-up / power – down

• Transmit mode

• RF channel selection

• Data rate

• Modulation format

• RF output power

• Data buffering with 64-byte transmit FIFO

• Packet radio hardware support

• Forward Error Correction (FEC) with

interleaving

• Data Whitening

Details of each configuration register can be

found in Section 28, starting on page 37.

Figure 4 shows a simplified state diagram that

explains the main

CC2550

states, together with

typical usage and current consumption. For

detailed information on controlling the

CC2550

state machine, and a complete state diagram,

see Section 16, starting on page 25.

Figure 4: Simplified State Diagram with Typical Current Consumption

CC2550

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9 Configuration Software

CC2550

can be configured using the SmartRF®

Studio software ([4]). The SmartRF® Studio

software is highly recommended for obtaining

optimum register settings, and for evaluating

performance and functionality. A screenshot of

the SmartRF® Studio user interface for

CC2550

is shown in Figure 5.

After chip reset, all the registers have default

values as shown in the tables in Section 28.

The optimum register setting might differ from

the default value. After a reset all registers that

shall be different from the default value

therefore needs to be programmed through the

SPI interface.

Figure 5: SmartRF® Studio [4] User Interface

10 4-wire Serial Configuration and Data Interface

CC2550

is configured via a simple 4-wire SPI-

compatible interface (SI, SO, SCLK and CSn)

where

CC2550

is the slave. This interface is

also used to write buffered data. All transfer on

the SPI interface are done most significant bit

first.

All transactions on the SPI interface start with

a header byte containing a R/W bit, a burst

access bit (B), and a 6-bit address (A5 – A0).

The CSn pin must be kept low during transfers

on the SPI bus. If CSn goes high during the

transfer of a header byte or during read/write

from/to a register, the transfer will be

cancelled. The timing for the address and data

transfer on the SPI interface is shown in Figure

6 with reference to Table 14.

When CSn is pulled low, the MCU must wait

until

CC2500

SO pin goes low before starting to

transfer the header byte. This indicates that

the crystal is running. Unless the chip was in

the SLEEP or XOFF states, the SO pin will

always go low immediately after taking CSn

low.

CC2550

SWRS039B Page 15 of 58

0A5 A4 A3 A2 A0A1 DW7

1

Read from register:

Writ e to reg ist er:

Hi-Z

X

SCLK:

CSn:

SI

SO

SI

SO Hi-Z

tsp tch tcl tsd thd tns

XX

Hi-Z

X

Hi-ZS7

X

DW6D

W5D

W4D

W3D

W2D

W1D

W0

BS5

S4 S3 S2 S1 S0 S7 S6 S5 S4 S3 S2 S1 S0

B

B A5A4A3A2A1A0

S7 B S5S4S3S2S1S0 D

R7D

R6D

R5D

R4D

R3D

R2D

R1D

R0

Figure 6: Configuration Registers Write and Read Operations

Parameter Description Min Max Units

SCLK frequency

100 ns delay inserted between address byte and data byte (single access), or between

address and data, and between each data byte (burst access).

- 10 MHz

SCLK frequency, single access

No delay between address and data byte 9 MHz

fSCLK

SCLK frequency, burst access

No delay between address and data byte, or between data bytes 6.5 MHz

tsp,pd CSn low to positive edge on SCLK, in power-down mode 150 - µs

tsp CSn low to positive edge on SCLK, in active mode 20 - ns

tch Clock high 50 - ns

tcl Clock low 50 - ns

trise Clock rise time - 5 ns

tfall Clock fall time - 5 ns

Single access 55 - ns tsd Setup data (negative SCLK edge) to

positive edge on SCLK

(tsd applies between address and data bytes, and

between data bytes)

Burst access 76 - ns

thd Hold data after positive edge on SCLK 20 - ns

tns Negative edge on SCLK to CSn high 20 - ns

Table 14: SPI Interface Timing Requirements

Note: The minimum tsp,pd figure in Table 14 can be used in cases where the user does not read the

CHIP_RDYn signal. CSn low to positive edge on SCLK when the chip is woken from power-down

depends on the start-up time of the crystal being used. The 150 us in Table 14 is the crystal oscillator

start-up time measured on CC2550EM reference design ([3]) using crystal AT-41CD2 from NDK.

10.1 Chip Status Byte

When the header byte, data byte, or command

strobe is sent on the SPI interface, the chip

status byte is sent by the

CC2550

on the SO

pin. The status byte contains key status

signals, useful for the MCU. The first bit, s7, is

the CHIP_RDYn signal; this signal must go low

before the first positive edge of SCLK. The

CHIP_RDYn signal indicates that the crystal is

running.

Bits 6, 5, and 4 comprise the STATE value.

This value reflects the state of the chip. The

XOSC and power to the digital core is on in the

IDLE state, but all other modules are in power

CC2550

SWRS039B Page 16 of 58

down. The frequency and channel

configuration should only be updated when the

chip is in this state. The TX state is active

when the chip is transmitting.

The last four bits (3:0) in the status byte

contains FIFO_BYTES_AVAILABLE. For write

operations (the R/W bit in the header byte is

set to 0), the FIFO_BYTES_AVAILABLE field

contains the number of bytes that can be

written to the TX FIFO. When

FIFO_BYTES_AVAILABLE=15, 15 or more

bytes are available/free.

Table 15 gives a status byte summary.

Bits Name Description

7 CHIP_RDYn Stays high until power and crystal have stabilized. Should always be low when using

the SPI interface.

6:4 STATE[2:0] Indicates the current main state machine mode

Value State Description

000 IDLE Idle state

(Also reported for some transitional states

instead of SETTLING or CALIBRATE)

001 Not used

010 TX Transmit mode

011 FSTXON Frequency synthesizer is on, ready to start

transmitting

100 CALIBRATE Frequency synthesizer calibration is running

101 SETTLING PLL is settling

110 Not used

111 TXFIFO_UNDERFLOW TX FIFO has underflowed. Acknowledge with

SFTX

3:0 FIFO_BYTES_AVAILABLE[3:0] The number of free bytes in the TX FIFO (the R/W bit in the header byte must be set

to 0)

Table 15: Status Byte Summary

10.2 Registers Access

The configuration registers on the

CC2550

are

located on SPI addresses from 0x00 to 0x2E.

Table 24 on page 39 lists all configuration

registers. It is highly recommended to use

SmartRF® Studio [4] to generate optimum

register settings. The detailed description of

each register is found in Section 28.1, starting

on page 41. All configuration registers can be

both written to and read. The R/W bit controls

if the register should be written to or read.

When writing to registers, the status byte is

sent on the SO pin each time a header byte or

data byte is transmitted on the SI pin. When

reading from registers, the status byte is sent

on the SO pin each time a header byte is

transmitted on the SI pin.

Registers with consecutive addresses can be

accessed in an efficient way by setting the

burst bit (B) in the header byte. The address

bits (A5 – A0) sets the start address in an

internal address counter. This counter is

incremented by one each new byte (every 8

clock pulses). The burst access is either a

read or a write access and must be terminated

by setting CSn high.

For register addresses in the range 0x30-

0x3D, the burst bit is used to select between

status registers, burst bit is one, and command

strobes, burst bit is zero (see Section 10.4

below). Because of this, burst access is not

available for status registers and they must be

accessed one at a time. The status registers

can only be read.

10.3 SPI Read

When reading register fields over the SPI

interface while the register fields are updated

CC2550

SWRS039B Page 17 of 58

by the radio hardware (e.g. MARCSTATE or

TXBYTES), there is a small, but finite,

probability that a single read from the register

is being corrupt. As an example, the probability

of any single read from TXBYTES being

corrupt, assuming the maximum data rate is

used, is approximately 80 ppm. Refer to the

CC2550

Errata Note [1] for more details.

10.4 Command Strobes

Command strobes may be viewed as single

byte instructions to

CC2550

. By addressing a

command strobe register, internal sequences

will be started. These commands are used to

disable the crystal oscillator, enable transmit

mode, flush the TX FIFO etc. The 9 command

strobes are listed in Table 23 on page 38.

The command strobe registers are accessed

by transferring a single header byte (no data is

being transferred). That is, only the R/W bit,

the burst access bit (set to 0), and the six

address bits (in the range 0x30 through 0x3D)

are written.

When writing command strobes, the status

byte is sent on the SO pin.

A command strobe may be followed by any

other SPI access without pulling CSn high.

However, if an SRES strobe is being issued,

one will have to wait for SO to go low again

before the next header byte can be issued as

shown in Figure 7. The command strobes are

executed immediately, with the exception of

the SPWD and the SXOFF strobes that are

executed when CSn goes high.

Figure 7: SRES Command Strobe

10.5 FIFO Access

The 64-byte TX FIFO is accessed through the

0x3F address and is write-only.

The burst bit is used to determine if the FIFO

access is a single byte access or a burst

access. The single byte access method

expects a header byte with the burst bit set to

zero and one data byte. After the data byte a

new header byte is expected; hence, CSn can

remain low. The burst access method expects

one header byte and then consecutive data

bytes until terminating the access by setting

CSn high.

The following header bytes access the FIFO:

• 0x3F: Single byte access to TX FIFO

• 0x7F: Burst access to TX FIFO

When writing to the TX FIFO, the status byte

(see Section 10.1) is output for each new data

byte on SO, as shown in Figure 6. This status

byte can be used to detect TX FIFO underflow

while writing data to the TX FIFO. Note that

the status byte contains the number of bytes

free before writing the byte in progress to the

TX FIFO. When the last byte that fits in the TX

FIFO is transmitted on SI, the status byte

received concurrently on SO will indicate that

one byte is free in the TX FIFO.

The TX FIFO may be flushed by issuing a

SFTX command strobe. A SFTX command

strobe can only be issued in the IDLE or

TX_UNDERFLOW states. The TX FIFO is

flushed when going to the SLEEP state.

Figure 8 gives a brief overview of different

register access types possible.

10.6 PATABLE Access

The 0x3E address is used to access the

PATABLE, which is used for selecting PA

power control settings. The PATABLE is an 8-

byte table, but not all entries into this table are

used. The entries to use are selected by the 3-

bit value FREND0.PA_POWER.

• When using 2-FSK, GFSK, or MSK

modulation only the first entry into this

table is used (index 0).

• When using OOK modulation the first two

entries into this table are used (index 0

and index 1).

Since the PATABLE is an 8-byte table, the

table is written and read from the lowest

setting (0) to the highest (7), one byte at a

time. An index counter is used to control the

access to the table. This counter is

incremented each time a byte is read or written

to the table, and set to the lowest index when

CSn is high. When the highest value is

reached the counter restarts at 0.

CC2550

SWRS039B Page 18 of 58

The access to the PATABLE is either single

byte or burst access depending on the burst

bit. When using burst access the index counter

will count up; when reaching 7 the counter will

restart at 0. The R/W bit controls whether the

access is a write access (R/W=0) or a read

access (R/W=1).

If one byte is written to the PATABLE and this

value is to be read out then CSn must be set

high before the read access in order to set the

index counter back to zero.

Note that the content of the PATABLE is lost

when entering the SLEEP state.

See Section 21 on page 30 for output power

programming details.

Figure 8: Register Access Types

11 Microcontroller Interface and Pin Configuration

In a typical system,

CC2550

will interface to a

microcontroller. This microcontroller must be

able to:

• Program

CC2550

into different modes

• Write buffered data

• Read back status information via the 4-wire

SPI-bus configuration interface (SI, SO,

SCLK and CSn)

11.1 Configuration Interface

The microcontroller uses four I/O pins for the

SPI configuration interface (SI, SO, SCLK and

CSn). The SPI is described in Section 14 on

page 14.

11.2 General Control and Status Pins

The

CC2550

has one dedicated configurable

pin (GDO0) and one shared pin (GDO1) that can

output internal status information useful for

control software. These pins can be used to

generate interrupts on the MCU. See Section

25 page 33 for more details of the signals that

can be programmed. GDO1 is shared with the

SO pin in the SPI interface. The default setting

for GDO1/SO is 3-state output. By selecting

any other of the programming options the

GDO1/SO pin will become a generic pin. When

CSn is low, the pin will always function as a

normal SO pin.

In the synchronous and asynchronous serial

modes, the GDO0 pin is used as a serial TX

data input pin while in transmit mode.

The GDO0 pin can also be used for an on-chip

analog temperature sensor. By measuring the

voltage on the GDO0 pin with an external ADC,

the temperature can be calculated.

Specifications for the temperature sensor are

found in Section 4.5 on page 8.

With default PTEST register setting (0x7F) the

temperature sensor output is only available

when the frequency synthesizer is enabled

(e.g. the MANCAL, FSTXON and TX states).

It is necessary to write 0xBF to the PTEST

register to use the analog temperature sensor

in the IDLE state. Before leaving the IDLE

state, the PTEST register should be restored to

its default value (0x7F).

CC2550

SWRS039B Page 19 of 58

12 Data Rate Programming

The data rate used when transmitting is

programmed by the MDMCFG3.DRATE_M and

the MDMCFG4.DRATE_E configuration

registers. The data rate is given by the formula

below. As the formula shows, the programmed

data rate depends on the crystal frequency.

()

XOSC

EDRATE

DATA f

MDRATE

R⋅

⋅+

=28

_

22_256

The following approach can be used to find

suitable values for a given data rate:

256

2

_

2

log_

_

28

20

2

−

⋅

=

⎥

⎦

⎥

⎢

⎣

⎢

⎟

⎠

⎞

⎜

⎝

⎛⋅

=

EDRATE

XOSC

DATA

XOSC

DATA

f

R

MDRATE

f

R

EDRATE

If DRATE_M is rounded to the nearest integer

and becomes 256, increment DRATE_E and

use DRATE_M=0.

The data rate can be set from 1.2 kBaud to

500 kBaud with a minimum step size of:

Data Rate

Start

[kBaud]

Typical

Data Rate

[kBaud]

Data Rate

Stop

[kBaud]

Data Rate

Step Size

[kBaud]

0.8 1.2/2.4 3.17 0.0062

3.17 4.8 6.35 0.0124

6.35 9.6 12.7 0.0248

12.7 19.6 25.4 0.0496

25.4 38.4 50.8 0.0992

50.8 76.8 101.6 0.1984

101.6 153.6 203.1 0.3967

203.1 250 406.3 0.7935

406.3 500 500 1.5869

Table 16: Data Rate Step Size

13 Packet Handling Hardware Support

The

CC2550

has built-in hardware support for

packet oriented radio protocols.

In transmit mode, the packet handler can be

configured to add the following elements to the

packet stored in the TX FIFO:

• A programmable number of preamble

bytes

• A two byte synchronization (sync) word.

Can be duplicated to give a 4-byte sync

word. It is not possible to only insert

preamble or only insert a sync word.

• A CRC checksum computed over the data

field.

In a system where

CC2550

is used as the

transmitter and

CC2500

as the receiver, the

recommended setting is 4-byte preamble and

4-byte sync word, except for 500 kBaud data

rate where the recommended preamble length

is 8 bytes.

In addition, the following can be implemented

on the data field and the optional 2-byte CRC

checksum:

• Whitening of the data with a PN9

sequence.

• Forward error correction by the use of

interleaving and coding of the data

(convolutional coding).

Note that register fields that control the packet

handling features should only be altered when

CC2550

is in the IDLE state.

13.1 Data whitening

From a radio perspective, the ideal over the air

data are random and DC free. This results in

the smoothest power distribution over the

occupied bandwidth. This also gives the

regulation loops in the receiver uniform

operation conditions (no data dependencies).

Real world data often contain long sequences

of zeros and ones. Performance can then be

improved by whitening the data before

transmitting, and de-whitening the data in the

receiver. With

CC2550

, in combination with a

CC2500

at the receiver end, this can be done

automatically by setting PKTCTRL0

CC2550

SWRS039B Page 20 of 58

.WHITE_DATA=1. All data, except the

preamble and the sync word, are then XOR-ed

with a 9-bit pseudo-random (PN9) sequence

before being transmitted as shown in Figure 9.

At the receiver end, the data are XOR-ed with

the same pseudo-random sequence. This way,

the whitening is reversed, and the original data

appear in the receiver. The PN9 sequence is

reset to all 1’s.

Data whitening can only be used when

PKTCTRL0.CC2400_EN=0 (default).

Figure 9: Data Whitening in TX Mode

13.2 Packet Format

The format of the data packet can be

configured and consists of the following items

(see Figure 10):

• Preamble

• Synchronization word

• Optional length byte

• Optional address byte

• Payload

• Optional 2 byte CRC

Preamble bits

(1010...1010)

Sync word

Length field

Address field

Data field

CRC-16

Optional CRC-16 calculation

Optionally FEC encoded/decoded

8 x n bits 16/32 bits 8

bits

8

bits 8 x n bits 16 bits

Optional data whitening Legend:

Inserted automatically in TX,

processed and removed in RX.

Optional user-provided fields processed in TX,

processed but not removed in RX.

Unprocessed user data (apart from FEC

and/or whitening)

Figure 10: Packet Format

The preamble pattern is an alternating

sequence of ones and zeros (101010101…).

The minimum length of the preamble is

programmable. When enabling TX, the

modulator will start transmitting the preamble.

When the programmed number of preamble

bytes has been transmitted, the modulator will

send the sync word and then data from the TX

FIFO if data is available. If the TX FIFO is

empty, the modulator will continue to send

preamble bytes until the first byte is written to

the TX FIFO. The modulator will then send the

CC2550

SWRS039B Page 21 of 58

sync word and then the data bytes. The

number of preamble bytes is programmed with

the MDMCFG1.NUM_PREAMBLE value.

The synchronization word is a two-byte value

set in the SYNC1 and SYNC0 registers. A one-

byte sync word can be emulated by setting the

SYNC1 value to the preamble pattern. It is also

possible to emulate a 32 bit sync word by

using MDMCFG2.SYNC_MODE=3 or 7. The sync

word will then be repeated twice.

CC2550

supports both fixed packet length

protocols and variable packet length protocols.

Variable or fixed packet length mode can be

used for packets up to 255 bytes. For longer

packets, infinite packet length mode must be

used.

Fixed packet length mode is selected by

setting PKTCTRL0.LENGTH_CONFIG=0. The

desired packet length is set by the PKTLEN

register.

In variable packet length mode,

PKTCTRL0.LENGTH_CONFIG=1, the packet

length is configured by the first byte after the

sync word. The packet length is defined as the

payload data, excluding the length byte and

the optional automatic CRC.

With PKTCTRL0.LENGTH_CONFIG=2, the

packet length is set to infinite and transmission

will continue until turned off manually. As

described in the next section, this can be used

to support packet formats with different length

configuration than natively supported by

CC2550

. One should make sure that TX mode

is not turned off during the transmission of the

first half of any byte. Refer to the

CC2550

Errata Notes [1] for more details.

Note that the minimum packet length

supported (excluding the optional length byte

and CRC) is one byte of payload data.

13.2.1 Packet Length > 255

Reprogramming the packet automation control

register, PCKCTRL0, during TX mode opens

the possibility to transmit packets that are

longer than 256 bytes and still be able to use

the packet handling hardware support. At the

start of the packet, the infinite packet length

mode (PCKCTRL0.LENGTH_CONFIG=2) must

be active. The PKTLEN register is set to

mod(length, 256). When less than 256 bytes

remains of the packet the MCU disables

infinite packet length mode and activates fixed

packet length mode. When the internal byte

counter reaches the PKTLEN value, the

transmission ends the radio enters the state

determined by TXOFF_MODE). Automatic CRC

appending can be used (by setting

PKTCTRL0.CRC_EN=1).

When for example a 600-byte packet is to be

transmitted, the MCU should do the following

(see also Figure 11):

• Set PKTCTRL0.LENGTH_CONFIG=2.

• Pre-program the PKTLEN register to

mod(600,256)=88.

• Transmit at least 345 bytes (600 – 255),

for example by filling the 64-byte TX FIFO

six times (384 bytes transmitted).

• Set PKTCTRL0.LENGTH_CONFIG=0.

• The transmission ends when the packet

counter reaches 88. A total of 600 bytes

are transmitted.

Figure 11: Packet Length > 255

CC2550

SWRS039B Page 22 of 58

13.3 Packet Handling in Transmit Mode

The payload that is to be transmitted must be

written into the TX FIFO. The first byte written

must be the length byte when variable packet

length is enabled. The length byte has a value

equal to the payload of the packet (including

the optional address byte). If fixed packet

length is enabled, then the first byte written to

the TX FIFO is interpreted as the destination

address, if this feature is enabled in the device

that receives the packet.

The modulator will first send the programmed

number of preamble bytes. If data is available

in the TX FIFO, the modulator will send the

two-byte (optionally 4-byte) sync word and

then the payload in the TX FIFO. If CRC is

enabled, the checksum is calculated over all

the data pulled from the TX FIFO and the

result is sent as two extra bytes at the end of

the payload data. If the TX FIFO runs empty

before the complete packet has been

transmitted, the radio will enter

TXFIFO_UNDERFLOW state. The only way to

exit this state is by issuing an SFTX strobe.

Writing to the TX FIFO after it has underflowed

will not restart TX mode.

If whitening is enabled, everything following

the sync words will be whitened. This is done

before the optional FEC/Interleaver stage.

Whitening is enabled by setting

PKTCTRL0.WHITE_DATA=1.

If FEC/Interleaving is enabled, everything

following the sync words will be scrambled by

the interleaver, and FEC encoded before being

modulated. FEC is enabled by setting

MDMCFG.FEC_EN=1.

13.4 Packet Handling in Firmware

When implementing a packet oriented radio

protocol in firmware, the MCU needs to know

when a packet has been transmitted.

Additionally, for packets longer than 64 bytes

the TX FIFO needs to be refilled while in TX.

This means that the MCU needs to know the

number of bytes that can be written to TX

FIFO. There are two possible solutions to get

the necessary status information:

a) Interrupt driven solution

It is possible to use one of the GDO pins to give

an interrupt when a sync word has been

transmitted and/or when a complete packet

has been transmitted (IOCFGx=0x06). In

addition, there are 2 configurations for the

IOCFGx register that are associated with the

TX FIFO (IOCFGx=0x02 and IOCFG=0x03)

that can be used as interrupt sources to

provide information on how many bytes are in

the TX FIFO. See Table 22.

b) SPI polling

The PKTSTATUS register can be polled at a

given rate to get information about the current

GDO0 value. The TXBYTES register can be

polled at a given rate to get information about

the number of bytes in the TX FIFO.

Alternatively, the number of bytes in the TX

FIFO can be read from the chip status byte

returned on the MISO line each time a header

byte, data byte, or command strobe is sent on

the SPI bus. This only valid when R/W = 0.

As explained in Section 10.3 and the

CC2550

Errata Notes [1], when using SPI polling there

is a small, but finite, probability that a single

read from registers PKTSTATUS and TXBYTES

is being corrupt. The same is the case when

reading the chip status byte. It is therefore

recommended to employ an interrupt driven

solution.

Refer to the TI website for SW examples ([5]

and [6]).

14 Modulation Formats

CC2550

supports amplitude, frequency and

phase shift modulation formats. The desired

modulation format is set in the

MDMCFG2.MOD_FORMAT register.

Optionally, the data stream can be Manchester

coded by the modulator. This option is enabled

by setting MDMCFG2.MANCHESTER_EN=1.

Manchester encoding is not supported at the

same time as using the FEC/Interleaver

option.

CC2550

SWRS039B Page 23 of 58

14.1 Frequency Shift Keyi ng

2-FSK can optionally be shaped by a

Gaussian filter with BT=1, producing a GFSK

modulated signal.

The frequency deviation is programmed with

the DEVIATION_M and DEVIATION_E values

in the DEVIATN register. The value has an

exponent/mantissa form, and the resultant

deviation is given by:

EDEVIATION

xosc

dev MDEVIATION

f

f_

17 2)_8(

2⋅+⋅=

The symbol encoding is shown in Table 17.

Format Symbol Coding

2-FSK\GFSK ‘0’ – Deviation

‘1’ + Deviation

Table 1 7: Symb ol Encodin g for 2 -FSK/G FSK

Modulation

14.2 Minimum Shift Keying

When using MSK1, the complete transmission

(preamble, sync word and payload) will be

MSK modulated.

Phase shifts are performed with a constant

transition time.

The fraction of a symbol period used to

change the phase can be modified with the

DEVIATN.DEVIATION_M setting. This is

equivalent to changing the shaping of the

symbol.

The MSK modulation format implemented in

CC2550

inverts the sync word and data

compared to e.g. signal generators.

14.3 Amplitude Modulation

The supported amplitude modulation On-Off

Keying (OOK) simply turns on or off the PA to

modulate 1 and 0 respectively.

1 Identical to offset QPSK with half-sine

shaping (data coding may differ)

15 Forward Error Correction with Interleaving

15.1 Forward Error Correction (FEC)

CC2550

has built in support for Forward Error

Correction (FEC) that can be used with

CC2500

[9] at the receiver end. To enable this option,

set MDMCFG1.FEC_EN=1. FEC is employed on

the data field and CRC word in order to reduce

the gross bit error rate when operating near

the sensitivity limit. Redundancy is added to

the transmitted data in such a way that the

CC2500

[9] can restore the original data in the

presence of some bit errors.

The use of FEC allows correct reception at a

lower SNR, thus extending communication

range. Alternatively, for a given SNR, using

FEC decreases the bit error rate (BER). As the

packet error rate (PER) is related to BER by:

lengthpacket

BERPER _

)1(1 −−=

a lower BER can be used to allow longer

packets, or a higher percentage of packets of

a given length, to be transmitted successfully.

Finally, in realistic ISM radio environments,

transient and time-varying phenomena will

produce occasional errors even in otherwise

good reception conditions. FEC will mask such

errors and, combined with interleaving of the

coded data, even correct relatively long

periods of faulty reception (burst errors).

The FEC scheme adopted for

CC2550

is

convolutional coding, in which n bits are

generated based on k input bits and the m

most recent input bits, forming a code stream

able to withstand a certain number of bit errors

between each coding state (the m-bit window).

The convolutional coder is a rate 1/2 code with

a constraint length of m=4. The coder codes

one input bit and produces two output bits;

hence, the effective data rate is halved. I.e. to

transmit at the same effective data rate when

using FEC, it is necessary to use twice as high

over-the-air data rate. I.e. to transmit at the

same effective data rate when using FEC, it is

necessary to use twice as high over-the-air

data rate. This will require a higher

CC2500

[9]

receiver bandwidth, and thus reduced

sensitivity. In other words, the improved

reception by using FEC and the degraded

CC2550

SWRS039B Page 24 of 58

sensitivity from a higher receiver bandwidth

will be counteracting factors.

15.2 Interleaving

Data received through radio channels will often

experience burst errors due to interference

and time-varying signal strengths. In order to

increase the robustness to errors spanning

multiple bits, interleaving is used when FEC is

enabled. After de-interleaving on the receiver

side, a continuous span of errors in the

received stream will become single errors

spread apart.

CC2550

employs matrix interleaving, which is

illustrated in Figure 12. The on-chip

interleaving buffer is a 4 x 4 matrix. The data

bits from the rate ½ convolutional coder are

written into the rows of the matrix, whereas the

bit sequence to be transmitted is read from the

columns of the matrix. Conversely, in a

CC2500

[9] receiver, the received symbols are written

into the rows of the matrix, whereas the data

passed onto the convolutional decoder is read

from the columns of the matrix.

When FEC and interleaving is used at least

one extra byte is required for trellis

termination. In addition, the amount of data

transmitted over the air must be a multiple of

the size of the interleaver buffer (two bytes).

The packet control hardware therefore

automatically inserts one or two extra bytes at

the end of the packet, so that the total length

of the data to be interleaved is an even

number. Note that these extra bytes are

invisible to the user, as they are removed

before the received packet enters the RX FIFO

in a

CC2500

[9].

When FEC and interleaving is used the

minimum data payload is 2 bytes.

Note that for the

CC2500

[9] transceiver FEC is

only supported in fixed packet length mode

(PKTCTRL0.LENGTH_CONFIG=0).

Packet

Engine

FEC

Encoder Modulator

Interleaver

Write buffer

Interleaver

Read buffer

Figure 12: General Principle of Matrix Interleaving

CC2550

SWRS039B Page 25 of 58

16 Radio Control

TX

19,20

IDLE

1

CALIBRATE

8

MANCAL

3,4,5

SETTLING

9,10,11

TX_UNDERFLOW

22

FSTXON

18

SFSTXON

FS_AUTOCAL = 00 | 10 | 11

&

STX | SFSTXON

STX

TXFIFO_UNDERFLOW

SFTX

SIDLE

SCAL

CAL_COMPLETE

FS_AUTOCAL = 01

&

STX | SFSTXON

CAL_COMPLETE

CALIBRATE

12

IDLE

1

TXOFF_MODE = 00

&

FS_AUTOCAL = 10 | 11

TXOFF_MODE = 00

&

FS_AUTOCAL = 00 | 01

TXOFF_MODE = 10

FS_WAKEUP

6,7

STX | SFSTXON

SLEEP

0

SPWD

XOFF

2

SXOFF

CSn = 0

TXOFF_MODE = 01

Figure 13: Complete Radio Control State Diagram

CC2550

has a built-in state machine that is

used to switch between different operation

states (modes). The change of state is done

either by using command strobes or by

internal events such as TX FIFO underflow.

A simplified state diagram, together with

typical usage and current consumption, is

shown in Figure 4 on page 13. The complete

radio control state diagram is shown in Figure

13. The numbers refer to the state number

readable in the MARCSTATE status register.

This register is primarily for test purposes.

16.1 Power-On Start-Up Sequence

When the power supply is turned on, the

system must be reset. One of the following two

CC2550

SWRS039B Page 26 of 58

sequences must be followed: Automatic

power-on reset (POR) or manual reset.

16.1.1 Automatic POR

A power-on reset circuit is included in the

CC2550

. The minimum requirements stated in

Section 4.7 must be followed for the power-on

reset to function properly. The internal power-

up sequence is completed when CHIP_RDYn

goes low. CHIP_RDYn is observed on the SO

pin after CSn is pulled low. See Section 10.1

for more details on CHIP_RDYn.

When the

CC2550

reset is completed the chip

will be in the IDLE state and the crystal

oscillator will be running. If the chip has had

sufficient time for the crystal oscillator to

stabilize after the power-on-reset, the SO pin

will go low immediately after taking CSn low. If

CSn is taken low before reset is completed the

SO pin will first go high, indicating that the

crystal oscillator is not stabilized, before going

low as shown in Figure 14.

Figure 14: Power-On Reset

16.1.2 Manual Reset

The other global reset possibility on

CC2550

is

the SRES command strobe. By issuing this

strobe, all internal registers and states are set

to the default, IDLE state. The manual power-

up sequence is as follows (see Figure 15):

• Strobe CSn low / high.

• Hold CSn high for at least 40 µs relative to

pulling CSn low

• Pull CSn low and wait for SO to go low

(CHIP_RDYn).

• Issue the SRES strobe on the SI line.

• When SO goes low again, reset is

complete and the chip is in the IDLE state.

CSn

SO

XOSC Stable

XOSC and voltage regulator switched on

SI SRES

40 us

Figure 15: Power-On Reset with SRES

Note that the above reset procedure is only

required just after the power supply is first

turned on. If the user wants to reset the

CC2550

after this, it is only necessary to issue

an SRES command strobe.

16.2 Crystal Control

The crystal oscillator is automatically turned on

when CSn goes low. It will be turned off if the

SXOFF or SPWD command strobes are issued;

the state machine then goes to XOFF or

SLEEP respectively. This can only be done

from the IDLE state. The XOSC will be turned

off when CSn is released (goes high). The

XOSC will be automatically turned on again

when CSn goes low. The state machine will

then go to the IDLE state. The SO pin on the

SPI interface must be pulled low before the

SPI interface is ready to be used; as described

in Section 10.1 on page 15.

Crystal oscillator start-up time depends on

crystal ESR and load capacitances. The

electrical specification for the crystal oscillator

can be found in Section 4.3 on page 7.

16.3 Voltage Regulator Control

The voltage regulator to the digital core is

controlled by the radio controller. When the

chip enters the SLEEP state, which is the state

with the lowest current consumption, the

voltage regulator is disabled. This occurs after

CSn is released when a SPWD command

strobe has been sent on the SPI interface. The

chip is now in the SLEEP state. Setting CSn

low again will turn on the regulator and crystal

oscillator and make the chip enter the IDLE

state.

All

CC2550

register values (with the exception

of the MCSM0.PO_TIMEOUT field) are lost in

CC2550

SWRS039B Page 27 of 58

the SLEEP state. After the chip gets back to

the IDLE state, the registers will have default

(reset) contents and must be reprogrammed

over the SPI interface.

16.4 TX Mode

Transmit mode is activated by the MCU by

using the STX command strobe.

The frequency synthesizer must be calibrated

regularly.

CC2550

has one manual calibration

option (using the SCAL strobe), and three

automatic calibration options, controlled by the

MCSM0.FS_AUTOCAL setting:

• Calibrate when going from IDLE to TX (or

FSTXON)

• Calibrate when going from TX to IDLE

automatically

• Calibrate every fourth time when going

from TX to IDLE automatically

If the radio goes from TX to IDLE by issuing an

SIDLE strobe, calibration will not be

performed. The calibration takes a constant

number of XOSC cycles (see Table 18 for

timing details).

After activating TX mode, the chip will remain

in the TX state until the current packet has

been successfully transmitted. Then the state

will change as indicated by the

MCSM1.TXOFF_MODE setting. The possible

destinations are:

• IDLE

• FSTXON: Frequency synthesizer on and

ready at the TX frequency. Activate TX

with STX.

• TX: Start sending preambles

The SIDLE command strobe can always be

used to force the radio controller to go to the

IDLE state.

16.5 Timing

The radio controller controls most timing in

CC2550

, such as synthesizer calibration and

PLL lock time. Timing from IDLE to TX is

constant, dependent on the auto calibration

setting. The calibration time is constant 18739

clock periods. Table 18 shows timing in crystal

clock cycles for key state transitions.

Power on time and XOSC start-up times are

variable, but within the limits stated in Table 6.

Note that in a frequency hopping spread

spectrum or a multi-channel protocol the

calibration time can be reduced from 721 µs to

approximately 150 µs. This is explained in

Section 27.2.

Description XOSC

Periods 26 MHz

Crystal

Idle to TX/FSTXON, no calibration 2298 88.4 µs

Idle to TX/FSTXON, with calibration ~21037 809 µs

TX to IDLE, no calibration 2 0.1 µs

TX to IDLE, including calibration ~18739 721 µs

Manual calibration ~18739 721 µs

Table 18: State Transition Timing

17 TX FIFO

The

CC2550

contains a 64 byte FIFO for data

to be transmitted. The SPI interface is used for

writing to the TX FIFO. Section 10.5 contains

details on the SPI FIFO access. The FIFO

controller will detect underflow in the TX FIFO.

When writing to the TX FIFO it is the

responsibility of the MCU to avoid TX FIFO

overflow. A TX FIFO overflow will result in an

error in the TX FIFO content.

The chip status byte that is available on the SO

pin while transferring the SPI address contains

the fill grade of the TX FIFO if the R/W bit in

the header byte is 0. Section 10.1 on page 15

contains more details on this.

The number of bytes in the TX FIFO can also

be read from the TXBYTES.NUM_TXBYTES

status register.

The 4-bit FIFOTHR.FIFO_THR setting is used

to program threshold points in the FIFO. Table

19 lists the 16 FIFO_THR settings and the

corresponding thresholds for the TX FIFO.

A signal will assert when the number of bytes

in the FIFO is equal to or higher than the

programmed threshold. The signal can be

CC2550

SWRS039B Page 28 of 58

viewed on the GDO pins (see Section 25 on

page 33).

Figure 17 shows the number of bytes in the TX

FIFO when the threshold flag toggles, in the

case of FIFO_THR=13. Figure 16 shows the

signal as the FIFO is filled above the

threshold, and then drained below.

6 7 8 9 678910

NUM_TXBYTES

GDO

Figure 16: FIFO_THR=13 vs. Number of

Bytes i n FIFO (GDOx_CFG=0x02)

FIFO_THR Bytes in TX FIFO

0 (0000) 61

1 (0001) 57

2 (0010) 53

3 (0011) 49

4 (0100) 45

5 (0101) 41

6 (0110) 37

7 (0111) 33

8 (1000) 29

9 (1001) 25

10 (1010) 21

11 (1011) 17

12 (1100) 13

13 (1101) 9

14 (1110) 5

15 (1111) 1

Table 19: FIFO_THR Settings and the

Corresponding FIFO Thresholds

8 bytes

Underflow

margin

FIFO_THR=13

TXFIFO

Figur e 17: Exam ple of FIFO a t Thresh old

18 Frequency Programming

The frequency programming in

CC2550

is

designed to minimize the programming

needed in a channel-oriented system.

To set up a system with channel numbers, the

desired channel spacing is programmed with

the MDMCFG0.CHANSPC_M and

MDMCFG1.CHANSPC_E registers. The channel

spacing registers are mantissa and exponent

respectively.

The base or start frequency is set by the 24 bit

frequency word located in the FREQ2, FREQ1

and FREQ0 registers. This word will typically

be set to the centre of the lowest channel

frequency that is to be used.

The desired channel number is programmed

with the 8-bit channel number register,

CHANNR.CHAN, which is multiplied by the

channel offset. The resultant carrier frequency

is given by:

()

(

)()

2_

16 2_256

2−

⋅+⋅+⋅= ECHANSPC

XOSC

carrier MCHANSPCCHANFREQ

f

CC2550

SWRS039B Page 29 of 58

With a 26 MHz crystal the maximum channel

spacing is 405 kHz. To get e.g. 1 MHz channel

spacing one solution is to use 333 kHz

channel spacing and select each third channel

in CHANNR.CHAN.

If any frequency programming register is

altered when the frequency synthesizer is

running, the synthesizer may give an

undesired response. Hence, the frequency

programming should only be updated when

the radio is in the IDLE state.

19 VCO

The VCO is completely integrated on-chip.

19.1 VCO and PLL Self-Calibration

The VCO characteristics will vary with

temperature and supply voltage changes, as

well as the desired operating frequency. In

order to ensure reliable operation,

CC2550

includes frequency synthesizer self-calibration

circuitry. This calibration should be done

regularly, and must be performed after turning

on power and before using a new frequency

(or channel). The number of XOSC cycles for

completing the PLL calibration is given in

Table 18 on page 27.

The calibration can be initiated automatically

or manually. The synthesizer can be

automatically calibrated each time the

synthesizer is turned on, or each time the

synthesizer is turned off automatically. This is

configured with the MCSM0.FS_AUTOCAL

register setting. In manual mode, the

calibration is initiated when the SCAL

command strobe is activated in the IDLE

mode.

The calibration values are not maintained in

sleep mode. Therefore, the

CC2550

must be

recalibrated after reprogramming the

configuration registers when the chip has been

in the SLEEP state.

To check that the PLL is in lock the user can

program register IOCFGx.GDOx_CFG to 0x0A

and use the lock detector output available on

the GDOx pin as an interrupt for the MCU (x =

0 or 1). A positive transition on the GDOx pin

means that the PLL is in lock. As an alternative

the user can read register FSCAL1. The PLL is

in lock if the register content is different from

0x3F. Refer also to the

CC2550

Errata Notes

[1]. For more robust operation the source code

could include a check so that the PLL is re-

calibrated until PLL lock is achieved if the PLL

does not lock the first time.

20 Voltage Regulators

CC2550

contains several on-chip linear voltage

regulators, which generate the supply voltage

needed by low-voltage modules. These

voltage regulators are invisible to the user, and

can be viewed as integral parts of the various

modules. The user must however make sure

that the absolute maximum ratings and

required pin voltages in Table 1 and Table 11

are not exceeded. The voltage regulator for

the digital core requires one external

decoupling capacitor.

Setting the CSn pin low turns on the voltage

regulator to the digital core and starts the

crystal oscillator. The SO pin on the SPI

interface must go low before the first positive

edge of SCLK (setup time is given in Table 14).

If the chip is programmed to enter power-down

mode, (SPWD strobe issued), the power will be

turned off after CSn goes high. The power and

crystal oscillator will be turned on again when

CSn goes low.

The voltage regulator output should only be

used for driving the

CC2550

.

CC2550

SWRS039B Page 30 of 58

21 Output Power Programming

The RF output power level from the device has

two levels of programmability, as illustrated in

Figure 18.

The RF output power level from the device is

programmed through the PATABLE register.

• If 2-FSK, GFSK or MSK modulation is

used the desired output power is

programmed to index 0 in the PATABLE

register (PATABLE(0)[7:0]). The 3-bit

FREND0.PA_POWER value shall be set to 0

(reset default value).

• If OOK modulation is used the desired

output power for the logic 0 and logic 1

power levels are programmed to index 0

and index 1 in the PATABLE register

respectively (PATABLE(0)[7:0] and

PATABLE(1)[7:0]). The 3-bit

FREND0.PA_POWER value shall be set to

1.

Table 20 contains recommended PATABLE

settings for various output levels and

frequency bands. See Section 10.6 on page

17 for PATABLE programming details. The

SmartRF® Studio software [4] should be used

to obtain optimum PATABLE settings for

various output powers.

PATABLE must be programmed in burst mode

if writing to other entries than PATABLE(0)

(OOK modulation). Note that all content of the

PATABLE is lost when entering the SLEEP

state.

Figure 18: PA_POWER and PATABLE

CC2550

SWRS039B Page 31 of 58

e.g 6

PA_POWER[2:0]

in FREND0 register

PATABLE(0)[7:0]

PATABLE(1)[7:0]

PATABLE(2)[7:0]

PATABLE(3)[7:0]

PATABLE(4)[7:0]

PATABLE(5)[7:0]

PATABLE(6)[7:0]

PATABLE(7)[7:0]

Index into PATABLE(7:0)

The PA uses this

setting.

Settings 0 to PA_POWER are

used during ramp-up at start of

transmission and ramp-down at

end of transmission, and for

OOK modulation.

The SmartRF® Studio software

should be used to obtain optimum

PATABLE settings for various

output powers.

Figure 19: PA_POWER and PATABLE

Output Power, Typical,

+25oC, 3.0 V [dBm] PATABLE

Value Current Consumption,

Typical [mA]

(–55 or less) 0x00 8.0

–30 0x44 9.3

–28 0x41 9.2

–26 0x43 9.7

–24 0x84 9.8

–22 0x82 9.7

–20 0x47 10.0

–18 0xC8 11.6

–16 0x85 10.2

–14 0x59 11.6

–12 0xC6 11.2

–10 0x97 12.0

–8 0xD6 12.9

–6 0x7F 14.7

–4 0xA9 16.2

–2 0xBF 18.1

0 0xEE 19.4

1 0xFF 21.3

Table 20: Optimum PATABLE Settings for Various Output Power Levels

CC2550

SWRS039B Page 32 of 58

22 Crystal Oscillator

A crystal in the frequency range 26-27 MHz

must be connected between the XOSC_Q1 and

XOSC_Q2 pins. The oscillator is designed for

parallel mode operation of the crystal. In

addition, loading capacitors (C51 and C71) for

the crystal are required. The loading capacitor

values depend on the total load capacitance,

CL, specified for the crystal. The total load

capacitance seen between the crystal

terminals should equal CL for the crystal to

oscillate at the specified frequency.

parasiticL C

CC

C+

+

=

7151

11 1

The parasitic capacitance is constituted by pin

input capacitance and PCB stray capacitance.

Total parasitic capacitance is typically 2.5 pF.

The crystal oscillator circuit is shown in Figure

20. Typical component values for different

values of CL are given in Table 21.

The crystal oscillator is amplitude regulated.

This means that a high current is used to start

up the oscillations. When the amplitude builds

up, the current is reduced to what is necessary

to maintain approximately 0.4 Vpp signal

swing. This ensures a fast start-up, and keeps

the drive level to a minimum. The ESR of the

crystal should be within the specification in

order to ensure a reliable start-up (see Section

4.3 on page 7).

XOSC_Q1 XOSC_Q2

XTAL

C51 C71

Figure 20: Crystal Oscillator Circuit

Component CL= 10 pF CL=13 pF CL=16 pF

C51 15 pF 22 pF 27 pF

C71 15 pF 22 pF 27 pF

Table 21: Crystal Oscillator Component Values

22.1 Reference Signal

The chip can alternatively be operated with a

reference signal from 26 to 27 MHz instead of

a crystal. This input clock can either be a full-

swing digital signal (0 V to VDD) or a sine

wave of maximum 1 V peak-peak amplitude.

The reference signal must be connected to the

XOSC_Q1 input. The sine wave must be

connected to XOSC_Q1 using a serial

capacitor. When using a full-swing digital

signal this capacitor can be omitted. The

XOSC_Q2 line must be left un-connected. C51

and C71 can be omitted when using a

reference signal

23 External RF Match

The balanced RF output of

CC2550

is designed

for a simple, low-cost matching and balun

network on the printed circuit board. A few

passive external components ensure proper

matching.

Although

CC2550

has a balanced RF output,

the chip can be connected to a single-ended

antenna with few external low cost capacitors

and inductors.

The passive matching/filtering network

connected to

CC2550

should have the following

differential impedance as seen from the RF-

port (RF_P and RF_N) towards the antenna:

Zout = 80 + j74 Ω

To ensure optimal matching of the

CC2550

differential output it is highly recommended to

follow the CC2550EM reference design [3] as

closely as possible. Gerber files for the

reference designs are available for download

from the TI website.

CC2550

SWRS039B Page 33 of 58

24 PCB Layout Recommendations

The top layer should be used for signal

routing, and the open areas should be filled

with metallization connected to ground using

several vias.

The area under the chip is used for grounding

and shall be connected to the bottom ground

plane with several vias for good thermal

performance and sufficiently low inductance to

ground. In the CC2550EM reference designs

[3] 5 vias are placed inside the exposed die

attached pad. These vias should be “tented”

(covered with solder mask) on the component

side of the PCB to avoid migration of solder

through the vias during the solder reflow

process.

The solder paste coverage should not be

100%. If it is, out gassing may occur during the

reflow process, which may cause defects

(splattering, solder balling). Using “tented” vias

reduces the solder paste coverage below

100%.

See Figure 21 for top solder resist and top

paste masks. See Figure 24 for recommended

PCB layout for QLP 16 package.

Each decoupling capacitor should be placed

as close as possible to the supply pin it is

supposed to decouple. Each decoupling

capacitor should be connected to the power

line by separate vias. The best routing is from

the power line to the decoupling capacitor and

then to the

CC2550

supply pin. Supply power

filtering is very important.

Each decoupling capacitor ground pad should

be connected to the ground plane using a

separate via. Direct connections between

neighboring power pins will increase noise

coupling and should be avoided unless

absolutely necessary.

The external components should ideally be as

small as possible (0402 is recommended) and

surface mount devices are highly

recommended. Please note that components

smaller than those specified may have

differing characteristics.

Precaution should be used when placing the

microcontroller in order to avoid noise

interfering with the RF circuitry.

A CC2500/2550DK Development Kit with a

fully assembled CC2550EM Evaluation

Module is available. It is strongly advised that

this reference layout is followed very closely in

order to get the best performance. The

schematic, BOM and layout Gerber files are all

available from the TI website [3].

Figure 21: Left: Top Paste Mask. Right: Top Solder Resist Mask (negative). Circles are Vias.

25 General Purpose / Test Output Control Pins

The two digital output pins GDO0 and GDO1 are

general control pins configured with

IOCFG0.GDO0_CFG and

IOCFG1.GDO1_CFG respectively. Table 22

shows the different signals that can be

monitored on the GDO pins. These signals can

be used as inputs to the MCU. GDO1 is the

same pin as the SO pin on the SPI interface,

thus the output programmed on this pin will

only be valid when CSn is high. The default

value for GDO1 is 3-stated, which is useful

when the SPI interface is shared with other

devices.

The default value for GDO0 is a 135-141 kHz

clock output (XOSC frequency divided by 192).

Since the XOSC is turned on at power-on-

CC2550

SWRS039B Page 34 of 58

reset, this can be used to clock the MCU in

systems with only one crystal. When the MCU

is up and running, it can change the clock

frequency by writing to IOCFG0.GDO0_CFG.

An on-chip analog temperature sensor is

enabled by writing the value 128 (0x80) to the

IOCFG0.GDO0_CFG register. The voltage on

the GDO0 pin is then proportional to

temperature. See Section 4.5 on page 8 for

temperature sensor specifications.

In SLEEP mode, GDO1 will be hardwired to 1

and GDO0 will be high impedance.

GDOx_CFG[5:0] Description

0 (0x00) Reserved – defined in the transceiver version.

1 (0x01) Reserved – defined in the transceiver version.

2 (0x02) Associated to the TX FIFO: Asserts when the TX FIFO is filled at or above the TX FIFO threshold. De-asserts when the

TX FIFO is below the same threshold.

3 (0x03) Associated to the TX FIFO: Asserts when TX FIFO is full. De-asserts when the TX FIFO is drained below theTX FIFO

threshold.

4 (0x04) Reserved – defined in the transceiver version.

5 (0x05) Asserts when the TX FIFO has underflowed. De-asserts when the FIFO is flushed.

6 (0x06) Asserts when sync word has been sent, and de-asserts at the end of the packet. The pin will also de-assert if the TX

FIFO underflows.

7 (0x07)

to Reserved

9 (0x09)

10 (0x0A) Lock detector output. The PLL is in lock if the lock detector output has a positive transition or is constantly logic high. To

check for PLL lock the lock detector output should be used as an interrupt for the MCU.

11 (0x0B) Serial Clock. Synchronous to the data in synchronous serial mode.

In TX mode, data is sampled by

CC2550

on the rising edge of the serial clock when GDOx_INV=0.

12 (0x0C)

to Reserved – used for test.

40 (0x28)

41 (0x29) CHIP_RDY

42 (0x2A) Reserved – used for test.

43 (0x2B) XOSC_STABLE

44 (0x2C) Reserved – used for test.

45 (0x2D) GDO0_Z_EN_N. When this output is 0, GDO0 is configured as input (for serial TX data).

46 (0x2E) High impedance (3-state)

47 (0x2F) HW to 0 (HW1 achieved with _INV signal). Can be used to control an external PA

48 (0x30) CLK_XOSC/1

49 (0x31) CLK_XOSC/1.5

50 (0x32) CLK_XOSC/2

51 (0x33) CLK_XOSC/3

52 (0x34) CLK_XOSC/4

53 (0x35) CLK_XOSC/6

54 (0x36) CLK_XOSC/8

55 (0x37) CLK_XOSC/12

56 (0x38) CLK_XOSC/16

57 (0x39) CLK_XOSC/24

58 (0x3A) CLK_XOSC/32

59 (0x3B) CLK_XOSC/48

60 (0x3C) CLK_XOSC/64

61 (0x3D) CLK_XOSC/96

62 (0x3E) CLK_XOSC/128

63 (0x3F) CLK_XOSC/192

Note: There are 2 GDO pins, but only one CLK_XOSC/n can be selected as an output at any

time. If CLK_XOSC/n is to be monitored on one of the GDO pins, the other GDO pin must be

configured to a value less than 0x30. The GDO0 default value is CLK_XOSC/192.

Table 22: GDOx Signal Selection (x = 0 or 1)

26 Asynchronous and Synchronous Serial Operation

Several features and modes of operation have

been included in the

CC2550

to provide

backward compatibility with previous Chipcon

products and other existing RF communication

systems. For new systems, it is recommended

to use the built-in packet handling features, as

they can give more robust communication,

significantly offload the microcontroller and

simplify software development.

26.1 Asynchronous Operation

For backward compatibility with systems

already using the asynchronous data transfer

from other Chipcon products, asynchronous

CC2550

SWRS039B Page 35 of 58

transfer is also included in

CC2550

. When

asynchronous transfer is enabled, several of

the support mechanisms for the MCU that are

included in

CC2550

will be disabled, such as

packet handling hardware, buffering in the

FIFO and so on. The asynchronous transfer

mode does not allow the use of the data

whitener, interleaver and FEC, and it is not

possible to use Manchester encoding.

Note that MSK is not supported for

asynchronous transfer.

Setting PKTCTRL0.PKT_FORMAT to 3

enables asynchronous serial mode.

The GDO0 pin is used for data input (TX data).

The

CC2550

modulator samples the level of the

asynchronous input 8 times faster than the

programmed data rate. The timing requirement

for the asynchronous stream is that the error in

the bit period must be less than one eighth of

the programmed data rate.

26.2 Synchronous Serial Operation

Setting PKTCTRL0.PKT_FORMAT to 1

enables synchronous serial operation mode. In

the synchronous mode, data is transferred on

a two wire serial interface. The

CC2550

provides a clock that is used to set up new

data on the data input line. Data input (TX

data) is the GDO0 pin. This pin will

automatically be configured as an input when

TX is active.

Preamble and sync word insertion may or may

not be active, dependent on the sync mode set

by the MDMCFG3.SYNC_MODE. If preamble and

sync word is disabled, all other packet handler

features and FEC should also be disabled.

The MCU must then handle preamble and

sync word insertion in software. If preamble

and sync word insertion is left on, all packet

handling features and FEC can be used.

When using the packet handling features in

synchronous serial mode, the

CC2550

will

insert the preamble and sync word and the

MCU will only provide the data payload. This is

equivalent to the recommended FIFO

operation mode.

27 System considerations and Guidelines

27.1 SRD Regulations

International regulations and national laws

regulate the use of radio receivers and

transmitters. The most important regulations

for the 2.4 Ghz band are EN 300 440 and EN

300 328 (Europe), FCC CFR47 part 15.247

and 15.249 (USA), and ARIB STD-T66

(Japan). A summary of the most important

aspects of these regulations can be found in

Application Note AN032 [2].

Please note that compliance with regulations

is dependent on complete system

performance. It is the customer’s responsibility

to ensure that the system complies with

regulations.

27.2 Frequency Hopping and Multi-

Channel Systems

The 2.400 – 2.4835 GHz band is shared by

many systems both in industrial, office and

home environments. It is therefore

recommended to use frequency hopping

spread spectrum (FHSS) or a multi-channel

protocol because the frequency diversity

makes the system more robust with respect to

interference from other systems operating in

the same frequency band. FHSS also combats

multipath fading.

CC2550

is highly suited for FHSS or multi-

channel systems due to its agile frequency

synthesizer and effective communication

interface. Using the packet handling support

and data buffering is also beneficial in such

systems as these features will significantly

offload the host controller.

Charge pump current, VCO current and VCO

capacitance array calibration data is required

for each frequency when implementing

frequency hopping for

CC2550

. There are 3

ways of obtaining the calibration data from the

chip:

1) Frequency hopping with calibration for each

hop. The PLL calibration time is approximately

720 µs. The blanking interval between each

frequency hop is then approximately 810 us.

2) Fast frequency hopping without calibration

for each hop can be done by calibrating each

frequency at startup and saving the resulting

CC2550

SWRS039B Page 36 of 58

FSCAL3, FSCAL2 and FSCAL1 register values

in MCU memory. Between each frequency

hop, the calibration process can then be

replaced by writing the FSCAL3, FSCAL2 and

FSCAL1 register values corresponding to the

next RF frequency. The PLL turn on time is

approximately 90 µs. The blanking interval

between each frequency hop is then

approximately 90 us. The VCO current

calibration result is available in FSCAL2 and is

not dependent on the RF frequency. Neither is

the charge pump current calibration result

available in FSCAL3. The same value can

therefore be used for all frequencies.

3) Run calibration on a single frequency at

startup. Next write 0 to FSCAL3[5:4] to

disable the charge pump calibration. After

writing to FSCAL3[5:4] strobe STX with

MCSM0.FS_AUTOCAL=1 for each new

frequency hop. That is, VCO current and VCO

capacitance calibration is done but not charge

pump current calibration. When charge pump

current calibration is disabled the calibration

time is reduced from approximately 720 µs to

approximately 150 µs. The blanking interval

between each frequency hop is then

approximately 240 us

There is a trade off between blanking time and

memory space needed for storing calibration

data in non-volatile memory. Solution 2) above

gives the shortest blanking interval, but

requires more memory space to store

calibration values. Solution 3) gives

approximately 570 µs smaller blanking interval

than solution 1).

27.3 Wideband Modulation not Using

Spread Spectrum

Digital modulation systems under FCC part

15.247 includes 2-FSK and GFSK modulation.

A maximum peak output power of 1 W (+30

dBm) is allowed if the 6 dB bandwidth of the

modulated signal exceeds 500 kHz. In

addition, the peak power spectral density

conducted to the antenna shall not be greater

than +8 dBm in any 3 kHz band.

Operating at high data rates and high

frequency separation, the

CC2550

is suited for

systems targeting compliance with digital

modulation systems as defined by FCC part

15.247. An external power amplifier is needed

to increase the output above +1 dBm.

27.4 Data Burst Transmissions

The high maximum data rate of

CC2550

opens

up for burst transmissions. A low average data

rate link (e.g. 10 kBaud), can be realized using

a higher over-the-air data rate. Buffering the

data and transmitting in bursts at high data

rate (e.g. 500 kBaud) will reduce the time in

TX mode, and hence also reduce the average

current consumption significantly. Reducing

the time in TX mode will reduce the likelihood

of collisions with other systems, e.g. WLAN.

27.5 Continuous Transmissions

In data streaming applications the

CC2550

opens up for continuous transmissions at 500

kBaud effective data rate. As the modulation is

done with a closed loop PLL, there is no

limitation in the length of a transmission (open

loop modulation used in some transceivers

often prevents this kind of continuous data

streaming and reduces the effective data rate.)

27.6 Spectrum Efficient Modulation

CC2500

also has the possibility to use

Gaussian shaped 2-FSK (GFSK). This

spectrum-shaping feature improves adjacent

channel power (ACP) and occupied

bandwidth. In ‘true’ 2-FSK systems with abrupt

frequency shifting, the spectrum is inherently

broad. By making the frequency shift ‘softer’,

the spectrum can be made significantly

narrower. Thus, higher data rates can be

transmitted in the same bandwidth using

GFSK.

27.7 Low Cost Systems

A differential antenna will eliminate the need

for a balun, and the DC biasing can be

achieved in the antenna topology, see Figure

3. The CC25XX Folded Dipole reference

design [7] contains schematics and layout files

for a CC2500EM with a folded dipole PCB

antenna. This design note can also be used

with the

CC2550

. Please see DN004 [8] for

more details on this design.

A HC-49 type SMD crystal is used in the

CC2550EM reference design. Note that the

crystal package strongly influences the price.

In a size constrained PCB design a smaller,

but more expensive, crystal may be used.

27.8 Battery Operated Systems

In low power applications, the SLEEP state

should be used when the

CC2550

is not active.

CC2550

SWRS039B Page 37 of 58

27.9 Increasing Output Power

In some applications it may be necessary to

extend the link range by adding an external

power amplifier.

The power amplifier should be inserted

between the antenna and the balun as shown

in Figure 22.

Figure 22: Block Diagram of

CC2550

Usage with External Power Amplifier

28 Configuration Registers

The configuration of

CC2550

is done by

programming 8-bit registers. The optimum

configuration data based on selected system

parameters are most easily found by using the

SmartRF® Studio software [4]. Complete

descriptions of the registers are given in the

following tables. After chip reset, all the

registers have default values as shown in the

tables. The optimum register setting might

differ from the default value. After a reset all

registers that shall be different from the default

value therefore needs to be programmed

through the SPI interface.

There are 9 command strobe registers, listed

in Table 23. Accessing these registers will

initiate the change of an internal state or

mode. There are 29 normal 8-bit configuration

registers, listed in Table 24. Some of these

registers are for test purposes only, and need

not be written for normal operation of

CC2550

.

There are also 6 status registers, which are

listed in Table 25. These registers, which are

read-only, contain information about the status

of

CC2550

.

The TX FIFO is accessed through one 8-bit

register. Only write operations are allowed to

the TX FIFO.

During the header byte transfer and while

writing data to a register or the TX FIFO, a

status byte is returned on the SO line. This

status byte is described in Table 15 on page

16.

Table 26 summarizes the SPI address space.

Registers that are only defined in the

CC2500

transceiver are also listed.

CC2500

and

CC2550

are register compatible, but registers and fields

only implemented in the transceiver always

contain 0 in

CC2550

. The address to use is

given by adding the base address to the left

and the burst and R/W bits on the top. Note

that the burst bit has different meaning for

base addresses above and below 0x2F.

Note that all registers, (with the exception of

the MSCM0.PO_TIMEOUT field) will lose their

content in SLEEP mode.

CC2550

SWRS039B Page 38 of 58

Address Strobe Name Description

0x30 SRES Reset chip.

0x31 SFSTXON

Enable and calibrate frequency synthesizer (if MCSM0.FS_AUTOCAL=1).

0x32 SXOFF Turn off crystal oscillator.

0x33 SCAL

Calibrate frequency synthesizer and turn it off (enables quick start). SCAL can be strobed in

IDLE state without setting manual calibration mode (MCSM0.FS_AUTOCAL=0).

0x35 STX

Enable TX. Perform calibration first if MCSM0.FS_AUTOCAL=1.

0x36 SIDLE Exit TX and turn off frequency synthesizer.

0x39 SPWD

Enter power down mode when CSn goes high.

0x3B SFTX Flush the TX FIFO buffer.

0x3D SNOP No operation. May be used to get access to the chip status byte.

Table 23: Command Strobes

CC2550

SWRS039B Page 39 of 58

Address Register Description Details on Page Number

0x01 IOCFG1

GDO1 output pin configuration 41

0x02 IOCFG0

GDO0 output pin configuration 41

0x03 FIFOTHR FIFO threshold 41

0x04 SYNC1 Sync word, high byte 42

0x05 SYNC0 Sync word, low byte 42

0x06 PKTLEN Packet length 42

0x08 PKTCTRL0 Packet automation control 42

0x0A CHANNR Channel number 43

0x0D FREQ2 Frequency control word, high byte 43

0x0E FREQ1 Frequency control word, middle byte 43

0x0F FREQ0 Frequency control word, low byte 43

0x10 MDMCFG4 Modulator configuration 43

0x11 MDMCFG3 Modulator configuration 43

0x12 MDMCFG2 Modulator configuration 44

0x13 MDMCFG1 Modulator configuration 45

0x14 MDMCFG0 Modulator configuration 45

0x15 DEVIATN Modulator deviation setting 46

0x17 MCSM1 Main Radio Control State Machine configuration 46

0x18 MCSM0 Main Radio Control State Machine configuration 47

0x22 FREND0 Front end TX configuration 47

0x23 FSCAL3 Frequency synthesizer calibration 48

0x24 FSCAL2 Frequency synthesizer calibration 48

0x25 FSCAL1 Frequency synthesizer calibration 48

0x26 FSCAL0 Frequency synthesizer calibration 48

0x29 FSTEST Frequency synthesizer calibration control 49

0x2A PTEST Production test 49

0x2C TEST2 Various test settings 49

0x2D TEST1 Various test settings 49

0x2E TEST0 Various test settings 49

Table 24: Configuration Registers Overview

Address Register Description Details on Page Number

0x30 (0xF0) PARTNUM

CC2550

part number 49

0x31 (0xF1) VERSION Current version number 49

0x35 (0xF5) MARCSTATE Control state machine state 50

0x38 (0xF8) PKTSTATUS Current GDOx status and packet status 50

0x39 (0xF9) VCO_VC_DAC Current setting from PLL calibration module 51

0x3A (0xFA) TXBYTES Underflow and number of bytes in the TX FIFO 51

Table 25 : Status Reg iste rs Overv ie w

CC2550

SWRS039B Page 40 of 58

Write Read

Sin

g

le b

y

te Bu

r

st Sin

g

le b

y

te Burst

+0x00 +0x40 +0x80 +0xC0

0x00 Reserved

0x01 IOCFG1

0x02 IOCFG0

0x03 FIFOTHR

0x04 SYNC1

0x05 SYNC0

0x06 PKTLEN

0x07 Reserved

0x08 PKTCTRL0

0x09 Reserved

0x0A CHANNR

0x0B Reserved

0x0C Rese

r

ved

0x0D FREQ2

0x0E FREQ1

0x0F FREQ0

0x10 MDMCFG4

0x11 MDMCFG3

0x12 MDMCFG2

0x13 MDMCFG1

0x14 MDMCFG0

0x15 DEVIATN

0x16 Reserved

0x17 MCSM1

0x18 MCSM0

0x19 Reserved

0x1A Rese

r

ved

0x1B Reserved

0x1C Reserved

0x1D Reserved

0x1E Reserved

0x1F Reserved

0x20 Reserved

0x21 Reserved

0x22 FREND0

0x23 FSCAL3

0x24 FSCAL2

0x25 FSCAL1

0x26 FSCAL0

0x27 Reserved

0x28 Reserved

0x29 FSTEST

0x2A PTEST

0x2B Reserved

0x2C TEST2

0x2D TEST1

0x2E TEST0

0x2F

R/W configuration registers, burst access possible

0x30 SRES SRES PARTNUM

0x31 SFSTXON SFSTXON VERSION

0x32 SXOFF SXOFF FREQEST

0x33 SCAL SCAL Reserved

0x34 Reserved Reserved Reserved

0x35 ST

X

ST

X

MARCSTATE

0x36 SIDLE SIDLE Reserved

0x37 Reserved

0x38 Reserved Reserved PKTSTATUS

0x39 SPWD SPWD VCO

_

VC

_

DAC

0x3A Reserved Reserved TXBYTES

0x3B SFT

X

SFT

X

Reserved

0x3C Reserved Reserved

0x3D SNOP SNOP

0x3E PATABLE PATABLE Reserved Reserved

0x3F TX FIFO TX FIFO RX FIFO RX FIFO

Command strobes, status registers (read only)

and multi byte registers

Table 26: SPI Address Space

CC2550

SWRS039B Page 41 of 58

28.1 Configuration Register Details

0x01: IOCFG1 – GDO1 Output Pin Configuration

Bit Field Name Reset R/W Description

7 GDO_DS 0 R/W Set high (1) or low (0) output drive strength on the

GDO pins.

6 GDO1_INV 0 R/W Invert output, i.e. select active low (1) / high (0)

5:0 GDO1_CFG[5:0] 46 (0x2E) R/W Default is 3-state (see Table 22 on page 34)

0x02: IOCFG0 – GDO0 Output Pin Configuration

Bit Field Name Reset R/W Description

7 TEMP_SENSOR_ENABLE 0 R/W Enable analog temperature sensor. Write 0 in all

other register bits when using temperature sensor.

Note: PTEST must be written to 0xBF to make the

on-chip temperature sensor available in the IDLE

state.

6 GDO0_INV 0 R/W Invert output, i.e. select active low (1) / high (0)

5:0 GDO0_CFG[5:0] 63 (0x3F) R/W Default is CLK_XOSC/192 (see Table 22on page 34)

0x03: FIFOTHR – TX FIFO Threshold

Bit Field Name Reset R/W Description

7:4 Reserved 0 (0000) R/W Write 0 (0000) for compatibility with possible future

extensions

3:0 FIFO_THR[3:0] 7 (0111) R/W Set the threshold for the TX FIFO. The threshold is

exceeded when the number of bytes in the FIFO is equal to

or higher than the threshold value.

Setting Bytes in TX FIFO

0 (0000) 61

1 (0001) 57

2 (0010) 53

3 (0011) 49

4 (0100) 45

5 (0101) 41

6 (0110) 37

7 (0111) 33

8 (1000) 29

9 (1001) 25

10 (1010) 21

11 (1011) 17

12 (1100) 13

13 (1101) 9

14 (1110) 5

15 (1111) 1

CC2550

SWRS039B Page 42 of 58

0x04: SYNC1– Sync Word, High Byte

Bit Field Name Reset R/W Description

7:0 SYNC[15:8] 211 (0xD3) R/W 8 MSB of 16-bit sync word

0x05: SYNC0 – Sync Word, Low Byte

Bit Field Name Reset R/W Description

7:0 SYNC[7:0] 145 (0x91) R/W 8 LSB of 16-bit sync word

0x06: PKTLEN – Packet Length

Bit Field Name Reset R/W Description

7:0 PACKET_LENGTH 255 (0xFF) R/W Indicates the packet length when fixed packet length

is enabled.

0x08: PKTCTRL0 – Packet Automation Control

Bit Field Name Reset R/W Description

7 Reserved R0

6 WHITE_DATA 1 R/W Turn data whitening on / off

0: Whitening off

1: Whitening on

Data whitening can only be used when

PKTCTRL0.CC2400_EN=0 (default).

5:4 PKT_FORMAT[1:0] 0 (00) R/W Format of TX data

Setting Packet format

0 (00) Normal mode, use TX FIFO

1 (01) Synchronous serial mode, used for backwards

compatibility

2 (10) Random TX mode; sends random data using PN9

generator. Used for test.

3 (11) Asynchronous serial mode. Data in on GDO0.

3 CC2400_EN 0 R/W Enable CC2400 support. Use same CRC implementation as

CC2400.

PKTCTRL0.WHITE_DATA must be 0 if

PKTCTRL0.CC2400_EN=1.

2 CRC_EN 1 R/W 1: CRC calculation enabled

0: CRC disabled

1:0 LENGTH_CONFIG[1:0] 1 (01) R/W Configure the packet length

Setting Packet length configuration

0 (00) Fixed packet length mode. Length configured in

PKTLEN register

1 (01) Variable packet length mode. Length configured

by the first byte after sync word

2 (10) Infinite packet length mode

3 (11) Reserved

CC2550

SWRS039B Page 43 of 58

0x0A: CHANNR – Channel Number

Bit Field Name Reset R/W Description

7:0 CHAN[7:0] 0 (0x00) R/W The 8-bit unsigned channel number, which is multiplied by

the channel spacing setting and added to the base

frequency.

0x0D: FREQ2 – Frequency Control Word, High Byte

Bit Field Name Reset R/W Description

7:6 FREQ[23:22] 1 (01) R FREQ[23:22] is always binary 01 (the FREQ2 register is in the range

85 to 95 with 26-27 MHz crystal)

5:0 FREQ[21:16] 30

(0x1E)

R/W FREQ[23:0] is the base frequency for the frequency synthesiser in

increments of FXOSC/216.

[]

0:23

216 FREQ

f

fXOSC

carrier ⋅=

0x0E: FREQ1 – Frequency Control Word, Middle Byte

Bit Field Name Reset R/W Description

7:0 FREQ[15:8] 196 (0xC4) R/W Ref. FREQ2 register

0x0F: FREQ0 – Frequency Control Word, Low Byte

Bit Field Name Reset R/W Description

7:0 FREQ[7:0] 236 (0xEC) R/W Ref. FREQ2 register

0x10: MDMCFG4 – Modulator Configuration

Bit Field Name Reset R/W Description

7:4 Reserved R0 Defined in the transceiver version

3:0 DRATE_E[3:0] 12 (1100) R/W The exponent of the user specified symbol rate

0x11: MDMCFG3 – Modulator Configuration

Bit Field Name Reset R/W Description

7:0 DRATE_M[7:0] 34 (0x22) R/W The mantissa of the user specified symbol rate. The symbol

rate is configured using an unsigned, floating-point number

with 9-bit mantissa and 4-bit exponent. The 9th bit is a

hidden ‘1’. The resulting data rate is:

(

)

XOSC

EDRATE

DATA f

MDRATE

R⋅

⋅+

=28

_

22_256

The default values give a data rate of 115.051 kBaud

(closest setting to 115.2 kBaud), assuming a 26.0 MHz

crystal.

CC2550

SWRS039B Page 44 of 58

0x12: MDMCFG2 – Modulator Configuration

Bit Field Name Reset R/W Description

7 Reserved R0

6:4 MOD_FORMAT[2:0] 1 (001) R/W The modulation format of the radio signal

Setting Modulation format

0 (000) 2-FSK

1 (001) GFSK

2 (010) -

3 (011) OOK

4 (100) -

5 (101) -

6 (110) -

7 (111) MSK

3 MANCHESTER_EN 0 R/W Enables Manchester encoding

0 = Disable

1 = Enable (Only supported for fixed packet length

mode, i.e. PKTCTRL0.LENGTH_CONFIG=0)

2:0 SYNC_MODE[2:0] 2 (010) R/W Sync-word mode.

Setting Sync-word mode

0 (000) Disable preamble and sync word

transmission

1 (001) Enable 16-bit sync word transmission

2 (010) Enable 16-bit sync word transmission

3 (011) Repeated sync word transmission

4 (100) Disable preamble and sync word

transmission

5 (101) Enable 16-bit sync word transmission

6 (110) Enable 16-bit sync word transmission

7 (111) Repeated sync word transmission

CC2550

SWRS039B Page 45 of 58

0x13: MDMCFG1 – Modulator Configuration

Bit Field Name Reset R/W Description

7 FEC_EN 0 R/W Enable Forward Error Correction (FEC) with interleaving for

packet payload

0 = Disable

1 = Enable

6:4 NUM_PREAMBLE[2:0] 2 (010) R/W Sets the minimum number of preamble bytes to be

transmitted

Setting Number of preamble bytes

0 (000) 2

1 (001) 3

2 (010) 4

3 (011) 6

4 (100) 8

5 (101) 12

6 (110) 16

7 (111) 24

3:2 Reserved R0

1:0 CHANSPC_E[1:0] 2 (10) R/W 2 bit exponent of channel spacing

0x14: MDMCFG0 – Modulator Configuration

Bit Field Name Reset R/W Description

7:0 CHANSPC_M[7:0] 248 (0xF8) R/W 8-bit mantissa of channel spacing (initial 1 assumed). The

channel spacing is multiplied by the channel number CHAN and

added to the base frequency. It is unsigned and has the format:

()

CHANMCHANSPC

f

fECHANSPC

XOSC

CHANNEL ⋅⋅+⋅=∆ _

18 2_256

2

The default values give 199.951 kHz channel spacing (the

closest setting to 200 kHz), assuming 26.0 MHz crystal

frequency.

CC2550

SWRS039B Page 46 of 58

0x15: DEVIATN – Modulator Deviation Setting

Bit Field Name Reset R/W Description

7 Reserved R0

6:4 DEVIATION_E[2:0] 4 (100) R/W Deviation exponent

3 Reserved R0

2:0 DEVIATION_M[2:0] 7 (111) R/W When MSK modulation is enabled:

Sets fraction of symbol period used for phase change. Refer

to the SmartRF® Studio software [4] for correct DEVIATN

setting when using MSK.

When 2-FSK/GFSK modulation is enabled:

Deviation mantissa, interpreted as a 4-bit value with MSB

implicit 1. The resulting deviation is given by:

EDEVIATION

xosc

dev MDEVIATION

f

f_

17 2)_8(

2⋅+⋅=

The default values give ±47.607 kHz deviation, assuming

26.0 MHz crystal frequency.

0x17: MCSM1 – Main Radio Control State Machine Configuration

Bit Field Name Reset R/W Description

7:6 Reserved R0

5:2 Reserved R0 Defined in the transceiver version

1:0 TXOFF_MODE[1:0] 0 (00) R/W Select what should happen when a packet has been sent

(TX)

Setting Next state after finishing packet transmission

0 (00) IDLE

1 (01) FSTXON

2 (10) Stay in TX (start sending preamble)

3 (11) Do not use, not implemented in

CC2550

(Go to RX)

CC2550

SWRS039B Page 47 of 58

0x18: MCSM0 – Main Radio Control State Machine Configuration

Bit Field Name Reset R/W Description

7:6 Reserved R0

5:4 FS_AUTOCAL[1:0] 0 (00) R/W Automatically calibrate when going to TX or back to IDLE

Setting When to perform automatic calibration

0 (00) Never (manually calibrate using SCAL strobe)

1 (01) When going from IDLE to TX (or FSTXON)

2 (10) When going from TX back to IDLE

3 (11) Every 4th time when going from TX to IDLE

3:2 PO_TIMEOUT 2 (10) R/W Programs the number of times the six-bit ripple counter must expire

after XOSC has stabilized before CHP_RDYn goes low.

If XOSC is on (stable) during power-down, PO_TIMEOUT should

be set so that the regulated digital supply voltage has time to

stabilize before CHP_RDYn goes low (PO_TIMEOUT=2

recommended). Typical start-up time for the voltage regulator is 50

us.

If XOSC is off during power-down and the regulated digital supply

voltage has sufficient time to stabilize while waiting for the crystal to

be stable, PO_TIMEOUT can be set to 0. For robust operation it is

recommended to use PO_TIMEOUT=2.

Setting Expire count Timeout after XOSC start

0 (00) 1 Approx. 2.3 – 2.4 µs

1 (01) 16 Approx. 37 – 39 µs

2 (10) 64 Approx. 149 – 155 µs

3 (11) 256 Approx. 597 – 620 µs

Exact timeout depends on crystal frequency.

In order to reduce start up time from the SLEEP state, this field is

preserved in powerdown (SLEEP state).

1:0 Reserved R0 Defined in the transceiver version

0x22: FREND0 – Front End TX Configuration

Bit Field Name Reset R/W Description

7:6 Reserved R0

5:4 LODIV_BUF_CURRENT_TX[1:0] 1 (01) R/W Adjusts current TX LO buffer (input to PA). The

value to use in this field is given by the SmartRF®

Studio software [4].

3 Reserved R0

2:0 PA_POWER[2:0] 0 (000) R/W Selects PA power setting. This value is an index to

the PATABLE. In OOK mode, this selects the

PATABLE index to use when transmitting a ‘1’.

PATABLE index zero is used in OOK when

transmitting a ‘0’.

CC2550

SWRS039B Page 48 of 58

0x23: FSCAL3 – Frequency Synthesizer Calibration

Bit Field Name Reset R/W Description

7:6 FSCAL3[7:6] 2 (10) R/W Frequency synthesizer calibration configuration. The value to write

in this register before calibration is given by the SmartRF® Studio

software [4].

5:4 CHP_CURR_CAL_EN[1:0] 2 (10) R/W Disable charge pump calibration stage when 0

3:0 FSCAL3[3:0] 9

(1001)

R/W Frequency synthesizer calibration result register. Digital bit vector

defining the charge pump output current, on an exponential scale:

IOUT=I0·2FSCAL3[3:0]/4

Fast frequency hopping without calibration for each hop can be

done by calibrating upfront for each frequency and saving the

resulting FSCAL3, FSCAL2 and FSCAL1 register values. Between

each frequency hop, calibration can be replaced by writing the

FSCAL3, FSCAL2 and FSCAL1 register values corresponding to

the next RF frequency.

0x24: FSCAL2 – Frequency Synthesizer Calibration

Bit Field Name Reset R/W Description

7:6 Reserved R0

5 VCO_CORE_H_EN 0 R/W Choose high (1) / low (0) VCO

4:0 FSCAL2[5:0] 10

(0x0A)

R/W Frequency synthesizer calibration result register. VCO current

calibration result and override value

Fast frequency hopping without calibration for each hop can be

done by calibrating upfront for each frequency and saving the

resulting FSCAL3, FSCAL2 and FSCAL1 register values. Between

each frequency hop, calibration can be replaced by writing the

FSCAL3, FSCAL2 and FSCAL1 register values corresponding to

the next RF frequency.

0x25: FSCAL1 – Frequency Synthesizer Calibration

Bit Field Name Reset R/W Description

7:6 Reserved R0

5:0 FSCAL1[5:0] 32

(0x20)

R/W Frequency synthesizer calibration result register. Capacitor array

setting for VCO coarse tuning.

Fast frequency hopping without calibration for each hop can be

done by calibrating upfront for each frequency and saving the

resulting FSCAL3, FSCAL2 and FSCAL1 register values. Between

each frequency hop, calibration can be replaced by writing the

FSCAL3, FSCAL2 and FSCAL1 register values corresponding to

the next RF frequency.

0x26: FSCAL0 – Frequency Synthesizer Calibration

Bit Field Name Reset R/W Description

7 Reserved R0

6:5 Reserved 0 (00) R0 Defined in the transceiver version

4:0 FSCAL0[4:0] 13

(0x0D)

R/W Frequency synthesizer calibration control. The value to use in

register field is given by the SmartRF® Studio software [4].

CC2550

SWRS039B Page 49 of 58

0x29: FSTEST – Frequency Synthesizer Calibration Control

Bit Field Name Reset R/W Description

7:0 FSTEST[7:0] 87

(0x57)

R/W For test only. Do not write to this register.

0x2A: PTEST – Production Test

Bit Field Name Reset R/W Description

7 PTEST[7:0] 127

(0x7F)

R/W Writing 0xBF to this register makes the on-chip temperature sensor

available in the IDLE state. The default 0x7F value should then be

written back before leaving the IDLE state.

Other use of this register is for test only.

0x2C: TEST2 – Various Test Settings

Bit Field Name Reset R/W Description

7:0 TEST2[7:0] 152

(0x98)

R/W The value to use in this register is given by the SmartRF® Studio

software [4].

0x2D: TEST1 – Various Test Settings

Bit Field Name Reset R/W Description

7:0 TEST1[7:0] 49 (0x31) R/W The value to use in this register is given by the SmartRF®

Studio software [4].

0x2E: TEST0 – Various Test Settings

Bit Field Name Reset R/W Description

7:2 TEST0[7:2] 2 (0x02) R/W The value to use in this register is given by the SmartRF®

Studio software [4].

1 VCO_SEL_CAL_EN 1 R/W Enable VCO selection calibration stage when 1

0 TEST0[0] 1 R/W

The value to use in this register is given by the SmartRF®

Studio software [4].

28.2 Status Register Details

0x30 (0xF0): PARTNUM – Chip ID

Bit Field Name Reset R/W Description

7:0 PARTNUM[7:0] 130 (0x82) R Chip part number

0x31 (0xF1): VERSION – Chip ID

Bit Field Name Reset R/W Description

7:0 VERSION[7:0] 2 (0x02) R Chip version number

CC2550

SWRS039B Page 50 of 58

0x35 (0xF5): MARCSTATE – Main Radio Control State Machine State

Bit Field Name Reset R/W Description

7:5 Reserved R0

4:0 MARC_STATE[4:0] R Main Radio Control FSM State

Value State name State (Figure 13, page 25)

0 (0x00) SLEEP SLEEP

1 (0x01) IDLE IDLE

2 (0x02) XOFF XOFF

3 (0x03) VCOON_MC MANCAL

4 (0x04) REGON_MC MANCAL

5 (0x05) MANCAL MANCAL

6 (0x06) VCOON FS_WAKEUP

7 (0x07) REGON FS_WAKEUP

8 (0x08) STARTCAL CALIBRATE

9 (0x09) BWBOOST SETTLING

10 (0x0A) FS_LOCK SETTLING

11 (0x0B) IFADCON SETTLING

12 (0x0C) ENDCAL CALIBRATE

13 (0x0D) NA NA

14 (0x0E) NA NA

15 (0x0F) NA NA

16 (0x10) NA NA

17 (0x11) NA NA

18 (0x12) FSTXON FSTXON

19 (0x13) TX TX

20 (0x14) TX_END TX

21 (0x15) NA NA

22 (0x16) TX_UNDERFLOW TX_UNDERFLOW

Note: it is not possible to read back the SLEEP or XOFF state

numbers because setting CSn low will make the chip enter the

IDLE mode from the SLEEP or XOFF states.

0x38 (0xF8): PKTSTATUS – Current GDOx Status and Packet Status

Bit Field Name Reset R/W Description

7:2 Reserved R0 Defined in the transceiver version

1 Reserved R0

0 GDO0 R Current GDO0 value. Note: the reading gives the non-inverted

value irrespective what IOCFG0.GDO0_INV is programmed to.

It is not recommended to check for PLL lock by reading

PKTSTATUS[0] with GDO0_CFG = 0x0A.

CC2550

SWRS039B Page 51 of 58

0x39 (0xF9): VCO_VC_DAC – Current Setting from PLL Calibration Module

Bit Field Name Reset R/W Description

7:0 VCO_VC_DAC[7:0] R Status register for test only

0x3A (0xFA): TXBYTES – Underflow and Number of Bytes

Bit Field Name Reset R/W Description

7 TXFIFO_UNDERFLOW R

6:0 NUM_TXBYTES R Number of bytes in TX FIFO

CC2550

SWRS039B Page 52 of 58

29 Package Description (QLP 16)

All dimensions are in millimetres, angles in degrees. NOTE: The

CC2550

is available in RoHS

lead-free package only.

Figure 23: Package Dimensions Drawing (the actual package has 16 pins)

Package

type A A1 A2 D D1 D2 E E1 E2 L T b e

Min 0.75 0.005 0.55 3.90 3.65 3.90 3.65 0.45 0.190 0.23

QLP 16 (4x4) Typ. 0.85 0.025 0.65 4.00 3.75 2.30 4.00 3.75 2.30 0.55 0.28 0.65

Max 0.95 0.045 0.75 4.10 3.85 4.10 3.85 0.65 0.245 0.35

Table 27: Package Dimensions

CC2550

SWRS039B Page 53 of 58

29.1 Recommended PCB Layout for Pa ckage (QLP 16)

Figure 24: Recommended PCB layout for QLP 16 package

Note: The figure is an illustration only and not to scale. There are five 10 mil diameter via holes

distributed symmetrically in the ground pad under the package. See also the CC2550EM

reference design [3].

29.2 Package Thermal Properties

Thermal Resistance

Air velocity [m/s] 0

Rth,j-a [K/W] 40.1

Table 28: Thermal Properties of QLP 16 Package

29.3 Soldering Information

The recommendations for lead-free reflow in IPC/JEDEC J-STD-020D should be followed.

CC2550

SWRS039B Page 54 of 58

29.4 Tray Specification

CC2550

can be delivered in standard QLP 4x4 mm shipping trays.

Tray Specification

Package Tray Width Tray Height Tray Length Units per Tray

QLP 16 135.9 mm 7.62 mm 322.6 mm 490

Table 29: Tray Specification

29.5 Carrier Tape and Reel Specification

Carrier tape and reel is in accordance with EIA Specification 481.

Tape and Reel Specification

Package Tape Width Component

Pitch

Hole

Pitch

Reel

Diameter

Units per Reel

QLP 16 12 mm 8 mm 4 mm 13 inches 2500

Table 30: Carrier Tape and Reel Specification

30 Ordering Information

Part Number Description Minimum Order Quantit y (MOQ)

CC2550RTK

CC2550

QLP16 RoHS Pb-free 490/tray 490 (tray)

CC2550RTKR

CC2550

QLP16 RoHS Pb-free 2500/T&R 2500 (tape and reel)

CC2500-CC2550DK

CC2500_CC2550

Development Kit 1

CC2550EMK

CC2500

Evaluation Module Kit 1

Table 31: Ordering Information

31 References

[1] CC2550 Errata Notes (swrz011.pdf)

[2] AN032 2.4 GHz Regulations (swra060.pdf)

[3] CC2550EM Reference Design 1.0 (swrr015.zip)

[4] SmartRF® Studio (swrc046.zip)

[5] CC1100 CC2500 Examples Libraries (swrc021.zip)

[6] CC1100/CC1150DK & CC2500/CC2550DK Development Kit Examples & Libraries User

Manual (swru109.pdf)

[7] CC25XX Folded Dipole Reference Design (swrc065.zip)

[8] DN004 Folded Dipole Antenna for CCC25xx (swra118.pdf)

[9] CC2500 Data Sheet (cc2500.pdf)

CC2550

SWRS039B Page 55 of 58

32 General Information

32.1 Document History

Revision Date Description/Changes

SWRS039B 2007-09-30

kbps replaced by kBaud throughout the document.

Some of the sections hav been re-written to be easier to read without having any new

info added.

Absolute maximum supply voltage rating increased from 3.6 V to 3.9 V.

FSK changed to 2-FSK throughout the document.

Updates to the Abbreviation table.

Updates to the Electrical Specifications section. Added ACP and OBW performance.

Added info about TX latency in serial mode.

Added info about default values after reset versus optimum register settings in the

Configuration Software section.

Changes to the SPI Interface Timing Requirements. Info added about tsp,pd

The following figures have been changed: Configuration Registers Write and Read

Operations, SRES Command Strobe, and Register Access Types.

In the Register Access section, the address range is changed.

Changes to PATABLE Access section.

In the Packet Format section, preamble pattern is changed to 10101010 and info

about bug related to turning off the transmitter in infinite packet length mode is added.

Added info about the initial value of the PN9 sequence in the Data Whitening section.

Added info about TX FIFO underflow state in the Packet Handling in Transmit Mode

section.

Added section Packet Handling in Firmware.

Removed all references to the voltage regulator in relation with the CHP_RDYn

signal, as this signal is only related to the crystal.

Removed references to the voltage regulator in the figures: Power-On Reset and

Power-On Reset with SRES. Changes to the SI line in the Power-On Reset with

SRES figure.

Added info on the three automatic calibration options.

The Output Power Programming section has been changed. Only 1 PATABLE entry

used for 2-FSK/GFSK/MSK and 2 PATABLE entries used for OOK. Added info about

PATABLE when entering SLEEP mode. New PA_POWER and PATABLE figure.

Added section on PCB Layout Recommendations.

In section General Purpose / Test Output Control Pins: Added info on GDO pins in

SLEEP state.

Asynchronous transparent mode is called asynchronous serial mode throughout the

document.

Removed comments about having to use NRZ coding in synchronous serial mode.

Added info that Manchester encoding cannot be used in asynchronous serial mode.

Changed field name and/or description of the following registers:

MCSM0, FSCAL3, FSCAL2, FSCAL1 and TEST0.

Added references.

1.2

SWRS039A

2006-06-28 Added figures to table on SPI interface timing requirements.

Added information about SPI read.

Updates to text and included new figure in section on arbitrary length configuration.

Added information that RF frequencies at n/2·crystal frequency (n is an integer

number) should not be used due to spurious signals at these frequencies .

Updates to text and included new figures in section on power-on start-up sequence.

Added information about how to check for PLL lock in section on VCO.

Better explanation of some of the signals in table of GDO signal selection.

Added section on wideband modulation not using spread spectrum under section on

system considerations and guidelines.

Added more detailed information on PO_TIMEOUT in register MCSM0.

Changes to ordering information.

1.1 2005-06-27 Updated TEST1 register default value. 26-27 MHz crystal range. Added matching

information. Added information about using a reference signal instead of a crystal.

1.0 2005-01-24 First preliminary data sheet release.

Table 32: Document History

CC2550

SWRS039B Page 56 of 58

32.2 Product Status Definitions

Data Sheet Identification Product Status Definition

Advance Information Planned or Under

Development

This data sheet contains the design specifications for

product development. Specifications may change in

any manner without notice.

Preliminary Engineering Samples

and Pre-Production

Prototypes

This data sheet contains preliminary data, and

supplementary data will be published at a later date.

Chipcon reserves the right to make changes at any

time without notice in order to improve design and

supply the best possible product. The product is not

yet fully qualified at this point.

No Identification Noted Full Production This data sheet contains the final specifications.

Chipcon reserves the right to make changes at any

time without notice in order to improve design and

supply the best possible product.

Obsolete Not In Production This data sheet contains specifications on a product

that has been discontinued by Chipcon. The data

sheet is printed for reference information only.

Table 33: Product Status Definitions

CC2550

SWRS039B Page 57 of 58

33 Address Information

Texas Instruments Norway AS

Gaustadalléen 21

N-0349 Oslo

NORWAY

Tel: +47 22 95 85 44

Fax: +47 22 95 85 46

Web site: http://www.ti.com/lpw

34 TI Worldwide Technical Support

Internet

TI Semiconductor Product Information Center Home Page: support.ti.com

TI Semiconductor KnowledgeBase Home Page: support.ti.com/sc/knowledgebase

Product Information Centers

Americas

Phone: +1(972) 644-5580

Fax: +1(972) 927-6377

Internet/Email: support.ti.com/sc/pic/americas.htm

Europe, Middle East and Africa

Phone:

Belgium (English) +32 (0) 27 45 54 32

Finland (English) +358 (0) 9 25173948

France +33 (0) 1 30 70 11 64

Germany +49 (0) 8161 80 33 11

Israel (English) 180 949 0107

Italy 800 79 11 37

Netherlands (English) +31 (0) 546 87 95 45

Russia +7 (0) 95 98 10 701

Spain +34 902 35 40 28

Sweden (English) +46 (0) 8587 555 22

United Kingdom +44 (0) 1604 66 33 99

Fax: +49 (0) 8161 80 2045

Internet: support.ti.com/sc/pic/euro.htm

Japan

Fax International +81-3-3344-5317

Domestic 0120-81-0036

Internet/Email International support.ti.com/sc/pic/japan.htm

Domestic www.tij.co.jp/pic

CC2550

SWRS039B Page 58 of 58

Asia

Phone International +886-2-23786800

Domestic Toll-Free Number

Australia 1-800-999-084

China 800-820-8682

Hong Kong 800-96-5941

India +91-80-51381665 (Toll)

Indonesia 001-803-8861-1006

Korea 080-551-2804

Malaysia 1-800-80-3973

New Zealand 0800-446-934

Philippines 1-800-765-7404

Singapore 800-886-1028

Taiwan 0800-006800

Thailand 001-800-886-0010

Fax +886-2-2378-6808

Email tiasia@ti.com or ti-china@ti.com

Internet support.ti.com/sc/pic/asia.htm

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