ADF7241_技术文档

Low Power IEEE 802.15.4 Zero-IF 2.4 GHz

Transceiver IC

ADF7241

On-chip low power processor performs

Radio control

Packet management

FEATURES

Frequency range (global ISM band)

2400 MHz to 2483.5 MHz

IEEE 802.15.4-2006-compatible (250 kbps)

Low power consumption

Packet management support

Insertion/detection of preamble address/SFD/FCS

IEEEE 802.15.4-2006 frame filtering

IEEEE 802.15.4-2006 CSMA/CA unslotted modes

Flexible 256-byte transmit/receive data buffer

SPORT mode

19 mA (typical) in receive mode

21.5 mA (typical) in transmit mode (P_O= 3 dBm)

1.7 μA, 32 kHz crystal oscillator wake-up mode

High sensitivity

Flexible multiple RF port interface

External PA/LNA support hardware

Switched antenna diversity support

Wake-up timer

−95 dBm at 250 kbps

Programmable output power

−20 dBm to +4.8 dBm in 2 dB steps

Integrated voltage regulators

1.8 V to 3.6 V input voltage range

Excellent receiver selectivity and blocking resilience

Zero-IF architecture

Complies with EN300 440 Class 2, EN300 328, FCC CFR47

Part 15, ARIB STD-T66

Digital RSSI measurement

Very few external components

Integrated PLL loop filter, receive/transmit switch, battery

monitor, temperature sensor, 32 kHz RC and crystal

oscillators

Flexible SPI control interface with block read/write access

Small form factor 5 mm × 5 mm 32-lead LFCSP package

Fast automatic VCO calibration

Automatic RF synthesizer bandwidth optimization

APPLICATIONS

Wireless sensor networks

Automatic meter reading/smart metering

Industrial wireless control

Healthcare

Wireless audio/video

Consumer electronics

ZigBee

FUNCTIONAL BLOCK DIAGRAM

ADF7241

4kB

8-BIT

DAC

ADC

PROGRAM

PROCESSOR

ROM

LNA1

DSSS

DEMOD

2kB

PROGRAM

RAM

RADIO

CONTROLLER

LNA2

256-BYTE

PACKET

RAM

ADC

DAC

AGC

OCL

CDR

PACKET

MANAGER

64-BYTE

BBRAM

256-BYTE

MCR

FRACTIONAL-N

RF SYNTHESIZER

PA

PRE-EMPHASIS FILTER

WAKE-UP CTRL

SPI

GPIO

SPORT

IRQ

32kHz

RC

OSC

32kHz

XTAL

OSC

BATTERY

MONITOR

TEMPERATURE

SENSOR

26MHz

OSC

LDO × 4

BIAS

Figure 1.

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registeredtrademarks arethe property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

Fax: 781.461.3113

www.analog.com

ADF7241

TABLE OF CONTENTS

Features .............................................................................................. 1

Automatic TX-to-RX Turnaround Mode ............................... 37

Applications....................................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 2

General Description......................................................................... 3

Specifications..................................................................................... 5

General Specifications ................................................................. 5

RF Frequency Synthesizer Specifications.................................. 5

Transmitter Specifications........................................................... 6

Receiver Specifications ................................................................ 6

Auxiliary Specifications............................................................... 8

Current Consumption Specifications ........................................ 9

Timing and Digital Specifications.............................................. 9

Timing Diagrams........................................................................ 11

Absolute Maximum Ratings.......................................................... 15

ESD Caution................................................................................ 15

Pin Configuration and Function Descriptions........................... 16

Typical Performance Characteristics ........................................... 18

Terminology .................................................................................... 22

Radio Controller............................................................................. 23

Sleep Modes................................................................................. 25

RF Frequency Synthesizer ............................................................. 26

RF Frequency Synthesizer Calibration .................................... 26

RF Frequency Synthesizer Bandwidth..................................... 27

RF Channel Frequency Programming..................................... 27

Reference Crystal Oscillator ..................................................... 27

Transmitter ...................................................................................... 28

Transmit Operating Modes....................................................... 28

IEEE 802.15.4 Automatic RX-To-TX Turnaround Mode..... 30

Power Amplifier.......................................................................... 30

Receiver............................................................................................ 33

Receive Operation ...................................................................... 33

Receiver Calibration................................................................... 33

Receive Timing and Control ....................................................... 35

Clear Channel Assessment (CCA)........................................... 36

Link Quality Indication (LQI).................................................. 36

IEEE 802.15.4 Frame Filtering, Automatic Acknowledge, and

Automatic CSMA/CA................................................................ 37

Receiver Radio Blocks ............................................................... 39

SPORT Interface............................................................................. 40

SPORT Mode .............................................................................. 40

Device Configuration .................................................................... 41

Configuration Values................................................................. 41

RF Port Configurations/Antenna Diversity................................ 42

Auxillary Functions........................................................................ 43

Temperture Sensor..................................................................... 43

Battery Monitor .......................................................................... 43

Wake-Up Controller (WUC).................................................... 43

Transmit Test Modes.................................................................. 44

Serial Peripheral interface (SPI) ................................................... 45

General Characteristics ............................................................. 45

Command Access....................................................................... 45

Status Word ................................................................................. 45

Memory Map .................................................................................. 47

BBRAM........................................................................................ 47

Modem Configuration RAM (MCR) ...................................... 47

Program ROM ............................................................................ 47

Program RAM ............................................................................ 47

Packet RAM ................................................................................ 47

Memory Access............................................................................... 49

Writing to the ADF7241............................................................ 50

Reading from the ADF7241...................................................... 50

Downloadable Firmware Modules............................................... 53

Interrupt Controller ....................................................................... 54

Configuration ............................................................................. 54

Description of Interrupt Sources ............................................. 55

Applications Circuits...................................................................... 56

Register Map ................................................................................... 60

Outline Dimensions....................................................................... 71

Ordering Guide .......................................................................... 71

REVISION HISTORY

1/11—Revision 0: Initial Version

Rev. 0 | Page 2 of 72

ADF7241

GENERAL DESCRIPTION

The ADF7241 is a highly integrated, low power, and high perfor-

mance transceiver for operation in the global 2.4 GHz ISM band. It

is designed with emphasis on flexibility, robustness, ease of use,

and low current consumption. The IC supports the IEEE 802.15.4-

2006 2.4 GHz PHY requirements in both packet and data

streaming modes. With a minimum number of external compo-

nents, it achieves compliance with the FCC CFR47 Part 15,

ETSI EN 300 440 (Equipment Class 2), ETSI EN 300 328

(FHSS, DR > 250 kbps), and ARIB STD T-66 standards.

The radio controller manages the state of the IC in various

operating modes and configurations. The host MCU can use

single byte commands to interface to the radio controller. In

transmit mode, the packet manager can be configured to add

preamble and SFD to the payload data stored in the on-chip

packet RAM. In receive mode, the packet manager can detect

and generate an interrupt to the MCU upon receiving a valid SFD,

and store the received data payload in the packet RAM. A total

of 256 bytes of transmit and receive packet RAM space is

provided to decouple the over-the-air data rate from the host

MCU processing speed. Thus, the ADF7241 packet manager

eases the processing burden on the host MCU and saves the

overall system power consumption.

The ADF7241 complies with the IEEE 802.15.4-2006 2.4 GHz

PHY requirements with a fixed data rate of 250 kbps and DSSS-

OQPSK modulation. The transmitter path of the ADF7241 is

based on a direct closed-loop VCO modulation scheme using a

low noise fractional-N RF frequency synthesizer. The

automatically calibrated VCO operates at twice the fundamental

frequency to reduce spurious emissions and avoid PA pulling

effects. The bandwidth of the RF frequency synthesizer is

automatically optimized for transmit and receive operations to

achieve best phase noise, modulation quality, and synthesizer

settling time performance. The transmitter output power is

programmable from −20 dBm to +4 dBm with automatic PA

ramping to meet transient spurious specifications. An

In addition, for applications that require data streaming, a

synchronous bidirectional serial port (SPORT) provides bit-

level input/output data, and has been designed to directly

interface to a wide range of DSPs, such as ADSP-21xx, SHARC®,

TigerSHARC®, and Blackfin®. The SPORT interface can option-

ally be used.

The processor also permits the download and execution of a set

of firmware modules, which include IEEE 802.15.4 automatic

modes, such as node address filtering, as well as unslotted

CSMA/CA. Execution code for these firmware modules is

available from Analog Devices, Inc.

integrated biasing and control circuit is available in the IC to

significantly simplify the interface to external PAs.

The receive path is based on a zero-IF architecture enabling very

high blocking resilience and selectivity performance, which are

critical performance metrics in interference dominated environ-

ments such as the 2.4 GHz band. In addition, the architecture

does not suffer from any degradation of blocker rejection in the

image channel, which is typically found in low IF receivers. The

IC can operate with a supply voltage between 1.8 V and 3.6 V with

very low power consumption in receive and transmit modes while

maintaining its excellent RF performance, making it especially

suitable for battery-powered systems.

To further optimize the system power consumption, the ADF7241

features an integrated low power 32 kHz RC wake-up oscillator,

which is calibrated from the 26 MHz crystal oscillator while the

transceiver is active. Alternatively, an integrated 32 kHz crystal

oscillator can be used as a wake-up timer for applications

requiring very accurate wake-up timing. A battery backed-up

RAM (BBRAM) is available on the IC where IEEE 802.15.4-

2006 network node addresses can be retained when the IC is in

the sleep state.

The ADF7241 also features a very flexible interrupt controller,

which provides MAC-level and PHY-level interrupts to the host

MCU. The IC is equipped with a SPI interface, which allows

burst mode data transfer for high data throughput efficiency.

The IC also integrates a temperature sensor with digital read-

back and a battery monitor.

The ADF7241 features a flexible dual-port RF interface that can

be used with an external LNA and/or PA in addition to support-

ing switched antenna diversity.

The ADF7241 incorporates a very low power custom 8-bit

processor that supports a number of transceiver management

functions. These functions are handled by the two main mod-

ules of the processor: the radio controller and the packet manager.

Rev. 0 | Page 3 of 72

ADF7241

4kB

PROGRAM

ROM

ADF7241

DAC

ADC

8-BIT

PROCESSOR

RFIO1P

2kB

PROGRAM

RAM

DSSS

DEMOD

LNA1

RFIO1N

RFIO2P

RADIO

CONTROLLER

256- BYTE

PACKET

RAM

LNA2

ADC

DAC

AGC

OCL

CDR

RFIO2N

PACKET

MANAGER

64-BYTE

BBRAM

256-BYTE

MCR

SDM

PFD

PRE-EMPHASIS

DSSS MOD

PA

DIV2

DIVIDER

CS

FILTER

MOSI

SCLK

MISO

SPI

CHARGE-

PUMP

LOOP FILTER

PABIAOP_ATB4

PAVSUP_ATB3

EXT PA

INTERFACE

WAKE-UP CTRL

TIMER UNIT

RXEN_GP6

TXEN_GP5

EXT LNA/PA

ENABLE

GPIO

PA

RAMP

BATTERY TEMPERATURE

MONITOR

ANALOG

TEST

SENSOR

TRCLK_CKO_GP3

DT_GP1

SPORT

26MHz

OSC

DR_GP0

32kHz

RC

OSC

32kHz

XTAL

OSC

IRQ1_GP4

RC

CAL

LDO1

LDO2

LDO3

LDO4

BIAS

IRQ

IRQ2_TRFS_GP2

CREGRF1, CREGVCO CREGSYNTH CREGDIG1, RBIAS XOSC26P XOSC26N

XOSC32KN_ATB2 XOSC32KP_GP7_ATB1

CREGRF2,

CREGRF3

CREGDIG2

Figure 2. Detailed Functional Block Diagram

Rev. 0 | Page 4 of 72

ADF7241

SPECIFICATIONS

VDD_BAT = 1.8 V to 3.6 V, GND = 0 V, T_A= T_MINto T_MAX, unless otherwise noted. Typical specifications are at VDD_BAT = 3.6 V, T_A= 25°C,

_CHANNEL= 2450 MHz. All measurements are performed using the ADF7241 reference design, RFIO2 port, unless otherwise noted.

f

GENERAL SPECIFICATIONS

Table 1.

Parameter

Min

Typ

Max

Unit

Test Conditions

GENERAL PARAMETERS

Voltage Supply Range

VDD_BAT Input

1.8

3.6

V

Frequency Range

Operating Temperature Range

Data Rate

2400

−40

2483.5 MHz

+85

°C

250

kbps

RF FREQUENCY SYNTHESIZER SPECIFICATIONS

Table 2.

Parameter

Min

Typ

10

3

Max

Unit

Test Conditions

CHANNEL FREQUENCY RESOLUTION

PHASE ERROR

kHz

Degrees

Receive mode; integration bandwidth from 10 kHz

to 400 kHz

1.5

52

Degrees

μs

Transmit mode; integration bandwidth from 10 kHz

to 1800 kHz

VCO CALIBRATION TIME

Applies to all modes

SYNTHESIZER SETTLING TIME

Frequency synthesizer settled to < 5 ppm of the

target frequency within this time following a VCO

calibration

53

80

μs

Receive mode

Transmit mode

PHASE NOISE

Receive mode

−135

−145

70

dBc/Hz

dBc

10 MHz frequency offset

≥50 MHz frequency offset

REFERENCE AND CLOCK-RELATED

SPURIOUS

Receive mode; f_CHANNEL= 2405 MHz, 2450 MHz, and

2480 MHz

INTEGER BOUNDARY SPURS

60

dBc

Receive mode; measured at 400 kHz offset from

f

_CHANNEL= 2405 MHz, 2418 MHz, 2431 MHz,

2444 MHz, 2457 MHz, 2470 MHz

CRYSTAL OSCILLATOR

Crystal Frequency

26

18

7

MHz

pF

Parallel load resonant crystal

Maximum Parallel Load Capacitance

Minimum Parallel Load Capacitance

Maximum Crystal ESR

365.3

Ω

Guarantees maximum crystal frequency error of

0.2 ppm; 33 pF on XOSC26P and XOSC26N

Sleep-to-Idle Wake-Up Time

300

μs

15 pF load on XOSC26N and XOSC26P

Rev. 0 | Page 5 of 72

ADF7241

TRANSMITTER SPECIFICATIONS

Table 3.

Parameter

Min Typ

Max

Unit

Test Conditions

TRANSMITTER SPECIFICATIONS

Maximum Transmit Power

Minimum Transmit Power

Maximum Transmit Power (High Power

Mode)

3

−25

4.8

dBm

Refer to Power Amplifier section for details on how

to enable this mode

Minimum Transmit Power (High Power

Mode)

Transmit Power Variation

−22

2

dBm

dB

Transmit power = 3 dBm, f_CHANNEL= 2400 MHz to

2483.5 MHz, T_A= −40°C to +85°C, VDD_BAT = 1.8 V

to 3.6 V

Transmit Power Control Resolution

Optimum PA Matching Impedance

Harmonics and Spurious Emissions

Compliance with ETSI EN 300 440

25 MHz to 30 MHz

2

dB

Ω

Transmit power = 3 dBm

For maximum transmit power = 3 dBm

43.7 + 35.2j

−36

−54

dBm

Unmodulated carrier, 10 kHz RBW¹

Unmodulated carrier, 100 kHz RBW¹

30 MHz to 1 GHz

47 MHz to 74 MHz, 87.5 MHz to

118 MHz, 174 MHz to 230 MHz,

470 MHz to 862 MHz

Otherwise Above 1 GHz

Compliance with ETSI EN 300 328

1800 MHz to 1900 MHz

5150 MHz to 5300 MHz

Compliance with FCC CFR47, Part15

4.5 GHz to 5.15 GHz

−30

dBm

Unmodulated carrier, 1 MHz RBW¹

Unmodulated carrier

−47

−97

dBm

dBm/Hz

−41

dBm

%

1 MHz RBW¹

Measured using Rohde & Schwarz FSU vector

analyzer with Zigbee™ option

f_CHANNEL= 2405 MHz to 2480 MHz, T_A= −40°C to

+85°C, VDD_BAT = 1.8 V to 3.6 V

7.25 GHz to 7.75 GHz

Transmit EVM

2

1

Transmit EVM Variation

%

Transmit PSD Mask

Transmit 20 dB Bandwidth

−56

2252

dBm

MHz

RBW = 100 kHz; |f – f_CHANNEL| > 3.5 MHz

¹RBW = resolution bandwidth.

RECEIVER SPECIFICATIONS

Table 4.

Parameter

Min

Typ

Max

Unit

Test Conditions

GENERAL RECEIVER SPECIFICATIONS

RF Front-End LNA and Mixer IIP3

−13.6

dBm

At maximum gain, f_BLOCKER1= 5 MHz,

f_BLOCKER2= 10.1 MHz, P_RF,IN= −35 dBm

At maximum gain, f_BLOCKER1= 20 MHz,

f_BLOCKER2= 40.1 MHz,

P_RF,IN= −35 dBm

At maximum gain, f_BLOCKER1= 40 MHz,

f_BLOCKER2= 80.1 MHz,

−12.6

−10.5

dBm

P

_RF,IN= −35 dBm

Rev. 0 | Page 6 of 72

ADF7241

Parameter

Min

Typ

Max

Unit

Test Conditions

At maximum gain, f_BLOCKER1= 5 MHz,

_BLOCKER2= 5.5 MHz, P_RF,IN= −50 dBm

RF Front-End LNA and Mixer IIP2

24.7

dBm

f

RF Front-End LNA and Mixer 1 dB

Compression Point

−20.5

dBm

At maximum gain

Receiver LO Level at RFIO2 Port

LNA Input Impedance at RFIO1x Port

LNA Input Impedance at RFIO2x Port

Receive Spurious Emissions

−100

50.2 − 52.2j

74.3 − 10.7j

dBm

Ω

IEEE 802.15.4 packet mode

Measured in RX state

Compliant with EN 300 440

30 MHz to 1000 MHz

1 GHz to 12.75 GHz

−57

−47

dBm

RECEIVE PATH IEEE 802.15.4-2006 MODE

Sensitivity (P_rf,in,min, IEEE 802.15.4)

−95

−15

dBm

1% PER with PSDU length of 20 bytes

according to the IEEE 802.15.4-2006

standard

1% PER with PSDU length of 20 bytes

P_RF,IN= P_RF,IN,MIN, IEEE 802.15.4 + 3 dB

Saturation Level

CW Blocker Rejection

5 MHz

55

60

63

64

dB

10 MHz

20 MHz

30 MHz

Modulated Blocker Rejection

5 MHz

P_RF,IN= P_RF,IN,MIN, IEEE 802.15.4 + 3 dB

48

61

62.5

65

dB

10 MHz

15 MHz

20 MHz

30 MHz

Co-Channel Rejection

Out-of Band Blocker Rejection

−6

P_RF,IN= P_RF,IN,MIN+ 10 dB modulated blocker

P_RF,IN= P_RF,IN,MIN, IEEE 802.15.4 + 3 dB,

measured at f_CHANNEL= 2405 MHz

−5 MHz

−34.2

−30.7

−29.7

−25.7

−24.2

dBm

−10 MHz

−20 MHz

−30 MHz

−60 MHz

P_RF,IN= P_RF,IN,MIN, IEEE 802.15.4 + 3 dB,

measured at f_CHANNEL= 2480 MHz

+5 MHz

+10 MHz

+20 MHz

+30 MHz

+60 MHz

−33.4

−29.9

−28.2

−23.7

−29.9

2252

dBm

kHz

Receiver Channel Bandwidth

Two-sided bandwidth; cascaded analog and

digital channel filtering

Frequency Error Tolerance

RSSI

−80

+80

ppm

P_RF,IN= P_RF,IN,MIN+ 3 dB

Measured using IEEE 802.15.4-2006 packet

mode

Dynamic range

Accuracy

85

3

dB

Averaging Time

Minimum Sensitivity

128

−95

μs

dBm

Rev. 0 | Page 7 of 72

ADF7241

AUXILIARY SPECIFICATIONS

Table 5.

Parameter

Min

Typ

Max

Unit

Test Conditions

32 kHz RC OSCILLATOR

Frequency

32.768

1

kHz

%

After calibration

After calibration at 25°C

Frequency Accuracy

Frequency Drift

Temperature Coefficient

Voltage Coefficient

Calibration Time

32 kHz CRYSTAL OSCILLATOR

Frequency

0.14

4

1

%/°C

%/V

ms

32.768

319.8

2000

kHz

kΩ

ms

Maximum ESR

Start-Up Time

10 pF on XOSC32KP and XOSC32KN

12.5 pF load capacitors on XOSC32KP and

XOSC32KN

WAKE-UP TIMER

Prescaler Tick Period

Wake-Up Period

TEMPERATURE SENSOR

Range

0.0305

20,000

ms

61 × 10⁻⁶

1.31 × 10⁵sec

−40

+85

°C

Resolution

Accuracy

4.7

6.4

Average of 1000 ADC readbacks, after

using linear fitting, with correction at

known temperature

BATTERY MONITOR

Trigger Voltage

1.7

3.6

V

Trigger Voltage Step Size

Start-Up Time

Current Consumption

62

5

30

mV

μs

μA

EXTERNAL PA INTERFACE

R_ON, PAVSUP_ATB3 to VDD_BAT

R_OFF, PAVSUP_ATB3 to GND

R_OFF, PABIASOP_ATB4 to GND

PABIASOP_ATB4 Source Current, Maximum

PABIASOP_ATB4 Sink Current, Minimum

PABIASOP_ATB4 Current Control Resolution

PABIASOP_ATB4 Compliance Voltage

Servo Loop Bias Current

5

10

80

−80

6

150

3.45

22

Ω

extpa_bias_mode = 0, 1, 2, 5, 6

extpa_bias_mode = 3, 4, power-down

extpa_bias_mode = 0, power-down

expta_bias_mode = 1, 3

extpa_bias_mode = 2, 4

extpa_bias_mode = 1, 2, 3, 4, 5

extpa_bias_mode = 2, 4

extpa_bias_mode = 1, 3

extpa_bias_mode = 5, 6

MΩ

μA

Bits

mV

V

mA

Servo Loop Bias Current Control Step

0.349

Rev. 0 | Page 8 of 72

ADF7241

CURRENT CONSUMPTION SPECIFICATIONS

Table 6.

Parameter

Min

Typ

Max

Unit

Test Conditions

CURRENT CONSUMPTION

TX Mode Current Consumption

−20 dBm

16.5

17.4

19.6

21.5

25

1.8

10

19

mA

μA

IEEE 802.15.4-2006 continuous packet transmission mode

XTO26M + digital active

−10 dBm

0 dBm

+3 dBm

+4 dBm

Idle Mode

PHY_RDY Mode

RX Mode Current Consumption

MEAS State

SLEEP_BBRAM

SLEEP_BBRAM_RCO

IEEE 802.15.4-2006 packet mode

3

0.3

1

BBRAM contents retained

32 kHz RC oscillator running, some BBRAM contents

retained, wake-up time enabled

μA

SLEEP_BBRAM_XTO

1.7

μA

32 kHz crystal oscillator running, some BBRAM contents

retained, wake-up time enabled

TIMING AND DIGITAL SPECIFICATIONS

Table 7. Logic Levels

Parameter

Min

Typ

Max

Unit

Test Conditions

LOGIC INPUTS

Input High Voltage, V_INH

Input Low Voltage, V_INL

Input Current, I_INH/I_INL

Input Capacitance, C_IN

LOGIC OUTPUTS

0.7 × VDD_BAT

V

μA

pF

0.2 × V_DD

1

10

Output High Voltage, V_OH

Output Low Voltage, V_OL

Output Rise/Fall

VDD_BAT − 0.4

V

ns

pF

I_OH= 500 μA

I_OL= 500 μA

0.4

5

7

Output Load

Table 8. GPIOs

Parameter

Min

Typ

Max

Unit

Test Conditions

GPIO OUTPUTS

Output Drive Level

5

mA

All GPIOs in logic high state

All GPIOs in logic low state

Table 9. SPI Interface Timing

Parameter Min

Typ

Max

Unit

ns

Description

t₁

15

CS falling edge to MISO setup time (TRX active)

CS to SCLK setup time

t₂

t₃

t₄

t₅

t₆

t₇

t₈

40

80

ns

SCLK high time

SCLK low time

SCLK period

SCLK falling edge to MISO delay

MOSI to SCLK rising edge setup time

MOSI to SCLK rising edge hold time

10

5

Rev. 0 | Page 9 of 72

ADF7241

Parameter Min

Typ

Max

Unit

ns

Description

t₉

40

SCLK to CS hold time

t₁₀

10

ns

CS high to SCLK wait time

t₁₁

270

ns

CS high time

t₁₂

300

400

20

μs

CS low to MISO high wake-up time, 26 MHz crystal with 10 pF load capacitance, T_A= 25°C

t₁₃

ns

SCLK rise time

t₁₄

20

ns

SCLK fall time

t₁₅, t₁₆

2

ms

CS high time on wake-up after RC_RESET or RC_SLEEP command (see Figure 5 and

Figure 31) 26 MHz crystal with 10 pF load

Table 10. IEEE 802.15.4 State Transition Timing

Parameter

Min

Typ

142

13.5

192

140

192

23

192

14.5

5.5

30.5

19

Max

Unit

μs

Test Conditions

Idle to PHY_RDY State

PHY_RDY to Idle State

PHY_RDY or TX to RX State (Different Channel)

PHY_RDY or RX to TX State (Different Channel)

PHY_RDY or TX to RX State (Same Channel)

RX or PHY_RDY to TX State (Same Channel)

RX Channel Change

TX Channel Change

TX to PHY_RDY State

PHY_RDY to CCA State

CCA to PHY_RDY State

RX to Idle State

TX to Idle State

Idle to MEAS State

MEAS to Idle State

CCA to Idle State

RX to CCA State

CCA to RX State

VCO calibration performed

VCO calibration skipped

VCO calibration performed

6

14.5

18

205

Table 11. Timing IEEE 802.15.4-2006 SPORT Mode

Parameter Min

Typ

Max

Unit

μs

Test Conditions/Comments

t₂₁

t₂₂

t₂₃

t₂₄

t₃₅

t₃₆

t₃₇

18

SFD detect to TRCLK_CKO_GP3 (data bit clock) active delay

TRCLK_CKO_GP3 bit period

DR_GP0 to TRCLK_CKO_GP3 falling edge setup time

TRCLK_CKO_GP3 symbol burst period

PA nominal power to TRCLK_CKO_GP3 activity/entry into TX state

RC_PHY_RDY to TRCLK_CKO_GP3 off

RC_PHY_RDY to PA power shutdown

2

0.51

1.3

16

6.2

14

10

Table 12. MAC Timing

Parameter Min

Typ

Max

Unit

μs

Test Conditions/Comments

t₂₆

t₂₇

38

Time from frame received to rx_pkt_rcvd interrupt generation

Time allowed, from issuing a RC_TX command, to update

Register delaycfg2, Bit mac_delay_ext (0x10B[7:0])

Time allowed, from issuing a RC_TX command, to cancel the RC_TX

command

IEEE 802.15.4 mode as defined by the standard

150

t₂₈

μs

t_{RX_MAC_DELAY}

192

Rev. 0 | Page 10 of 72

ADF7241

TIMING DIAGRAMS

SPI Interface Timing Diagram

CS

t₁₁

t₂

t₃t₄

t₅

t₉t₁₀

SCLK

MISO

t₁

t₆

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

BIT 7

BIT 0

X

BIT 7

t₈

t₇

MOSI

7

6

5

4

3

2

1

0

7

Figure 3. SPI Interface Timing

Additional description and timing diagrams are available in the Serial Peripheral interface section.

Sleep-to-Idle SPI Timing Diagrams

CS

t₉

SCLK

MISO

7

6

5

4

3

2

1

0

t₁₂

t₆

t₁

X

Figure 4. Sleep-to-Idle State Timing

t₁₆

CS

RC_RESET OR

RC_SLEEP

SPI COMMAND

TO ADF7242

IDLE, PHY_RDY, RX

SLEEP

IDLE

DEVICE STATUS

Figure 5. Wake-Up After an RC_RESET or RC_SLEEP Command

Rev. 0 | Page 11 of 72

ADF7241

MAC Delay Timing Diagram

PACKET

TRANSMITTED

FRAME IN TX_BUFFER

PACKET

RECEIVED

VALID IEEE802.15.4-2006 FRAME

PHY_RDY

RC_STATUS

RX

TX

tx_mac_delay +

mac_delay_ext

t₂₆

t_27,t₂₈

REGISTER irq_src0, FIELD rc_ready

REGISTER irq_src1, FIELD rx_pkt_rcvd

REGISTER irq_src1, FIELD tx_pkt_sent

Figure 6. IEEE 802.15.4 MAC Timing

Rev. 0 | Page 12 of 72

ADF7241

IEEE 802.15.4 RX SPORT Mode Timing Diagrams

Table 13. IEEE 802.15.4 RX SPORT Modes Configurations

Register rc_cfg, Field rc_mode

(0x13E[7:0])

Register gp_cfg, Field gpio_config

(0x32C[7:0])

Functionality

2

0

1

7

Bit clock and data available (see Figure 7)

Symbol clock and data available (see Figure 8)

RC_RX

RC_PHY_RDY

COMMAND

PREVIOUS STATE

RC_STATUS

RX

PHY_RDY

t₂₉

t_{RX_MAC_DELAY}

PREAMBLE SFD

PHR

t₂₁

PSDU

t₂₁

TRCLK_CKO_GP3

DR_GP0

t₂₄

.....

DATA

INVALID

.....

TRCLK_CKO_GP3

_{DR_GP0}.....

t₂₃

t₂₂

Figure 7. IEEE 802.15.4 RX SPORT Mode: Bit Clock and Data Available

RC_RX

RC_PHY_RDY

COMMAND

PREVIOUS STATE

RC_STATUS

RX

PHY_RDY

t₂₉

t_{RX_MAC_DELAY}

PREAMBLE SFD

PHR

t₂₁

PSDU

t₂₆

t₂₁

TRCLK_CKO_GP3

1

SYMBOL

GP6, GP5, GP1, GP0

[3:0]

[3:0] [3:0]

[3:0]

1

GP6 = RXEN_GP6

GP5 = TXEN_GP5

GP1 = DT_GP1

GP0 = DR_GP0

Figure 8. IEEE 802.15.4 RX SPORT Mode: Symbol Clock Output

Rev. 0 | Page 13 of 72

ADF7241

IEEE 802.15.4 TX SPORT Mode Timing Diagram

Table 14. IEE 802.15.4 TX SPORT Mode Configurations

Register rc_cfg, Field rc_mode

(0x13E[7:0])

Register gp_cfg, Field gpio_config

(0x32C[7:0])

Functionality

3

1 or 4

Transmission starts after PA ramp up (see Figure 9)

gpio_config = 1: data clocked in on rising edge of clock

gpio_config = 4: data clocked in on falling edge of clock

RC_TX

RC_PHY_RDY

PHY_RDY

t₃₇

PHY_RDY

TX

RC STATE

PA POWER

t₃₅

PACKET

COMPONENT

PREAMBLE

SFD

PHR

PSDU

t₃₆

TRCLK_CKO_GP3

DT_GP1

.....

PACKET DATA

.....

REGISTER gp_cfg, FIELD gpio_config = 1

DATA CLOCKED IN ON RISING EDGE

t₃₂

REGISTER gp_cfg, FIELD gpio_config = 4

DATA CLOCKED IN ON FALLING EDGE

t₃₂

TRCLK_CKO_GP3

DT_GP1 SAMPLE

DT_GP1

t₃₃

t₃₄

Figure 9. IEEE 802.15.4-2006 TX SPORT Mode

t₃₃

t₃₄

Refer to the SPORT Interface section for further details.

Rev. 0 | Page 14 of 72

ADF7241

ABSOLUTE MAXIMUM RATINGS

T_A= 25°C, unless otherwise noted.

The exposed paddle of the LFCSP package should be connected

to ground.

Table 15.

This device is a high performance RF integrated circuit with an

ESD rating of <2 kV, and it is ESD sensitive. Proper precautions

should be taken for handling and assembly.

Parameter

Rating

VDD_BAT to GND

−0.3 V to +3.9 V

Operating Temperature Range

Industrial

Storage Temperature Range

Maximum Junction Temperature

LFCSP θ_JAThermal Impedance

Reflow Soldering

−40°C to +85°C

−65°C to +125°C

150°C

ESD CAUTION

26°C/W

Peak Temperature

Time at Peak Temperature

260°C

40 sec

Stresses above those listed under Absolute Maximum Ratings

may cause permanent damage to the device. This is a stress

rating only; functional operation of the device at these or any

other conditions above those indicated in the operational

section of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect

device reliability.

Rev. 0 | Page 15 of 72

ADF7241

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

CREGRF1 1

24 CS

23

2

RBIAS

MOSI

CREGRF2 3

RFIO1P 4

22 SCLK

21 MISO

ADF7241

TOP VIEW

5

6

20

19

RFIO1N

RFIO2P

IRQ1_GP4

TRCLK_CKO_GP3

(Not to Scale)

RFIO2N 7

CREGRF3 8

18 IRQ2_TRFS_GP2

17 DT_GP1

NOTES

1. THE EXPOSED PADDLE MUST BE CONNECTED TO GROUND.

Figure 10. Pin Configuration

Table 16. Pin Function Descriptions

Pin No.

Mnemonic

Description

1

CREGRF1

Regulated Supply Terminal for RF Section. Connect a 220 nF decoupling capacitor from this pin to

GND.

2

RBIAS

Bias Resistor 27 kΩ to Ground.

3

4

5

6

7

8

9

10

11

12

CREGRF2

RFIO1P

RFIO1N

RFIO2P

RFIO2N

CREGRF3

CREGVCO

VCOGUARD

CREGSYNTH

XOSC26P

Regulated Supply for RF Section. Connect a 100 pF decoupling capacitor to ground.

Differential RF Input Port 1 (Positive Terminal). A 10 nF coupling capacitor is required.

Differential RF Input Port 1 (Negative Terminal). A 10 nF coupling capacitor is required.

Differential RF Input/Output Port 2 (Positive Terminal). A 10 nF coupling capacitor required.

Differential RF Input/Output Port 2 (Negative Terminal). A 10 nF coupling capacitor required.

Regulated Supply for RF Section. Connect a 100 pF decoupling capacitor from this pin to GND.

Regulated Supply for VCO Section. Connect a 220 nF decoupling capacitor from this pin to GND.

Guard Trench for VCO Section. Connect to Pin 9 (CREGVCO).

Regulated Supply for PLL Section. Connect a 220 nF decoupling capacitor from this pin to GND.

Terminal 1 of External Crystal and Loading Capacitor. This pin is no connect (NC) when an external

oscillator is used.

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

XOSC26N

DGUARD

CREGDIG2

DR_GP0

Terminal 2 of External Crystal and Loading Capacitor. Input for external oscillator.

Guard Trench for Digital Section. Connect to Pin 15 (CREGDIG2).

Regulated Supply for Digital Section. Connect a 220 nF decoupling capacitor to ground.

SPORT Receive Data Output/General-Purpose IO Port.

SPORT Transmit Data Input/General-Purpose IO Port.

Interrupt Request Output 2/IEEE 802.15.4-2006 Symbol Clock/General-Purpose IO Port.

SPORT Clock Output/General-Purpose IO Port.

Interrupt Request Output 1/General-Purpose IO Port.

SPI Interface Serial Data Output.

SPI Interface Data Clock Input.

SPI Interface Serial Data Input.

DT_GP1

IRQ2_TRFS_GP2

TRCLK_CKO_GP3

IRQ1_GP4

MISO

SCLK

MOSI

CS

SPI Interface Chip Select Input (and Wake-Up Signal).

TXEN_GP5

RXEN_GP6

CREGDIG1

XOSC32KP_GP7_ATB1

XOSC32KN_ATB2

External PA Enable Signal/General-Purpose IO Port.

External LNA Enable Signal/General-Purpose IO Port.

Regulated Supply for Digital Section. Connect a 1 nF decoupling capacitor from this pin to ground.

Terminal 1 of 32 kHz Crystal Oscillator/General-Purpose IO Port/Analog Test Bus 1.

Terminal 2 of 32 kHz Crystal Oscillator/Analog Test Bus 2.

Rev. 0 | Page 16 of 72

ADF7241

Pin No.

30

Mnemonic

VDD_BAT

Description

Unregulated Supply Input from Battery.

31

32

33 (EPAD)

PAVSUP_ATB3

PABIAOP_ATB4

GND

External PA Supply Terminal/Analog Test Bus 3.

External PA Bias Voltage Output/Analog Test Bus 4.

Common Ground Terminal. The exposed paddle must be connected to ground.

Rev. 0 | Page 17 of 72

ADF7241

TYPICAL PERFORMANCE CHARACTERISTICS

80

70

60

50

40

30

20

10

0

2.0

2.405GHz, 1.8V, +25°C

2.48GHz, 1.8V, +25°C

1.8

2.405GHz, 3.6V, +25°C

2.48GHz, 3.6V, +25°C

1.6

2.405GHz, 1.8V, –40°C

2.48GHz, 1.8V, –40°C

1.4

2.405GHz, 3.6V, –40°C

2.48GHz, 3.6V, –40°C

1.2

2.405GHz, 1.8V, +85°C

2.48GHz, 1.8V, +85°C

1.0

2.405GHz, 3.6V, +85°C

2.48GHz, 3.6V, +85°C

0.8

1.8V, +25°C

3.6V, +25°C

1.8V, –40°C

3.6V, –40°C

1.8V, +85°C

3.6V, +85°C

0.6

0.4

0.2

0

–10

–45 –40 –35 –30 –25 –20 –15 –10 –5

0

5

10 15 20 25 30

–100

–90

–93

–80

–70

–60

–50

–40

–30

–20

BLOCKER FREQUENCY OFFSET (MHz)

RF INPUT POWER LEVEL (dBm)

–96

Figure 11. IEEE 802.15.4-2006 Packet Mode Sensitivity vs. Temperature and

VDD_BAT, f_CHANNEL= 2.405 GHz, 2.45 GHz, 2.48 GHz, RFIO2x

Figure 14. IEEE 802.15.4-2006 Packet Mode Blocker Rejection vs. Temperature

and VDD_BAT, Modulated Blocker, P_WANTED= −85 dBm + 3 dB,

f

_CHANNEL= 2.45 GHz, RFIO2x

2.0

80

70

60

50

40

30

20

10

0

3.6V, +25°C

1.8V, +25°C

3.6V, –40°C

1.8V, –40°C

3.6V, +85°C

1.8V, +85°C

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

VDD_BAT = 3.6V

TEMPERATURE = 25°C

–10

–20

–100

–90

–80

–70

–60

–50

–40

–30

–20

–110 –90 –70 –50 –30 –10 10

50

70

90 110

RF INPUT POWER LEVEL (dBm)

BLOCKER FREQUENCY OFFSET (MHz)

–96.5 –95

Figure 15. IEEE 802.15.4-2006 Packet Mode Wide-Band Blocker Rejection,

CW Blocker, P_WANTED= −95 dBm + 3 dB, f_CHANNEL= 2.45 GHz, RFIO2x

Figure 12. IEEE 802.15.4-2006 Packet Mode PER vs. RF Input Power Level vs.

Temperature and VDD_BAT, f_CHANNEL= 2.45 GHz, RFIO2x

80

70

60

50

40

30

20

10

0

2.0

2.405GHz, 1.8V, +25°C

2.450GHz, 1.8V, +25°C

2.475GHz, 1.8V, +25°C

2.405GHz, 3.6V, +25°C

2.450GHz, 3.6V, +25°C

2.475GHz, 3.6V, +25°C

2.405GHz, 1.8V, –40°C

2.450GHz, 1.8V, –40°C

2.475GHz, 1.8V, –40°C

2.405GHz, 3.6V, –40°C

2.450GHz, 3.6V, –40°C

2.475GHz, 3.6V, –40°C

2.405GHz, 1.8V, +85°C

2.450GHz, 1.8V, +85°C

2.475GHz, 1.8V, +85°C

2.405GHz, 3.6V, +85°C

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

2.450GHz, 3.6V, +85°C

2.475GHz, 3.6V, +85°C

VDD_BAT = 3.6V

TEMPERATURE = 25°C

–10

–20

0.2

0

–20 –16 –12

–8

–4

0

4

8

12

16

20

–100 –98 –96 –94

–92 –90 –88 –86 –84 –82 –80

RF INPUT POWER LEVEL (dBm)

BLOCKER FREQUENCY OFFSET (MHz)

–96 –93

Figure 16. IEEE 802.15.4 Packet Mode Narrow-Band Blocker Rejection,

CW Blocker, P_WANTED= −95 dBm + 3 dB, f_CHANNEL= 2.45 GHz, RFIO2x

Figure 13. IEEE 802.15.4 Packet Mode Sensitivity vs. Temperature and

VDD_BAT, f_CHANNEL= 2.405 GHz, 2.45 GHz, 2.475 GHz, RFIO1x

Rev. 0 | Page 18 of 72

ADF7241

6

5

4

3

2

1

80

MAX 1.8V, +25°C

MIN 1.8V, +25°C

MAX 3.6V, +25°C

MIN 3.6V, +25°C

MAX 1.8V, –40°C

MIN 1.8V, –40°C

MAX 3.6V, –40°C

MIN 3.6V, –40°C

70

60

50

40

30

20

10

0

–1

–2

–3

–4

–5

1.8V, +25°C

3.6V, +25°C

1.8V, –40°C

3.6V, –40°C

1.8V, +85°C

3.6V, +85°C

MAX 1.8V, +85°C

MIN 1.8V, +85°C

MAX 3.6V, +85°C

MIN 3.6V, +85°C

–6

–10

–95 –90 –85 –80 –75 –70 –65 –60 –55 –50 –45 –40 –35 –30 –25 –20

RF INPUT LEVEL (dBm)

–45 –40 –35 –30 –25 –20 –15 –10 –5

0

5

10 15 20 25 30

BLOCKER FREQUENCY OFFSET (MHz)

Figure 17. IEEE 802.15.4 Packet Mode Wide-Band Blocker Rejection vs.

Temperature and VDD_BAT, Modulated Blocker, P_WANTED= −95 dBm + 3 dB,

f_CHANNEL= 2.45 GHz, RFIO2x

Figure 20. IEEE 802.15.4 Packet Mode RSSI Error vs. RF Input Power Level vs.

Temperature and VDD_BAT, f_CHANNEL= 2.45 GHz, RFIO2x

80

70

60

50

40

30

275

250

225

200

175

150

125

MAX 1.8V, +25°C

MAX 3.6V, +25°C

MAX 1.8V, –40°C

MAX 3.6V, –40°C

MAX 1.8V, +85°C

MAX 3.6V, +85°C

MIN 1.8V, +25°C

MIN 3.6V, +25°C

MIN 1.8V, –40°C

MIN 3.6V, –40°C

MIN 1.8V, +85°C

MIN 3.6V, +85°C

100

75

20

10

1.8V, +25°C

3.6V, +25°C

1.8V, –40°C

3.6V, –40°C

1.8V, +85°C

3.6V, +85°C

50

0

25

0

–10

–20 –16 –12

–8

–4

0

4

8

12

16

20

–100 –95 –90 –85 –80 –75 –70 –65 –60 –55 –50 –45 –40 –35 –30 –25–20

INTERFERER FREQUENCY OFFSET (MHz)

RF INPUT LEVEL (dBm)

Figure 18. IEEE 802.15.4 Packet Mode Narrow-Band Blocker Rejection vs.

Temperature and VDD_BAT, Modulated Blocker, P_WANTED= −95 dBm + 3 dB,

f_CHANNEL= 2.45 GHz, RFIO2x

Figure 21. IEEE 802.15.4 Packet Mode SQI vs. RF Input Power Level vs.

Temperature and VDD_BAT, f_CHANNEL= 2.45 GHz, RFIO2x

–20

110

CHANNEL 2.405GHz

THRESHOLD =

100

CHANNEL 2.48GHz

–22

–80

–70

–60

–50

dBm

–40

dBm

–30

dBm

–20

dBm

dBm dBm

90

80

70

60

50

40

30

–24

–26

–28

–30

–90

dBm

–32

–34

–36

20

10

0

–110 –90 –70 –50 –30 –10 10

30

50

70

90 110

–90 –85 –80 –75 –70 –65 –60 –55 –50 –45 –40 –35 –30 –25 –20 –15

RF INPUT POWER LEVEL (dBm)

BLOCKER FREQUENCY OFFSET (MHz)

Figure 19. IEEE 802.15.4 Packet Mode Out-of-Band Blocker Rejection,

CW Blocker, P_WANTED= −95 dBm + 3 dB, f_CHANNEL= 2.405 GHz and 2.48 GHz,

RFIO2x, VDD_BAT = 3.6 V, Temperature = 25°C

Figure 22. IEEE 802.15.4-2006 CCA Operation vs. RSSI Threshold,

f_CHANNEL= 2.45 GHz, VDD_BAT = 3.6 V, Temperature = 25°C, RFIO2x

Rev. 0 | Page 19 of 72

ADF7241

0

–10

–20

–30

–40

–50

4

1.8V, +25°C

3.6V, +25°C

1.8V, –40°C

3.6V, –40°C

1.8V, +85°C

3.6V, +85°C

2

0

–2

–4

–6

–8

–10

–12

–14

–16

–18

–20

3.6V, +85°C

3.6V, +25°C

3.6V, –40°C

1.8V, –40°C

1.8V, +25°C

1.8V, +80°C

–22

–24

–26

–60

–70

–28

–5

–4

–3

–2

–1

0

1

2

3

4

5

3

4

5

6

7

8

9

10 11 12 13 14 15

PA LEVEL SETTING

FREQUENCY ERROR (kHz)

Figure 26. PA Output Power vs. Control Word, Temperature, and VDD_BAT,

f_CHANNEL= 2.44 GHz (A discrete matching network and a harmonic filter are

used as per the ADF7241 reference design.)

Figure 23. IEEE 802.15.4-2006 Transmitter Spectrum vs. Temperature and

VDD_BAT, f_CHANNEL= 2.45 GHz, Output Power = 3 dBm

5.0

2.5

EVM 1.8V, +25°C

EVM 3.6V, +25°C

2.4

2.3

2.2

2.1

2.0

1.9

EVM 1.8V, –40°C

EVM 3.6V, –40°C

EVM 1.8V, +85°C

EVM 3.6V, +85°C

0

–2.5

–5.0

–7.5

–10.0

–12.5

–15.0

–17.5

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

–20.0

HIGH POWER MODE

DEFAULT MODE

–22.5

–25.0

–27.5

1.0

2405

3

4

5

6

7

8

9

10 11 12 13 14 15 16

2415

2425

2435

2445

2455

2465

2475

POWER AMPLIFIER CONTROL WORD

CHANNEL FREQUENCY (MHz)

Figure 27. Transmitter Output Power vs. Control Word for Default and High

Power Modes, f_CHANNEL= 2.45 GHz, VDD_BAT = 3.6 V, Temperature = 25°C,

RF Carrier Frequency, Temperature, and VDD_BAT

Figure 24. IEEE 802.15.4-2006 Transmitter EVM vs. Temperature and

VDD_BAT at All Channels, Output Power = 3 dBm

(A discrete matching network and a harmonic filter are used as per the

ADF7241 reference design.)

26.0

25.5

25.0

24.5

24.0

4.0

3.5

3.0

2.5

2.0

HIGH POWER MODE

DEFAULT MODE

23.5

23.0

22.5

22.0

21.5

21.0

20.5

20.0

19.5

19.0

18.5

18.0

17.5

17.0

16.5

16.0

1.5

3.6V, +85°C

3.6V, +25°C

3.6V, –40°C

1.8V, –40°C

1.8V, +25°C

1.0

0.5

1.8V, +80°C

0

2.40

3

4

5

6

7

8

9

10 11 12 13 14 15

2.41

2.42

2.43

2.44

2.45

2.46 2.47

2.48

POWER AMPLIFIER CONTROL WORD

FREQUENCY (GHz)

Figure 28. Transmitter Current Consumption vs. Control Word, for Default

and High Power Modes, f_CHANNEL= 2.45 GHz, VDD_BAT = 3.6 V,

Temperature = 25°C

Figure 25. PA Output Power vs. RF Carrier Frequency, Temperature, and VDD_BAT

(A discrete matching network and a harmonic filter are used as per the

ADF7241 reference design.)

Rev. 0 | Page 20 of 72

ADF7241

85

80

75

70

3-SIGMA TEMPERATURE ERROR

TEMPERATURE READING (LINEAR FITTING)

TEMPERATURE READING

65

60

(POLYNOMIAL FITTING)

55

50

45

40

35

30

25

20

15

10

5

0

–5

–10

–15

–20

–25

–30

–35

–40

–40 –30 –20 –10

0

10 20 30 40 50 60 70 80

TEMPERATURE (°C)

Figure 29. Temperature Sensor Performance

(Average of 1000 ADC Readbacks) and 3-∑ Error vs. Temperature,

VDD_BAT = 3.6 V

Rev. 0 | Page 21 of 72

ADF7241

TERMINOLOGY

OCL

ACK

Offset correction loop

IEEE 802.15.4-2006 acknowledgment frame

OQPSK

ADC

Offset-quadrature phase shift keying

Analog-to-digital converter

PA

AGC

Power amplifier

Automatic gain control

PHR

PHY header

Battmon

Battery monitor

PHY

Physical layer

CCA

Clear channel assessment

POR

Power-on reset

BBRAM

Backup battery random access memory

PSDU

PHY service data unit

CSMA/CA

Carrier-sense-multiple-access with collision avoidance

RC

DR

Data rate

Radio controller

RCO32K

32 kHz RC oscillator

DSSS

Direct sequence spread spectrum

RSSI

FCS

Receive signal strength indicator

Frame check sequence

RTC

Real-time clock

FHSS

Frequency hopping spread spectrum

SFD

FCF

Start-of-frame delimiter

Frame control field

SQI

LQI

Signal quality indicator

Link quality indicator

VCO

MCR

Voltage-controlled oscillator

Modem configuration register

WUC

Wake-up controller

MCU

Microcontroller unit

XTO26M

26 MHz crystal oscillator

NC

Not connected

XTO32K

32 kHz crystal oscillator

Rev. 0 | Page 22 of 72

ADF7241

RADIO CONTROLLER

COLD START

(BATTERY APPLIED)

CONFIGURE DEVICE

FIRMWARE DOWNLOAD

FOR EXAMPLE, IEEE 802.15.4 AUTO-MODES

WUC TIMEOUT

RC_MEAS

RC_IDLE

CS

MEAS

IDLE

SLEEP

RC_SLEEP

(FROM ANY STATE)

RC_RESET

(FROM ANY STATE)

CCA COMPLETE

RC_PHY_RDY

CCA

PHY_RDY

RC_CCA

RC_TX

RC_RX

RX

TX

RC_RX

RC_TX

2

AUTO_RX_TO_TX_TURNAROUND

AUTO_TX_TO_RX_TURNAROUND

2

1

2

AVAILABLE IN PACKET MODE.

THESE TRANSITIONS ARE CONFIGURED IN BUFFERCFG (0x107[3:2]).

KEY

STATE TRANSITION INITIATED BY HOST MCU

AUTOMATIC STATE TRANSITION INITIATED BY RADIO CONTROLLER

RADIO STATE

Figure 30. State Diagram

Rev. 0 | Page 23 of 72

ADF7241

The ADF7241 incorporates a radio controller that manages the

state of the IC in various operating modes and configurations.

The host MCU can use single-byte commands to interface to

the radio controller. The function of the radio controller

includes the control of the sequence of powering up and

powering down various blocks as well as system calibrations in

different states of the device. Figure 30 shows the state diagram

of the ADF7241 with possible transitions that are initiated by

the host MCU and automatically by the radio controller.

The PHY_RDY state can be entered from the idle, RX, TX, or

CCA state by issuing an RC_PHY_RDY command.

RX State

The RF frequency synthesizer is automatically calibrated to the

programmed channel frequency upon entering the RX state from

the PHY_RDY or TX state. The frequency synthesizer calibra-

tion can be omitted for single-channel communication systems

if short turnaround times are required. Following a programmable

MAC delay period, the ADF7241 starts searching for a preamble

and a synchronization word if enabled by the user.

Device Initialization

When the battery voltage is first applied to the ADF7241, a cold

start-up sequence should be followed, as shown in Figure 31.

The start-up sequence is as follows:

The RX state can be entered from the PHY_RDY, CCA, and TX

states by issuing an RC_RX command. Depending on whether

the device is configured to operate in packet or SPORT mode by

setting Register buffercfg, Field rx_buffer_mode, the device can

revert automatically to the PHY_RDY state when a packet is

received, or remain in the RX state until a command to enter a

different state is issued. Refer to the Receiver section for further

details.

•

Apply the battery voltage, VDD_BAT, to the device with

the desired voltage ramp rate. After a time, t_RAMP

VDD_BAT reaches its final voltage value.

,

•

After t_RAMP, execute the SPI command, RC_RESET. This

command resets and shuts down the device.

CS

After the specified time, t₁₅, the host MCU can set the

port of the SPI low.

CCA State

Upon entering the CCA state, a clear channel assessment is

performed. The CCA state can be entered from the PHY_RDY

or RX state by issuing an RC_CCA command. By default, upon

completion of the clear channel assessment, the ADF7241

automatically reverts to the state from which the RC_CCA

command originated.

Wait until the MISO output of the SPI (SPI_READY flag)

goes high, at which time the device is in the idle state and

ready to accept commands.

CS

A power-on reset takes place when the host MCU sets the

port of the SPI low. All device LDOs are enabled together with

the 26 MHz crystal oscillator and the digital core. After the

radio controller initializes the configuration registers to their

default values, the device enters the idle state.

TX State

Upon entering the TX state, the RF frequency synthesizer is

automatically calibrated to the programmed channel frequency.

The frequency synthesizer calibration can be omitted for

communication systems operating on a single channel if short

turnaround times are required. Following a programmable

delay period, the PA is ramped up and transmission is initiated.

The cold start-up sequence is needed only when the battery

voltage is first applied to the device. Afterwards, a warm start-

up sequence can be used where the host MCU can wake up the

CS

device from a sleep state by setting the

port of the SPI low.

The TX state can be entered from the PHY_RDY or RX state by

issuing the RC_TX command. Depending on whether the

device is configured to operate in packet or SPORT mode by

setting Register buffercfg, Field rx_buffer_mode, the device can

revert automatically to the PHY_RDY state when a packet is

transmitted, or remain in the TX state until a command to enter

a different state is issued. Refer to the Transmitter section for

further details.

Idle State

In this state, the receive and transmit blocks are powered down.

The digital section is enabled and all configuration registers, as

well as the packet RAM, are accessible. The host MCU must set

any configuration parameters, such as modulation scheme,

channel frequency, and WUC configuration, in this state.

CS

Bringing the

input low in the sleep state causes a transition

into the idle state. The transition from the sleep state to the idle

state timing is shown in Figure 4. The idle state can also be

entered by issuing an RC_IDLE command in any state other

than the sleep state.

MEAS State

The MEAS state is used to measure the chip temperature. The

transmitter and receiver blocks are not enabled in this state. The

chip temperature is measured using the ADC, which can be

read from Register adc_rbk, Field adc_out, and is continuously

updated with the chip temperature reading.

PHY_RDY State

Upon entering the PHY_RDY state from the idle state, the RF

frequency synthesizer is enabled and a system calibration is

carried out. The receive and transmit blocks are not enabled

in this state. The system calibration is omitted when the

PHY_RDY state is entered from the RX, TX, or CCA state.

This state is enabled by issuing the RC_MEAS command from the

idle state and can be exited using the RC_IDLE command.

Rev. 0 | Page 24 of 72

ADF7241

Sleep States

SLEEP_BBRAM_XTO

The sleep state is entered with the RC_SLEEP command. The

sleep state can be configured to operate in three different

modes, which are listed in Table 17.

This mode enables the 32 kHz crystal oscillator and retains

certain configuration registers in the BBRAM during the sleep

state. To enable SLEEP_BBRAM_XTO mode, set Register

tmr_cfg1, Field sleep_config = 5. A wake-up interrupt can be

set using, for example, Register irq1_en0, Field wakeup = 1.

Refer to the Wake-Up Controller (WUC) section for details on

how to configure the ADF7241 WUC.

Table 17. ADF7241 Sleep Modes

Active

Circuits

Sleep Mode

Functionality

SLEEP_BBRAM

BBRAM

Packet RAM and modem

configuration register (MCR)

contents are not maintained.

BBRAM retains the IEEE

802.15.4-2006 node

SLEEP_BBRAM_RCO

This mode enables the 32 kHz RC oscillator and retains certain

configuration registers in the BBRAM during the sleep state.

This mode can be used when lower timer accuracy is acceptable

by the communication system. It is enabled by setting Register

tmr_cfg1, Field sleep_config = 11. A wake-up interrupt can be

set using, for example, Register irq1_en0, Field wakeup = 1.

Refer to the Wake-Up Controller (WUC) section for details on

how to configure the ADF7241 WUC.

addresses¹.

SLEEP_BBRAM_XTO BBRAM and

32 kHz crystal oscillator is

enabled, with data retention

in the BBRAM.

32 kHz

crystal

oscillator

SLEEP_BBRAM_RCO BBRAM and

32 kHz RC oscillator is

enabled, with data retention

in the BBRAM.

32 kHz RC

Oscillator

Wake-Up from the Sleep State

¹Refer to the Receiver Configuration in Packet Mode section for further

details.

CS

The host MCU can bring

low at any time to wake the

CS

ADF7241 from the sleep state. After bringing

low, it must

SLEEP MODES

wait until the MISO output (SPI_READY flag) goes high prior

to accessing the SPI port. This delay reflects the start-up time of

the ADF7241. When the MISO output is high, the voltage

regulator of the digital section and the crystal oscillator have

stabilized. Unless the chip is in the sleep state, the MISO pin

The sleep modes are configurable with the wake-up configura-

tion registers, tmr_cfg0 and tmr_cfg1. The contents of Register

tmr_cfg0 and Register tmr_cfg1 are reset in the sleep state.

SLEEP_BBRAM

CS

always goes high immediately after bringing

low. The sleep

This mode is suitable for applications where the MCU is equipped

with its own wake-up timer. SLEEP_BBRAM mode is enabled

by setting Register tmr_cfg1, Field sleep_config = 1.

state can also be exited by a timeout event with the WUC

configured. Refer to the Wake-Up Controller (WUC) section

for details on how to configure the ADF7241 WUC.

t₁₅

APPLY

VDD_BAT

CS

RC_RESET

(0xC8)

SPI COMMAND

TO ADF7241

DEVICE STATE

IDLE

SLEEP

IDLE

Figure 31. Cold Start Sequence from Application of the Battery

Rev. 0 | Page 25 of 72

ADF7241

RF FREQUENCY SYNTHESIZER

used to mitigate the effect of temperature, supply voltage, and

process variations on the VCO performance.

A fully integrated RF frequency synthesizer is used to generate

both the transmit signal and the receive LO signal. The architec-

ture of the frequency synthesizer is shown in Figure 32. The

receiver uses the frequency synthesizer circuit to generate the

local oscillator (LO) for downconverting an RF signal to the

baseband. The transmitter is based on a direct closed-loop VCO

modulation scheme using a low noise fractional-N RF fre-

quency synthesizer, where a high resolution Σ-Δ modulator is

used to generate the required frequency deviations at the RF in

response to the data being transmitted.

The VCO calibration phase must not be skipped during the system

calibration in the PHY_RDY state. Therefore, it is important to

ensure that Register vco_cal_cfg, Field skip_vco_cal = 9 prior to

entering the PHY_RDY state from the idle state. This is the

default setting and, therefore, only requires programming if

skipping of the calibration was previously selected.

The VCO calibration can be skipped on the transition from the

PHY_RDY state to the RX, TX, and CCA states on the condi-

tion that the calibration has been performed in the PHY_RDY

state on the same channel frequency to be used in the RX, TX,

and CCA states. The following sequence should be used if

skipping the VCO calibration is required in any state following

the PHY_RDY state:

The VCO and the frequency synthesizer loop filter of the ADF7241

are fully integrated. To reduce the effect of VCO pulling by the

power-up of the power amplifier, as well as to minimize spurious

emissions, the VCO operates at twice the RF frequency. The

VCO signal is then divided by 2 giving the required frequency

for the transmitter and the required LO frequency for the receiver.

The frequency synthesizer also features automatic VCO calibra-

tion and bandwidth selection.

1. After the system calibration is performed in the PHY_RDY

state, the VCO frequency band in Register vco_band_rb,

Field vco_band_val_rb and the VCO bias DAC code in

Register vco_idac_rb, Field vco_idac_val_rb should be read

back.

RX AND TX

CIRCUITS

CHANNEL SELECTION

SDM

2. Before transitioning to any other state and assuming

operation on the same channel frequency, the VCO

frequency band and amplitude DAC should be overwritten

as follows:

IN RX OR TX

N-DIVIDER

DIV2

CHARGE-PUMP

AND

LOOP FILTER

PFD

26MHz XOSC

+ DOUBLER

a) Set Register vco_cal_cfg, Field skip_vco_cal = 15 to

skip the VCO calibration.

AUTO SYNTH

BANDWIDTH

SELECTION

b) Enable the VCO frequency over-write mode by setting

Register vco_ovrw_cfg, Field vco_band_ovrw_en = 1.

c) Write the VCO frequency band read back after the

system calibration in the PHY_RDY state to Register

vco_band_ovrw, Field vco_band_ovrw_val.

VCO

CALIBRATION

Figure 32. Synthesizer Architecture

RF FREQUENCY SYNTHESIZER CALIBRATION

The ADF7241 requires a system calibration prior to being

used in the RX, CCA, or TX state. Because the calibration

information is reset when the ADF7241 enters a sleep state, a

full system calibration is automatically performed on the

transition between the idle and PHY_RDY states. The system

calibration is omitted when the PHY_RDY state is entered from

the TX, RX, or CCA state.

d) Enable the VCO bias DAC over-write mode by setting

Register vco_ovrw_cfg, Field vco_idac_ovrw_en = 1

e) Write the VCO bias DAC read back after the system

calibration in the PHY_RDY state to Register

vco_idac_ovrw, Field vco_idac_ovrw_val .

Following the preceding procedure, the device can transition

to other states, which use the same channel frequency without

performing a VCO calibration. If it is required to change the

channel frequency before entering the RX, TX, or CCA state at any

point after the preceding procedure has been used, Register vco_

cal_cfg, Field skip_vco_cal must be set to 9 before transitioning

to the respective state. Then the VCO calibration is automati-

cally performed.

142µs

SYNTHESIZER

PWR Up RC Cal

24µs 20µs

VCO Cal

52µs

SETTLING

46µs

DO NOT SKIP,

SET REGISTER vco_cal_cfg, FIELD skip_vco_cal = 9

Figure 33. System Calibration Following RC_PHY_RDY

Figure 33 shows a breakdown of the total system calibration

time. It comprises a power-up delay, calibration of the receiver

baseband filter (RC Cal), and a VCO calibration (VCO Cal). Once

the VCO is calibrated, the frequency synthesizer is allowed to

settle to within 5 ppm of the target frequency. A fully auto-

matic fast VCO frequency and amplitude calibration scheme is

Rev. 0 | Page 26 of 72

ADF7241

RF FREQUENCY SYNTHESIZER BANDWIDTH

REFERENCE CRYSTAL OSCILLATOR

The ADF7241 radio controller optimizes the RF frequency synthe-

sizer bandwidth based on whether the device is in the RX or the

TX state. If the device is in the RX state, the frequency synthe-

sizer bandwidth is set by the radio controller to ensure optimum

blocker rejection. If the device is in the TX state, the radio

controller sets the frequency synthesizer bandwidth based on

the required data rate to ensure optimum modulation quality.

The on-chip crystal oscillator generates the reference frequency

for the frequency synthesizer and system timing. The oscillator

operates at a frequency of 26 MHz. The crystal oscillator is

amplitude controlled to ensure a fast start-up time and stable

operation under different operating conditions. The crystal and

associated external components should be chosen with care

because the accuracy of the crystal oscillator can have a significant

impact on the performance of the communication system. Apart

from the accuracy and drift specification, it is important to con-

sider the nominal loading capacitance of the crystal. Crystals

with a high loading capacitance are less sensitive to frequency

pulling due to tolerances of external capacitors and the printed

circuit board parasitic capacitances. When selecting a crystal, these

advantages should be balanced against the higher current

consumption, longer start-up time, and lower trimming range

resulting from a larger loading capacitance.

RF CHANNEL FREQUENCY PROGRAMMING

The frequency of the synthesizer is programmed with the

frequency control word, ch_freq[23:0], which extends over

Register ch_freq0, Register ch_freq1, and Register ch_freq2.

The frequency control word, ch_freq[23:0], contains a binary

representation of the absolute frequency of the desired channel

divided by 10 kHz.

Writing a new channel frequency value to the frequency control

word, ch_freq[23:0], takes effect after the next frequency synthe-

sizer calibration phase. The frequency synthesizer is calibrated

by default during the transition into the PHY_RDY from the

idle state as well as in the TX, RX and CCA states. Refer to the

RF Frequency Synthesizer Calibration, Transmitter, and

Receiver sections for further details. To facilitate fast channel

frequency changes, a new frequency control word can be

written in the RX state before a packet has been received. The

next RC_RX or RC_TX command initiates the required

frequency synthesizer calibration and settling cycle. Similarly, a

new frequency control word can be written after a packet has

been transmitted while in the TX state and the next RC_RX or

RC_TX command initiates the frequency synthesizer

calibration and settling cycle.

The total loading capacitance must be equal to the specified

load capacitance of the crystal and comprises the external

parallel loading capacitors, the parasitic capacitances of the

XOSC26P and XOSC26N pins, as well as the parasitic capaci-

tance of tracks on the printed circuit board.

The ADF7241 has an integrated crystal oscillator tuning capacitor

that facilitates the compensation of systematic production

tolerance and temperature drift. The tuning capacitor is con-

trolled with Register xto26_trim _cal, Field xto26_trim (0x371).

The tuning range provided by the tuning capacitor depends on

the loading capacitance of a specific crystal. The total tuning

range is typically 25 ppm.

Rev. 0 | Page 27 of 72

ADF7241

TRANSMITTER

appended to the frame in TX_BUFFER. In this case, the

number of bytes written to TX_BUFFER must be equal to the

length specified in the PHR field minus two.

TRANSMIT OPERATING MODES

The two primary transmitter operating modes are:

•

IEEE 802.15.4-2006 packet mode

IEEE 802.15.4-2006 SPORT mode

The format of the frame in TX_BUFFER, both with automatic

FCS field generation enabled and with it disabled, is shown in

Figure 34.

The desired mode of operation is selected via Register rc_cfg,

Field rc_mode.

Details of how to configure IEEE 802.15.4-2006 TX SPORT

mode are given in the SPORT Interface section.

The modulator preemphasis filter must be enabled with

Register tx_m, Field preemp_filt = 1. This is enabled by

default if using packet mode only, but must be programmed

if using SPORT mode.

IEEE 802.15.4-2006 Transmitter Timing and Control

This section applies when IEEE 802.15.4-2006 packet mode is

enabled. Accurate control over the transmission slot timing is

maintained by two delay timers (Register delaycfg1, Field

tx_mac_delay and Register delaycfg2, Field mac_delay_ext),

which introduce a controlled delay between the rising edge of the

IEEE 802.15.4-2006-compatible mode with packet manager

support is selected with Register rc_cfg, Field rc_mode = 0

(0x13E). In this mode, the ADF7241 packet manager automati-

cally generates the IEEE 802.15.4-2006-compatible preamble

and SFD. There is also an option to use a nonstandard SFD by

programming Register sfd_15_4 with the desired alternative

SFD. Refer to the Programmable SFD subsection of the Receiver

section for further details. There are 256 bytes of dedicated

RAM (packet RAM), which constitute TX_BUFFER and

RX_BUFFER, available to store transmit and receive packets.

The packet header must be the first byte written to TX_BUFFER.

The address of the first byte of TX_BUFFER is stored in Register

txpb, Field tx_pkt_base.

CS

signal following the RC_TX command and the start of the

transmit operation. Figure 35 illustrates the timing of the

transmit operation assuming that the ADF7241 was operating

in PHY_RDY, RX, or TX state prior to the execution of an

RC_TX command.

If enabled, the external PA interface, as described in the Power

Amplifier section, is powered up prior to the synthesizer calibra-

tion to allow sufficient time for the bias servo loop to settle.

Ramp-up of the PA is completed shortly before the overall MAC

delay has elapsed. If enabled, an rc_ready interrupt (see the

Interrupt Controller section) is generated at the transition into

the TX state. Following the completion of the PA ramp-up

phase, the transceiver enters the TX state. The minimum and

maximum times for the PA ramp-up to complete prior to the

transceiver entering the TX state are given by Parameter t₃₅in

Table 11.

If the automatic FCS field generation has been disabled

(Register pkt_cfg, Field auto_fcs_off = 1), the full frame

including FCS must be written to TX_BUFFER. In this case, the

number of bytes written to TX_BUFFER must be equal to the

length specified in the PHR field.

If automatic FCS field generation has been enabled (Register

pkt_cfg, Field auto_fcs_off = 0), the FCS is automatically

1

2

1

0 TO 20

n

2

ADDRESS

INFORMATION

FRAME

PAYLOAD

REGISTER pkt_cfg, FIELD auto_fcs_off = 1

REGISTER txpb, FIELD tx_pkt_base

+ 5 + (0 to 20) + n

REGISTER rc_cfg, FIELD rc_mode = 0

1

2

1

0 TO 20

n

ADDRESS

INFORMATION

FRAME

PAYLOAD

REGISTER pkt_cfg, FIELD auto_fcs_off = 0

REGISTER txpb, FIELD tx_pkt_base

+ 5 + (0 to 20) + n – 2

Figure 34. Field Format of TX_BUFFER

Rev. 0 | Page 28 of 72

ADF7241

EXTERNAL

PA BIAS

PA OUTPUT

POWER

TRANSMITTED

PACKET

PREAMBLE SFD PHR PSDU

RC_TX

PREVIOUS STATE

TX

PHY_RDY

RC_STATUS

tx_mac_delay +

mac_delay_ext

OPERATION

SYNTH CALIBRATION

REGISTER irq_src0, FIELD rc_ready

REGISTER irq_src1, FIELD tx_sfd

REGISTER irq_src1, FIELD tx_pkt_sent

Figure 35. Transmit Timing and Control

192µs

tx_mac_delay

0µs TO 1020µs

mac_delay_ext

154µs

SYNTHESIZER

SETTLING

PA

RAMP

PA

RAMP

. . . . . . . . . . . . .

INIT

VCO_cal

22µs

52µs

80µs

<6µs

SKIPPED IF

REGISTER vco_cal_cfg,

FIELD skip_vco_cal = 15

Figure 36. Synthesizer Calibration Following RC_TX

updated up until the time, t₂₇, specified in Table 12. This allows

a dynamic adjustment of the transmission timing for acknowl-

edge (ACK) frames for networks using slotted CSMA/CA. To

ensure correct settling of the synthesizer prior to PA ramp-up,

the total TX MAC delay should not be programmed to a value

shorter than specified by the PHY_RDY or RX to TX timing

specified in Table 10. The RC_TX command can be aborted up

to the time specified by Parameter t₂₈in Table 12 by means of

issuing an RC_PHY_RDY, RC_RX, or RC_IDLE command.

The radio controller first transmits the automatically generated

preamble and SFD. If it has been enabled, an SFD interrupt is

asserted after the SFD is transmitted. The packet manager then

reads TX_BUFFER, starting with the PHR byte and transmits

its contents. Following the transmission of the entire frame, the

radio controller turns the PA off and asserts a tx_pkt_sent

interrupt. The ADF7241 then automatically returns to the

PHY_RDY state unless automatic operating modes have been

configured.

The VCO calibration (VCO_cal) can be skipped if shorter turna-

round times are required. Skipping the VCO calibration is

possible if the channel frequency control word ch_freq[23:0]

has remained unchanged since the last RC_PHY_RDY, RC_RX,

RC_CCA, or RC_TX command was issued with VCO_cal

enabled. The initialization, synthesizer settling, and PA ramping

phases are mandatory however because the synthesizer band-

width is changed between receive and transmit operation.

Skipping the VCO calibration is an option for single-channel

communication systems, or systems where an ACK frame is

transmitted on the same channel upon reception of a packet.

By default, the synthesizer is recalibrated each time an RC_TX

command is issued. Figure 36 shows the synthesizer calibration

sequence that is performed each time the transceiver enters the

TX state. The total TX MAC delay is defined by the combined

delay configured with Register delaycfg1, Field tx_mac_delay

and Register delaycfg2, Field mac_delay_ext. Register delaycfg1,

Field tx_mac_delay is programmable in steps of 1 μs, whereas

Register delaycfg2, Field mac_delay_ext is programmable in

steps of 4 μs. The default value of Register delaycfg1, Field

tx_mac_delay is the length of 12 IEEE 802.15.4-2006-2.4 GHz

symbols or 192 μs.

VCO_cal is skipped by setting Register vco_cal_cfg, Field

skip_vco_cal = 15. In this case, tx_mac_delay can be reduced to

140 μs. The VCO calibration is executed if Register vco_cal_cfg,

Field skip_vco_cal = 9.

The default value of Register delaycfg2, Field mac_delay_ext is

0 μs. Following the issue of the RC_TX command, while the

delay defined by Register delaycfg1, Field tx_mac_delay is

elapsing, Register delaycfg2, Field mac_delay_ext can be

Rev. 0 | Page 29 of 72

ADF7241

PACKET

TRANSMITTED

FRAME IN TX_BUFFER

PACKET

RECEIVED

VALID IEEE802.15.4-2006 FRAME

PHY_RDY

RC_STATUS

RX

TX

tx_mac_delay +

mac_delay_ext

t₂₆

t_27,t₂₈

REGISTER irq_src0, FIELD rc_ready

REGISTER irq_src1, FIELD rx_pkt_rcvd

REGISTER irq_src1, FIELD tx_pkt_sent

Figure 37. IEEE 802.15.4 Auto RX-to-TX Turnaround Mode

PA Ramping Controller

IEEE 802.15.4 AUTOMATIC RX-TO-TX

TURNAROUND MODE

The PA ramping controller of the ADF7241 minimizes spectral

splatter generated by the transmitter. Upon entering the TX state,

the ramping controller automatically ramps the output power of

the PA from the minimum output power to the specified nominal

value. In packet mode, transmission of the packet commences

after the ramping phase. When the transmission of the packet is

complete or the TX state is exited, the PA is turned off immedi-

ately. It is also possible to allow the PA to ramp down its output

power using the same ramp rate for the ramp-up phase, by

setting Register ext_ctrl, Field pa_shutdown_mode to 1.

The ADF7241 features an automatic RX-to-TX turnaround mode

when it is operating in IEEE 802.15.4-2006 packet mode

(Register rc_cfg, Field rc_mode = 0). The automatic RX-to-TX

turnaround mode facilitates the timely transmission of

acknowledgment frames.

Figure 37 illustrates the timing of the automatic RX-to-TX

turnaround mode. When enabled by setting Register buffercfg,

Field auto_rx_to_tx_turnaround, the ADF7241 automatically

enters the TX state following the reception of a valid IEEE

802.15.4-2006 frame. After the combined transmit MAC delay

(tx_mac_delay + mac_delay_ext), the ADF7241 enters the TX

state and transmits the frame stored in TX_BUFFER. After the

transmission is complete, the ADF7241 enters the PHY_RDY

state. There is a 38 μs delay between the reception of the last

symbol and the generation of the rx_pkt_rcvd interrupt. The

transmit MAC delay timeout period begins immediately after

the reception of the last symbol. Therefore, the host MCU has

up to t₂₈μs (see Table 12) after a frame has been received to cancel

the transmit operation by means of issuing an RC_IDLE,

RC_PHY_RDY, or RC_RX command.

Figure 38 illustrates the shape of the PA ramping profile and its

timing. It follows a linear-in-dB shape. The ramp time depends on

the output power setting in Register extpa_msc, Field pa_pwr

and is specified with Register pa_rr, Field pa_ramp_rate

according to the following equation:

t_ramp = 2^{pa_rr.pa_ramp_rate}× 2.4 ns × extpa_msc.pa_pwr

External PA Interface

The ADF7241 has an integrated biasing block for external PA

circuits as shown in Figure 39. It is suitable for external PA circuits

based on a single GaAs MOSFET and a wide range of integrated

PA modules. The key components are shown in Figure 40. A

switch between Pin VDD_BAT and Pin PAVSUP_ATB3 controls

the supply current to the external FET. PABIOP_ATB4 can be

used to set a bias point for the external FET. The bias point is

controlled by a 5-bit DAC and/or a bias servo loop.

POWER AMPLIFIER

The integrated power amplifier (PA) is connected to the RFIO2P

and RFIO2N RF ports. It is equipped with a built-in harmonic

filter to simplify the design of the external harmonic filter. The

output power of the PA is set with Register extpa_msc, Field

pa_pwr with an average step size of 2 dB. The step size increases

at the lower end of the control range. Refer to Figure 26 for the

typical variation of output power step size with the control word

value. The PA also features a high power mode, which can be

enabled by setting Register pa_bias, Field pa_bias_ctrl = 63 and

Register pa_cfg, Field pa_bridge_dbias = 21.

To have the external PA interface under direct control of the host

MCU, set Register ext_ctrl, Field extpa_auto_en = 0. The host

MCU can then use Register pd_aux, Field extpa_bias_en to enable

or disable the external PA. If Register ext_ctrl, Field extpa_auto_en

= 1, the external PA automatically turns on when entering, and

turns off when exiting the TX state. If this setting is used, the host

MCU should not alter the configuration of Register pd_aux, Field

extpa_bias_en.

Rev. 0 | Page 30 of 72

ADF7241

The function of the two pins, PAVSUP_ATB3 and PABIAOP_

ATB4, depends on the mode selected with Register extpa_msc,

Field extpa_bias_mode, as shown in Table 18.

derived from the external bias resistor. If Register extpa_msc,

Field extpa_bias_src = 1, the current is derived from the

internal reference generator. The first option is more accurate

and is recommended whenever possible.

The reference current source for the DAC is controlled with

Register extpa_msc, Field extpa_bias_src (0x3AA[3]). If

Register extpa_msc, Field extpa_bias_src = 0, the current is

PA OUTPUT

POWER

TRANSMISSION OF

PACKET COMPLETE

OR LEAVING TX STATE

pa_ramp_rate = 0:

× 2.4ns PER 2dB STEP

pa_ramp_rate = 7:

2 × 2.4ns PER 2dB STEP

0

7

2

RC_TX

ISSUED

2dB

DATA

TRANSMISSION

ACTIVE

t

P

, MIN

O

tx_mac_delay + mac_delay_ext

Figure 38. PA Ramping Profile

Rev. 0 | Page 31 of 72

ADF7241

reference current. The reference current for the bias servo

loop is generated by the 5-bit reference DAC. In this mode,

the bias servo loop expects the current in the FET to increase

with increasing voltage at the PABIAOP_ATB4 output.

Mode 6 is the same as Mode 5, except that the bias servo

loop expects the current in the FET to increase with

decreasing voltage at the PABIAOP_ATB4 output.

External PA Interface Modes

•

Mode 0 allows supply to an external circuit to be switched

on or off. This is useful for circuits that have no dedicated

power-down pin and/or have a high power-down current.

Mode 1 allows the supply to an external circuit to be switched

on or off. In addition, the PABIOP_ATB4 pin acts as a

programmable current source. A programmable voltage

can be generated if a suitable resistor is connected between

PABIAOP_ATB4 and GND.

•

RFIO1P

LNA

BALUN

RFIO1N

•

Mode 2 allows the supply to an external PA circuit to be

switched on or off. In addition, the PABIOP_ATB4 pin acts

as a programmable current sink. A programmable voltage

can be generated if a suitable resistor is connected between

PABIAOP_ATB4 and VDD_BAT.

VDD_BAT

PAVSUP_ATB3

PABIAOP_ATB4

EXTERNAL PA

INTERFACE

CIRCUIT

PA

•

Mode 3 is the same as Mode 1, except that the switch

between PAVSUP_ATB3 and VDD_BAT is open.

Mode 4 is the same as Mode 2, except that the switch

between PAVSUP_ATB3 and VDD_BAT is open.

Mode 5 is intended for a PA circuit based on a single

external FET. The supply voltage to this FET is controlled

through the PAVSUP_ATB3 pin to ensure a low leakage

current in the power-down state. The bias servo loop

controls the gate bias voltage of the external FET such that

the current through the supply switch is equal to a

RFIO2P

LNA

BALUN

RFIO2N

TXEN_GP5

ADF7241

GaAs

pHEMT FET

Figure 39. Typical External PA Applications Circuit

Table 18. PA Interface

Register extpa_msc,

Field extpa_bias_mode

Register pd_aux,

Field extpa_bias_en¹VDD_BAT to PAVSUP_ATB3 Switch

Function of Pin PABIAOP_ATB4

X²

0

1

2

3

4

5

6

7

0

1

Open

Not used

Current source

Current sink

Current source

Current sink

Bias current servo output, positive polarity

Bias current servo output, negative polarity

Reserved

Closed

Open

Closed

Reserved

¹Autoenabled when Register ext_ctrl, Field extpa_auto_en = 1.

²X = don’t care.

REGISTER ext_ctrl, FIELD extpa_auto_en

ADF7241

&

state == TX

VDD_BAT

REGISTER pd_aux, FIELD extpa_bias_en

SWITCH

3

5

PAVSUP_ATB3

CONTROL

LOGIC

REGISTER extpa_msc, FIELD extpa_bias_mode

PABIAOP_ATB4

DAC

REGISTER extpa_cfg, FIELD extpa_bias

REGISTER extpa_msc, FIELD extpa_bias_src

Figure 40. Details of External PA Interface circuit

Rev. 0 | Page 32 of 72

ADF7241

RECEIVER

incoming frame, and all data following and including the frame

length (PHR) is written to RX_BUFFER.

RECEIVE OPERATION

The two primary receiver operating modes are

If Register pkt_cfg, Field auto_fcs_off = 1, the FCS of the incoming

frame is stored in RX_BUFFER. When the entire frame has been

received, an rx_pkt_rcvd interrupt is asserted irrespective of the

correctness of the FCS. If auto_fcs_off = 0, the radio controller

calculates the FCS of the incoming frame according to the FCS

polynomial defined in the IEEE 802.15.4-2006 standard (see

Equation 1), and compares the result against the FCS of the

incoming frame. An rx_pkt_rcvd interrupt is asserted only if

both FCS fields match. The FCS is not written to RX_BUFFER

but is replaced with the measured RSSI and signal quality

indicator (SQI ) values of the received frame (see Figure 41).

•

IEEE 802.15.4-2006 packet manager mode

IEEE 802.15.4-2006 SPORT mode

The desired operating mode is selected with Register rc_cfg,

Field rc_mode. The SPORT modes are explained in more detail

in the SPORT Interface section.

The output of the post demodulator filter is fed into a bank of

correlators, which compare the incoming data sequences to the

expected IEEE 802.15.4-2006 sequences. The receiver block

operates in three primary states.

•

Preamble qualification

Symbol timing recovery

Data symbol reception

G₁₆(x) = x¹⁶+ x¹²+ x⁵+1

(1)

The behavior of the radio controller following the reception

of a frame can be configured with Register buffercfg, Field rx_

buffer_mode (0x107[1:0]). With the default setting rx_buffer_

mode = 0, the part reverts automatically to PHY_RDY when an

rx_pkt_rcvd interrupt condition occurs. This mode prevents

RX_BUFFER from being overwritten by the next frame before

the host MCU can read it from the ADF7241. This is because a

new frame is always written to RX_BUFFER starting from the

address stored in Register rxpb, Field rx_pkt_base (0x315[7:0]).

Note that reception of the next frame is inhibited until the MAC

delay following an RC_RX command has elapsed.

During preamble qualification, the correlators check for the pres-

ence of preamble. When preamble is qualified, the device enters

symbol timing recovery mode. The device symbol timing is

achieved once a valid SFD is detected. The ADF7241 supports

programmable SFDs. Refer to the Programmable SFD section

for further details.

The received symbols are then passed to the packet manager in

packet mode or the SPORT interface in SPORT mode. In SPORT

mode, four serial clocks are output on Pin TRCLK_CKO_GP3,

and four data bits are shifted out on Pin DR_GP0 for each received

symbol. Refer to the SPORT Interface section for further details.

If Register buffercfg, Field rx_buffer_mode = 1 (0x107[1:0]),

the part remains in the RX state, and the reception of the next

packet is enabled one MAC delay period after the frame has

been written to RX_BUFFER. Depending on the network setup,

this mode can cause an unnoticed violation of RX_BUFFER

integrity if a frame arrives prior to the MCU having read the

frame from RX_BUFFER.

If in packet mode, when the packet manager determines the end

of a packet, the ADF7241 automatically transitions to PHY_RDY

or TX or remains in RX, depending on the setting in Register

buffercfg, Field rx_buffer_mode (see Receiver Configuration in

Packet Mode section). If in SPORT mode, the part remains in

RX until the user issues a command to change to another state.

If Register buffercfg, Field rx_buffer_mode = 2 (0x107[1:0]),

the reception of frames is disabled. This mode is useful for RSSI

measurements and CCA, if the contents of RX_BUFFER are to

be preserved.

Programmable SFD

An alternative to the standard IEEE 802.15.4-2006 SFD byte can

optionally be selected by the user. The default setting of Register

sfd_15_4, Field sfd_symbol_1 and Field sfd_symbol_2 (0x3F4[7:0])

is the standard IEEE 802.15.4-2006 SFD. If the user programs

this register with an alternative value, this is used as the SFD in

receive and transmit. The requirements are as follows:

RECEIVER CALIBRATION

The receive path is calibrated each time an RC_RX command is

issued. Figure 42 outlines the synthesizer and receive path

calibration sequence and timing. The calibration step VCO_cal is

omitted by setting Register vco_cal_cfg, Field skip_vco_cal = 15

(0x36F[3:0]), which is an option if the value of ch_freq[23:0]

remains unchanged during transitions between the PHY_RDY,

RX, and TX states. The synthesizer settling phase is always

required because the PLL bandwidth is optimized differently for

RX and TX operation. The static offset correction phase

(OCL_stat) and dynamic offset correction phase (OCL_dyn) are

also mandatory.

•

The value must not be a repeated symbol (for example, not

0x11 or 0x22).

•

The value must not be similar to the preamble symbol (that

is, not Symbol 0x0 or Symbol 0x8).

Receiver Configuration in Packet Mode

Packet management support is selected when Register rc_cfg,

Field rc_mode = 0 (0x13E[7:0]). RX_BUFFER is overwritten

when the ADF7241 enters the RX state following an RC_RX

command and an SFD is detected. The SFD is stripped off the

Rev. 0 | Page 33 of 72

ADF7241

1

2

1

0 TO 20

n

2

ADDRESS

INFORMA-

TION

FRAME

PAYLOAD

REGISTER pkt_cfg, FIELD auto_fcs_off = 1

REGISTER txpb, FIELD rx_pkt_base

+ 5 + (0 to 20) + n

REGISTER rxpb, FIELD rx_pkt_base

1

2

1

0 TO 20

n

1

ADDRESS

INFORMA-

TION

FRAME

PAYLOAD

REGISTER pkt_cfg, FIELD auto_fcs_off = 0

REGISTER txpb, FIELD rx_pkt_base

+ 5 + (0 to 20) + n

REGISTER rxpb, FIELD rx_pkt_base

Figure 41. IEEE 802.15.4-2006 Packet Fields Stored by the Packet Manager in RX_BUFFER

0µs TO 1020µs

192µs

rx_mac_delay

mac_delay_ext

SYNTH

OCL

INIT

VCO_cal

52µs

SETTLING STATIC

DYNAMIC

18µs

53µs 10µs

55µs

SKIPPED IF

REGISTER vco_cal_cfg,

FIELD skip_vco_cal = 15

188µs

Figure 42. RX Path Calibration

Rev. 0 | Page 34 of 72

ADF7241

Figure 43 shows the timing sequence for packet mode. If

RECEIVE TIMING AND CONTROL

SPORT mode is enabled, the timing sequence is the same except

that no rx_pkt_rcvd interrupt is generated and no automatic

transition into the PHY_RDY state occurs.

Register rc_cfg, Field rc_mode = 0 (0x13E[7:0]) for packet

mode, and Register rc_cfg, Field rc_mode = 2 for RX SPORT

mode. See the SPORT Interface section for details on the

operation of the SPORT interface. By default, ADF7241

performs a synthesizer and a receiver path calibration imme-

diately after it receives an RC_RX command. The transition into

the RX state occurs after the receiver MAC delay has elapsed. The

total receiver MAC delay is determined by the sum of the delay

times configured in Register delaycfg0, Field rx_mac_delay

(0x109[7:0]) and Register delaycfg2, Field mac_delay_ext

(0x10B[7:0]). Register delaycfg0, Field rx_mac_delay (0x109[7:0])

is programmable in steps of 1 μs, whereas Register delaycfg2,

Field mac_delay_ext (0x10B[7:0]) is programmable in steps of

4 μs. Register delaycfg2, Field mac_delay_ext is typically set to

0. It can, however, be dynamically used to accurately align the

RX slot timing.

When entering the RX state, if Register cca2, Field rx_auto_cca = 1

(0x106[1]), a CCA measurement is started. The radio controller

asserts a cca_complete interrupt when the CCA result is

available in the status word. Upon detection of the SFD, the

radio controller asserts an rx_sfd interrupt, which can be used

by the host MCU for synchronization purposes. By default, the

ADF7241 transitions into the PHY_RDY state when a valid

frame has been received into RX_BUFFER and, if enabled, an

rx_pkt_rcvd interrupt is asserted. This mechanism protects the

integrity of RX_BUFFER. The RX state can be exited at any

time by means of an appropriate radio controller command.

RECEIVED

PACKET

PREAMBLE

RX

SFD PHR

PSDU

RC_RX

PREVIOUS STATE

PHY_RDY

RC_STATUS

rx_mac_delay +

mac_delay_ext

OPERATION

RX CALIBRATION

SFD SEARCH

CCA

OPTIONAL

REGISTER irq_src1, FIELD cca_complete

REGISTER irq_src0, FIELD rc_ready

REGISTER irq_src1, FIELD rx_sfd

REGISTER irq_src1, FIELD rx_pkt_rcvd

Figure 43. RX Timing and Control

Rev. 0 | Page 35 of 72

ADF7241

CLEAR CHANNEL ASSESSMENT (CCA)

The CCA function of the ADF7241 complies with CCA Mode 1

as per IEEE 802.15.4-2006. A CCA can be specifically requested

by means of an RC_CCA command or automatically obtained

when the transceiver enters the RX state. In both cases, the start of

the CCA averaging window is defined by when the RC_CCA or

RC_RX command is issued and when the delay is configured in

Register delaycfg0, Field rx_mac_delay (0x109[7:0]) and Register

delaycfg2, Field mac_delay_ext (0x10B[7:0]). The CCA result is

determined by comparing Register cca1, Field cca_thres

(0x105[7:0]) against the average RSSI value measured through-

out the CCA averaging window. If the measured RSSI value is

less than the threshold value configured in Register cca1, Field

cca_thres (0x105[7:0]), CCA_RESULT in the status word is set;

otherwise, it is reset. The cca_complete interrupt is asserted

when CCA_RESULT in the status word is valid.

This configuration is useful for longer channel scans. CCA_

RESULT in the status word can be used to identify if the config-

ured CCA RSSI threshold value has been exceeded during a

CCA averaging period. Alternatively, the RSSI value in Register

rrb, Field rssi_readback can be read by the host MCU after each

cca_complete interrupt. As indicated in Figure 45, the RSSI

readback value holds the results of the previous RSSI measurement

cycle throughout the CCA averaging window and is updated

only shortly before the cca_complete interrupt is asserted.

LINK QUALITY INDICATION (LQI)

The link quality indication (LQI) is defined in the IEEE 802.15.4-

2006 standard as a measure of the signal strength and signal quality

of a received IEEE 802.15.4-2006 frame. The ADF7241 makes

several measurements available from which an IEEE 802.15.4-2006-

compliant LQI value can be calculated in the MCU. The first

parameter is the RSSI value (see the Automatic Gain Control

(AGC) and Receive Signal Strength Indicator (RSSI) subsection

of the Receiver Radio Blocks section).

Figure 44 shows the timing sequence after issuing the RC_CCA

command when Register cca2, Field continuous_cca = 0

(0x106[2]). Following the RC_CCA command, the transceiver

starts the CCA observation window after the delay specified by

the sum of Register delaycfg0, Field rx_mac_delay (0x109[7:0])

and Register delaycfg2, field mac_delay_ext (0x10b[7:0]) has

elapsed. A cca_complete interrupt is asserted at the end of the

CCA averaging window, and the transceiver enters the

PHY_RDY state.

The second parameter required for the LQI calculation can be

read from Register lrb, Field sqi_readback (0x30D[7:0]), which

contains an 8-bit value representing the quality of a received

IEEE 802.15.4-2006 frame. It increases monotonically with the

signal quality and must be scaled to comply with the IEEE

802.15.4-2006 standard.

When Register cca2, Field continuous_cca = 1 (0x106[2]), the

transceiver remains in CCA state and continues to calculate

CCA results repeatedly until a RC_PHY_RDY command is

issued. This case is illustrated in Figure 45. The first cca_complete

interrupt occurs when the first CCA averaging window after the

RX MAC delay has elapsed. The transceiver then repeatedly

restarts the CCA averaging window each time a cca_complete

interrupt is asserted.

If the ADF7241 is operating in packet mode (Register rc_cfg,

Field rc_mode = 0 (0x13E[7:0])), and Register pkt_cfg, Bit

auto_fcs_off = 0 (0x108[0]), the SQI of a received frame is

measured and stored together with the frame in RX_BUFFER.

The SQI is measured over the entire packet and stored in place

of the second byte of the FCS of the received frame in

RX_BUFFER.

RC_CCA

PHY_RDY

CCA

PHY_RDY

RC_STATUS

rx_mac_delay +

mac_delay_ext

OPERATION

RX CALIBRATION

CCA

REGISTER irq_src1, FIELD cca_complete

REGISTER irq_src0, FIELD rc_ready

Figure 44. CCA Timing Sequence, Register cca2, Field continuous_cca = 0 (0x106[2])

RC_CCA

RC_PHY_RDY

PHY_RDY

CCA

PHY_RDY

RC_STATUS

rx_mac_delay +

mac_delay_ext

OPERATION

RX CALIBRATION

CCA1 CCA2

RSSI1 RSSI2

CCAn

REGISTER rrb, FIELD rssi_readback

X

RSSIn

REGISTER irq_src1, FIELD cca_complete

REGISTER irq_src0, FIELD rc_ready

Figure 45. CCA Timing Sequence, Register cca2, Field continuous_cca = 1 (0x106[2])

Rev. 0 | Page 36 of 72

ADF7241

Frame Filtering

AUTOMATIC TX-TO-RX TURNAROUND MODE

Frame filtering is available when the ADF7241 operates in IEEE

802.15.4 packet mode. The frame filtering function rejects

received frames not intended for the wireless node. The filtering

procedure is a superset of the procedure described in Section

7.5.6.2 (third filtering level) of the IEEE 802.15.4-2006 standard.

Field addon_en in Register pkt_cfg controls whether frame

filtering is enabled

The ADF7241 features an automatic TX-to-RX turnaround

mode when operating in IEEE 802.15.4-2006 packet mode. The

automatic TX-to-RX turnaround mode facilitates the timely

reception of acknowledgment frames.

Figure 46 illustrates the timing of the automatic TX-to-RX

turnaround mode. When enabled by setting Register buffercfg,

Field auto_tx_to_rx_turnaround (0x107[3]), the ADF7241

automatically enters the RX state following the transmission of

an IEEE 802.15.4-2006 frame. After the combined receiver

MAC delay (Register delaycfg0, Field rx_mac_delay + Register

delaycfg2, Field mac_delay_ext), the ADF7241 enters the RX

state and is ready to receive a frame into RX_BUFFER.

Subsequently, when a valid IEEE 802.15.4-2006 frame is

received, the ADF7241 enters the PHY_RDY state.

Automatic Acknowledgment

The ADF7241 has a feature that enables the automatic transmis-

sion of acknowledgment frames after successfully receiving a

frame. The automatic acknowledgment feature of the receiver

can only be used in conjunction with the IEEE 802.15.4 frame

filtering feature. When enabled, an acknowledgment frame is

automatically transmitted when the following conditions are met:

IEEE 802.15.4 FRAME FILTERING, AUTOMATIC

ACKNOWLEDGE, AND AUTOMATIC CSMA/CA

•

The received frame is accepted by the frame filtering

procedure.

The received frame is not a beacon or acknowledgment

frame.

The acknowledgment request bit is set in the FCF of the

received frame.

The following IEEE 802.15.4-2006 functions are enabled by the

firmware module, RCCM_IEEEX:

•

Automatic IEEE 802.15.4 frame filtering

Automatic acknowledgment of received valid IEEE

802.15.4 frames

•

Automatic frame transmission using unslotted CSMA/CA

with automatic retries

See the Downloadable Firmware Modules and Writing to the

ADF7241 sections for details on how to download a firmware

module to the ADF7241.

PACKET TRANSMITTED

PACKET RECEIVED

FRAME IN TX_BUFFER

VALID IEEE802.15.4-2006 FRAME

TX

RX

PHY-RDY

RC_STATUS

rx_mac_delay +

mac_delay_ext

REGISTER irq_src0, FIELD rc_ready

REGISTER irq_src1, FIELD rx_pkt_rcvd

REGISTER irq_src1, FIELD rx_pkt_sent

Figure 46. IEEE 802.15.4-2006 Auto TX-to-RX Turnaround Mode

Rev. 0 | Page 37 of 72

ADF7241

Figure 47 shows the format of the acknowledgment frame

assembled by the ADF7241. The sequence number (Seq. Num.)

is copied from the frame stored in RX_BUFFER. The automatic

acknowledgment feature of the receiver uses TX_BUFFER to

store the constructed acknowledgment frame prior to its

transmission. Any data present in TX_BUFFER is overwritten

by the acknowledgment frame prior to its transmission.

Automatic Unslotted CSMA/CA Transmit Operation

The automatic CSMA/CA transmit operation automatically

performs all necessary steps to transmit frames in accordance

with the IEEE 802.15.4-2006 standard for unslotted CSMA/CA

network operation. It includes automatic CCA retries with

random backoff, frame transmission, reception of the

acknowledgment frame, and automatic retries in the case of

transmission failure. Partial support is provided for slotted

CSMA/CA operation.

4

1

2

1

2

PREAMBLE

The number of CSMA/CA CCA retries can be specified

between 0 and 5 in accordance with the IEEE 802.15.4 standard.

The CSMA/CA can also be disabled, causing the transmission

of the frame to commence immediately after the MAC delay has

expired. This configuration facilitates the implementation of the

transmit procedure in networks using slotted CSMA/CA. In this

case, the timing of the CCA operation must be controlled by the

host MCU, and the number of retries must be set to 1.

Figure 47. ACK Frame Format

The transmission of the ACK frame starts after the combined

delay given by the sum of the delays specified in Register

delaycfg1, Field tx_mac_delay and Register delay_cfg2, Field

mac_delay_ext has elapsed. The default settings of Register

delaycfg1, Field tx_mac_delay = 192 and Register delay_cfg2,

Field mac_delay_ext = 0 result in a delay of 192 μs, which suits

networks using unslotted CSMA/CA. Optionally, Register

delay_cfg2, Field mac_delay_ext can be updated dynamically

while the delay specified in Register delaycfg1, Field

Prior to the transmission of the frame stored in TX_BUFFER, the

radio controller checks if the acknowledge request bit in the

FCF of that frame is set. If it is set, then an acknowledgment

frame is expected following the transmission. Otherwise, the

transaction is complete after the frame has been transmitted.

The acknowledgment request bit is Bit 5 of the byte located at

the address contained in Register txpb, Field tx_packet_base + 1.

tx_mac_delay elapses. This option enables accurate alignment

of the acknowledgment frame with the back-off slot boundaries

in networks using slotted CSMA/CA.

When the receiver automatic acknowledgment mode is enabled,

the ADF7241 remains in the RX state until a valid frame has

been received. When enabled, an rx_pkt_rcvd interrupt is

generated. The ADF7241 then automatically enters the TX state

until the transmission of the acknowledgment frame is

complete. When enabled, a tx_pkt_sent interrupt is generated to

signal the end of the transmission phase. Subsequently, the

ADF7241 returns to the PHY_RDY state.

Figure 48 depicts the automatic CSMA/CA operation. The

firmware module download enables an additional command,

RC_CSMACA, to initiate this CSMA/CA operation. It also

enables an additional interrupt, csma_ca_complete, to be set to

indicate when the CSMA/CA procedure is completed. As per

the IEEE 802.15.4-2006 standard for unslotted CSMA/CA, the

first CCA is delayed by a random number of backoff periods,

where a unit backoff period is 320 μs. The CCA is carried out

for a period of 128 μs as specified in the IEEE 802.15.4-2006

standard.

FRAME Tx RETRY LOOP

OPTION TO SKIP FOR

SLOTTED CSMA/CA

SKIPPED IF

ACK REQUEST BIT IS NOT SET

CSMA-CA PHASE

ACK RX PHASE

RC_CSMACA

COMMAND

FRAME

TRANSMIT

RECEIVE

ACK

CCA

BE

rx_mac_delay

rnd(2 – 1)

192µs (def)

320µs

128µs

106µs

192µs

<864µs

RX

STATE

PREVIOUS STATE

CCA

TX

PHY_RDY

csma_ca_complete

Figure 48. Automatic CSMA/CA Transmit Operation (with CCA)

Rev. 0 | Page 38 of 72

ADF7241

If a busy channel is detected during the CCA phase, the radio

controller performs the next delay/CCA cycle until the maxi-

mum number of CCA retries specified has been reached. If the

maximum number of allowed CCA retries has been reached,

the operation is aborted, and the device transitions to the

PHY_RDY state.

Automatic Gain Control (AGC) and Receive Signal

Strength Indicator (RSSI)

The ADF7241 AGC circuit features fast overload recovery using

dynamic bandwidth adjustments for fast preamble acquisition

and optimum utilization of the dynamic range of the receiver path.

The radio controller automatically enables the AGC after an

offset correction phase, which is carried out when the trans-

ceiver enters the RX state.

If the CCA is successful, the radio controller changes the device

state from the CCA state to the TX state and transmits the

frame stored in TX_BUFFER. The minimum turnaround time

from RX to TX is 106 μs. If neither the acknowledge request bit

in the transmitted frame nor the csma_ca_turnaround bit are set,

the device returns to the PHY_RDY state immediately upon

completion of the frame transmission. Otherwise, it enters the

RX state and waits for up to 864 μs for an acknowledgment. If an

acknowledgment is not received within this time and the

maximum number of frame retries has not been reached, the

ADF7241 remains inside the frame transmit retry loop and

starts the next CSMA/CA cycle. Otherwise, it exits to the PHY_

RDY state. The procedure exits with a csma_ca_complete interrupt.

The RSSI readback value is continuously updated while the

ADF7241 is in the RX state. The result is provided in Register rrb,

Field rssi_readback (0x30C[7:0]) in decibels relative to 1 mW

(dBm) using signed twos complement notation. The RSSI

averaging window is synchronized with the start of the active

RX phase at the end of the MAC delay following an RC_RX

command.

The RSSI averaging period is 128 μs, or eight symbol periods, in

compliance with the IEEE 802.15.4-2006 standard. If the ADF7241

is operating in the IEEE 802.15.4-2006 packet mode, the RSSI of

received frames is measured and stored together with the frame

in RX_BUFFER. The RSSI is measured in a window with a length

of eight symbols immediately following the detected SFD. The

result is then stored in place of the first byte of the FCS of the

received frame in RX_BUFFER. It is also possible to compen-

sate for systematic errors of the measured RSSI value and/or

production tolerances by adjusting the RSSI readback value by

an offset value that can be programmed in Register agc_cfg5,

Field rssi_offs (0x3B9[4:2]). The adjustment resolution is in

1 dB steps.

RECEIVER RADIO BLOCKS

Baseband Filter

Baseband filtering on the ADF7241 is accomplished by a cascade of

analog and digital filters. These are configured for optimum

performance assuming a crystal frequency tolerance of 40 ppm.

Offset Correction Loop (OCL)

The ADF7241 is equipped with a fast and autonomous offset

correction loop (OCL), which cancels both static and dynamic

time-varying offset voltages present in the zero-IF receiver path.

The OCL operates continuously and is not constrained by the

formatting, timing, or synchronization of the data being

received. The scheme is suitable for frequency hopping spread-

spectrum (FHSS) communication systems.

Rev. 0 | Page 39 of 72

ADF7241

SPORT INTERFACE

The SPORT interface is a high speed synchronous serial interface

suitable for interfacing to a wide variety of MCUs and DSPs,

without the use of glue logic. These include, among others, the

ADSP-21xx, SHARC, TigerSHARC and Blackfin DSPs. Figure 66

and Figure 67 show typical application diagrams using one of the

available SPORT modes. The interface uses four signals, a clock

output (TRCLK_CKO_GP3), a receive data output (DR_GP0),

a transmit data input (DT_GP1), and a framing signal output

(IRQ2_TRFS_GP2). The IRQ2 output functionality is not

available while the SPORT interface is enabled. The SPORT

interface supports receive and transmit operations. Table 19 lists

the SPORT interface options. Refer to Device Configuration

section for further details on register programming requirements.

To use the SPORT interface for transmitting IEEE 802.15.4 the

symbol chipping operation must be performed externally.

SPORT interface remains active until an RC_RX command is

reissued or the RX state is exited by another command. The

rx_pkt_rvcd interrupt is not available in this mode. Figure 7

illustrates the timing for this configuration. Refer to Table 19

for details of pins relevant to the SPORT interface mode.

Receive Symbol Clock in SPORT Mode

The ADF7241 offers a symbol clock output option during IEEE

802.15.4 packet reception. This option is useful when a tight

timing synchronization between incoming packets and the

network is required, and the SFD interrupt (rx_sfd) cannot be

used to achieve this. When in IEEE 802.15.4-2006 packet mode

(Register rc_cfg, Field rc_mode = 0), set Register gp_cfg, Field

gpio_config = 7 (0x32C[7:0]) to enable the symbol clock output.

SPORT Mode Transmit Operation

TX SPORT mode is enabled by setting Register rc_cfg, Field

rc_mode = 3. It is necessary for the host MCU to perform the

IEEE 802.15.4 chipping sequence in this mode. The data, sent

through the SPORT interface on Pin DT_GP1, should be

synchronized with the clock signal that appears on Pin TRCLK_

CKO_GP3. Figure 9 shows the timing for this configuration.

The polarity of this clock signal can be set by Register gp_cfg,

Field gpio_config. The tx_pkt_sent interrupt is not available in

this mode. See Table 19 for details of pins relevant to this

SPORT mode.

SPORT MODE

SPORT Mode Receive Operation

The ADF7241 provides an operating mode in which the SPORT

interface is active and the packet manager is bypassed. It allows

the reception of packets of arbitrary length. The mode is enabled

by setting Register rc_cfg, Field rc_mode = 2 (0x13E[7:0]) and

Register gp_cfg, Field gpio_config = 1 (0x32C[7:0]). When the

SFD is detected, data and clock signals appear on the SPORT

outputs, DR_GP0 and TRCLK_CKO_GP3, respectively. The

Table 19. SPORT Interface Configuration

Register

gp_cfg, Field

gpio_config

Register

rc_cfg, Field

rc_mode

IRQ2_TRFS_GP2

DR_GP0

DT_GP1

RXEN_GP5

RXEN_GP6

TRCLK_CKO_GP3

1

2

RX: ignore

RX: data output,

changes at rising

edge of data

clock

RX: ignore

RX: data clock

7

1

2

3

RX: ignore

TX: ignore

RX: Symbol 0

TX: ignore

RX: Symbol 1

RX: Symbol 2 RX: Symbol 3

RX: symbol clock

TX: data clock

TX: data input, TX: ignore

sampled at

TX: ignore

rising edge of

data clock

4

3

TX: ignore

TX: data input, TX: ignore

sampled at

TX: ignore

TX: data clock

falling edge of

data clock

Rev. 0 | Page 40 of 72

ADF7241

DEVICE CONFIGURATION

After a cold start, or wake-up from sleep, it is necessary to

configure the ADF7241. The device can be configured in two

ways: an IEEE 802.15.4-2006 packet mode and an IEEE

802.15.4-2006 SPORT mode. Registers applicable to the setup

each of the two primary modes are detailed in Table 22.

Table 20. Settings Required to Select Between LNA Port 1

and LNA Port 2

Address

Register Field

Value

0x39B[4]

rxfe_cfg, lna_sel

0x0: LNA1

0x1: LNA2

Table 20 and Table 21 detail the values that should be written to

the register locations given in Table 22 to configure the

ADF7241 in the desired mode of operation.

Configuration Values for IEEE 802.15.4-2006 Packet and

SPORT Modes

No register writes are required to configure IEEE 802.15.4

packet mode unless it is desired to select RF Port 1 rather than

RF Port 2. For SPORT mode, the values detailed in Table 21

should be written to the ADF7241.

CONFIGURATION VALUES

If it is desired to use RF Port 1 rather than RF Port 2 (see the RF

Port Configurations/Antenna Diversity section), the value

specific to the desired operating mode given in Table 20 should

be written to the relevant register field.

Table 21. IEEE 802.15.4 Configuration Settings

Address

0x13E

0x306

Register Name

rc_cfg

tx_m

Packet Mode

SPORT Mode

See Table 19

0x01

N/A

0x32C

gp_cfg

See Table 19

Note that, if it is desired to use a nonstandard SFD, an addi-

tional register write is required. Refer to the Programmable SFD

section for details.

Table 22. Register Writes Required to Configure the ADF7241

Register Group Description

Register

0x39B

0x13E

0x32C

0x3F4¹

0x306

IEEE 802.15.4 Packet Mode

IEEE 802.15.4 SPORT Mode

RFIO Port

Yes

No

Yes¹

No

Yes

Yes¹

Yes

Packet/SPORT Mode Selection

SPORT Mode Configuration

Sync Word

Transmit Filters

¹This applies only when the user wishes to program a nonstandard SFD.

Rev. 0 | Page 41 of 72

ADF7241

RF PORT CONFIGURATIONS/ANTENNA DIVERSITY

ADF7241 is equipped with two fully differential RF ports. Port 1

is capable of receiving, whereas Port 2 is capable of receiving or

transmitting. RF Port 1 comprises Pin RFIO1P and Pin RFIO1N,

and RF Port 2 comprises Pin RFIO2P and Pin RFIO2N. Only

one of the two RF ports can be active at any one time.

preamble component of the packet. In a static communication

system, it is often sufficient to select the optimum antenna once.

Configuration C

Configuration C shows that connecting an external PA and/or

LNA is possible with a single external receive/transmit switch. The

PA transmits on RF Port 2. RF Port 1 is configured as the receive

input (Register rxfe_cfg, Field lna_sel = 0).

The availability of two RF ports facilitates the use of switched

antenna diversity and results in a simplified application circuit

if the ADF7241 is connected to an external LNA and/or PA.

Port selection for receive operation is configured through

Register rxfe_cfg, Field lna_sel (0x39B[4]).

ADF7241 provides two signals, RXEN_GP6 and TXEN_GP5, to

automatically enable an external LNA and/or a PA. If Register

ext_ctrl, Field txen_en = 1, the ADF7241 outputs a logic high

level at the TXEN_GP5 pin while in TX state, and a logic low level

while in any other state. If Register ext_ctrl, Field rxen_en = 1, the

ADF7241 outputs a logic high level at the RXEN_GP6 pin while

in RX state and a logic low level while in any other state.

Configuration A

Configuration A of Figure 49 is the default connection where a

single antenna is connected to RF Port 2. This selection is made

by setting Register rxfe_cfg, Field lna_sel = 1 (default setting).

Configuration B

The RXEN_GP6 and TXEN_GP5 outputs have high impedance

in the sleep state. Therefore, appropriate pull-down resistors

must be provided to define the correct state of these signals

during power-down. See the PA Ramping Controller section for

further details on the use of an external PA, including details of

the integrated biasing block, which simplifies connection to PA

circuits based upon a single FET.

Configuration B shows a dual-antenna configuration that is

suitable for switched antenna diversity. In this case, the link

margin can be maximized by comparing the RSSI level of the

signal received on each antenna and thus selecting the optimum

antenna. In addition, the SQI value in Register lrb, Field

sqi_readback can be used in the antenna selection decision.

Configuration D

Suitable algorithms for the selection of the optimum antenna

depend on the particulars of the underlying communication

system. Switching between two antennas is likely to cause a

short interruption of the received data stream. Therefore, it is

advisable to synchronize the antenna selection phase with the

Configuration D is similar to Configuration A, except that a

dipole antenna is used. In this case, a balun is not required.

RFIO1P

4

RFIO1P

LNA

BALUN

RFIO1N

5

RFIO1N

PA

LNA

PA

LNA

RFIO2P

RFIO2N

RFIO2P

RFIO2N

6

7

6

7

BALUN

A

B

RXEN_GP6

RFIO1P

26

4

5

RFIO1P

RFIO1N

LNA

BALUN

RFIO1N

5

PA

LNA

PA

LNA

RFIO2P

RFIO2N

RFIO2P

RFIO2N

6

7

6

7

MATCH

NETWORK

PA

BALUN

TXEN_GP5

25

D

C

Figure 49. RF Interface Configuration Options (A: Single Antenna; B: Antenna Diversity; C: External LNA/PA; D: Dipole Antenna)

Rev. 0 | Page 42 of 72

ADF7241

AUXILLARY FUNCTIONS

TEMPERTURE SENSOR

WAKE-UP CONTROLLER (WUC)

Circuit Description

To perform a temperature measurement, the MEAS state is

invoked using the RC_MEAS command. The result can be read

back from Register adc_rbk, Field adc_out (0x3AE[5:0]). Averag-

ing multiple readings improves the accuracy of the result. The

temperature sensor has an operating range from −40°C to +85°C.

The ADF7241 features a 16-bit wake-up timer with a programma-

ble prescaler. The 32.768 kHz RC oscillator or the 32.768 kHz

external crystal provides the clock source for the timer. This tick

rate clocks a 3-bit programmable prescaler whose output clocks

a preloadable 16-bit down counter. An overview of the timer

circuit is shown in Figure 50 lists the possible division rates for

the prescaler. This combination of programmable prescaler and

16-bit down counter gives a total WUC range of 30.52 μs to

36.4 hours.

The die (ambient) temperature is calculated as follows:

t

_die= (4.72°C × Register adc_rbk, Field adc_out) + 65.58°C

+ correction value.

where correction value can be determined by performing a

readback at a single known temperature. Note also that averag-

ing a number of ADC readbacks can improve the accuracy of the

temperature measurement.

Table 23. Prescaler Division Factors

Tick

timer_prescal (0x316[2:0]) 32.768 kHz Divider Period

BATTERY MONITOR

000

001

010

011

100

101

110

111

1

4

8

16

128

1024

8,192

65,536

30.52 μs

122.1 μs

244.1 μs

488.3 μs

3.91 ms

31.25 ms

250 ms

The battery monitor features very low power consumption and

can be used in any state other than the sleep state. The battery

monitor generates a batt_alert interrupt for the host MCU

when the battery voltage drops below the programmed

threshold voltage. The default threshold voltage is 1.7 V, and

can be increased in 62 mV steps to 3.6 V with Register bm_cfg,

Field battmon_voltage (0x3E6[4:0]).

2000 ms

An interrupt generated when the wake-up timer has timed out

can be enabled in Register irq1_en0 or Register irq2_en0.

HARDWARE TIMER

tmr_cfg1[6:3]

(ADDRESS 0x317)

tmr_cfg0[2:0]

(ADDRESS 0x316)

tmr_rld0[15:8], tmr_rld1[7:0]

(ADDRESS 0x318, 0x319)

32.768kHz

RC

OSCILLATOR

WAKE UP

irq_src0[2]

(ADDRESS 0x3CB)

16-BIT DOWN

COUNTER

PRESCALER

32.768kHz

TICK RATE

32.768kHz

XTAL

Figure 50. Hardware Wake-Up Timer Diagram

Rev. 0 | Page 43 of 72

ADF7241

WUC Configuration and Operation

The calibration time is typically 1 ms. When the calibration is

complete Register wuc_32khzosc_status, Field rc_osc_cal_ready

is high. Following calibration, the host MCU can transition to

the SLEEP_BBRAM_RCO sleep state, by following the full

procedure given in the WUC Configuration and Operation

section.

The wake-up timer can be configured as follows:

•

The clock signal for the timer is taken from the external

32.768 kHz crystal or the internal RC oscillator. This is

selectable via Register tmr_cfg1, Field sleep_config

(0x317[6:3]).

TRANSMIT TEST MODES

•

A 3-bit prescaler, which is programmable via Register

tmr_cfg0, Field timer_prescal (0x316[2:0]) determines the

tick period.

The ADF7241 has various transmit test modes that can be used

in SPORT mode. These test modes can be enabled by writing to

Register tx_test (Location 0x3F0), as described in Table 24. A

continuous packet transmission mode is also available in packet

mode. This mode can be enabled using the following procedure:

This is followed by a preloadable 16-bit down counter. After the

clock is selected, the reload value for the down counter

(tmr_rld0 and tmr_rld1) and the prescaler values (Register

tmr_cfg0, Field timer_prescal) can be programmed. When the

clock has been enabled, the counter starts to count down at the

tick rate starting from the reload value. If wake-up interrupts

are enabled, the timer unit generates an interrupt when the

timer value reaches 0x0000. When armed, the wake-up

interrupt triggers a wake-up from sleep.

1. An IEEE 80.215.4-2006 packet with random payload

should be written to TX_BUFFER as described in the

Transmitter section. It is recommended to use a packet

with the maximum length of 127 bytes.

2. Set Register buffercfg, Field trx_mac_delay = 1.

3. Set Register buffercfg, Field tx_buffer_mode = 3.

4. Set Register pkt_cfg, Field skip_synth_settle = 1.

5. Issue Command RC_TX. The transmitter continuously

transmits the packet stored in TX_BUFFER.

The reliable generation of wake-up interrupts requires the

WUC timeout flag to be reset immediately after the reload value

has been programmed. To do this, first write 1 and then write 0

to Register tmr_ctrl, Field wake_timer_flag_reset. To enable

automatic wake-up from the sleep state, arm the timer unit for

wake-up operation by writing 1 to Register tmr_cfg1, Field

wake_on_timeout. After writing this sequence to the ADF7241,

a sleep command can be issued.

6. If Command RC_PHY_RDY is issued at any point after

this step, all the preceding configuration registers must be

rewritten to the device before reissuing Command RC_TX.

Note that the transmitter momentarily transmits an RF carrier

between packets due to a finite delay from when the packet

handler finishes transmitting a packet in TX_BUFFER and

going back to transmit the start of TX_BUFFER again.

Calibrating the RC oscillator

The RC oscillator is not automatically calibrated. If it is desired

to use the RC oscillator as the clock source for the WUC, the

host MCU should initiate a calibration. This can be performed

at any time in advance of entering the sleep state. To perform a

calibration, the host MCU should

•

Set Register tmr_ctrl, Field wuc_rc_osc_cal = 0

Set Register tmr_ctrl, Field wuc_rc_osc_cal = 1

Table 24. 0x3F0: tx_test

Bit

[7:2]

1

Name

R/W

Reset Value Description

Reserved

carrier_only

Reserved

2

0

Reserved, set to default.

Transmits unmodulated tone at the programmed frequency f_CH.

Reserved, set to default.

0

Rev. 0 | Page 44 of 72

ADF7241

SERIAL PERIPHERAL INTERFACE (SPI)

GENERAL CHARACTERISTICS

The ADF7241 is equipped with a 4-wire SPI interface, using the

CS

All commands are executed after

goes high again or at the

next positive edge of the SCLK input. The latter condition

occurs in the case of a memory access command. In this case,

the command is executed on the positive SCLK clock edge

corresponding to the most significant bit of the first parameter

input must be brought high again after a

command has been shifted into the ADF7241 to enable the

recognition of successive command words. This is because a

CS

SCLK, MISO, MOSI, and

pins. The ADF7241 always acts as

a slave to the host MCU. Figure 51 shows an example connec-

tion diagram between the host MCU and the ADF7241. The

diagram also shows the direction of the signal flow for each pin.

The SPI interface is active and the MISO output enabled only

CS

word. The

CS

while the

input is low. The interface uses a word length of

CS

single command can be issued only during a

(with the exception of a double NOP command).

low period

eight bits, which is compatible with the SPI hardware of most

microprocessors. The data transfer through the SPI interface

occurs with the most significant bit of address and data first.

Refer to Figure 3 for the SPI interface timing diagram. The

MOSI input is sampled at the rising edge of SCLK. As com-

mands or data are shifted in from the MOSI input at the SCLK

rising edge, the status word or data is shifted out at the MISO

CS

RC OR SPI

MOSI

COMMAND

STATUS

MISO

CS

pin synchronous with the SCLK clock falling edge. If

is

Figure 52. Command Write

brought low, the most significant bit of the status word appears

on the MISO output without the need for a rising clock edge on

the SCLK input.

The execution of certain commands by the radio controller may

take several instruction cycles, during which the radio control-

ler unit is busy. Prior to issuing a radio controller command, it

is, therefore, necessary to read the status word to determine if

the ADF7241 is ready to accept a new radio controller command.

This is best accomplished by shifting in SPI_NOP commands,

which cause status words to be shifted out. The RC_READY

variable is used to indicate when the radio controller is ready to

accept a new RC command, whereas the SPI_READY variable

indicates when the memory can be accessed. To take the burden

of repeatedly polling the status word off the host MCU for

complex commands such as RC_RX, RX_TX, and RC_PHY_RDY,

the IRQ handler can be configured to generate an RC_READY

interrupt. See the Interrupt Controller section for details.

Otherwise, the user can program timeout periods according to

the command execution times provided under the state transi-

tion timing given in Table 10.

VBAT

CS

SCLK

MOSI

MISO

PF1

ADF7241

SCLK

MOSI

MISO

GPI

ADSP-21xx

OR

IRQ1_GP4

BLACKFIN

DSP

IRQ2_TRFS_GP2

DR_GP0

RFS

DR

DT

DT_GP1

RSCLK

TSCLK

TRCLK_CKO_GP3

Figure 51. SPI Interface Connection

COMMAND ACCESS

The ADF7241 is controlled through commands. Command

words are single-byte instructions that control the state

transitions of the radio controller and access to the registers and

packet RAM. The complete list of valid commands is given in

Table 25. Commands with the RC prefix are handled by the

radio controller, whereas memory access commands, which

have the SPI prefix are handled by an independent controller.

Thus, SPI commands can be issued independent of the state of

the radio controller.

STATUS WORD

The status word of the ADF7241 is automatically returned over

the MISO each time a byte is transferred over the MOSI. The

meaning of the various status word bit fields is illustrated in

Table 26. The RC_STATUS field reflects the current state of the

radio controller. By definition, RC_STATUS reflects the state of

a completed state transition. During the state transition,

RC_STATUS maintains the value of the state from which the

state transition was invoked.

CS

A command is initiated by bringing

low and shifting in the

command word over the SPI as shown in Figure 52.

Rev. 0 | Page 45 of 72

ADF7241

Table 25. Command List

Command

Code

0xFF

0x10

Description

SPI_NOP

SPI_PKT_WR

No operation. Use for dummy writes.

Write data to the packet RAM starting from the transmit packet base address pointer,

Register txpb, Field tx_pkt_base (0x314[7:0]).

SPI_PKT_RD

0x30

Read data from the packet RAM starting from the receive packet base address pointer,

Register rxpb, Field rx_pkt_base (0x315[7:0]).

SPI_MEM_WR

SPI_MEM_RD

0x18 + memory address[10:8] Write data to MCR or packet RAM sequentially.

0x38 + memory address[10:8] Read data from MCR or packet RAM sequentially.

SPI_MEMR_WR 0x08 + memory address[10:8] Write data to MCR or packet RAM as a random block.

SPI_MEMR_RD 0x28 + memory address[10:8] Read data from MCR or packet RAM as a random block.

SPI_PRAM_WR 0x1E

Write data to the program RAM.

RC_SLEEP

RC_IDLE

RC_PHY_RDY

RC_RX

RC_TX

RC_MEAS

RC_CCA

0xB1

0xB2

0xB3

0xB4

0xB5

0xB6

0xB7

0xC7

Invoke transition of the radio controller into the sleep state

Invoke transition of the radio controller into the idle state

Invoke transition of the radio controller into the PHY_RDY state

Invoke transition of the radio controller into the RX state

Invoke transition of the radio controller into the TX state

Invoke transition of the radio controller into the MEAS state

Invoke clear channel assessment

RC_PC_RESET

Program counter reset. This should only be used after a firmware download to the

program RAM

RC_RESET

0xC8

Resets the ADF7241 and puts it in the sleep state

Table 26. SPI Status Word

Bit

Name

Description

7

SPI_READY

0: SPI is not ready for access.

1: SPI is ready for access.

6

IRQ_STATUS

0: no pending interrupt condition.

1: pending interrupt condition. (IRQ_STATUS = 1 when either the IRQ1_GP4 or

IRQ2_TRFS_GP2 pin is high)

5

4

RC_READY

0: radio controller is not ready to accept RC_xx command strobe.

1: radio controller is ready to accept new RC_xx command strobe.

CCA_RESULT

0: channel busy.

1: channel idle.

Valid when Register irq_src1, Bit cca_complete (0x3CC[0]) is asserted.

[3:0]

RC_STATUS

Radio controller status:

0: reserved.

1: idle.

2: MEAS.

3: PHY_RDY.

4: RX.

5: TX.

6 to 15: reserved.

Rev. 0 | Page 46 of 72

ADF7241

MEMORY MAP

The various memory locations used by the ADF7241 are shown

in Figure 53. The radio control and packet management of the

part are realized through the use of an 8-bit, custom processor,

and an embedded ROM. The processor executes instructions

stored in the embedded program ROM. There is also a local

RAM, subdivided into three sections, that is used as a data

packet buffer, both for transmitted and received data (packet

RAM), and for storing the radio and packet management

configuration (BBRAM and MCR). The RAM addresses of

these variables are 11 bits in length.

PROGRAM RAM

The program RAM consists of 2 kB of volatile memory. This

memory space is used for various software modules, such as

address filtering and CSMA/CA, which are available from

Analog Devices. The software modules are downloaded to the

program RAM memory space over the SPI by the host

microprocessor. See the Program RAM Write subsection of the

Memory Access section for details on how to write to the

program RAM.

PACKET RAM

BBRAM

The packet RAM consists of 256 bytes of memory space from

Address 0x000 to Address 0x0FF, as shown in Figure 53. This

memory is allocated for storage of data from valid received

packets and packet data to be transmitted. The packet manager

stores received payload data at the memory location indicated

by the value of Register rxpb, Field rx_pkt_base, the receive

address pointer. The value of Register txpb, Field tx_pkt_base,

the transmit address pointer, determines the start address of

data to be transmitted by the packet manager. This memory can

be arbitrarily assigned to store single or multiple transmit or

receive packets, both with and without overlap as shown in

Figure 54. The rx_pkt_base value should be chosen to ensure

that there is enough allocated packet RAM space for the

maximum receiver payload length.

The 64-byte battery back-up, or BBRAM, is used to maintain

settings needed at wake-up from sleep state by the wake-up

controller.

MODEM CONFIGURATION RAM (MCR)

The 256-byte modem configuration RAM, or MCR, contains

the various registers used for direct control or observation of

the physical layer radio blocks of the ADF7241. Contents of the

MCR are not retained in the sleep state.

PROGRAM ROM

The program ROM consists of 4 kB of nonvolatile memory. It

contains the firmware code for radio control, packet manage-

ment, and smart wake mode.

11-BIT

ADDRESSES

0x3FF

PROGRAM

MCR

REGISTER prampg, FIELD pram_page[3:0]

RAM

256 BYTES

2kB

ADDRESS

[7:0]

0x300

CS

MISO

NOT USED

PROGRAM

ROM

SPI

MOSI

0x13F

4kB

SCLK

BBRAM

64 BYTES

0x100

SPI/PH

MEMORY

ARBITRATION

0x0FF

PACKET

INSTRUCTION/DATA

[7:0]

PACKET

RAM

256 BYTES

MANAGER

PACKET

MANAGER

ADDRESS/

DATA

MUX

CLOCK

8-BIT

ADDRESS[10:0]

DATA[7:0]

0x000

PROCESSOR

Figure 53. ADF7241 Memory Map

Rev. 0 | Page 47 of 72

ADF7241

TRANSMIT

AND RECEIVE

PACKET

256-BYTE TRANSMIT

OR RECEIVE

PACKET

MULTIPLE TRANSMIT

AND RECEIVE

PACKETS

tx_pkt_base

rx_pkt_base

tx_pkt_base

(PACKET 1)

tx_pkt_base

0x000

TRANSMIT

PAYLOAD

TRANSMIT

PAYLOAD

tx_pkt_base

(PACKET 2)

TRANSMIT

PAYLOAD 2

rx_pkt_base

(PACKET 1)

TRANSMIT OR

RECEIVE

PAYLOAD

rx_pkt_base

PAYLOAD

RECEIVE

PAYLOAD

rx_pkt_base

(PACKET 2)

RECEIVE

PAYLOAD 2

0x0FF

Figure 54. Example Packet RAM Configurations Using the Transmit Packet and Receive Packet Address Pointers

Rev. 0 | Page 48 of 72

ADF7241

MEMORY ACCESS

Memory locations are accessed by invoking the relevant SPI

command. An 11-bit address is used to identify registers or

locations in the memory space. The most significant three bits

of the address are incorporated into the command by append-

ing them as the LSBs of the command word. Figure 55

illustrates the command, address, and data partitioning. The

various SPI memory access commands are different depending

on the memory location being accessed. This is described in

Table 27.

An SPI command should be issued only if the SPI_READY bit

of the status word is high.

In addition, an SPI command should not be issued while the

radio controller is initializing. SPI commands can be issued in

any radio controller state including during state transition.

CS

SPI_MEM_WR

MEMORY ADDRESS

BITS[7:0]

DATA BYTE

MOSI

5 BITS

MEMORY ADDRESS

BITS[10:0]

DATA

n × 8 BITS

Figure 55. SPI Memory Access Command/Address Format

Table 27. Summary of SPI Memory Access Commands

SPI Command Command Value

Description

SPI_PKT_WR

SPI_PKT_RD

SPI_MEM_WR

= 0x10

Write telegram to the packet RAM starting from the transmit packet base address pointer,

Register txpb, Field tx_pkt_base (0x314[7:0]).

Read telegram from the packet RAM starting from receive packet base address pointer,

Register rxpb, Field rx_pkt_base (0x315[7:0]).

Write data to BBRAM, MCR, or packet RAM sequentially. An 11-bit address is used to identify

memory locations. The most significant three bits of the address are incorporated into the

command (xxxb). This command is followed by the remaining eight bits of the address.

= 0x30

= 0x18 (packet RAM)

= 0x19 (BBRAM)

= 0x1B (MCR)

SPI_MEM_RD

= 0x38 (packet RAM)

= 0x39 (BBRAM)

= 0x3B (MCR)

Read data from BBRAM, MCR, or packet RAM sequentially. An 11-bit address is used to identify

memory locations. The most significant three bits of the address are incorporated into the

command (xxxb). This command is followed by the remaining eight bits of the address, which

is subsequently followed by the appropriate number of SPI_NOP commands.

SPI_MEMR_WR = 0x08 (packet RAM)

= 0x09 (BBRAM)

Write data to BBRAM/MCR or packet RAM at random.

= 0x0B (MCR)

SPI_MEMR_RD = 0x28 (packet RAM)

= 0x29 (BBRAM)

Read data from BBRAM/MCR or packet RAM at random.

= 0x2B (MCR)

SPI_PRAM_WR =0x1E (program RAM)

Write data to program RAM.

Read data from program RAM

No operation. Use for dummy writes when polling the status word and used as dummy data on

the MOSI line when performing a memory read.

SPI_PRAM_RD

SPI_NOP

= 0x3E (program RAM)

= 0xFF

Rev. 0 | Page 49 of 72

ADF7241

relative location of a byte to Address Pointer rx_pkt_base

(Register rxpb; 0x315[7:0]) or Address Pointer tx_pkt_base

(Register txpb; 0x314[7:0]), respectively.

WRITING TO THE ADF7241

Block Write

Packet RAM memory locations can be written to in block

format using the SPI_PKT_WR. The SPI_PKT_WR command

is 0x10. This command provides pointer-based write access to

the packet RAM. The address of the location written to is calcu-

lated from the base address in Register txpb, Field tx_pkt_base

(0x314[7:0]), plus an index. The index is zero for the first data

word following the command word and is auto-incremented

for each consecutive data word written. The first data word follow-

ing an SPI_PKT_WR command is, thus, stored in the location

with Address txpb, Field tx_pkt_base (0x314[7:0]), the second

in packet RAM location with Address txpb, Field tx_pkt_base + 1,

and so on. This feature makes this command efficient for bulk

writes of data that recurrently begin at the same address. Figure 56

shows the access sequence for Command SPI_PKT_WR.

Program RAM Write

The program RAM can only be written to using the memory

block write, as illustrated in Figure 59. The SPI_PRAM_WR

command is 0x1E. The program RAM is organized in eight

pages with a length of 256 bytes each. The code module must be

stored in the program RAM starting from Address 0x0000, or

Address 0x00 in Page 0. The current program RAM page is

selected with Register prampg, Field pram_page (0x313[3:0]).

Prior to uploading the program RAM, the radio controller code

module must be divided into blocks of 256 bytes commensurate

with the size of the program RAM pages. Each 256-byte block is

uploaded into the currently selected program RAM page using

the SPI_PRAM_WR command. Figure 59 illustrates the

sequence required for uploading a code block of 256 bytes to a

PRAM page. The SPI_PRAM_WR command code is followed

by Address Byte 0x00 to align the code block with the base

address of the program RAM page. Figure 60 shows the overall

upload sequence. With the exception of the last page written to

the program RAM, all pages must be filled with 256 bytes of

module code.

The MCR, BBRAM, and packet RAM memory locations can be

written to in block format using the SPI_MEM_WR command.

The SPI_MEM_WR command code is 00011xxxb, where xxxb

represent Bits[10:8] of the first 11-bit address. If more than one

data byte is written, the write address is automatically incre-

CS

mented for every byte sent until is set high, which terminates

the memory access command. See Figure 57 for more details.

The maximum block write for the MCR, packet RAM, and

BBRAM memories are 256 bytes, 256 bytes, and 64 bytes,

respectively. These maximum block-write lengths should not be

exceeded.

READING FROM THE ADF7241

Block Read

Command SPI_PKT_RD provides pointer-based read access

from the packet RAM. The SPI_PKT_RD command is 0x30.

The address of the location to be read is calculated from the base

address in Register rxpb, Field rx_pkt_base, plus an index. The

index is zero for the first readback word. It is auto-incremented

for each consecutive SPI_NOP command. The first data byte

following a SPI_PKT_RD command is invalid and should be

ignored. Figure 61 shows the access sequence for Command

SPI_PKT_RD.

Example

Write 0x00 to the rc_cfg register (Location 0x13E).

•

The first five bits of the SPI_MEM_WR command are

00011.

•

The 11-bit address of rc_cfg is 00100111110.

The first byte sent is 00011001 or 0x19.

The second byte sent is 00111110 or 0x3E.

The third byte sent is 0x00.

The SPI_MEM_RD command can be used to perform a block

read of MCR, BBRAM, and packet RAM memory locations.

The SPI_MEM_RD command code is 00111xxxb, where xxxb

represent Bits[10:8] of the first 11-bit address. This command is

followed by the remaining eight bits of the address to be read

and then two SPI_NOP commands (dummy byte). The first

byte available after writing the address should be ignored, with

the second byte constituting valid data. If more than one data

byte is to be read, the read address is automatically incremented

for subsequent SPI_NOP commands sent. See Figure 62 for

more details.

Thus, 0x193F00 is written to the part.

Random Address Write

MCR, BBRAM, and packet RAM memory locations can be

written to in random address format using the SPI_MEMR_WR

command. The SPI_MEMR_WR command code is 00001xxxb,

where xxxb represent Bits[10:8] of the 11-bit address. The lower

eight bits of the address should follow this command and then

the data byte to be written to the address. The lower eight bits of

the next address are entered followed by the data for that

address until all required addresses within that block are

written, as shown in Figure 58. Note that the SPI_MEMR_WR

command facilitates the modification of individual elements of

a packet in RX_BUFFER and TX_BUFFER without the need to

download and upload an entire packet.

Random Address Read

MCR, BBRAM, and Packet RAM memory locations can be read

from in a nonsequential manner using the SPI_MEMR_RD

command. The SPI_MEMR_RD command code is 00101xxxb,

where xxxb represent Bits[10:8] of the 11-bit address. This

command is followed by the remaining eight bits of the address

to be written and then two SPI_NOP commands (dummy byte).

The address location of a particular byte in RX_BUFFER and

TX_BUFFER in the packet RAM is determined by adding the

Rev. 0 | Page 50 of 72

ADF7241

The data byte from memory is available on the second SPI_NOP

command. For each subsequent read, an 8-bit address should be

followed by two SPI_NOP commands as shown in Figure 63.

Thus, 0x393EFFFF is written to the part.

The value shifted out on the MISO line while the fourth byte is

sent is the value stored in the rc_cfg register.

Example

This allows individual elements of a packet in RX_BUFFER and

TX_BUFFER to be read without the need to download the

entire packet.

Read the value stored in the rc_cfg register.

•

The first five bits of the SPI_MEM_RD command are 00111.

The 11-bit address of rc_cfg register is 00100111111.

The first byte sent is 00111001, or 0x39.

The second byte sent is 00111110, or 0x3E.

The third byte sent is 0xFF (SPI_NOP).

Program RAM Read

The SPI_PRAM_RD command is used to read from the

program RAM. This may be performed to verify that a

firmware module has been correctly written to the program

RAM. Like the SPI_PRAM_WR command, the host MCU must

select the program RAM page to read via Register prampg, Field

pram_page. Following this, the host MCU may use the

SPI_PRAM_RD command to block read the selected program

RAM page. The structure of this command is identical to the

SPI_MEM_RD command.

The fourth byte sent is 0xFF.

[MAX N = (256 – tx_pkt_base)]

CS

DATA FOR ADDRESS

[tx_pkt_base]

DATA FOR ADDRESS

[tx_pkt_base + 1]

DATA FOR ADDRESS

[tx_pkt_base + 2]

DATA FOR ADDRESS

[tx_pkt_base + 3]

DATA FOR ADDRESS

[tx_pkt_base + N]

MOSI

MISO

SPI_PKT_WR

STATUS

Figure 56. Packet RAM Write

(tx_pkt_base is the address base pointer value for TX, which is programmed in Register txbp, Bit tx_pkt_base.)

[MAX N = (256 – INITIAL ADDRESS)]

CS

DATA FOR

[ADDRESS]

DATA FOR

SPI_MEM_WR

STATUS

ADDRESS

STATUS

MOSI

[ADDRESS + 1]

[ADDRESS + 2]

[ADDRESS + N]

STATUS

MISO

Figure 57. Memory (Register or Packet RAM) Block Write

CS

SPI_MEMR_WR

STATUS

ADDRESS 1

STATUS

DATA 1

ADDRESS 2

STATUS

DATA 2

DATA N

STATUS

MOSI

STATUS

MISO

Figure 58. Memory (Register or Packet RAM) Random Address Write

Rev. 0 | Page 51 of 72

ADF7241

CS

SPI_MEM_WR

+0x03

PAGE NUMBER

n

0x13

SPI_PRAM_WR

STATUS

0x00

CODE[0x00]

STATUS

CODE[0xFF]

STATUS

MOSI

MISO

STATUS

SET PRAM PAGE NUMBER n

UPLOAD 256 BYTES OF CODE TO PRAM PAGE NUMBER n

Figure 59. Upload Sequence for a Program RAM Page

DOWNLOAD 256 BYTES BLOCK 0

TO PRAM PAGE 0

DOWNLOAD 256 BYTES BLOCK 0

SET PRAM PAGE 0

SET PRAM PAGE 1

SET PRAM PAGE 2

TO PRAM PAGE 1

Figure 60. Download Sequence for Code Module

MAX N = (256 – tx_pkt_base)

SPI_NOP

CS

MOSI

SPI_PKT_RD

STATUS

SPI_NOP

STATUS

SPI_NOP

DATA FROM

ADDRESS

rx_pkt_base

DATA FROM

ADDRESS

rx_pkt_base + 1

DATA FROM

ADDRESS

rx_pkt_base + 2

DATA FROM

ADDRESS

rx_pkt_base + N

MISO

Figure 61. Packet RAM Read

(rx_pkt_base is the address base pointer value for RX, which is programmed in Register rxbp, Bit rx_pkt_base.)

[MAX N = (256 – INITIALADDRESS)]

CS

MOSI

SPI_MEM_RD

STATUS

ADDRESS

STATUS

SPI_NOP

STATUS

SPI_NOP

DATA FROM

ADDRESS

DATA FROM

ADDRESS + 1

DATA FROM

ADDRESS + N

MISO

Figure 62. Memory (Register or Packet RAM) Block Read

CS

ADDRESS 2

ADDRESS N

SPI_NOP

MOSI

MISO

SPI_MEM_RD

ADDRESS 1

ADDRESS 3

SPI_NOP

ADDRESS 4

DATA FROM

ADDRESS 1

DATA FROM

ADDRESS 2

DATA FROM

ADDRESS N – 2

DATA FROM

ADDRESS N – 1

DATA FROM

ADDRESS N

STATUS

Figure 63. Memory (Register or Packet RAM) Random Address Read

Rev. 0 | Page 52 of 72

ADF7241

DOWNLOADABLE FIRMWARE MODULES

The program RAM of the ADF7241 can be used to store

firmware modules for the on-chip processor that provide extra

functionality. The executable code for these firmware modules

and details on their functionality are available from Analog

Devices. See the Writing to the ADF7241 section for details on

how to download these firmware modules to program RAM.

Rev. 0 | Page 53 of 72

ADF7241

INTERRUPT CONTROLLER

resources. For instance, an rx_sfd interrupt can be associated

with a timer-capture unit of the MCU, while all other interrupts

are handled by a normal interrupt handling routine. When

operating in SPORT mode, Pin IRQ2_TRFS_GP2 acts as a

frame synchronization signal and is disconnected from the

interrupt controller.

CONFIGURATION

The ADF7241 is equipped with an interrupt controller that is

capable of handling up to 16 independent interrupt events. The

interrupt events can be triggered either by hardware circuits or

the packet manager and are captured in Register irq_src0

(0x3CB) and Register irq_src1(0x3CC).

When in the sleep state, the IRQ1_GP4 and IRQ2_TRFS_GP2

pins have high impedance.

The interrupt signals are available on two interrupt pins: IRQ1_

GP4 and IRQ2_TRFS_GP2. Each of the 16 interrupt sources

can be individually enabled or disabled. The irq1_en0 (0x3C7)

and irq1_en1 (0x3C8) registers control the functionality of the

IRQ1_GP4 interrupt pin. The irq2_en0 (0x3C9) and irq2_en1

(0x3CA) registers control the functionality of the IRQ2_TRFS_

GP2 interrupt pin. Refer to Table 28 and Table 29 for details on

which bits in the relevant interrupt source and interrupt enable

registers correspond to the different interrupts.

When not in the sleep state, Pin IRQ1_GP4 and Pin IRQ2_

TRFS_GP2 are configured as push-pull outputs, using positive

logic polarity.

Following a power-on reset or wake-up from sleep, Register

irq1_en0, Field powerup and Register irq2_en0, Field powerup

are set, while all other bits in the irq1_en0, irq1_en1, irq2_en0,

and irq2_en1 registers are reset. Therefore, a power-up interrupt

signal is asserted on the IRQ1_GP4 and IRQ2_TRFS_GP2 pins

after a power-on-reset event or wake-up from the sleep state.

Provided the wake-up from sleep event is caused by the wake-

up timer, the power-up interrupt signal can be used to power

up the host MCU.

The IRQ_STATUS bit of the SPI status word, is asserted if an

interrupt is present on either IRQ1 or IRQ2. This is useful for

host MCUs that may not have interrupt pins available.

The irq_src1 and irq_src0 registers can be read back to establish

the source of an interrupt. An interrupt is cleared by writing 1

to the corresponding bit location in the appropriate interrupt

source register (irq_src1 or irq_src0). If 0 is written to a bit

location in the interrupt source registers, its state remains

unchanged. This scheme allows interrupts to be cleared

individually and facilitates hierarchical interrupt processing.

After the ADF7241 is powered up, the rc_ready, wake-up, and

power-on reset interrupts are also asserted in the irq_src0

register. However, these interrupts are not propagated to the

IRQ1_GP4 and IRQ2_TRFS_GP2 pins because the correspond-

ing mask bits are reset. The irq_src0 and irq_src1 registers

should be cleared during the initialization phase.

The availability of two interrupt outputs permits a flexible

allocation of interrupt source to two different MCU hardware

REGISTER irq_src1

REGISTER irq_src0

INTERRUPT

SOURCES

(16 INTERRUPT SOURCES

AVAILABLE)

15 14 13 12 11 10

9

8

7

6

5

4

3

2

1

0

INTERRUPT

MASKS

(2 × 16 INDEPENDENT

INTERRUPT MASKS)

REGISTER irq2_en1

REGISTER irq2_en0

REGISTER irq1_en1

REGISTER irq1_en0

INTERRUPT OUTPUTS

(2 INTERRUPT PINS AND

INTERRUPT PENDING BIT

AVAILABLE ON THE

STATUS_WORD)

IRQ1_GP4

Status_word[6]

IRQ2_TRFS_GP2

Figure 64. Interrupt Controller

Rev. 0 | Page 54 of 72

ADF7241

Table 28. Bit Locations in the Interrupt Source Register

irq_src1, with Corresponding Interrupt Enables in irq1_en1,

irq2_en1

tx_sfd

This interrupt is asserted if the SFD is transmitted when in

IEEE 802.15.4-2006 packet mode.

Bit Name

Notes

rx_sfd

7

6

5

4

3

2

1

0

Reserved

Don’t care; set mask to 0.

TX packet transmission complete.

Packet received in RX_BUFFER.

SFD has been transmitted.

SFD has been detected.

CCA_RESULT in status word is valid.

This interrupt is asserted if a SFD is detected while in the RX

state in either IEEE 802.15.4 mode.

Reserved

tx_pkt_sent

rx_pkt_rcvd

tx_sfd

cca_complete

The interrupt is asserted at the end of a CCA measurement

following a RC_RX or RC_CCA command. The interrupt

indicates that the CCA_RESULT flag in the status word is valid.

rx_sfd

cca_complete

batt_alert

The interrupt is asserted if the battery monitor signals a battery

alarm. This occurs when the battery voltage drops below the

programmed threshold value. The battery monitor must be

enabled and configured. See the Battery Monitor section for

further details.

Table 29. Bit Locations in the Interrupt Source Register

irq_src0, with Corresponding Interrupt Enables in irq1_en0,

irq2_en0

Bit Name

Notes

7

6

5

Reserved Don’t care; set mask to 0.

batt_alert Battery voltage has dropped below

programmed threshold value.

rc_ready

The interrupt is asserted if the radio controller is ready to accept

a new command. This condition is equivalent to the rising edge

of the RC_READY flag in the status word.

4

3

por

rc_ready

Power-on reset event.

Radio controller ready to accept new

command.

wakeup

2

1

0

wakeup

powerup

Timer has timed out.

Chip is ready for access.

The interrupt is asserted if the WUC timer has decremented to

zero. Prior to enabling this interrupt, the WUC timer unit must

be configured with the tmr_cfg0, tmr_cfg1, tmr_rld0, and

tmr_rld1 registers. A wake-up interrupt can be asserted while

the ADF7241 is active or has woken up from the sleep state

through a timeout event. See the Wake-Up Controller (WUC)

section or further details.

Reserved Don’t care; set mask to 0.

DESCRIPTION OF INTERRUPT SOURCES

tx_pkt_sent

This interrupt is asserted when in IEEE 802.15.4-2006 packet

mode and the transmission of a packet in TX_BUFFER is

complete.

powerup

The interrupt is asserted if the ADF7241 is ready for SPI access

following a wake-up from the sleep state. This condition reflects

a rising edge of the flag SPI_READY in the status word. If the

rx_pkt_rcvd

This interrupt is asserted when in IEEE 802.15.4-2006 packet

mode and a packet with a valid FCS has been received and is

available in RX_BUFFER.

CS

ADF7241 has been woken up from the sleep state using the

input, this interrupt is useful to detect that the ADF7241 has

powered up without the need to poll the MISO output. Register

irq1_mask, Field powerup and Register irq2_mask, Field

powerup are automatically set on exit from the sleep state.

Therefore, this interrupt is generated when a transition from

CS

sleep is triggered by

being pulled low or by a timeout event.

Rev. 0 | Page 55 of 72

ADF7241

APPLICATIONS CIRCUITS

C15

C14

C39

C40

C41

C28

SENSOR

32kHz

SCS

MOSI

SCLK

MISO

VBAT

32 31 30 29 28 27 26 25

MICRO-

CONTROLLER

R10

24

C18

C17

C16

R12

GPIO0

1

C21

C22

CREGRF1

GPIO1

MOSI

SCLK

MISO

CS

GND

BALP

BALM

23

22

21

2

3

4

RBIAS

MOSI

UNBAL

GND

CREGRF2

RFIO1P

RFIO1N

RFIO2P

RFIO2N

CREGRF3

SCLK

MISO

10

20

19

18

17

5

6

7

8

ADF7241

IRQ1IN

IRQ2IN

IRQ1_GP4

TRCLK_CKO_GP3

IRQ2_TRFS_GP2

DT_GP1

C25

C26

C32

C27

12

9

10 11 12 13 14 15 16

26MHz

C34

C29

C30

C32

C35

C36

C37

Figure 65. Typical ADF7241 Application Circuit Using Antenna Diversity

Rev. 0 | Page 56 of 72

ADF7241

C15

C14

C39

C40

C41

C28

32kHz

VBAT

32 31 30 29 28 27 26 25

R10

C18

C17

C16

C4

L3

DSP

BFxxx

R12

24

1

C5

C7

CREGRF1

GPIO1

MOSI

SCLK

MISO

CS

23

22

21

2

3

4

RBIAS

MOSI

C6

L1

SPI

CREGRF2

RFIO1P

RFIO1N

RFIO2P

RFIO2N

CREGRF3

SCLK

MISO

L2

20

19

18

17

5

6

7

8

ADF7241

IRQ1IN

IRQ1_GP4

TRCLK_CKO_GP3

IRQ2_TRFS_GP2

DT_GP1

L4

C8

SPORT

C9

C27

L6

C11

L5

C10

9

10 11 12 13 14 15 16

26MHz

C34

C29

C30

C32

C35

C36

C37

Figure 66. Typical ADF7241 Application Circuit with DSP Using Antenna Diversity

Rev. 0 | Page 57 of 72

ADF7241

C41

C28

C15

C14

C39

C40

32kHz

R14

R15

VBAT

32 31 30 29 28 27 26 25

R10

C18

C17

C16

DSP

R12

BFxxx

24

1

C21

C22

CREGRF1

RBIAS

GPIO1

MOSI

SCLK

MISO

CS

GND BALP

ENABLE

LNA

23

22

21

2

3

4

MOSI

SCLK

UNBAL

SPI

CREGRF2

RFIO1P

10

GND BALM

MISO

20

19

18

17

5

6

7

8

ADF7241

IRQ1IN

RFIO1N

RFIO2P

IRQ1_GP4

TRCLK_CKO_GP3

IRQ2_TRFS_GP2

DT_GP1

SPORT

C25

C26

RFIO2N

CREGRF3

ENABLE

GND BALP

PA

UNBAL

C27

12

GND BALM

9

10 11 12 13 14 15 16

26MHz

C34

C29

C30

C32

C35

C36

C37

Figure 67. Typical ADF7241 Application Circuit with External LNA and External PA

Rev. 0 | Page 58 of 72

ADF7241

7 6 0 2 - 9 3 0 2

5 P G _ N E T X

0 P

D R _ G

C R E G

6 P _ G N R X E

2 G I D

1 G I D

C R E G

R D U A D G

B T 1 A 7 _ P G _

3 2 C K S P O X

2 6 C N S O X

B T 2 A N _ C S 3 2 K X O

P 6 2 C S X O

T A B _

V D D

H

Y N S T

U A G R O C V

O C V C R E G

C R E G

3 B T A _ P U V S P A

B T 4 A P _ A O B A I P

D

E L

A P D D

Figure 68. Typical ADF7241 Application Circuit with Discrete External PA

Rev. 0 | Page 59 of 72

ADF7241

REGISTER MAP

It is recommended that configuration registers be programmed in the idle state. Note that all registers that include fields that are denoted

as RC_CONTROLLED must be programmed in the idle state only.

Reset values are shown in decimal notation.

Table 30. Register Map Overview

Address

0x100

0x105

0x106

0x107

0x108

0x109

0x10A

0x10B

0x13E

0x300

0x301

0x302

0x306

0x30C

0x30D

0x313

0x314

0x315

0x316

0x317

0x318

0x319

0x31A

0x31B

0x31E

0x32C

0x32D

0x33D

0x353

0x354

0x355

0x36E

0x36F

0x371

0x380

0x381

0x395

0x396

0x39B

0x3A7

0x3A8

0x3A9

0x3AA

0x3AE

0x3B9

0x3C7

Register Name

Access Mode

R/W

R

Description

ext_ctrl

cca1

cca2

buffercfg

pkt_cfg

delaycfg0

delaycfg1

delaycfg2

rc_cfg

ch_freq0

ch_freq1

ch_freq2

tx_m

External LNA/PA and internal PA control configuration bits

RSSI threshold for CCA

CCA mode configuration

RX and TX buffer configuration

Firmware download module enable and FCS control

RC_RX command to SFD search delay

RC_TX command to TX state delay

MAC delay extension

Packet/SPORT mode configuration

Channel frequency settings—low byte

Channel frequency settings—middle byte

Channel frequency settings—two MSBs

Preemphasis filter configuration

rrb

lrb

prampg

txpb

RSSI readback register

Signal quality indicator quality readback register

PRAM page

R

R/W

R

R/W

R

Transmit packet storage base address

Receive packet storage base address

Wake-up timer configuration register—high byte

Wake-up timer configuration register—low byte

Wake-up timer value register—high byte

Wake-up timer value register—low byte

Wake-up timer timeout flag configuration register

32 kHz oscillator/WUC status

rxpb

tmr_cfg0

tmr_cfg1

tmr_rld0

tmr_rld1

tmr_ctrl

wuc_32khzosc_status

pd_aux

gp_cfg

Battery monitor and external PA bias enable

GPIO configuration

gp_out

rc_cal_cfg

vco_band_ovrw

vco_idac_ovrw

vco_ovwr_cfg

pa_bias

vco_cal_cfg

xto26_trim_cal

vco_band_rb

vco_idac_rb

rxcal0

rxcal1

rxfe_cfg

pa_rr

pa_cfg

extpa_cfg

extpa_msc

adc_rbk

agc_cfg5

irq1_en0

RC calibration setting

Overwrite value for the VCO frequency band

Overwrite value for the VCO bias current DAC

VCO calibration settings overwrite enable

PA bias control

VCO calibration parameters

26 MHz crystal oscillator configuration

Readback VCO band after calibration

Readback of the VCO bias current DAC after calibration

Receiver baseband filter calibration word, LSB

Receiver baseband filter calibration word, MSB

Receive baseband filter bandwidth and LNA selection

PA ramp rate

R

R/W

R

PA output stage current control

External PA bias DAC configuration

External PA interface circuit configuration

ADC readback

AGC configuration parameters

Interrupt Mask Set Bits[7:0] of Bits[15:0] for IRQ1

R/W

Rev. 0 | Page 60 of 72

ADF7241

Address

0x3C8

0x3C9

0x3CA

0x3CB

0x3CC

0x3E3

0x3E6

0x3F0

0x3F4

Register Name

irq1_en1

irq2_en0

irq2_en1

irq_src0

irq_src1

gp_drv

bm_cfg

tx_test

Access Mode

R/W

Description

Interrupt Mask Set Bits[15:8] of [15:0] for IRQ1

Interrupt Mask Set Bits[7:0] of [15:0] for IRQ2

Interrupt Mask Set Bits[15:8] of [15:0] for IRQ2

Interrupt Source Bits[7:0] of [15:0] for IRQ

Interrupt Source Bits[15:8] of [15:0] for IRQ

GPIO and SPI I/O pads drive strength configuration

Battery monitor threshold voltage setting

TX test mode configuration

sfd_15_4

R/W

Option to set nonstandard SFD

Table 31. 0x100: ext_ctrl

Reset

Value Description

Bit

Field Name

R/W

[7]

pa_shutdown_mode

R/W

0

PA shutdown mode.

0: fast ramp-down.

1: user defined ramp-down.

[6:5]

4

Reserved

rxen_en

R/W

0

Reserved, set to default.

1: RXEN_GP6 is set high while in the RX state; otherwise, it is low.

0: RXEN_GP6 is under user control (refer to Register gp_out); refer to

Register gp_cfg for restrictions

3

txen_en

R/W

0

1: TXEN_GP5 is set high while in the TX state; otherwise, it is low.

0: TXEN_GP5 is under user control (refer to Register gp_out); refer to

Register gp_cfg for restrictions.

2

extpa_auto_en

Reserved

R/W

0

1: RC enables external PA controller while in the TX state.

0: Register pd_aux, Bit extpa_bias_en (0x31E[4]) is under user control.

[1:0]

Reserved, set to default.

Table 32. 0x105: cca1

Reset

Value Description

Bit

Field Name

cca_thres

R/W

[7:0]

R/W

171

RSSI threshold for CCA. Signed twos complement notation (in dBm). When CCA is

completed:

Status Word CCA_RESULT = 1 if Register rrb, Bit rssi_readback (0x30C[7:0]) <

cca_thres

Status Word CCA_RESULT = 0 if Register rrb, Bit rssi_readback (0x30C[7:0]) ≥

cca_thres

Table 33. 0x106: cca2

Reset

Value

Bit

[7:3]

2

Field Name

R/W

Description

Reserved

0

Reserved, set to default.

continuous_cca

0: continuous CCA off.

1: generate a CCA interrupt every 128 μs.

1

0

rx_auto_cca

Reserved

R/W

0

0: automatic CCA off.

1: generate a CCA interrupt 128 μs after entering the RX state.

Reserved, set to default.

Rev. 0 | Page 61 of 72

ADF7241

Table 34. 0x107: buffercfg

Bit

Field Name

R/W

Reset Value Description

7

trx_mac_delay

R/W

0

0: tx_mac_delay (0x10A[7:0]) and rx_mac_delay (0x109[7:0]) enabled.

1: tx_mac_delay (0x10A[7:0]) and rx_mac_delay (0x109[7:0]) disabled.

6

Reserved

R/W

RW

0

Reserved, set to default.

[5:4] tx_buffer_mode

0: return to PHY_RDY after frame in TX_BUFFER is transmitted once.

1: cyclic transmission of frame in TX_BUFFER after TX MAC delay with PA

ramp-up/down between packets.

2: reserved.

3: cyclic transmission of frame in TX_BUFFER after TX MAC delay with PA

kept on.

3

2

auto_tx_to_rx_turnaround

auto_rx_to_tx_turnaround

R//W

R/W

0

0: as per tx_buffer_mode setting.

1: automatically goes to RX after TX data transmitted.

0: as per rx_buffer_mode setting.

1: automatically goes to TX after RX packet received.

[1:0] rx_buffer_mode

0: first frame following a RC_RX command is stored in RX_BUFFER; device

returns to PHY_RDY state after reception of first frame.

1: continuous reception of frames enabled; a new frame overwrites previous

frame.

2: new frames not written to buffer.

3: reserved.

Table 35. 0x108: pkt_cfg

Bit

Field Name

R/W

Reset Value Description

[7:5] Reserved

0

Reserved, set to default.

4

3

addon_en

0: firmware add-on module disabled.

1: firmware add-on module enabled; module must be loaded prior to setting

this bit.

skip_synt_settle

R/W

0

0: the RF frequency synthesizer calibration and settling phase is performed.

1: skip the RF frequency synthesizer calibration and settling phase. This must

only be used when the continuous packet transmission mode is enabled.

Refer to the WUC Configuration and Operation section.

[2:1] Reserved

R/W

2

0

Reserved, set to default.

0

auto_fcs_off

The rx_pkt_rcvd interrupt is asserted.

0: receive operation—FCS automatically validated; FCS replaced with RSSI

and SQI values in RX_BUFFER.

Transmit operation—FCS automatically appended to transmitted packet; FCS

field in TX_BUFFER is ignored.

1: receive operation—received FCS is stored in RX_BUFFER without

validation.

Transmit operation—FCS field in TX_BUFFER is transmitted.

Table 36. 0x109: delaycfg0

Bit

Field Name

R/W

Reset Value Description

192

Programmable delay from issue of RC_RX command to SFD search and for

start of RSSI measurement window.

[7:0] rx_mac_delay

R/W

Table 37. 0x10A: delaycfg1

Bit

Field Name

R/W

Reset Value Description

192

Programmable delay from issue of RC_TX command to entering the TX state.

[7:0]

tx_mac_delay

R/W

Programmable in steps of 1 μs in both modes.

Rev. 0 | Page 62 of 72

ADF7241

Table 38. 0x10B: delaycfg2

Bit

Field Name

R/W

Reset Value Description

Programmable MAC delay extension. Programmable in steps of 4 μs. Applies in

both the RX and TX states.

[7:0]

mac_delay_ext

R/W

0

Table 39. 0x13E: rc_cfg

Bit

Field Name

R/W

Reset Value Description

0 Configure packet format:

[7:0]

rc_mode

R/W

0: IEEE 802.15.4-2006 packet mode.

1: reserved.

2: IEEE 802.15.4-2006 receive SPORT mode.

3: IEEE 802.15.4-2006 transmit SPORT mode.

4, 5 to 255: reserved.

Table 40. 0x300: ch_freq0

Bit

Field Name

R/W

Reset Value Description

[7:0]

ch_freq[7:0]

R/W

128

Channel frequency [Hz]/10 kHz, Bits[7:0] of Bits[23:0].

Table 41. 0x301: ch_freq1

Bit

Field Name

R/W

Reset Value Description

[7:0]

ch_freq[15:8]

R/W

169

Channel frequency [Hz]/10 kHz, Bits[15:8] of Bits[23:0].

Table 42. 0x302: ch_freq2

Bit

Field Name

R/W

Reset Value Description

[7:0]

ch_freq[23:16]

R/W

3

Channel frequency [Hz]/10 kHz, Bits[23:16] of Bits[23:0].

Table 43. 0x306: tx_m

Bit

[7:1]

0

Field Name

R/W

Reset Value Description

RC_CONTROLLED

preemp_filt

0

1

Controlled by radio controller.

1: enable; 0: disable preemphasis filter.

Table 44. 0x30C: rrb

Bit

Field Name

R/W

Reset Value Description

[7:0]

rssi_readback

R

0

Receive input power in dBm; signed twos complement.

Table 45. 0x30D: lrb

Bit

Field Name

R/W

Reset Value Description

[7:0]

sqi_readback

R

0

Signal quality indicator readback value.

Table 46. 0x313: prampg

Bit

Field Name

R/W

Reset Value Description

[7:4]

[3:0]

Reserved

0

Reserved, set to default.

pram_page

Program PRAM page.

Rev. 0 | Page 63 of 72

ADF7241

Table 47. 0x314: txpb

Bit

Field Name

R/W

Reset Value Description

[7:0]

tx_pkt_base

R/W

128

Base address of TX_BUFFER in packet RAM.

Table 48. 0x315: rxpb

Bit

Field Name

R/W

Reset Value Description

[7:0]

rx_pkt_base

R/W

0

Base address of RX_BUFFER in packet RAM.

Table 49. 0x316: tmr_cfg0

Bit

Field Name

R/W

Reset Value Description

[7:3]

[2:0]

Reserved

0

Reserved, set to default.

timer_prescal

Divider factor for XTO32K or RCO.

0: ÷1.

1: ÷4.

2: ÷8.

3: ÷16.

4: ÷128.

5: ÷1024.

6: ÷8192.

7: ÷65,536.

Note that this is a write-only register and should be written to prior to writing to

Register tmr_cfg1. Settings become effective only after writing to Register tmr_cfg1.

Table 50. 0x317: tmr_cfg1

Bit

Field Name

R/W

Reset Value Description

7

Reserved

0

Reserved, set to default.

[6:3]

sleep_config

1: SLEEP_BBRAM.

4: SLEEP_XTO.

5: SLEEP_BBRAM_XTO.

11: SLEEP_BBRAM_RCO.

0, 2, 3, 6 to 10, 12 to 15: reserved.

Refer to note in Register tmr_cfg0.

[2:1]

0

Reserved

R/W

0

Reserved, set to default.

wake_on_timeout R/W

1: enable, 0: disable wake-up on timeout event.

Table 51. 0x318: tmr_rld0

Bit

Field Name

R/W

Reset Value Description

0 Timer reload value, Bits[15:8] of Bits[15:0].

[7:0]

timer_reload[15:8] R/W

Note that this is a write-only register and should be written to prior to writing to

Register tmr_rld1. Settings become effective only after writing to Register tmr_rld1.

Table 52. 0x319: tmr_rld1

Bit

Field Name

R/W

Reset Value Description

Timer reload value, Bits[7:0] of Bits[15:0]. Refer to note in Register tmr_rld0.

[7:0]

timer_reload[7:0]

R/W

0

Rev. 0 | Page 64 of 72

ADF7241

Table 53. 0x31A: tmr_ctrl

Bit

[7:2]

1

Field Name

R/W

Reset Value Description

Reserved

0

Reserved, set to default.

wuc_rc_osc_cal

1: enable.

0: disable 32 kHz RC oscillator calibration.

0

wake_timer_flag_reset R/W

0

Timer flag reset.

0: normal operation.

1: reset Field wuc_tmr_prim_toflag and Field wuc_porflag (0x31B).

Table 54. 0x31B: wuc_32khzosc_status

Bit

[7:6]

5

Field Name

R/W

Reset Value

Description

Reserved

R

0

Reserved, set to default.

rc_osc_cal_ready

R

32 kHz RC oscillator calibration (only valid if wuc_rc_osc_cal = 1). Calibration

takes 1 ms.

0: calibration in progress.

1: calibration finished.

4

xosc32_ready

R

0

32 kHz crystal oscillator (only valid if sleep_config (0x317[6:3]) = 4 or 5).

0: oscillator not settled.

1: oscillator has settled.

3

2

Reserved

R

0

Reserved, set to default.

wuc_porflag

Chip cold start event registration.

0: not registered.

1: registered.

1

0

wuc_tmr_prim_toflag

Reserved

R

0

WUC timeout event registration (the output of a latch triggered by a timeout

event).

0: not registered.

1: registered.

Reserved, set to default.

Table 55. 0x31E: pd_aux

Bit

Field Name

R/W

Reset Value

Description

7

Reserved

0

Reserved, set to default.

Controlled by radio controller.

6

RC_CONTROLLED

battmon_en

5

1: enable.

0: disable battery monitor.

4

extpa_bias_en

R/W

0

1: enable.

0: disable external PA biasing circuit.

Controlled by radio controller when Register ext_ctrl, Field extpa_auto_en = 1

(0x100[2]).

[3:0]

RC_CONTROLLED

R/W

0

Controlled by radio controller.

Table 56. 0x32C: gp_cfg

Bit

Field Name

R/W

Reset Value Description

0 0: IRQ1, IRQ2 functionality.

[7:0]

gpio_config

Register gp_out, Bit gpio_dout[6] controls RXEN output.

Register gp_out, Bit gpio_dout[5] controls TXEN output.

1: TRCLK and data pins active in RX, gated by synchronization word detection.

1, 4: TRCLK and data pins active in TX.

7: symbol clock output on TRCLK pin and symbol data output on GP6, GP5, GP1,

and GP0.

Refer to Table 19 for further details of SPORT mode configurations.

2, 3, 5, 6, 8 to 255: reserved.

Rev. 0 | Page 65 of 72

ADF7241

Table 57. 0x32D: gp_out

Bit

Field Name

R/W

Reset Value Description

0 GPIO output value if Register gp_cfg, Field gpio_config = 4.

[7:0]

gpio_dout

R/W

gpio_dout[7:0] = GP7 to GP0.

If Register ext_ctrl, Field rxen_en = 1, then Register gp_out,

Bit gpio_dout[6] is controlled by radio controller.

If Register ext_ctrl, Field txen_en = 1, then Register gp_out,

Bit gpio_dout[5] is controlled by radio controller.

Table 58. 0x33D: rc_cal_cfg

Bit

Field Name

R/W

Reset Value Description

[7:2]

[1:0]

Reserved

skip_rc_cal

15

0

Reserved, set to default.

0: do not skip RC calibration. This calibration is performed only when

transitioning from idle to PHY_RDY.

3: skip RC calibration.

Table 59. 0x353: vco_band_ovrw

Bit

Field Name

R/W

Reset Value

Description

[7:0]

vco_band_ovrw_val R/W

0

Overwrite value for the VCO frequency band. Enabled when vco_band_ovrw_en = 1

and Register vco_cal_cfg, Field skip_vco_cal = 15.

Table 60. 0x354: vco_idac_ovrw

Bit

Field Name

R/W

Reset Value

Description

[7:0]

vco_idac_ovrw_val R/W

0

Overwrite value for the VCO bias current DAC. Enabled when Register

vco_cal_cfg, Field skip_vco_cal = 15 and Field vco_idac_ovrw_en = 1.

Table 61. 0x355: vco_ovrw_cfg

Bit

[7:2]

1

Field Name

R/W

Reset Value

Description

Reserved

2

0

Reserved, set to default.

vco_idac_ovrw_en

VCO bias current DAC overwrite. Effective only if Register vco_cal_cfg,

Field skip_vco_cal = 15.

0: disable.

1: enable.

0

vco_band_ovrw_en R/W

0

VCO frequency band overwrite. Effective only if Register vco_cal_cfg,

Field skip_vco_cal = 15.

0: disable.

1: enable.

Table 62. 0x36E: pa_bias

Bit

Field Name

R/W

Reset Value

Description

7

Reserved

0

Reserved, set to default.

[6:1]

0

pa_bias_ctrl

Reserved

55

1

Set to 63 if maximum PA output power of 4.8 dBm is required.

Reserved, set to default.

Table 63. 0x36F: vco_cal_cfg

Bit

Field Name

R/W

Reset Value

Description

[7:4]

[3:0]

Reserved

0

9

Reserved, set to default.

skip_vco_cal

9: do not skip VCO calibration.

15: skip VCO calibration.

Rev. 0 | Page 66 of 72

ADF7241

Table 64. 0x371: xto26_trim_cal

Bit

Field Name

R/W

Reset Value

Description

[7:6]

[5:3]

Reserved

0

4

Reserved, set to default.

xto26_trim

26 MHz crystal oscillator (XOSC26N ) tuning capacitor control word. The load

capacitance is adjusted according to the value of xto26_trim as follows:

0: −4 × 187.5 fF.

1: −3 × 187.5 fF.

2: −2 × 187.5 fF.

3: −1 × 187.5 fF.

4: 0 × 187.5 fF.

5: 1 × 187.5 fF.

6: 2 × 187.5 fF.

7: 3 × 187.5 fF.

[2:0]

Reserved

R/W

0

Reserved, set to default.

Table 65. 0x381: vco_band_rb

Bit

Field Name

R/W

Reset Value

Description

[7:2]

vco_band_val_rb

R

0

Readback for the VCO frequency band after calibration.

Table 66. 0x381: vco_idac_rb

Bit

Field Name

R/W

Reset Value

Description

[7:2]

vco_idac_val_rb

R

0

Readback of the VCO bias current DAC after calibration.

Table 67. 0x395: rxcal0

Bit

Field Name

R/W

Reset Value Description

[7:0]

dcap_ovwrt_low

R/W

0

RXBB filter tuning overwrite word, LSB.

Table 68. 0x396: rxcal1

Bit

[7:2]

1

Field Name

R/W

Reset Value Description

Reserved

2

0

Reserved, set to default.

dcap_ovwrt_en

dcap_ovwrt_high

RXBB filter tuning overwrite word enable.

RXBB filter tuning overwrite word, MSB.

0

Table 69. 0x39B: rxfe_cfg

Bit

[7:5]

4

Field Name

Reserved

lna_sel

R/W

Reset Value Description

0

1

Reserved, set to default.

Receive:

0: use LNA1.

1: use LNA2.

[3:0]

Reserved

R/W

13

Reserved, set to default.

Table 70. 0x3A7: pa_rr

Bit

Field Name

R/W

Reset Value Description

[7:3]

[2:0]

Reserved

0

7

Reserved, set to default.

pa_ramp_rate

PA ramp rate:

2^pa_ramp_rate× 2.4 ns per PA power step.

Rev. 0 | Page 67 of 72

ADF7241

Table 71. 0x3A8: pa_cfg

Bit

Field Name

R/W

Reset Value Description

7

Reserved

0

Reserved, set to default.

[6:5]

[4:0]

Reserved

0

Set to default.

pa_bridge_dbias

13

Set to 21 if output power of 4.8 dBm is required from PA.

Table 72. 0x3A9: extpa_cfg

Bit

Field Name

R/W

Reset Value Description

[7:5]

[4:0]

Reserved

0

Reserved, set to default.

extpa_bias

If Register extpa_msc, Field extpa_bias_mode = 1, 2, 3, or 4,

PABIAOP_ATB4 pin DAC current = 80 μA − 2.58 μA × extpa_bias.

If Register extpa_msc, Field extpa_bias_mode = 5 or 6,

PAVSUP_ATB3 pin servo current set point = 22 mA − 0.349 mA × extpa_bias.

Table 73. 0x3AA: extpa_msc

Bit

Field Name

R/W

Reset Value Description

[7:4]

pa_pwr

R/W

15

PA output power after ramping phase:

3: minimum power.

15: maximum power.

Nominal power step size 2 dB per LSB.

3

extpa_bias_src

R/W

0

1

0: select RBIAS-referred reference current.

1: select band gap-referred reference current.

[2:0]

extpa_bias_mode

External PA interface configuration:

0: PAVSUP_ATB3 = on; PABIAOP_ATB4 = floating.

1: PAVSUP_ATB3 = on; PABIAOP_ATB4 = current source.

2: PAVSUP_ATB3 = on; PABIAOP_ATB4 = current sink.

3: PAVSUP_ATB3 = off; PABIAOP_ATB4 = current source.

4: PAVSUP_ATB3 = off; PABIAOP_ATB4 = current sink.

5: PAVSUP_ATB3 = on; PABIAOP_ATB4 = positive servo output.

6: PAVSUP_ATB3 = on; PABIAOP_ATB4 = negative servo output.

7: reserved.

Table 74. 0x3AE: adc_rbk

Bit

Field Name

Reserved

adc_out

R/W

R

Reset Value Description

[7:6]

[5:0]

0

Ignore.

R

ADC output code.

Table 75. 0x3B9: agc_cfg5

Bit

Field Name

Reserved

rssi_offs

R/W

Reset Value Description

[7:5]

[4:2]

[1:0]

0

4

3

Set to 0.

RSSI offset adjust, rssi_offs is added to Register rrb, Field rssi_readback.

Reserved, set to default.

Reserved

Table 76. 0x3C7: irq1_en0

Bit

Field Name

Reserved

batt_alert

por

rc_ready

wakeup

powerup

Reserved

R/W

Reset Value Description

7

6

5

4

3

2

1

0

1

0

Set to 0.

Battery monitor interrupt.

Power-on reset event.

Radio controller ready to accept new command.

Timer has timed out.

Chip is ready for access.

Set to 0.

Rev. 0 | Page 68 of 72

ADF7241

Table 77. 0x3C8: irq1_en1

Bit

Field Name

Reserved

tx_pkt_sent

rx_pkt_rcvd

tx_sfd

R/W

Reset Value Description

7

6

5

4

3

2

1

0

Set to 0.

Packet transmission complete.

Packet received in RX_BUFFER.

SFD was transmitted.

SFD was detected.

CCA_RESULT in status word is valid.

rx_sfd

cca_complete

Table 78. 0x3C9: irq2_en0

Bit

Field Name

Reserved

batt_alert

por

rc_ready

wakeup

powerup

Reserved

R/W

Reset Value Description

7

6

5

4

3

2

1

0

1

0

Set to 0.

Battery monitor interrupt.

Power-on reset event.

Radio controller ready to accept new command.

Timer has timed out.

Chip is ready for access.

Set to 0.

Table 79. 0x3CA: irq2_en1

Bit

Field Name

Reserved

tx_pkt_sent

rx_pkt_rcvd

tx_sfd

R/W

Reset Value Description

7

6

5

4

3

2

1

0

Set to 0.

Packet transmission complete.

Packet received in RX_BUFFER.

SFD was transmitted.

SFD was detected.

CCA_RESULT in status word is valid.

rx_sfd

cca_complete

Table 80. 0x3CB: irq_src0

Bit

Field Name

Reserved

batt_alert

por

rc_ready

wakeup

powerup

Reserved

R/W

Reset Value

Description

7

6

5

4

3

2

1

0

Set to 0.

Battery monitor interrupt.

Power-on reset event.

Radio controller ready to accept new command.

Timer has timed out.

Chip is ready for access.

Set to 0.

Rev. 0 | Page 69 of 72

ADF7241

Table 81. 0x3CC: irq_src1

Bit

Field Name

Reserved

tx_pkt_sent

rx_pkt_rcvd

tx_sfd

R/W

Reset Value

Description

7

6

5

4

3

2

1

0

Set to 0.

Packet transmission complete.

Packet received in RX_BUFFER.

SFD was transmitted.

SFD was detected.

CCA_RESULT in status word is valid.

rx_sfd

cca_complete

Table 82. 0x3E3: gp_drv

Bit

Field Name

R/W

Reset Value

Description

[7:4]

[3:2]

Reserved

0

Reserved, set to default.

gpio_slew

GPIO and SPI slew rate.

0: very slow.

1: slow.

2: very fast.

3: fast.

[1:0]

gpio_drive

R/W

0

GPIO and SPI drive strength.

0: 4 mA.

1: 8 mA.

2: >8 mA.

3: reserved.

Table 83. 0x3E6: bm_cfg

Bit

Field Name

R/W

Reset Value

Description

7:5]

[4:0]

Reserved

0

Reserved, set to default.

battmon_voltage

Battery monitor trip voltage:

1.7 V + 62 mV × battmon_voltage; the batt_alert interrupt is asserted when

VDD_BAT drops below the trip voltage.

Table 84. 0x3F0: tx_test

Bit

[7:2]

1

Field Name

R/W

Reset Value

Description

Reserved

2

0

Reserved, set to default.

carrier_only

Reserved

Transmits unmodulated tone at the programmed frequency f_CH.

Reserved, set to default.

0

Table 85. 0x3F4: sfd_15_4

Bit

Field Name

R/W

Reset Value

Description

[7:4]

[3:0]

sfd_symbol_2

sfd_symbol_1

10

7

Symbol 2 of SFD note: IEEE 802.15.4-2006 requires SFD1 = 10.

Symbol 1 of SFD note: IEEE 802.15.4-2006 requires SFD1 = 7.

Rev. 0 | Page 70 of 72

ADF7241

OUTLINE DIMENSIONS

5.10

5.00 SQ

4.90

0.30

0.25

0.18

PIN 1

INDICATOR

PIN 1

INDICATOR

25

32

24

1

0.50

BSC

3.45

3.30 SQ

3.15

EXPOSED

PAD

17

8

16

9

0.50

0.40

0.30

0.25 MIN

TOP VIEW

BOTTOM VIEW

FOR PROPER CONNECTION OF

THE EXPOSED PAD, REFER TO

THE PIN CONFIGURATION AND

FUNCTION DESCRIPTIONS

0.80

0.75

0.70

0.05 MAX

0.02 NOM

SECTION OF THIS DATA SHEET.

COPLANARITY

0.08

0.20 REF

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MO-220-WHHD.

Figure 69. 32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]

5 mm × 5 mm Body, Very Thin Quad

(CP-32-13)

Dimensions shown in millimeters

ORDERING GUIDE

Model¹

Temperature Range

Package Description

Package Option

CP-32-13

ADF7241BCPZ

−40°C to +85°C

32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]

Evaluation Platform Daughterboard

ADF7241BCPZ-RL7

EVAL-ADF7241DB1Z

EVAL-ADF7XXXMB3Z

Evaluation Platform Motherboard

¹Z = RoHS Compliant Part.

Rev. 0 | Page 71 of 72

ADF7241

NOTES

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D09322-0-1/11(0)

Rev. 0 | Page 72 of 72


型号：	ADF7241
厂家：	ADI
描述：	Low Power IEEE 802.15.4 Zero-IF 2.4 GHz Transceiver IC 低功耗IEEE 802.15.4零中频的2.4 GHz收发器IC
文件：	总72页 (文件大小：709K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

ADF7241 [ADI]

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