AT86RF230 - Complete

AT86RF230
Features
• High Performance RF-CMOS 2.4 GHz Radio Transceiver Targeted for IEEE
802.15.4™, ZigBee®, 6LoWPAN, RF4CE, SP100, WirelessHART™ and ISM
Applications
• Industry Leading Link Budget (104 dB):
- Programmable Output Power from -17 dBm up to 3 dBm
- Receiver Sensitivity -101 dBm
• Ultra-Low Power Consumption:
- SLEEP: 20 nA
- RX: 15.5 mA
- TX: 16.5 mA (at max Transmit Power of 3 dBm)
• Ultra-Low Supply Voltage (1.8V to 3.6V) with Internal Regulator
• Optimized for Low BoM Cost and Ease of Production:
- Few External Components Necessary (Crystal, Capacitors and Antenna)
• Excellent ESD Robustness
• Easy to Use Interface:
- Registers and Frame Buffer Accessible through Fast SPI
- Only Two Microcontroller GPIO Lines Necessary
- One Interrupt Pin from Radio Transceiver
- Clock Output with Prescaler from Radio Transceiver
• Radio Transceiver Features:
- 128-byte SRAM for Data Buffering
- Programmable Clock Output to Clock the Host Microcontroller or as Timer
Reference
- Integrated TX/RX Switch
- Fully Integrated PLL with on-chip Loop Filter
- Fast PLL Settling Time
- Battery Monitor
- Fast Power-Up Time < 1 ms
• Special IEEE 802.15.4-2003 Hardware Support:
- FCS Computation
- Clear Channel Assessment
- Energy Detection / RSSI Computation
- Automatic CSMA-CA
- Automatic Frame Retransmission
- Automatic Frame Acknowledgement
- Automatic Address Filtering
• Industrial Temperature Range:
- -40° C to 85° C
• I/O and Packages:
- 32-pin Low-Profile QFN
- RoHS/Fully Green
• Compliant to EN 300 328/440, FCC-CFR-47 Part 15, ARIB STD-66, RSS-210
• Compliant to IEEE 802.15.4-2003
Low Power
2.4 GHz
Transceiver
for ZigBee,
IEEE 802.15.4,
6LoWPAN,
RF4CE and ISM
Applications
AT86RF230
5131E-MCU Wireless-02/09
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1 Pin-out Diagram
AVSS
AVSS
AVSS
AVDD
EVDD
AVSS
XTAL2
XTAL1
Figure 1-1. AT86RF230 Pin-Out Diagram
1
2
3
4
5
6
7
8
32 31 30 29 28 27 26 25
24
Exposed Paddle
23
AVSS
22
21
AT86RF230 20
19
18
17
9 10 11 12 13 14 15 16
IRQ
SEL
MOSI
DVSS
MISO
SCLK
DVSS
CLKM
DVSS
DVSS
SLP_TR
DVSS
DVDD
DVDD
DEVDD
DVSS
AVSS
AVSS
AVSS
RFP
RFN
AVSS
TST
RST
Note: The exposed paddle is electrically connected to the die inside the package. It
shall be soldered to the board to ensure electrical and thermal contact and good
mechanical stability.
Disclaimer
Typical values contained in this datasheet are based on simulations and testing. Min
and Max values will be available when the radio transceiver has been fully
characterized.
2 Overview
The AT86RF230 is a low-power 2.4 GHz radio transceiver especially designed for
ZigBee/IEEE 802.15.4 applications. The AT86RF230 is a true SPI-to-antenna solution.
All RF-critical components except the antenna, crystal and de-coupling capacitors are
integrated on-chip. Therefore, the AT86RF230 is particularly suitable for applications
like:
• 2.4 GHz IEEE 802.15.4 and ZigBee systems
• 6LoWPAN and RF4CE systems
• Wireless sensor networks
• Industrial control, sensing and automation (SP100, WirelessHART)
• Home and building automation
• Consumer electronics
• PC peripherals
The AT86RF230 can be operated by using an external microcontroller like ATMEL’s
AVR microcontrollers. A comprehensive software programming description can be
found in the application note AVR2009 “AT86RF230 – Software Programming Model”.
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5131E-MCU Wireless-02/09
AT86RF230
3 General Circuit Description
This single-chip radio transceiver provides a complete radio transceiver interface
between the antenna and the microcontroller. It comprises the analog radio transceiver
and the digital demodulation including time and frequency synchronization, and data
buffering. The number of external components is minimized such that only an antenna,
a crystal and four decoupling capacitors are required. The bidirectional differential
antenna pins are used for transmission and reception, so that no external antenna
switch is needed.
The AT86RF230 block diagram is shown in Figure 3-1.
XTAL2
XTAL1
Figure 3-1. Block Diagram of the AT86RF230
Analog Domain
Digital Domain
FTN
DCLK
TX power
control
AVREG
XOSC
DVREG
IRQ
BATMON
PA
Frequency
Synthesis
TX Data
SEL
TX BBP
MISO
RFP
SPI
Slave
Interface
Control Logic/
Configuration
Registers
RFN
MOSI
I
LNA
SSBF
PPF
SCLK
Limiter
ADC
RX BBP
Fame
Buffer
Q
CLKM
AGC
RSSI
SLP_TR
5
RST
The received RF signal at pins RFN and RFP is differentially fed through the low-noise
amplifier (LNA) to the RF filter (PPF) to generate a complex signal. This signal is
converted down by mixers to an intermediate frequency and fed to the integrated
channel filter (SSBF). The limiting amplifier provides sufficient gain to drive the
succeeding analog-to-digital converter (ADC) and generates a digital RSSI signal with
3 dB granularity. The ADC output signal is sampled by the digital base band receiver
(RX BBP).
The transmit modulation scheme is offset-QPSK (O-QPSK) with half-sine pulse shaping
and 32-length block coding (spreading) according to [1]. The modulation signal is
generated in the digital transmitter (TX BBP) and applied to the fractional-N frequency
synthesis (PLL) generating a coherent phase modulation required for demodulation of
O-QPSK signals. The frequency-modulated RF signal is fed to the power amplifier (PA).
An internal 128 byte RAM for RX and TX (Frame Buffer) buffers the data to be
transmitted or the received data. Two on chip low dropout (LDO) voltage regulators
provide the internal analog and digital 1.8V supply.
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4 Pin Description
Table 4-1. AT86RF230 Pin List
Number
Name
Type
Description
1
AVSS
Ground
Analog ground
2
AVSS
Ground
Analog ground
3
AVSS
Ground
Ground for RF signals
4
RFP
RF I/O
Differential RF signal
5
RFN
RF I/O
Differential RF signal
6
AVSS
Ground
Ground for RF signals
7
TST
Digital input
Enables Continuous Transmission Test Mode; active high
8
RST
Digital input
Chip reset; active low
9
DVSS
Ground
Digital ground
10
DVSS
Ground
Digital ground
11
SLP_TR
Digital input
Controls sleep, transmit start and receive states; active high
12
DVSS
Ground
Digital ground
13
DVDD
Supply
Regulated 1.8V supply voltage; digital domain
14
DVDD
Supply
Regulated 1.8V supply voltage; digital domain
15
DEVDD
Supply
External supply voltage; digital domain
16
DVSS
Ground
Digital ground
17
CLKM
Digital output
Master clock signal output
18
DVSS
Ground
Digital ground
19
SCLK
Digital input
SPI clock
20
MISO
Digital output
SPI data output (master input slave output)
21
DVSS
Ground
Digital ground
22
MOSI
Digital input
SPI data input (master output slave input)
23
SEL
Digital input
SPI select; active low
24
IRQ
Digital output
Interrupt request signal; active high
25
XTAL1
Analog input
Crystal pin or external clock supply
26
XTAL2
Analog input
Crystal pin
27
AVSS
Ground
Analog ground
28
EVDD
Supply
External supply voltage; analog domain
29
AVDD
Supply
Regulated 1.8V supply voltage; analog domain
30
AVSS
Ground
Analog ground
31
AVSS
Ground
Analog ground
32
AVSS
Ground
Analog ground
Paddle
AVSS
Ground
Analog ground; Exposed Paddle of QFN package
4.1 Supply and Ground Pins
EVDD, DEVDD
EVDD and DEVDD are analog and digital supply voltage pins of the AT86RF230 radio
transceiver.
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5131E-MCU Wireless-02/09
AT86RF230
AVDD, DVDD
AVDD and DVDD are outputs of the internal 1.8V voltage regulators. The voltage
regulators are controlled independently by the radio transceivers state machine and are
activated depending on the current radio transceiver state. The voltage regulators can
be configured for external supply. For details refer to section 9.4.
AVSS, DVSS
AVSS and DVSS are analog and digital ground pins respectively.
The analog and digital power domains should be separated on the PCB, for further
details see application note AVR2005 "Design Considerations for the AT86RF230".
4.2 Analog and RF Pins
RFP, RFN
A differential RF port (RFP/RFN) provides common-mode rejection to suppress the
switching noise of the internal digital signal processing blocks. At the board-level, the
differential RF layout ensures high receiver sensitivity by rejecting any spurious
interspersions originating from other digital ICs such as a microcontroller.
The RF port is designed for a 100Ω differential load. A DC path between the RF pins is
allowed. A DC path to ground or supply voltage is not allowed. Therefore, when
connecting a RF-load providing a DC path to the power supply or to ground, capacitive
coupling is required as indicated in Table 4-2.
A simplified schematic of the RF front end is shown in Figure 4-1.
Figure 4-1. Simplified RF Front-End Schematic
PCB
AT86RF230
RFP
RFN
0.9V
M0
LNA
RX
PA
TX
CM
Feedback
RXTX
RF port DC values depend on the operating mode. In TRX_OFF state (see section
7.1.2), when the analog front end is disabled, the RF pins are pulled to ground,
preventing a floating voltage.
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In receive mode, the RF input provides a low-impedance path to ground when transistor
M0 (see Figure 4-1) pulls the inductor center tap to ground. A DC voltage drop of 20 mV
across the on-chip inductor can be measured at the RF pins.
In transmit mode, a control loop provides a common-mode voltage of 0.9V. Transistor
M0 is off, allowing the PA to set the common-mode voltage. The common-mode
capacitance at each pin to ground shall be < 30 pF to ensure the stability of this
common-mode feedback loop.
XTAL1, XTAL2
The pin XTAL1 is the input of the reference oscillator amplifier (XOSC), XTAL2 is the
output. A detailed description of the crystal oscillator setup and the related
XTAL1/XTAL2 pin configuration can be found in section 9.6.
When using an external clock reference signal, XTAL1 shall be used as input pin. For
further details refer to section 9.6.3.
Table 4-2. Comments on Analog and RF Pins
Pin
Condition
Recommendation/Comment
RFP/RFN
VDC = 0.9V (TX)
VDC = 20 mV (RX) at both pins
AC-coupling is required if an antenna with a DC path to ground is used.
Serial capacitance must be < 30 pF.
XTAL1/XTAL2
CPAR = 3 pF
VDC = 0.9V at both pins
Parasitic capacitance (CPAR) of the pins must be considered as additional
load capacitance to the crystal.
4.3 Digital Pins
The digital interface of the AT86RF230 compromises pins SEL , SCLK, MOSI and
MISO forming the serial peripheral interface (SPI) and pins CLKM, IRQ, SLP_TR and
RST used as additional control signal between radio transceiver and microcontroller.
The digital radio transceiver interface is described in detail in section 6.
4.3.1 Driver Strength Settings of Digital Output Pins
The driver strength of the digital output pins (MISO, IRQ) and CLKM pin can be
configured by register 0x03 (TRX_CTRL_0) as described in Table 4-3.
The capacitive load should be as small as possible and not larger than 50 pF when
using the 2 mA minimum driver strength setting. Generally, the output driver strength
should be adjusted to the lowest possible value in order to keep the current
consumption and the emission of digital signal harmonics low.
Table 4-3. Digital Output Driver Configuration
6
AT86RF230
Pin
Default Driver Strength
Comment
MISO, IRQ
2 mA
Adjustable to 2 mA, 4 mA, 6 mA and 8 mA
CLKM
4 mA
Adjustable to 2 mA, 4 mA, 6 mA and 8 mA
5131E-MCU Wireless-02/09
AT86RF230
4.3.2 Pull-up and Pull-down Configuration of Digital Input Pins
Pulling resistors are internally connected to all digital input pins in radio transceiver
state P_ON (see section 7.1.2). Table 4-4 summarizes the pull-up and pull-down
configuration.
Table 4-4 Pull-Up/Pull-Down Configuration of Digital Input Pins in P_ON State
Pin
H ≙ pull-up, L ≙ pull-down
RST
H
SEL
H
SCLK
L
MOSI
L
SLP_TR
L
In all other radio transceiver states, no pull-up or pull-down resistors are connected to
any of the digital input pins.
4.3.3 Register Description
Register 0x03 (TRX_CTRL_0)
The TRX_CTRL_0 register controls the drive current of the digital output pads and the
CLKM clock rate.
Bit
7
6
0x03
Read/Write
Reset value
Bit
0x03
5
PAD_IO
R/W
0
R/W
0
3
2
CLKM_SHA_SEL
Read/Write
Reset value
4
PAD_IO_CLKM
TRX_CTRL_0
R/W
0
R/W
1
1
0
CLKM_CTRL
R/W
1
R/W
0
R/W
0
TRX_CTRL_0
R/W
1
• Bit [7:6] – PAD_IO
The register bits PAD_IO set the output driver current of digital output pads MISO and
IRQ.
Table 4-5. Digital Output Driver Strength
Register Bit
PAD_IO
Notes:
Value
Description
(1)
2 mA
1
4 mA
2
6 mA
3
8 mA
0
1. Reset values of register bits are underlined characterized in the document.
• Bit [5:6] – PAD_IO_CLKM
The register bits PAD_IO_CLKM set the output driver current of pin CLKM.
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Table 4-6. CLKM Driver Strength
Register Bit
PAD_IO_CLKM
Value
Description
0
2 mA
1
4 mA
2
6 mA
3
8 mA
• Bit 3 – CLKM_SHA_SEL
Refer to section 9.6.5.
• Bit [2:0] – CLKM_CTRL
Refer to section 9.6.5.
5 Application Circuit
An application circuit of the AT86RF230 radio transceiver with a single-ended RF
connector is shown in Figure 5-1. The balun B1 transforms the 100Ω differential RF port
(RFP/RFN) to a 50Ω single-ended RF port. The capacitors C1 and C2 provide AC
coupling of the RF signals to the RF pins.
Figure 5-1. Application Circuit Schematic
SEL
RST
The power supply decoupling capacitors (CB2, CB4) are connected to the external
analog supply pin (EVDD, pin 28) and the external digital supply pin (DEVDD, pin 15).
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AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Capacitors CB1 and CB3 are bypass capacitors for the integrated analog and digital
voltage regulators to ensure stable operation (1 µF recommended value). All decoupling
and bypass capacitors should be placed as close as possible to the AT86RF230 pins
and should have a low-resistance and low-inductance connection to ground to achieve
the best performance.
The crystal (XTAL), the two load capacitors (CX1, CX2), and the internal circuitry
connected to pins XTAL1 and XTAL2 form the crystal oscillator. To achieve the best
accuracy and stability of the reference frequency, large parasitic capacitances should
be avoided. Crystal lines should be routed as short as possible and not in proximity of
digital I/O signals.
Crosstalk from digital signals on the crystal pins or the RF pins can degrade the system
performance. Therefore, a low-pass filter (C3, R2) is placed close to the CLKM output
pin to reduce the radiation of signal harmonics. This is not needed if the CLKM pin is
not used. Then the output should be turned off during device initialization.
The application board ground plane should be separated into four independent
fragments, the analog, the digital, the antenna and the XTAL ground plane. The
exposed paddle shall act as reference of the individual grounds.
For further details see application note AVR2005 "Design Considerations for the
AT86RF230".
Table 5-1. Example Bill of Materials
Designator
Description
Value
Manufacturer
Part Number
Comment
B1
SMD balun
2.45 GHz
Wuerth
748421245
2.45 GHz Balun
B1
SMD balun / filter
(alternatively)
2.45 GHz
Johanson
Technology
2450FB15L0001
2.45 GHz Balun / Filter
CB1
LDO VREG
bypass capacitor
1 µF
AVX
Murata
0603YD105KAT2A
X5R
GRM188R61C105KA12D (0603)
10%
16V
CB2
Power supply
decoupling
1 µF
CB3
LDO VREG
bypass capacitor
1 µF
CB4
Power supply
decoupling
1 µF
CX1
Crystal load capacitor
12 pF
12 pF
COG
(0603)
50V
Crystal load capacitor
06035A120JA
GRP1886C1H120JA01
5%
CX2
AVX
Murata
C1
RF coupling capacitor
22 pF
C2
RF coupling capacitor
22 pF
Epcos
Epcos
AVX
B37930
B37920
06035A220JAT2A
C0G
5%
(0402 or 0603)
C3
CLKM low-pass
filter capacitor
2.2 pF
AVX
Murata
06035A229DA
GRP1886C1H2R0DA01
COG
±0.5 pF 50V
(0603)
Designed for fCLKM = 1 MHz
R1
Pull-down resistor
10 kΩ
Recommended 0Ω, if
continuous transmission is
not required
R2
CLKM low-pass
filter resistor
680Ω
Designed for fCLKM = 1 MHz
XTAL
Crystal
CX-4025 16 MHz ACAL Taitjen
SX-4025 16 MHz Siward
50V
XWBBPL-F-1
A207-011
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5131E-MCU Wireless-02/09
6 Microcontroller Interface
This section describes the AT86RF230 to microcontroller interface. The interface
comprises a slave SPI and additional control signals, see Figure 6-1. The SPI timing
and protocol are described.
Figure 6-1. Microcontroller to AT86RF230 Interface
AT86RF230
Slave
SEL
SEL
SEL
MOSI
MOSI
MOSI
MISO
MISO
MISO
SCLK
SCLK
SCLK
GPIO1/CLK
CLKM
CLKM
GPIO2/IRQ
IRQ
GPIO3
SLP_TR
GPIO4
RST
SPI
Microcontroller
Master
IRQ
SLP_TR
RST
Microcontrollers with a master SPI, such as Atmel’s AVR family, interface directly to the
AT86RF230. The SPI is used for Frame Buffer and register access. The additional
control signals are connected to the GPIO/IRQ interface of the microcontroller. Table
6-1 introduces the radio transceiver I/O signals and their functionality.
Table 6-1. Signal Description of Microcontroller Interface
Signal
10
AT86RF230
Description
SEL
SPI select signal, active low
MOSI
SPI data (master output slave input) signal
MISO
SPI data (master input slave output) signal
SCLK
SPI clock signal
CLKM
AT86RF230 clock output, usable as:
- Microcontroller clock source
- High precision timing reference
IRQ
AT86RF230 interrupt request signal
SLP_TR
AT86RF230 multi purpose control signal (functionality is state-depended):
- Sleep/Wakeup
- TX start
- Controls CLKM output
RST
AT86RF230 reset signal, active low
5131E-MCU Wireless-02/09
AT86RF230
6.1 SPI Timing Description
The SPI is designed to work in synchronous or asynchronous mode.
In synchronous mode, the CLKM output of the radio transceiver is used as the master
clock of the microcontroller. In this case the maximum SPI clock frequency is 8 MHz.
In asynchronous mode, the SPI master clock (SCLK) is generated by the
microcontroller itself. The maximum SPI clock rate is limited to 7.5 MHz using this
operating mode. If the clock signal from the radio transceiver pin CLKM is not required,
it may be disabled.
Figure 6-2 and Figure 6-3 illustrate the SPI timing and introduce its parameters. The
corresponding timing parameter definition is given in Table 11-4.
Figure 6-2. SPI Timing, Global Map and Definition of Timing Parameters t5, t6, t8 and t9
Figure 6-3. SPI Timing, Detailed View and Definition of Timing Parameters t0 to t4
SEL
SCLK
t3
MOSI
t4
Bit 7
t0
Bit 6
t1
MISO
Bit 5
t2
Bit 7
Bit 6
Bit 5
The SPI is based on a byte-oriented protocol and is always a bidirectional
communication between master and slave. The SPI master starts the transfer by
asserting SEL = L. Then the master generates eight SPI clock cycles to transfer a byte
to the radio transceiver (via MOSI). At the same time the slave transmits one byte to the
master (via MISO). When the master wants to receive one byte of data from the slave it
must also transmit one byte to the slave. All bytes are transferred MSB first. An SPI
transaction is finished by releasing SEL = H.
A SPI register access consists of two bytes, a Frame Buffer or SRAM access of two or
more bytes, as described in section 6.2.
SEL = L enables the MISO output driver of the radio transceiver. The MSB of MISO is
valid after t1 (see section 11.4 parameter 11.4.3) and is updated at each falling edge of
SCLK. If the MISO output driver is disabled, there is no internal pull-up resistor
connected to the output. Driving the appropriate signal level must be ensured by the
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5131E-MCU Wireless-02/09
master device or an external pull-up resistor. Note, when both
active, the MISO output driver is also enabled.
SEL and RST are
The MOSI line is sampled by the radio transceiver at the rising edge of SCLK. The
signal must be stable before and after the rising edge of SCLK as specified by t3 and t4,
refer to section 11.4 parameters 11.4.5 and 11.4.6.
This mode of SPI operation is commonly called “SPI Mode 0”.
6.2 SPI Protocol
Each transfer sequence starts with transferring a command byte from SPI master via
MOSI (see Table 6-2) with MSB first. This command byte defines the access mode and
additional mode-dependent information.
Table 6-2. SPI Command Byte Definition
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Mode
1
0
Register address [5:0]
Register Access Mode – Read Access
1
1
Register address [5:0]
Register Access Mode – Write Access
0
0
1
Reserved
Frame Buffer Access Mode – Read Access
0
1
1
Reserved
Frame Buffer Access Mode – Write Access
0
0
0
Reserved
SRAM Access Mode – Read Access
0
1
0
Reserved
SRAM Access Mode – Write Access
The different access modes are described within the following sections.
In Figure 6-4 to Figure 6-14 logic values stated with X on MOSI are ignored by the radio
transceiver, but need to have a valid level. Return values on MISO stated as X shall be
ignored by the microcontroller.
6.2.1 Register Access Mode
The Register access mode is a two-byte read/write operation and is initiated by setting
SEL = L. The first transferred byte on MOSI is the command byte and must indicate a
register access (see Table 6-2) and a register address (see Table 12-1).
On write access the second byte transferred on MOSI contains the write data to the
selected address (see Figure 6-4).
Figure 6-4. Packet Structure – Register Write Access
byte 1 (command byte)
MOSI
MISO
1 1
address[5:0]
XX
byte 2 (data byte)
write data[7:0]
XX
On read access the content of the selected register address is returned in the second
byte on MISO (see Figure 6-5).
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5131E-MCU Wireless-02/09
AT86RF230
Figure 6-5. Packet Structure – Register Read Access
byte 1 (command byte)
MOSI
1 0
MISO
address[5:0]
XX
byte 2 (data byte)
XX
read data[7:0]
Each register access must be terminated by setting SEL = H.
Figure 6-6 illustrates a typical SPI sequence for a register access sequence for write
and read respectively.
Figure 6-6. Example SPI Sequence - Register Access Mode
Register Write Access
Register Read Access
SEL
SCLK
MOSI
WRITE COMMAND
MISO
XX
WRITE DATA
XX
READ COMMAND
XX
XX
READ DATA
6.2.2 Frame Buffer Access Modes
The Frame Buffer read access and the Frame Buffer write access are used to upload or
download frames to the microcontroller.
Each access starts by setting SEL = L. The first byte transferred on MOSI is the
command byte and must indicate a Frame Buffer access mode according to the
definition in Table 6-2.
On Frame Buffer write access the second byte transferred on MOSI contains the frame
length (PHR field) followed by the payload data (PSDU) as shown by Figure 6-7.
Figure 6-7. Packet Structure - Frame Buffer Write Access
On Frame Buffer read access PHR and PSDU are transferred via MISO starting with
the second byte. After the PSDU data bytes one more byte can be transferred
containing the link quality indication (LQI) value of the received frame, for details refer
to section 8.5. Figure 6-8 illustrates the packet structure of a Frame Buffer read access.
Note, the Frame Buffer read access can be terminated at any time without any
consequences by setting SEL = H, e.g. after reading the frame length byte only.
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5131E-MCU Wireless-02/09
Figure 6-8. Packet Structure - Frame Buffer Read Access
The number of bytes n for one Frame Buffer access is calculated as follow:
Receive:
n = 3 + frame_length
[command byte, frame length byte, PSDU data, LQI byte]
Transmit:
n = 2 + frame_length
[command byte, frame length byte, PSDU data]
The maximum value of frame_length is 127 bytes. That means that n ≤ 130 for Frame
Buffer read access and n ≤ 129 for Frame Buffer write access. Each read or write of a
data byte increments automatically the address counter of the Frame Buffer until the
access is terminated by setting SEL = H.
Figure 6-9 and Figure 6-10 illustrate an example SPI sequence of a Frame Buffer
access to write and read a frame with 4-byte PSDU respectively.
Figure 6-9. Example SPI Sequence - Frame Buffer Write Sequence of a Frame with 4-byte PSDU
SEL
SCLK
MOSI
MISO
COMMAND
XX
PHR
XX
PSDU 1
XX
PSDU 2
XX
PSDU 3
XX
PSDU 4
XX
Figure 6-10. Example SPI Sequence - Frame Buffer Read Sequence of a Frame with 4-byte PSDU
SEL
SCLK
MOSI
MISO
COMMAND
XX
XX
PHR
XX
PSDU 1
XX
PSDU 2
XX
PSDU 3
XX
PSDU 4
XX
LQI
Access violations during a Frame Buffer write or read access are indicated by a
TRX_UR interrupt. For further details refer to section 9.3.3.
6.2.3 SRAM Access Mode
The SRAM access mode allows access to certain bytes within the Frame Buffer. This
may reduce SPI traffic.
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AT86RF230
The SRAM access mode is useful, for instance, if a transmit frame is already stored in
the Frame Buffer and certain bytes (e.g. sequence number or address field) need to be
replaced before retransmitting the frame. Furthermore, it can be used to access only
the LQI value after frame reception. A detailed description of the user accessible frame
content can be found in section 9.3.2.
Each access starts by setting SEL = L. The first transferred byte on MOSI shall be the
command byte and must indicate a SRAM access mode according to the definition in
Table 6-2. The following byte indicates the start address of the write or read access.
The address space is 0x00 to 0x7F. The microcontroller software has to ensure to
access only to the valid address space.
On SRAM write access, one or more bytes of write data are transferred on MOSI
starting with the third byte of the access sequence (see Figure 6-11).
Figure 6-11. Packet Structure - SRAM Write Access
On SRAM read access, one or more bytes of read data are transferred on MISO
starting with the third byte of the access sequence (see Figure 6-12).
Figure 6-12. Packet Structure - SRAM Read Access
As long as SEL is logic low, every subsequent byte read or write increments the
address counter of the Frame Buffer until the SRAM access is terminated by setting
SEL = H.
Figure 6-13 and Figure 6-14 illustrate an example SPI sequence of a SRAM access to
write and read a data package of 5 byte length respectively.
Figure 6-13. Example SPI Sequence – SRAM Write Access Sequence of a 5 byte Data Package
SEL
SCLK
MOSI
MISO
COMMAND
XX
ADDRESS
XX
DATA 1
XX
DATA 2
XX
DATA 3
XX
DATA 4
XX
DATA 5
XX
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5131E-MCU Wireless-02/09
Figure 6-14. Example SPI Sequence – SRAM Read Access Sequence of a 5 byte Data Package
SEL
SCLK
MOSI
MISO
COMMAND
ADDRESS
XX
XX
XX
XX
DATA 1
XX
DATA 2
XX
DATA 3
XX
DATA 4
DATA 5
Notes:
• Because the Frame Buffer is shared between TX and RX, the frame data are
overwritten by new incoming frames. If the TX frame data is to be retransmitted, it
must be ensured that no frame was received meanwhile.
• If the SRAM access mode is used to upload received frames, the Frame Buffer
contains all frame data except the frame length byte. The frame length information
can be accessed only using the Frame Buffer read access.
• It is not possible to transmit received frames without a Frame Buffer read and write
operation by the microcontroller.
• Frame Buffer access violations are not indicated by a TXR_UR interrupt when using
the SRAM access mode (see section 9.3.3)
6.3 Radio Transceiver Identification
The AT86RF230 can be identified by four registers. One register contains an unique
part number and one register the corresponding version number. Additional two
registers contain the JEDEC manufacturer ID.
6.3.1 Register Description
Register 0x1C (PART_NUM)
Bit
7
6
5
Read/Write
R
R
R
R
Reset value
0
0
0
0
0x1C
4
3
2
1
0
R
R
R
R
0
0
1
0
PART_NUM
PART_NUM
• Bit [7:0] – PART_NUM
This register bits PART_NUM contain the radio transceiver part number.
Table 6-3. Radio Transceiver Part Number
Register Bits
Value[7:0]
PART_NUM
2
Description
AT86RF230 part number
Register 0x1D (VERSION_NUM)
Bit
7
6
5
0x1D
16
AT86RF230
4
3
2
1
0
VERSION_NUM
VERSION_NUM
Read/Write
R
R
R
R
R
R
R
R
Reset value
0
0
0
0
0
0
1
0
5131E-MCU Wireless-02/09
AT86RF230
• Bit [7:0] – VERSION_NUM
This register bits VERSION_NUM contain the radio transceiver version number.
Table 6-4. Radio Transceiver Version Number
Register Bits
Value[7:0]
VERSION_NUM
Description
1
AT86RF230 Revision A
2
AT86RF230 Revision B
Register 0x1E (MAN_ID_0)
Bit
7
6
5
4
Read/Write
R
R
R
R
Reset value
0
0
0
1
0x1E
3
2
1
0
R
R
R
R
1
1
1
1
MAN_ID_0
MAN_ID_0
• Bit [7:0] – MAN_ID_0
Bits [7:0] of the 32 bit JEDEC manufacturer ID are stored in register bits MAN_ID_0.
Bits [15:8] are stored in register 0x1F (MAN_ID_1). The highest 16 bits of the ID are not
stored in registers.
Table 6-5. JEDEC Manufacturer ID – Bits [7:0]
Register Bits
Value[7:0]
Description
MAN_ID_0
0x1F
Atmel JEDEC manufacturer ID
Bits [7:0] of 32 bit manufacturer ID: 00 00 00 1F
Register 0x1F (MAN_ID_1)
Bit
7
6
5
4
Read/Write
R
R
R
R
Reset value
0
0
0
0
0x1F
3
2
1
0
R
R
R
R
0
0
0
0
MAN_ID_1
MAN_ID_1
• Bit [7:0] – MAN_ID_1
Bits [15:8] of the 32 bit JEDEC manufacturer ID are stored in register bits MAN_ID_1.
Bits [7:0] are stored in register 0x1E (MAN_ID_0). The upper 16 bits of the ID are not
stored in registers.
Table 6-6. JEDEC Manufacturer ID – Bits [15:8]
Register Bits
Value[7:0]
Description
MAN_ID_1
0x00
Atmel JEDEC manufacturer ID
Bits [15:8] of 32 bit manufacturer ID: 00 00 00 1F
6.4 Sleep/Wake-up and Transmit Signal (SLP_TR)
The SLP_TR signal is a multi-functional pin. Its function relates to the current state of
the AT86RF230 and is summarized in Table 6-7. The radio transceiver states are
explained in detail in section 7.
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5131E-MCU Wireless-02/09
Table 6-7. SLP_TR Multi-Functional Pin
Radio Transceiver Status
Function
Transition
Description
TRX_OFF
Sleep
LÆH
Takes the radio transceiver into SLEEP state
SLEEP
Wakeup
HÆL
Takes the radio transceiver into TRX_OFF state
RX_ON
Disable CLKM
LÆH
Takes the radio transceiver into RX_ON_NOCLK state and disables
CLKM
RX_ON_NOCLK
Enables CLKM
HÆL
Takes the radio transceiver into RX_ON state and enables CLKM
RX_AACK_ON
Disable CLKM
LÆH
Takes the radio transceiver into RX_AACK_ON_NOCLK state and
disables CLKM
RX_AACK_ON_NOCLK
Enables CLKM
HÆL
Takes the radio transceiver into RX_AACK_ON state and enables
CLKM
PLL_ON
TX start
LÆH
Starts frame transmission
TX_ARET_ON
TX start
LÆH
Starts TX_ARET transaction
In states PLL_ON and TX_ARET_ON, the SLP_TR pin is used as trigger input to
initiate a TX transaction. Here pin SLP_TR is sensitive on rising edge only.
After initiating a state change by a rising edge at pin SLP_TR in radio transceiver states
TRX_OFF, RX_ON or RX_AACK_ON the radio transceiver remains in the new state as
long as the pin is logical high and returns to the preceding state with the falling edge.
The SLEEP state is used when radio transceiver functionality is not required, and thus
the AT86RF230 can be powered down to reduce the overall power consumption.
A power-down scenario is shown in Figure 6-15. When the radio transceiver is in
TRX_OFF state the microcontroller force the AT86RF230 to SLEEP by setting
SLP_TR = H. If the CLKM output provides a clock to the microcontroller this clock is
switched off after 35 clock cycles. This enables a microcontroller in a synchronous
system to complete its power-down routine and prevent dead-lock situations. The
AT86RF230 awakes when the microcontroller releases pin SLP_TR. This concept
provides the lowest possible power consumption.
Figure 6-15. Sleep and Wake-up Initiated by Asynchronous Microcontroller Timer Output (for Timing Information see
Table 7-1)
ttTR2
TR2
CLKM
a s y n c t im e r ( m ic r o c o n t ro lle r ) e la p s e d
35 main clock cycles
SLP_TR
For synchronous systems, where CLKM is used as a microcontroller clock source and
the SPI master clock (SCLK) is directly derived from CLKM, the AT86RF230 supports
an additional power-down mode for receive operating states RX_ON and
RX_AACK_ON.
If an incoming frame is expected and no other applications are running on the
microcontroller, it can be powered down without missing incoming frames.
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AT86RF230
This can be achieved by a rising edge on pin SLP_TR which turns off the CLKM output
35 clock cycles afterwards. The radio transceiver state changes from RX_ON or
RX_AACK_ON to RX_ON_NOCLK or RX_AACK_ON_NOCLK respectively.
In case that a frame is received the radio transceiver enters the state
BUSY_RX/BUSY_RX_AACK and the clock output CLKM is automatically switched on
again. This scenario is shown in Figure 6-16.
The power consumption of the radio transceiver is similar in state
RX_ON_NOCLK/RX_AACK_ON_NOCLK and state RX_ON, because only the CLKM
output is switched off.
Figure 6-16. Wake-Up Initiated by Radio Transceiver Interrupt
CLKM
35 main clock cycles
typ. 5µs
SLP_TR
t r a n s c e iv e r IR Q is s u e d
IRQ
6.5 Interrupt Logic
6.5.1 Overview
The AT86RF230 differentiates between six interrupt events. Each interrupt is enabled
or disabled by writing the corresponding bit to the interrupt mask register 0x0E
(IRQ_MASK). Internally, each interrupt is stored as a separate bit of the interrupt status
register. All interrupt lines are combined via logical “OR” to one external interrupt line
(IRQ). If the IRQ pin issues, the microcontroller shall read the interrupt status register
0x0F (IRQ_STATUS) to determine the reason for the interrupt. A read access to this
register clears the interrupt status register and the IRQ pin, too. Interrupts are not
cleared automatically when the event that caused them is not valid anymore. Exception:
the PLL_LOCK IRQ clears the PLL_UNLOCK IRQ and vice versa. The supported
interrupts for the Basic Operating Mode (see section 7.1) are summarized in Table 6-8.
Table 6-8. Interrupt Description in Basic Operating Mode
IRQ Name
Comments
Details
IRQ_7: BAT_LOW
Indicates a supply voltage below the programmed threshold.
Section 9.5.3
IRQ_6: TRX_UR
Indicates a Frame Buffer access violation (under run).
Section 9.3.3
IRQ_3: TRX_END
RX:
TX:
Indicates the completion of a frame reception.
Indicates the completion of a frame transmission.
Section 7.1.3
Section 7.1.3
IRQ_2: RX_START
Indicates a SFD detection. The TRX_STATE changes to BUSY_RX.
Section 7.1.3
IRQ_1: PLL_UNLOCK
Indicates PLL unlock. The PA is turned off immediately, if the radio transceiver is in
BUSY_TX/BUSY_TX_ARET state.
Section 9.7.4
IRQ_0: PLL_LOCK
Indicates PLL lock
Section 9.7.4
Using the Extended Operating Mode, the interrupts are handled in a slightly different
way. A detailed description can be found in section 7.2.4.
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5131E-MCU Wireless-02/09
6.5.2 Register Description
Register 0x0E (IRQ_MASK)
The IRQ_MASK register is used to enable (set register bit to 1) or disable (set register
bit to 0) interrupt events by writing the corresponding bit to the interrupt mask register.
Bit
0x0E
Read/Write
Reset value
Bit
0x0E
Read/Write
Reset value
7
6
MASK_BAT_LOW
MASK_TRX_UR
5
4
R/W
1
R/W
1
R/W
1
R/W
1
3
2
1
0
Reserved
IRQ_MASK
MASK_TRX_END MASK_RX_START MASK_PLL_UNLOCK MASK_PLL_LOCK
R/W
1
R/W
1
R/W
1
IRQ_MASK
R/W
1
If an interrupt will be enabled or disabled, it is recommended to read the interrupt status
register 0x0F (IRQ_STATUS) first to clear the history.
Register 0x0F (IRQ_STATUS)
The IRQ_STATUS register contains the status of the individual interrupts. A read
access to this register resets all interrupt bits.
Bit
0x0F
Read/Write
Reset value
Bit
0x0F
Read/Write
Reset value
7
6
BAT_LOW
TRX_UR
R
0
R
0
5
4
Reserved
R
0
IRQ_STATUS
R
0
3
2
1
0
TRX_END
RX_START
PLL_UNLOCK
PLL_LOCK
R
0
R
0
R
0
R
0
IRQ_STATUS
By reading the register after an interrupt is signaled at IRQ pin, the reason for the
interrupt can be identified.
A detailed description of the individual interrupts can be found in Table 6-8.
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AT86RF230
7 Operating Modes
7.1 Basic Operating Mode
This section summarizes all states to provide the basic functionality of the AT86RF230,
such as receiving and transmitting frames, and powering up and down. The Basic
Operating Mode is designed for IEEE 802.15.4 applications; the corresponding radio
transceiver states are shown in Figure 7-1.
TR
X_
O
FF
RX
_O
SFD
Detected
FF
O
X_
TR
ON
L_
PL
N
FF
O
X_
TR
SL
P_
TR
SL
=L
P_
TR
=H
Figure 7-1. Basic Operating Mode State Diagram (for State Transition Timing Data Refer to Table 7-1)
=H
TR
_
=L
P
TR
SL
_
P
SL
7.1.1 State Control
The radio transceiver state is controlled by two signal pins (SLP_TR, RST ) and the
register 0x02 (TRX_STATE). A successful state change shall be confirmed by reading
the radio transceiver status from register 0x01 (TRX_STATUS).
If TRX_STATUS = 0x1F (STATE_TRANSITION_IN_PROGRESS) the AT86RF230 is
on a state transition. Do not try to initiate a further state change while the radio
transceiver is in STATE_TRANSITION_IN_PROGRESS.
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5131E-MCU Wireless-02/09
The pin SLP_TR is a multifunctional pin. Depending on radio transceiver state the rising
edge of SLP_TR causes the following state transitions:
• TRX_OFF Æ
SLEEP
• RX_ON
Æ
RX_ON_NOCLK
• PLL_ON
Æ
BUSY_TX
For further details to the functionality of pin SLP_TR refer to section 6.4.
The pin RST causes a reset of all registers (register bits CLKM_SHA_SEL and
CLKM_CTRL are shadowed, for details refer to section 9.6.4) and forces the radio
transceiver into TRX_OFF state. However, if the device is in the P_ON state it remains
in the P_ON state.
For all states, the state change commands FORCE_TRX_OFF or TRX_OFF lead to a
transition into TRX_OFF state. If the radio transceiver is in the BUSY_RX or BUSY_TX
state, the command FORCE_TRX_OFF interrupts the active receiving or transmitting
process, and forces an immediate transition. In contrast to that the TRX_OFF command
is stored until a currently ongoing frame reception or transmission has finished. After
the end of the frame, the transition to TRX_OFF is performed.
The completion of each requested state change shall always be confirmed by reading
the register 0x01 (TRX_STATUS).
7.1.2 Basic Operating Mode Description
7.1.2.1 P_ON - Power-on after VDD
When the external supply voltage (VDD) is firstly applied to the radio transceiver, the
system goes into the P_ON state. An on-chip reset is performed. The crystal oscillator
gets activated and the master clock is provided to the CLKM pin after the crystal
oscillator has stabilized. CLKM can be used as a clock source to the microcontroller.
The on-chip power-on-reset sets all registers to their default values. A dedicated reset
signal from the microcontroller at the pin RST is not necessary, but recommended for
hardware/software synchronization reasons. The reset impulse should have a minimum
length as specified in section 11.4, see parameter 11.4.12.
All digital inputs have pull-up or pull-down resistors (see Table 4-4). This is necessary
to support microcontrollers where GPIO signals are floating after reset. The input pullup and pull-down resistors are disabled when the radio transceiver leaves the P_ON
state.
Prior to leaving P_ON, the microcontroller must set all digital input pins (MOSI, RST ,
SCLK, SEL , SLP_TR) to their default operating values.
Once the supply voltage has stabilized and the crystal oscillator has settled (see section
11.5, parameter 11.5.5), a SPI write access to the register 0x02 (TRX_STATE) with the
command TRX_OFF or FORCE_TRX_OFF initiates a state change from P_ON to
TRX_OFF.
7.1.2.2 SLEEP – Sleep State
In SLEEP state, the entire radio transceiver is disabled. No circuitry is operating. The
AT86RF230 current consumption is reduced to leakage current only.
This state can only be entered from state TRX_OFF by setting the pin SLP_TR = H. If
CLKM is enabled, the SLEEP state is entered 35 CLKM cycles after the rising edge. At
that time CLKM is turned off. If the CLKM output is turned off (bits CLKM_CTRL = 0 in
register 0x03), the SLEEP state is entered immediately.
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AT86RF230
Setting SLP_TR = L returns the radio transceiver to the TRX_OFF state. It is
recommended that pin SLP_TR should be active for a minimum of 40 CLKM cycles to
completely power down the radio transceiver.
During SLEEP state, the register contents remain valid while the content of the Frame
Buffer is cleared.
7.1.2.3 TRX_OFF – Clock State
In TRX_OFF state the SPI interface and the crystal oscillator are enabled. The digital
voltage regulator (DVREG) is enabled and provides 1.8V to the digital core to make the
Frame Buffer available (see section 9.1). The microcontroller can access all digital
functions and if enabled, the CLKM output supplies a clock. The pin SLP_TR is enabled
for state control.
7.1.2.4 PLL_ON – PLL State
Entering the PLL_ON state from TRX_OFF state enables the analog voltage regulator
(AVREG) first. After the voltage regulator has been settled, the PLL frequency
synthesizer is enabled. When the PLL has been settled at the receive frequency, a
successful PLL lock is indicated by issuing a PLL_LOCK interrupt.
If an RX_ON command is issued in PLL_ON state, the receiver is immediately enabled.
If the PLL has not been settled before, actual frame reception can only happen once the
PLL has locked.
The PLL_ON state corresponds to the TX_ON state in IEEE 802.15.4.
7.1.2.5 RX_ON and BUSY_RX – RX Listen and Receive State
In RX_ON state the receiver blocks and the PLL frequency synthesizer are enabled.
The AT86RF230 receive mode is internally divided into RX_ON state and BUSY_RX
state. There is no difference between these states with respect to the analog radio
transceiver circuitry, which is always turned on. During RX_ON state, only the preamble
detection of the digital signal processing is running. When a preamble and a valid SFD
are detected, also the digital receiver is turned on. The radio transceiver enters the
BUSY_RX state and a RX_START interrupt is generated.
During the frame reception frame data are stored continuously in the Frame Buffer until
the last byte was received. The completion of the frame reception is indicated by a
TRX_END interrupt and the radio transceiver reenters the state RX_ON. At the same
time the register bit RX_CRC_VALID (register 0x06) is updated with the result of the
FCS check (see section 8.2).
Note, settings of address registers 0x20 to 0x2B do not affect the frame reception in
Basic Operating Mode. Frame address filtering is only applied when using the Extended
Operating Mode (see section 7.2).
7.1.2.6 RX_ON_NOCLK – RX Listen State without CLKM
If the radio transceiver is listening for an incoming frame and the microcontroller is not
running an application, the microcontroller can be powered down to decrease the total
system power consumption. This special power-down scenario for systems running in
clock synchronous mode (see section 6.4) is supported by the AT86RF230 using the
state RX_ON_NOCLK.
This state can only be entered by setting SLP_TR = H while the AT86RF230 is in the
RX_ON state. The CLKM pin is disabled 35 clock cycles after the rising edge at the
SLP_TR pin. This allows the microcontroller to complete its power-down sequence. The
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5131E-MCU Wireless-02/09
reception of a frame is indicated to the microcontroller by a RX_START interrupt. CLKM
is turned on again, and the radio transceiver enters the BUSY_RX state (see section
6.4, Figure 6-16).
The end of the transaction is indicated to the microcontroller by a TRX_END interrupt.
After the transaction has been completed, the radio transceiver enters the RX_ON
state. The radio transceiver only reenters the RX_ON_NOCLK state, when the next
rising edge at pin SLP_TR occurs.
If the radio transceiver is in the RX_ON_NOCLK state, and the SLP_TR pin is reset to
logic low, it enters the RX_ON state, and it starts to supply clock on the CLKM pin
again.
In states RX_ON_NOCLK and RX_ON, the current consumption is about the same,
because only the CLKM output is switched off in state RX_ON_NOCLK.
7.1.2.7 BUSY_TX – Transmit State
A transmission can only be started in state PLL_ON. There are two ways to start a
transmission:
• Rising edge of SLP_TR
• TX_START command to register 0x02 (TRX_STATE).
Either of these causes the AT86RF230 to enter the BUSY_TX state.
During the transition to BUSY_TX state, the PLL frequency shifts to the transmit
frequency. Transmission of the first data chip of the preamble starts after 16 µs to allow
PLL settling and PA ramping, see Figure 7-2. After transmission of the preamble and
the SFD, the Frame Buffer content is transmitted.
The last two bytes to be transmitted are the FCS (see Figure 8-2). The radio transceiver
can be configured to autonomously compute the FCS bytes and append it to the
transmit data. The register bit TX_AUTO_CRC_ON in register 0x05 (PHY_TX_PWR)
needs to be set to 1 to enable this feature. For further details refer to section 8.2.When
the frame transmission is completed, the radio transceiver automatically turns off the
power amplifier, generates a TRX_END interrupt and returns to PLL_ON state.
Note that in case the PHR indicates a frame length of zero, the transmission is aborted.
7.1.3 Interrupt Handling in Basic Operating Mode
All interrupts of the AT86RF230 (see Table 6-8) are supported during operation in Basic
Operating Mode.
Two interrupts are used to support RX and TX operation of the radio transceiver. On
receive the RX_START interrupt indicates the detection of a valid SFD. The TRX_END
interrupt indicates the completion of the frame reception or frame transmission.
Figure 7-2 shows a receive/transmit transaction and the related interrupt events in
Basic Operating Mode. One device is assumed to operate as transmitter (device 1), the
second one as receiver (device 2). Processing delays are typical values.
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AT86RF230
Figure 7-2. Timing of RX_START and TRX_END Interrupts in Basic Operating Mode (see register 0x0F)
160
PLL_ON
192
352
BUSY_TX
time [µs]
PLL_ON
SLP_TR
TRX_END
IRQ
Typ. Processing Delay
Number of Octets
Frame Content
TRX_STATE
4
1
1
5
Preamble
SFD
PHR
PSDU
RX_LISTEN
Frame
on Air
16 µs
BUSY_RX
IRQ
RX_LISTEN
RX_START
Typ. Processing Delay
TRX_END
8 µs
16 µs
RX
(Device 2)
TRX_STATE
128
TX
(Device1)
-16 0
7.1.4 Basic Mode Timing
The following paragraphs depict the transitions between states and their timing.
7.1.4.1 Power-on and Wake-up Procedure
The power-on sequence and the wake-up procedure is shown in Figure 7-3.
Figure 7-3. Wake-Up Procedure from SLEEP and P_ON to RX_ON (PLL Locked)
0
XOSC delivers
clock
Signals/Events
State
600
CLKM delivers
clock
700
800
900
1000
TRX_OFF
XOSC
Timer 128 μs
Timer 256 μs
FTN BG
DVREG
PLL_ON,
RX_ON
SLP_TR=0
1100
Clock
stable
SLEEP
Active Blocks
Command
Pin
500
~400
PLL_ON
AVREG
16
μs
Time[μs]
IRQ
PLL locked
RX_ON
PLL
Time[μs]
RX_ON
Signals/Events
EVDD on
Typical block settling time, stays on
State
P_ON
Block active
waiting for SPI commands
Active Blocks
Command
XOSC
Timer 128 μs
CLKM_CTRL
TRX_OFF
Setting pin SLP_TR = L in SLEEP state enables the crystal oscillator. After 0.4 ms
(typ.), the internal clock signal is available. After another 128 µs the clock signal is
provided at the CLKM pin if enabled. An additional 256 µs timer ensures that frequency
stability is sufficient to drive filter tuning (FTN) and the PLL. After the digital voltage
regulator has been settled, the radio transceiver enters the TRX_OFF state and waits
for further commands.
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5131E-MCU Wireless-02/09
In TRX_OFF state, entering the commands PLL_ON or RX_ON initiates a ramp-up
sequence of the analog voltage regulator. RX_ON state can be entered any time during
PLL_ON state regardless whether the PLL has already locked.
When the wake-up sequence is started from P_ON state (VDD first applied to the radio
transceiver) the state machine stops after the 128 µs timer expires to wait for a valid
TRX_OFF command from the microcontroller. The default CLKM frequency in P_ON
state is 1 MHz.
7.1.4.2 Reset Procedure
RST = L sets all registers to their default values (see Table 12-2). Exception, register
bits CLKM_CTRL of register 0x03 (TRX_CTRL_0) are shadowed at reset. For details
refer to section 9.6.4.
After releasing the reset pin ( RST = H) a calibration cycle of the FTN is started and the
digital voltage regulator is turned on. The state TRX_OFF is entered and the status of
the main state machine changes from STATE_TRANSITION_IN_PROGRESS to
TRX_OFF.
This sequence is identical for all radio transceiver states except in state P_ON. The
state machine does not leave the state P_ON after a reset in this state. Instead, the
procedure described in section 7.1.2.1 must be followed to enter the TRX_OFF state for
the very first time. Figure 7-4 describes the reset procedure once the P_ON state was
left.
Note that the access to the device should not occur earlier than 625 ns after releasing
the reset pin. During the reset procedure the SPI interface shall be inactive ( SEL = H;
SCLK = L).
Figure 7-4. Reset Procedure
x+100
x
0 20
Time[μs]
Typical block settling time, stays on
Signals/Events
State
Active Blocks
Block active
RESET
TRX_OFF
XOSC
FTN BG
DVREG
waiting for SPI commands
Time[μs]
Command
Pin
RST=0
RST=1
7.1.4.3 State Transition Timing
The transition numbers (first column) in Table 7-1 correspond to Figure 7-1 and do not
include SPI access time if not otherwise stated. See measurement setup in Figure 5-1.
Table 7-1. State Transition Timing
No
Symbol
Transition
1
tTR1
P_ON
→
TRX_OFF
880
Depends on external bypass capacitor at DVDD (1 µF nom)
and crystal oscillator setup (CL = 10 pF)
2
tTR2
SLEEP
→
TRX_OFF
880
Depends on external bypass capacitor at DVDD (1 µF nom)
and crystal oscillator setup (CL = 10 pF)
3
tTR3
TRX_OFF →
SLEEP
35
fCLKM = 1 MHz
4
tTR4
TRX_OFF →
PLL_ON
180
Depends on external bypass capacitor at AVDD (1 µF nom).
26
Time [µs]
(tppical)
AT86RF230
Comments
5131E-MCU Wireless-02/09
AT86RF230
No
Symbol
Transition
Time [µs]
(tppical)
5
tTR5
PLL_ON
6
tTR6
TRX_OFF →
RX_ON
7
tTR7
RX_ON
→
TRX_OFF
1
8
tTR8
PLL_ON
→
RX_ON
1
9
tTR9
RX_ON
→
PLL_ON
1
10
tTR10
PLL_ON
→
BUSY_TX
16
When asserting SLP_TR pin first symbol transmission is
delayed by 16 µs (PLL settling and PA ramp up).
11
tTR11
BUSY_TX →
PLL_ON
32
32 µs PLL settling time
12
tTR12
All states
→
TRX_OFF
1
Using TRX_CMD FORCE_TRX_OFF (see register 0x02), not
valid for SLEEP mode
13
tTR13
RST = L
→
TRX_OFF
120
Depends on external bypass capacitor at DVDD (1 µF nom),
not valid for P_ON mode
→
TRX_OFF
Comments
1
180
Depends on external bypass capacitor at AVDD (1 µF nom).
The state transition timing is calculated based on the timing of the individual blocks as
shown in Figure 7-3. The worst case values include maximum operating temperature,
minimum supply voltage, and device parameter variations.
Table 7-2. Block Settling Time
Block
Time [µs]
(typical)
Time [µs]
(worst case)
Comments
XOSC
500
1000
Until clock signal is provided at CLKM pin.
Depends on crystal Q factor and load capacitor
DVREG
60
1000
Depends on external bypass capacitor at DVDD (CB3 = 1 µF nom.,
10 µF worst case)
AVREG
60
1000
Depends on external bypass capacitor at AVDD (CB1 = 1 µF nom.,
10 µF worst case)
PLL, initial
100
150
PLL, RX → TX
16
PLL settling time
PLL, TX → RX
32
PLL settling time
7.1.5 Register Description
Register 0x01 (TRX_STATUS)
The TRX_STATUS register signals the current state of the radio transceiver as well as
the status of the CCA measurement. Note, a read access to the register clears bits
CCA_DONE and CCA_STATUS.
This register is used for Extended and Basic Operating Mode. The Extended Operating
Mode functionality is described in section 7.2.
Bit
0x01
Read/Write
Reset value
7
6
5
4
CCA_DONE
CCA_STATUS
Reserved
TRX_STATUS
R
0
R
0
R
0
R
0
TRX_STATUS
27
5131E-MCU Wireless-02/09
Bit
3
2
0x01
1
0
R
0
R
0
TRX_STATUS
R
0
Read/Write
Reset value
R
0
TRX_STATUS
• Bit 7 – CCA_DONE
Refer to section 8.6.
• Bit 6 – CCA_STATUS
Refer to section 8.6.
• Bit 5 – Reserved
• Bit [4:0] – TRX_STATUS
The register bits TRX_STATUS signal the current radio transceiver status. If the
requested state transition is not completed yet, the TRX_STATUS returns
STATE_TRANSITION_IN_PROGRESS. State transition timings are defined in Table
7-1.
Table 7-3. Radio Transceiver Status, Register Bits TRX_STATUS
Register Bits
Value[4:0]
State Description
TRX_STATUS
0x00
P_ON
0x01
BUSY_RX
0x02
BUSY_TX
0x06
RX_ON
0x08
TRX_OFF (Clock State)
0x09
PLL_ON (TX_ON)
0x0F
SLEEP
0x11(1)
BUSY_RX_AACK
0x12
(1)
BUSY_TX_ARET
0x16
(1)
RX_AACK_ON
0x19
(1)
TX_ARET_ON
0x1C
RX_ON_NOCLK
0x1D(1)
RX_AACK_ON_NOCLK
0x1E(1)
BUSY_RX_AACK_NOCLK
0x1F
STATE_TRANSITION_IN_PROGRESS
All other values are reserved
Notes:
1. Extended Operating Mode only, refer to section 7.2.
Register 0x02 (TRX_STATE)
The register TRX_STATE controls the radio transceiver states via register bits
TRX_CMD. The status and the result of a TX_ARET/RX_AACK transaction is indicated
by register bits TRAC_STATUS.
A successful state transition shall be confirmed by reading register bits TRX_STATUS
in register 0x01 (TRX_STATUS).
This register is used for Basic and Extended Operating Mode. The Extended Operating
Mode functionality is described in section 7.2.
28
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Bit
7
0x02
6
5
TRAC_STATUS
Read/Write
Reset value
R
0
R
0
Bit
3
2
0x02
4
TRX_CMD
R
0
R/W
0
1
0
R/W
0
R/W
0
TRX_CMD
Read/Write
Reset value
R/W
0
R/W
0
TRX_STATE
TRX_STATE
• Bit [7:5] – TRAC_STATUS
Refer to section 7.2.6.
• Bit [4:0] – TRX_CMD
A write access to register bits TRX_CMD initiates a radio transceiver state transition
towards the new state.
Table 7-4. State Control Commands, Register Bits TRX_CMD
Register Bits
TRX_CMD
Value[4:0]
State Transition towards
0x00
(1)
NOP
0x02
(2)
TX_START
0x03
FORCE_TRX_OFF
0x06
RX_ON
0x08
TRX_OFF (Clock State)
0x09
PLL_ON (TX_ON)
0x16(3)
RX_AACK_ON
(3)
TX_ARET_ON
0x19
All other values are reserved
Notes:
1. TRX_CMD = 0 after power-on reset (POR) only
2. Frame transmission starts 16 µs (1 symbol) after TX_START
3. Extended Operating Mode only, refer to section 7.2
7.2 Extended Operating Mode
The Extended Operating Mode goes beyond the basic radio transceiver functionality
provided by the Basic Operating Mode. Specific functionality requested by the
IEEE 802.15.4-2003 standard is supported such as automatic acknowledgement and
automatic frame retransmission. This results in a more efficient IEEE 802.15.4-2003
software MAC implementation including reduced code size, the possible use of a
smaller microcontroller or the ability to simplify the handling of time-critical tasks.
The Extended Operating Mode is designed to support IEEE 802.15.4-2003 standard
compliant frames. While using the Extended Operating Mode, the AT86RF230 radio
transceiver supports:
• Automatic address filtering
• Automatic acknowledgement (RX_AACK) and
• Automatic CSMA-CA with optional frame retransmission (TX_ARET)
Note, the Extended Operating Mode does not support slotted CSMA-CA.
29
5131E-MCU Wireless-02/09
The RX_AACK transaction consists of:
• Frame reception
• Address filtering and automatic FCS check
• Interrupt indicating frame reception, if it passes address filtering and FCS check
• Automatic ACK frame transmission, if necessary
For details on RX_AACK transaction see section 7.2.3.1.
The TX_ARET transaction consists of:
• CSMA-CA including automatic retry
• Frame transmission and automatic FCS field generation
• Reception of ACK frame, if requested
• Automatic retry of transmissions if ACK was expected but not received
• Interrupt and transaction return code generation
For details on TX_ARET transaction see section 7.2.3.2.
The AT86RF230 state diagram including the Extended Operating Mode states is shown
in Figure 7-5. Yellow marked states represent the Basic Operating Mode, blue marked
states represent the Extended Operating Mode.
30
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Figure 7-5. Extended Operating Mode State Diagram
SLEEP
(Sleep State)
XOSC=ON
Pull=ON
XOSC=OFF
Pull=OFF
FF
O
X_
TR
FORCE_TRX_OFF
1
SL
P_
TR
SL
=L
P_
TR
=H
P_ON
(Power-on after VDD)
2
TRX_OFF
12
(from all states)
RST=L
RST=H
13
(Clock State)
(all states except SLEEP)
3
(all states except P_ON)
RESET
TR
X_
O
FF
RX
_
(Receive State)
8
N
RX_ON
FF
SFD
Detected
BUSY_RX
5
O
X_
TR
6
7
O
L_
PL
O
N
XOSC=ON
Pull=OFF
10
TX_START
or
SLP_TR=H
N
N
RX
_A
AC
K_
O
=L
BUSY_TX
(Transmit State)
9
PL
L_
O
=H
TR
R
Frame
End
(PLL State)
PLL_ON
SL
P_
SL
T
P_
11
PLL_ON
RX_ON
(Rx Listen State)
Frame
End
4
RX_ON_NOCLK
From
TRX_OFF
From
TRX_OFF
_O
N
_A
RX
CLKM=OFF
AC
_A
RE
T
(Rx Listen State)
N
TX
O
K_
SFD
Detected
RX_AACK_ON
BUSY_RX_AACK
Transaction
Finished
BUSY_RX_
AACK_NOCLK
CLKM=OFF
SFD
Detected
Frame
Rejected
TX_START
or
SLP_TR=H
TX_ARET_ON
BUSY_TX_ARET
Frame
End
RX_AACK_
ON_NOCLK
CLKM=OFF
Legend:
Blue:
SPI Write to Register TRX_STATE (0x02)
Red:
Control signals via IC Pin
Green: Event
Basic Operating Mode States
Extended Operating Mode States
X
State transition number, timing data in Table 7-1
7.2.1 State Control
The Extended Operating Mode states can be entered from states TRX_OFF or
PLL_ON as described by the state diagram in Figure 7-5. The completion of each
requested state change shall always be confirmed by reading the register 0x01
(TRX_STATUS).
31
5131E-MCU Wireless-02/09
RX_AACK:
The state RX_AACK_ON is entered by writing the command RX_AACK_ON to the
register bits TRX_CMD in register 0x02 (TRX_STATE). The state change shall be
confirmed by reading register 0x01 (TRX_STATUS) that changes to RX_AACK_ON or
BUSY_RX_AACK on success.
TX_ARET:
Similarly, TX_ARET_ON state is activated by setting register bits TRX_CMD (register
0x02) to TX_ARET_ON. The radio transceiver is in the TX_ARET_ON state after
TRX_STATUS (register 0x01) has changed to TX_ARET_ON.
Notes:
1. It is not recommended to use the FORCE_TRX_OFF command while being in state
BUSY_TX_ARET without appending a SLEEP cycle by activating SLP_TR for at
least 2 µs.
2. After state transition from state RX_AACK_ON to state PLL_ON, start of frame
transmission shall be confirmed by reading register 0x01 (TRX_STATUS). If register
bits TRX_STATUS do not return BUSY_TX during frame transmission, the frame
transmission needs to be initiated again. If the frame has been downloaded before
initiating the frame transmission, it has to be downloaded again.
7.2.2 Configuration
The use of the Extended Operating Mode is based on Basic Operating Mode
functionality. Only features beyond the basic radio transceiver functionality are
described in the following sections. For details to the Basic Operating Mode refer to
section 7.1.
When using the RX_AACK or TX_ARET modes, the following registers needs to be
configured.
RX_AACK:
• Setup registers 0x20 – 0x2B for PAN-ID and IEEE addresses
• Set register bit AACK_SET_PD (register 0x2E)
• Configure register bit I_AM_COORD (register 0x2E)
TX_ARET:
• Configure CSMA-CA
- MAX_FRAME_RETRIES (register 0x2C)
-
MAX_CSMA_RETRIES (register 0x2C)
-
CSMA_SEED (registers 0x2D, 0x2E)
-
MIN_BE (register 0x2E)
• Configure CCA (see section 8.7)
The MIN_BE register bits (register 0x2E) sets the minimum back-off exponent (refer to
IEEE 802.15.4-2003 section 7.5.1.3), and the CSMA_SEED_0 and CSMA_SEED_1
register bits (registers 0x2D, 0x2E) define a random seed for the back-off-time randomnumber generator in the AT86RF230. The register bits MAX_CSMA_RETRIES (register
0x2C) configures how often the radio transceiver retries the CSMA-CA algorithm after a
busy channel is detected. MAX_FRAME_RETRIES (register 0x2C) defines the
maximum number of frame retransmissions.
32
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
7.2.3 Extended Operating Mode Description
7.2.3.1 RX_AACK_ON – Receive with Automatic ACK
In the RX_AACK_ON state, the radio transceiver listens for incoming frames. After
detecting a frame start (SFD), the radio transceiver state changes to BUSY_RX_AACK
(register 0x01) and the TRAC_STATUS bits (register 0x02) are set to INVALID. The
AT86RF230 starts to parse the MAC header (MHR) and a filtering procedure as
described in IEEE 802.15.4-2003 section 7.5.6.2. (third level filter rules) is applied
accordingly. It accepts only frames that satisfy all of the following requirements (quote
from IEEE 802.15.4 2003):
• The frame type subfield of the frame control field shall not contain an illegal frame
type.
• If the frame type indicates that the frame is a beacon frame, the source PAN
identifier shall match macPANId unless macPANId is equal to 0xFFFF, in which
case the beacon frame shall be accepted regardless of the source PAN identifier.
• If a destination PAN identifier is included in the frame, it shall match macPANId or
shall be the broadcast PAN identifier (0xFFFF).
• If a short destination address is included in the frame, it shall match either
macShortAddress or the broadcast address (0xFFFF). Otherwise, if an extended
destination address is included in the frame, it shall match an ExtendedAddress.
• If only source addressing fields are included in a data or MAC command frame, the
frame shall be accepted only if the device is a PAN coordinator and the source PAN
identifier matches macPANId. Any frames rejected by these rules are discarded.
The AT86RF230 requires to satisfy two additional rules:
• The frame type indicates that the frame is not an ACK frame (refer to Table 8-1)
• At least one address field must be present (refer to Table 8-2)
A frame is also discarded if the FCS is invalid. Otherwise, the TRX_END interrupt is
issued and the register bits TRAC_STATUS are set to SUCCESS after the reception of
the frame was completed. The microcontroller can then upload the frame.
The AT86RF230 detects whether an ACK frame needs to be sent. In that case, the
radio transceiver automatically generates an ACK frame which is transmitted 12 symbol
periods after the end of the received frame. If the frame that needs to be acknowledged
is a valid MAC command data request frame, the content of register bit AACK_SET_PD
in register 0x2E (CSMA_SEED_1) is copied to the frame pending subfield of the ACK
and the frame sequence number is copied likewise. During these operations the radio
transceiver remains in BUSY_RX_AACK state.
After the completion of the RX_AACK transaction the radio transceiver reenters the
state RX_AACK_ON.
The flow diagram of the RX_AACK algorithm is shown in Figure 7-6.
The timing of an RX_AACK transaction is shown in Figure 7-7. It shows a reception of a
data frame of length 10 with the ACK request bit set to one. A state change to
BUSY_RX_AACK is performed after SFD detection. The completion of the frame
reception is indicated by a TRX_END interrupt. The ACK frame is transmitted after a
wait period of 12 symbols (192 µs).
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5131E-MCU Wireless-02/09
Figure 7-6. Flow Diagram of RX_AACK
Figure 7-7. Example Timing of an RX_AACK Transaction
Frame Type
TRX_STATE
SFD
Data Frame (Length = 10, ACK=1)
RX_AACK_ON
RX/TX
34
AT86RF230
1088
RX
RX_AACK_ON
TX
TRX_END
16 μs
time [μs]
ACK Frame
BUSY_RX_AACK
IRQ
Typ. Processing Delay
704
512
Frame
on Air
64
RX
RX/TX
0
192 μs
(12 symbols)
5131E-MCU Wireless-02/09
AT86RF230
7.2.3.2 TX_ARET_ON – Transmit with Automatic CSMA-CA Retry
The implemented TX_ARET algorithm is shown in Figure 7-8.
The TX_ARET transaction is started by either a rising edge on SLP_TR pin or by writing
a TX_START command to register 0x02 (TRX_STATE). The radio transceiver sets the
TRAC_STATUS bits to INVALID and executes the CSMA-CA algorithm as defined by
IEEE 802.15.4-2003 section 7.5.1.4. If a clear channel is detected during CSMA-CA
execution, the radio transceiver proceeds to transmit the frame.
During frame transmission the AT86RF230 parses the frame control field of the
downloaded frame to check if an ACK reply is expected. If an ACK is expected, the
radio transceiver switches into receive mode to wait for valid ACK reply. An ACK is
considered as valid if its FCS is correct, and if the sequence number of the ACK
matches the sequence number of the previously transmitted frame.
If no valid ACK is received or a timeout (after 864 μs) occurred, the radio transceiver
retries the entire transaction, including CSMA-CA execution. This repeats until the
frame has been acknowledged or the maximum number of retransmissions (as set by
the register bits MAX_FRAME_RETRIES in register 0x2C) has been reached. In this
case, the TRX_END interrupt is issued and the value of TRAC_STATUS is set to
NO_ACK.
If a valid ACK is found, the TRX_END interrupt is issued. The Frame Pending subfield
of the ACK frame is parsed and the register bits TRAC_STATUS are updated. If the
frame pending subfield of the ACK frame is set, TRAC_STATUS is updated with
SUCCESS_DATA_PENDING, otherwise TRAC_STATUS is updated with SUCCESS.
While in receive mode for ACK reception, incoming data do not overwrite the Frame
Buffer content. Transmit data in the Frame Buffer are not changed during the TX_ARET
transaction.
If no ACK is expected, the radio transceiver issues a TRX_END interrupt after the frame
transmission has been completed. The value of register bits TRAC_STATUS (register
0x02) is set to SUCCESS.
If the CSMA-CA did not detect a clear channel, the channel access is retried as often as
specified by the register bits MAX_CSMA_RETRIES (register 0x2C). In case that
CSMA-CA does not detect a clear channel after MAX_CSMA_RETRIES, the
transaction is aborted and the TRX_END interrupt is issued. The TRAC_STATUS
register bits are updated with CHANNEL_ACCESS_FAILURE.
Note that it is recommended to download the transmit data before starting a TX_ARET
transaction.
35
5131E-MCU Wireless-02/09
Figure 7-8 Flow Diagram of TX_ARET
Figure 7-9 shows a TX_ARET transaction with the related timing. In this example a data
frame of length 10 with ACK request is transmitted. Furthermore the following
constrains are assumed:
• Register bits MIN_BE (register 0x2E) are set to 0 to not delay the execution of the
CCA algorithm after the rising edge at pin SLP_TR
• A clear channel is assumed (no CSMA-CA retry, no frame retransmission).
36
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Figure 7-9 Timing Example of a TX_ARET Transaction
128
FrameType
TRX_STATE
Data Frame (Length = 10, ACK=1)
TX_ARET_ON
RX/TX
ACK Frame
BUSY_TX_ARET
TX_ARET_ON
RX
TX
RX/TX
CSMA-CA
time [μs]
x+352
x
672
Frame
on Air
0
SLP_TR
IRQ
TRX_END
128 μs
Typ. Processing Delay
16 μs
32 μ s
16 μs
Register settings:
0x2C: MAX_FRAME_RETRIES=0
0x2C: MAX_CSMA_RRTRIES=0
0x2E: MIN_BE=0
7.2.3.3 RX_AACK_ON_NOCLK – RX_AACK_ON without CLKM
If the AT86RF230 is listening for an incoming frame and the microcontroller is not
running an application, the microcontroller can be powered down to decrease the total
system power consumption. This special power-down scenario for systems running in
clock synchronous mode (see section 6.4) is supported by the AT86RF230 using the
state RX_AACK_ON_NOCLK. The radio transceiver functionality in this state is based
on that in state RX_AACK_ON (see section 7.2.3.1), only the clock on pin CLKM is
disabled.
The RX_AACK_ON_NOCLK state is entered from RX_AACK_ON by a rising edge at
SLP_TR pin. The return to RX_AACK_ON state results either from a successful frame
reception or a falling edge on pin SLP_TR.
The CLKM pin is disabled 35 clock cycles after the rising edge at SLP_TR pin. This
allows the microcontroller to complete its power-down sequence.
In case of frame reception, the radio transceiver enters the BUSY_RX_AACK_ON state
and parses the address field and the FCS of the incoming frame. If it passes address
filtering and has a correct FCS the frame is accepted and the radio transceiver state
changes to BUSY_RX_AACK, the TRX_END interrupt is issued and CLKM is turned
on. If an ACK was requested the radio transceiver follows the procedure described in
section 7.2.3.1.
After the transaction has been completed, the radio transceiver enters the
RX_AACK_ON state. Note, the radio transceiver reenters the RX_AACK_ON_NOCLK
state only, when the next rising edge at SLP_TR pin occurs.
7.2.4 Interrupt Handling in Extended Operating Mode
The interrupts in the Extended Operating Mode are handled slightly different compared
to the Basic Operating Mode (see section 7.1.3). The number of possible interrupts is
reduced to a necessary minimum of events. This minimizes the interaction between
microcontroller and AT86RF230 to reduce the overall power consumption. The
differences in the interrupt handling are described in Table 7-5.
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5131E-MCU Wireless-02/09
Table 7-5. Interrupt Description for Extended Operating Mode
IRQ
Handling in Extended Operating Mode
IRQ_7: BAT_LOW
No special handling (see section 6.5)
IRQ_6: TRX_UR
No special handling (see section 6.5)
IRQ_3: TRX_END
TX_ARET:
RX_AACK:
IRQ_2: RX_START
Not used
IRQ_1: PLL_UNLOCK
Disabled for regular operation. In case of occurrence, the device
status needs to be examined (refer to AVR2009 “AT86RF230 –
Software Programming Model”).
IRQ_0: PLL_LOCK
Disabled for regular operation. In case of occurrence, the device
status needs to be examined (refer to AVR2009 “AT86RF230 –
Software Programming Model”).
Indicates the completion of TX_ARET algorithm.
Indicates the successful frame reception. Frame data
can be uploaded to the microcontroller.
7.2.5 Register Summary
Table 7-6. Register Summary
Reg.-Address
Register Name
Description
0x01
TRX_STATUS
Radio transceiver status, CCA result
0x02
TRX_STATE
State control
0x20 - 0x2B
0x2C
Address filter configuration
XAH_CTRL
Retries value control
0x2D
CSMA_SEED_0
CSMA-CA seed value
0x2E
CSMA_SEED_1
CSMA-CA seed value, MIN_BE, AACK_SET_PD, I_AM_COORD
7.2.6 Register Description – Control Registers
Register 0x01 (TRX_STATUS)
The TRX_STATUS register signals the current state of the radio transceiver as well as
the status of the CCA measurement. Note, a read access to the register clears bits
CCA_DONE and CCA_STATUS. This register is also used for Basic Operating Mode,
refer to section 7.1.
Bit
0x01
7
6
5
4
CCA_DONE
CCA_STATUS
Reserved
TRX_STATUS
Read/Write
Reset value
R
0
R
0
R
0
R
0
Bit
3
2
1
0
0x01
Read/Write
Reset value
TRX_STATUS
R
0
R
0
TRX_STATUS
TRX_STATUS
R
0
R
0
• Bit 7 – CCA_DONE
Refer to section 8.6.
38
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
• Bit 6 – CCA_STATUS
Refer to section 8.6.
• Bit 5 – Reserved
• Bit [4:0] – TRX_STATUS
The register bits TRX_STATUS signal the current radio transceiver status. If the
requested state transition is not completed yet, the TRX_STATUS returns
STATE_TRANSITION_IN_PROGRESS. State transition timings are defined in Table
7-1.
Table 7-7. Radio Transceiver Status, Register Bits TRX_STATUS
Register Bits
Value[4:0]
State Description
TRX_STATUS
0x00
P_ON
0x01
BUSY_RX
0x02
BUSY_TX
0x06
RX_ON
0x08
TRX_OFF (Clock State)
0x09
PLL_ON (TX_ON)
0x0F
SLEEP
0x11
BUSY_RX_AACK
0x12
BUSY_TX_ARET
0x16
RX_AACK_ON
0x19
TX_ARET_ON
0x1C
RX_ON_NOCLK
0x1D
RX_AACK_ON_NOCLK
0x1E
BUSY_RX_AACK_NOCLK
0x1F
STATE_TRANSITION_IN_PROGRESS
All other values are reserved
Register 0x02 (TRX_STATE)
The register TRX_STATE controls the radio transceiver states via register bits
TRX_CMD. The status and the result of a TX_ARET/RX_AACK transaction is indicated
by register bits TRAC_STATUS.
A successful state transition shall be confirmed by reading register bits TRX_STATUS
in register 0x01 (TRX_STATUS).
Bit
7
0x02
6
5
TRAC_STATUS
4
TRX_CMD
Read/Write
Reset value
R
0
R
0
R
0
R/W
0
Bit
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
0x02
Read/Write
Reset value
TRX_CMD
TRX_STATE
TRX_STATE
39
5131E-MCU Wireless-02/09
• Bit [7:5] – TRAC_STATUS
The status of the TX_ARET algorithm is indicated by register bits TRAC_STATUS.
Details of the algorithm and a description of the status information are given in section
7.2.3.2.
Table 7-8. State Control Register, Register Bits TRAC_STATUS TX_ARET
Register Bits
Value[7:5]
TRAC_STATUS
Description
0
SUCCESS
1
SUCCESS_DATA_PENDING
3
CHANNEL_ACCESS_FAILURE
5
NO_ACK
7
INVALID
All other values are reserved
• Bit [4:0] – TRX_CMD
A write access to register bits TRX_CMD initiates a radio transceiver state transition
towards the new state.
Table 7-9. State Control Register, Register Bits TRX_CMD
Register Bits
Value[4:0]
TRX_CMD
State Description
0x00
(1)
NOP
0x02
(2)
TX_START
0x03
FORCE_TRX_OFF
0x06
RX_ON
0x08
TRX_OFF (Clock State)
0x09
PLL_ON (TX_ON)
0x16
RX_AACK_ON
0x19
TX_ARET_ON
All other values are reserved
Notes:
1. TRX_CMD = 0 after power-on reset (POR)
2. Frame transmission starts 16 µs (1 symbol) after TX_START
Register 0x2C (XAH_CTRL)
The XAH_CTRL register controls the TX_ARET transaction in the Extended Operating
Mode of the radio transceiver.
Bit
7
0x2C
Read/Write
Reset value
Bit
R/W
0
3
0x2C
Read/Write
Reset value
40
AT86RF230
6
5
4
MAX_FRAME_RETRIES
R/W
0
R/W
1
2
1
MAX_CSMA_RETRIES
R/W
1
R/W
0
XAH_CTRL
R/W
1
0
Reserved
R/W
0
XAH_CTRL
R/W
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5131E-MCU Wireless-02/09
AT86RF230
• Bit [7:4] – MAX_FRAME_RETRIES
MAX_FRAME_RETRIES specifies the maximum number of frame retransmission in
TX_ARET transaction.
• Bit [3:1] – MAX_CSMA_RETRIES
MAX_CSMA_RETRIES specifies the maximum number of retries in TX_ARET
transaction to repeat the random back-off/CCA procedure before the transaction gets
cancelled. Even though the valid range of MAX_CSMA_RETRIES is [0, 1 … 5]
according to IEEE 802.15.4-2003, the AT86RF230 can be configured up to a maximum
value of 7 retries.
• Bit 0 – Reserved
Register 0x2D (CSMA_SEED_0)
The CSMA_SEED_0 register contains a fraction of the CSMA_SEED value for the
CSMA-CA algorithm.
Bit
7
6
5
4
0x2D
3
2
1
0
CSMA_SEED_0
CSMA_SEED_0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
1
1
1
0
1
0
1
0
• Bit [7:0] – CSMA_SEED_0
The register bits CSMA_SEED_0 contain the lower 8 bits of the CSMA_SEED. The
upper 3 bits are stored in register bits CSMA_SEED_1 of register 0x2E
(CSMA_SEED_1). CSMA_SEED is the seed of the random number generator for the
CSMA-CA algorithm.
Register 0x2E (CSMA_SEED_1)
The CSMA_SEED_1 register contains a fraction of the CSMA_SEED value, the backoff exponent for the CSMA-CA algorithm and configuration bits for address filtering in
RX_AACK operation.
Bit
7
0x2C
Read/Write
Reset value
Bit
0x2C
Read/Write
Reset value
6
MIN_BE
R/W
1
R/W
1
3
2
I_AM_COORD
R/W
0
5
4
AACK_SET_PD
Reserved
R/W
0
R
0
1
0
CSMA_SEED_1
R/W
0
R/W
1
CSMA_SEED_1
CSMA_SEED_1
R/W
0
• Bit [7:6] – MIN_BE
The register bit MIN_BE defines the minimal back-off exponent used in the CSMA-CA
algorithm to generate a pseudo random number for back-off the CCA. For details refer
to IEEE 802.15.4-2003 section 7.5.1.3. If set to zero, the start of the CCA algorithm is
not delayed.
• Bit 5 – AACK_SET_PD
This register bit defines the content of the frame pending subfield for acknowledgement
frames in RX_AACK mode. If this bit is enabled the frame pending subfield of the
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5131E-MCU Wireless-02/09
acknowledgment frame is set in response to a MAC command data request frame,
otherwise not. The register bit has to be set before finishing the SHR transmission of
the acknowledgment frame. This is 352 µs (192 µs ACK wait time + 160 µs SHR
transmission) after the TRX_END interrupt issued by the frame to be acknowledged.
• Bit 4 – Reserved
• Bit 3 – I_AM_COORD
This register bit has to be set if the node is a PAN coordinator. This register bit is used
for address filtering in RX_AACK. If I_AM_COORD = 1 and if only source addressing
fields are included in a data or MAC command frame, the frame shall be accepted only
if the device is the PAN coordinator and the source PAN identifier matches macPANId,
for details refer to IEEE 802.15.4-2003, section 7.5.6.2 (third-level filter rules).
• Bit [2:0] – CSMA_SEED_1
The register bits CSMA_SEED_1 contain the upper 3 bits of the CSMA_SEED. The
lower part is defined in register 0x2D (CSMA_SEED_0).
7.2.7 Register Description – Address Registers
Register 0x20 (SHORT_ADDR_0)
This register contains bits [7:0] of the 16 bit short address for address filtering.
Bit
7
6
5
0x20
4
3
2
1
0
SHORT_ADDRESS_0
SHORT_ADDR_0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x21 (SHORT_ADDR_1)
This register contains bits [15:8] of the 16 bit short address for address filtering.
Bit
7
6
5
0x21
4
3
2
1
0
SHORT_ADDRESS_1
SHORT_ADDR_1
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x22 (PAN_ID_0)
This register contains bits [7:0] of the 16 bit PAN ID for address filtering.
Bit
7
6
5
4
Read/Write
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0x22
3
2
1
0
R/W
R/W
R/W
R/W
0
0
0
0
PAN_ID_0
PAN_ID_0
Register 0x23 (PAN_ID_1)
This register contains bits [15:8] of the 16 bit PAN ID for address filtering.
Bit
7
6
5
0x23
42
AT86RF230
4
3
2
1
0
PAN_ID_1
PAN_ID_1
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
5131E-MCU Wireless-02/09
AT86RF230
Register 0x24 (IEEE_ADDR_0)
This register contains bits [7:0] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
0x24
4
3
2
1
0
IEEE_ADDR_0
IEEE_ADDR_0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x25 (IEEE_ADDR_1)
This register contains bits [15:8] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
Read/Write
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0x25
4
3
2
1
0
R/W
R/W
R/W
R/W
0
0
0
0
IEEE_ADDR_1
IEEE_ADDR_1
Register 0x26 (IEEE_ADDR_2)
This register contains bits [23:16] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
0x26
4
3
2
1
0
IEEE_ADDR_2
IEEE_ADDR_2
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x27 (IEEE_ADDR_3)
This register contains bits [31:24] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
0x27
4
3
2
1
0
IEEE_ADDR_3
IEEE_ADDR_3
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x28 (IEEE_ADDR_4)
This register contains bits [39:32] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
0x28
4
3
2
1
0
IEEE_ADDR_4
IEEE_ADDR_4
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x29 (IEEE_ADDR_5)
This register contains bits [47:40] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
Read/Write
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0x29
4
3
2
1
0
R/W
R/W
R/W
R/W
0
0
0
0
IEEE_ADDR_5
IEEE_ADDR_5
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Register 0x2A (IEEE_ADDR_6)
This register contains bits [55:48] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
0x2A
4
3
2
1
0
IEEE_ADDR_6
IEEE_ADDR_6
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Register 0x2B (IEEE_ADDR_7)
This register contains bits [63:56] of the 64 bit IEEE address for address filtering.
Bit
7
6
5
Read/Write
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0x2B
44
AT86RF230
4
3
2
1
0
R/W
R/W
R/W
R/W
0
0
0
0
IEEE_ADDR_7
IEEE_ADDR_7
5131E-MCU Wireless-02/09
AT86RF230
8 Functional Description
8.1 Introduction - Frame Format
Figure 8-1 provides an overview of the physical layer frame structure as defined by the
IEEE 802.15.4-2003 standard. Figure 8-2 shows details of the defined MAC layer frame
structure.
Figure 8-1 IEEE 802.15.4-2003 Frame Format – PHY Layer Frame Structure
Figure 8-2 IEEE 802.15.4-2003 Frame Format – MAC Layer Frame Structure
8.1.1 PHY Protocol Layer Data Unit (PPDU)
8.1.1.1 Synchronization Header (SHR)
The SHR consists of a four-octet preamble field (all zero), followed by a single SFD
octet which has the predefined value 0xA7. When transmitting, the SHR is automatically
generated by the AT86RF230, and prefixed to the frame that has been read from the
Frame Buffer. The transmission of the SHR requires 160 µs (10 symbols). This allows
the microcontroller to initiate a transmission and to start downloading the frame
contents subsequently. Note, that in this case the SPI transfer rate must be equal or
faster than the PHY data rate.
During frame reception, the SHR is used for PHY synchronization purposes. In Basic
Operating Mode an RX_START interrupt is issued 8 µs after detection of the SFD field.
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8.1.1.2 PHY Header (PHR)
The PHY header consists of a single octet following the SHR. The least significant
7 bits of that octet denote the frame length of the following PSDU, while the most
significant bit of that octet is reserved.
During transmission, the PHR field has to be supplied by the microcontroller during
Frame Buffer write access.
On receive, the radio transceiver does not write the PHR field into the Frame Buffer.
Instead it is prefixed to the PSDU during Frame Buffer read access. Note, that the
reserved MSB of the PHR octet is always set to 0.
8.1.1.3 PHY Payload (PHY Service Data Unit, PSDU)
The PSDU has a variable length between one and 127 octets.
8.1.2 MAC Protocol Layer Data Unit (MPDU)
8.1.2.1 MAC Header (MHR) Fields
The MAC header consists of the Frame Control Field (FCF), a sequence number, and
the variable length addressing fields.
8.1.2.2 Frame Control Field (FCF)
The FCF consists of 16 bits, and occupies the first two octets of the MPDU.
Bit [2:0] describe the frame type. Table 8-1 summarizes frame types defined by
IEEE 802.15.4-2003, section 7.2.1.1.1.
Table 8-1. IEEE 802.15.4-2003 Frame Types
Frame Control field bit assignments
Description
Bit [2:0]
value
000
0
Beacon
001
1
Data
010
2
Acknowledge
011
3
MAC command
100 – 111
4–7
Reserved
These bits are used for address filtering by applying the IEEE 802.15.4-2003 third level
filter rules. Only frame types 0 – 3 pass the third level filter rules. Automatic address
filtering by the AT86RF230 is enabled when using the RX_AACK operation (see section
7.2.3.1).
Bit 3: indicates whether security processing applies to this frame. This field is not
evaluated by the AT86RF230.
Bit 4 is the “frame pending” subfield. This field can be set in an acknowledgement
frame. It indicates that the transmitter of the acknowledgement frame has more data to
send for the recipient of the acknowledgement frame. For acknowledgment frames
automatically generated by the AT86RF230, this bit is set according to the content of
register bit AACK_SET_PD in register 0x2E (CSMA_SEED_1).
Bit 5 forms the “acknowledgment request” subfield. If this bit is set within a data or MAC
command frame that is not broadcast, the recipient shall acknowledge the reception of
the frame within the time specified by IEEE 802.15.4-2003 (i.e. within 192 µs for
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5131E-MCU Wireless-02/09
AT86RF230
nonbeacon-enabled networks). The AT86RF230 parses this bit during RX_AACK
operation and transmits an acknowledgment frame if necessary.
Bit 6 the “Intra-PAN” subfield indicates that in a frame, where both, the destination and
source addresses are present, the PAN ID is omitted from the source address field.
This bit is evaluated by the AT86RF230 address filter logic when using RX_AACK
operation.
Bit [11:10] the “Destination address mode” subfield describes the format of the
destination address of the frame. The values of the address modes are summarized in
Table 8-2, according to IEEE 802.15.4-2003:
Table 8-2. IEEE 802.15.4-2003 Address Modes
Addressing Mode Value
Description
Bit [11:10]
Bit [15:14]
value
00
0
Address not present
01
1
Reserved, must not be used
10
2
Address is 16-bit short
11
3
Address is 64-bit extended address
If the destination address mode is either 2 or 3 (i.e. if the destination address is present
at all), it always consists of a 16-bit PAN ID first, followed by either the 16-bit or 64-bit
address as described by the mode.
Bit [15:14] form the “Source address mode” subfield, with a similar meaning as
“Destination address mode”.
The address field description bits of the FCF (Bits 6, 10, 11, 14, 15) affect the address
filter logic of the AT86RF230 while operating in RX_AACK states (see section 7.2.3.1).
8.1.2.3 Sequence number
The one-octet sequence number following the FCF identifies a particular frame, so that
duplicated frame transmissions can be detected. While operating in RX_AACK states,
the content of this field is copied from the frame to be acknowledged into the
acknowledgment frame.
8.1.2.4 Addressing fields
The addressing fields terminate the MHR. The destination address (if present) is always
transmitted first, followed by the source address (if present). Each address consists of
the PAN ID and a device address. If both addresses are present, and the “Intra PAN”
subfield in the FCF is set to 1, the source PAN ID is omitted.
Note that in addition to these general rules, IEEE 802.15.4-2003 further restricts the
valid address combinations for the individual possible MAC frame types. For example,
the situation where both addresses are omitted (source addressing mode = 0 and
destination addressing mode = 0) is only allowed for acknowledgment frames. The
address filter in the AT86RF230 has been designed to apply to IEEE 802.15.4-2003
compliant frames only.
8.1.2.5 MAC Service Data Unit (MSDU)
This is the actual MAC payload. It is usually structured according to the individual frame
type descriptions in IEEE 802.15.4-2003.
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5131E-MCU Wireless-02/09
8.1.2.6 MAC Footer (MFR) Fields
The MAC footer consists of a two-octet frame checksum (FCS). The AT86RF230 can
generate and evaluate this FCS automatically, for details refer to section 8.2.
8.2 Frame Check Sequence (FCS)
The frame check sequence main features are:
•
•
•
•
Indicates bit errors, based on a cyclic redundancy check (CRC) of length 16 bit
Uses International Telecommunication Union (ITU) CRC polynomial
Automatically evaluated during reception
Can be automatically generated during transmission
8.2.1.1 Overview
The FCS is intended for use at the MAC level to detect corrupted frames. It is computed
by applying an ITU CRC polynomial to all transferred bytes following the length field
(MHR and MSDU fields). The frame check sequence has a length of 16 bit and is
located in the last two bytes of a frame (MAC footer, see Figure 8-2).
The AT86RF230 applies an FCS check on each received frame. The FCS check result
is stored to register bit RX_CRC_VALID in register 0x06 (PHY_RSSI). On transmit the
radio transceiver can be configured to autonomously compute and append the FCS
bytes.
8.2.2 CRC calculation
The CRC polynomial used in IEEE 802.15.4-2003 networks is defined by
G16 ( x) = x 16 + x 12 + x 5 + 1 .
The FCS shall be calculated for transmission using the following algorithm:
Let
M ( x) = b0 x k −1 + b1 x k − 2 + K + bk − 2 x + bk −1
be the polynomial representing the sequence of bits for which the checksum is to be
computed. Multiply M(x) by x16, giving the polynomial
N ( x) = M ( x) ⋅ x16 .
Divide N(x) modulo 2 by the generator polynomial, G16(x), to obtain the remainder
polynomial,
R ( x) = r0 x15 + r1 x14 + ... + r14 x + r15
The FCS field is given by the coefficients of the remainder polynomial, R(x).
Example:
Considering a 5 octet ACK frame. The MHR field consists of
0100 0000 0000 0000 0101 0110.
The leftmost bit (b0) is transmitted first in time. The FCS would be following
0010 0111 1001 1110.
The leftmost bit (r0) is transmitted first in time.
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AT86RF230
8.2.3 Automatic FCS generation
The AT86RF230 automatic FCS generation and insertion is enabled by setting register
bit TX_AUTO_CRC_ON to 1.
For a frame with a frame length field (PHR) specified as N (3 ≤ N ≤ 127), the FCS is
calculated on the first N-2 PSDU octets in the Frame Buffer, and the resulting 16 bit
FCS field is appended during transmission. Note, if the AT86RF230 automatic FCS
generation is enabled, the frame download to the Frame Buffer can be stopped right
after MAC payload. There is no need to download FCS dummy bytes.
In RX_AACK states, when a received frame needs to be acknowledged, the FCS of the
ACK frame is always automatically generated by the AT86RF230.
Example:
A frame transmission of length five with the register bit TX_AUTO_CRC_ON set, is
started with a frame download of five bytes (the last two bytes can be omitted). The first
three bytes are used for FCS generation, the last two bytes are replaced by the
internally calculated FCS.
8.2.4 Automatic FCS check
An FCS check is applied on each incoming frame with a frame length N ≥ 2. The result
of the FCS check is stored to register bit RX_CRC_VALID in register 0x06
(PHY_RSSI). The register bit is updated at the event of the TRX_END interrupt and
remains valid until the next TRX_END interrupt caused by a new frame reception.
In RX_AACK states, if FCS of the received frame is not valid, the radio transceiver
rejects the frame and the TRX_END interrupt will not be generated.
In TX_ARET states, the FCS of an ACK is automatically checked. If it is not correct, the
ACK is not accepted.
8.2.5 Register Description
Register 0x05 (PHY_TX_PWR)
The PHY_TX_PWR register sets the transmit power and controls the FCS algorithm for
TX operation.
Bit
0x05
7
6
Read/Write
Reset value
R/W
0
Bit
3
4
Reserved
R
0
R
0
2
1
PHY_TX_PWR
R
0
0
TX_PWR
0x05
Read/Write
Reset value
5
TX_AUTO_CRC_ON
R/W
0
R/W
0
PHY_TX_PWR
R/W
0
R/W
0
• Bit 7 – TX_AUTO_CRC_ON
Register bit TX_AUTO_CRC_ON controls the automatic FCS generation for TX
operation. The automatic FCS algorithm is performed autonomously by the radio
transceiver if register bit TX_AUTO_CRC_ON = 1.
• Bit [6:4] – Reserved
• Bit [3:0] – TX_PWR
Refer to section 9.2.3.
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5131E-MCU Wireless-02/09
Register 0x06 (PHY_RSSI)
The PHY_RSSI register is a multi purpose register to indicate the current received
signal strength (RSSI) and the FCS validity of a received frame.
Bit
0x06
7
6
RX_CRC_VALID
Read/Write
Reset value
R
0
R
0
Bit
3
2
0x06
Read/Write
Reset value
5
Reserved
4
RSSI
R
0
R
0
1
0
RSSI
R
0
R
0
PHY_RSSI
PHY_RSSI
R
0
R
0
• Bit 7 – RX_CRC_VALID
This register bit indicates whether a received frame has a valid FCS. The register bit is
updated when issuing the TRX_END interrupt remains valid until the next TRX_END
interrupt caused by a new frame reception.
Table 8-3. RX FCS Result
Register Bit
Value
RX_CRC_VALID
Description
0
FCS is not valid.
1
FCS is valid.
• Bit [6:5] – Reserved
• Bit [4:0] – RSSI
Refer to section 8.4.4.
8.3 Energy Detection (ED)
The main features for the Energy Detection module are:
• 85 unique energy levels defined
• 1 dB resolution
8.3.1 Overview
The receiver Energy Detection measurement is used by a network layer as part of a
channel selection algorithm. It is an estimation of the received signal power within the
bandwidth of an IEEE 802.15.4-2003 channel. No attempt is made to identify or decode
signals on the channel. The ED value is calculated by averaging RSSI values over eight
symbols (128 µs).
8.3.2 Request an ED Measurement
There are two ways implemented in the AT86RF230 to initiate an ED measurement:
• Manually, by a write access to register 0x07 (PHY_ED_LEVEL), or
• Automatically, by detecting a valid SFD of an incoming frame.
For manually initiated ED measurement the radio transceiver needs to be in one of the
states RX_ON or BUSY_RX. An automated ED measurement is started, if a SFD field
is detected. A valid SFD detection is signalized by an RX_START interrupt in Basic
Operating Mode.
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AT86RF230
The measurement result is stored to register 0x07 (PHY_ED_LEVEL) 140 µs after its
initialization. The value is always 0 if the AT86RF230 is not in any of the RX states.
Thus by using Basic Operating Mode, a valid ED value from the currently received
frame is accessible 140 µs after the RX_START interrupt and remains valid until a new
RX_START interrupt is generated by the next incoming frame or until another ED
measurement is initiated manually.
By using the Extended Operating Mode, the RX_START interrupt is always masked
and cannot be used as timing reference. Here successful frame reception is only
signalized by the TRX_END interrupt. The minimum time between a TRX_END
interrupt and a following SFD detection is 96 µs. Including the ED measurement time,
the ED value needs to be read within 224 µs after the TRX_END interrupt; otherwise, it
could be overwritten by the result of the next measurement cycle.
Note, it is not recommended to initiate manually an ED measurement when using the
Extended Operating Mode.
8.3.3 Data Interpretation
The PHY_ED_LEVEL is an 8 bit register. The ED value of the AT86RF230 radio
transceiver has a valid range from 0 to 84 with a resolution of 1 dB. All other values do
not occur. If zero is read from the PHY_ED_LEVEL register, this indicates that the
measured energy is less than -91 dBm (see parameter 11.7.16). Due to environmental
conditions (temperature, voltage, semiconductor parameters, etc.) the computed energy
value has an accuracy of ±5 dBm, this is to be considered as constant offset over the
measurement range.
8.3.4 Register Description
Register 0x07 (PHY_ED_LEVEL)
The ED_LEVEL register contains the result after an ED measurement.
Bit
7
6
5
0x07
4
3
2
1
0
ED_LEVEL[7:0]
ED_LEVEL
Read/Write
R
R
R
R
R
R
R
R
Reset value
0
0
0
0
0
0
0
0
• Bit [7:0] – ED_LEVEL
The minimum ED value (ED_LEVEL = 0) indicates receiver power less than
RSSI_BASE_VAL. The range is 84 dB with a resolution of 1 dB and an absolute
accuracy of ±5 dB. The measurement period is 8 symbol periods.
A manual ED measurement can be initiated by a write access to the register.
8.4 Received Signal Strength Indicator (RSSI)
The Received Signal Strength Indicator main features are:
•
•
•
•
Minimum RSSI sensitivity is -91 dBm (RSSI_BASE_VAL, see parameter 11.7.16)
Dynamic range is 81 dB
Minimum RSSI value is 0
Maximum RSSI value is 28
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5131E-MCU Wireless-02/09
8.4.1 Overview
The RSSI is a 5-bit value indicating the receive power in the selected channel, in steps
of 3 dB. No attempt is made to distinguish between IEEE 802.15.4 signal and other
signal source, only the received signal power is evaluated. The RSSI provides the basis
for ED measurement.
8.4.2 Reading RSSI
Using the Basic Operating Mode, the RSSI value is valid at any RX state, and is
updated every 2 μs. The current RSSI value is stored to the PHY_RSSI register.
Note, it is not recommended to read the RSSI value when using the Extended
Operating Mode. The automatically generated ED value should be used alternatively
(see section 8.3).
8.4.3 Data Interpretation
The PHY_RSSI is an 8-bit register, however, the value is represented in the lowest five
bits [4:0] and the range is 0 – 28.
An RSSI value of 0 indicates an RF input power of < -91 dBm. For an RSSI value in the
range of 1 to 28, the RF input power can be calculated as follows:
PRF = RSSI_BASE_VAL + 3•(RSSI - 1)
8.4.4 Register Description
Register 0x06 (PHY_RSSI)
The PHY_RSSI register is a multi purpose register to indicate the current received
signal strength (RSSI) and the FCS validity of a received frame.
Bit
0x06
7
6
RX_CRC_VALID
Read/Write
Reset value
R
0
R
0
Bit
3
2
0x06
Read/Write
Reset value
5
Reserved
4
RSSI
R
0
R
0
1
0
RSSI
R
0
R
0
PHY_RSSI
PHY_RSSI
R
0
R
0
• Bit 7 – RX_CRC_VALID
Refer to section 8.2.5.
• Bit [6:5] – Reserved
• Bit [4:0] – RSSI
The register bits RSSI contain the result of the automated RSSI measurement. The
value is updated every 2 μs in receive states.
The read value is a number between 0 and 28 indicating the received signal strength as
a linear curve on a logarithmic input power scale (dBm) with a resolution of 3 dB. An
RSSI value of 0 indicates an RF input power of < -91 dBm (see parameter 11.7.17), a
value of 28 a power of ≥ -10 dBm (see parameter 11.7.18).
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8.5 Link Quality Indication (LQI)
The IEEE 802.15.4 standard defines the LQI measurement as a characterization of the
strength and/or quality of a received packet. The use of the LQI result by the network or
application layer is not specified in this standard. LQI values shall be an integer ranging
from 0 to 255. The minimum and maximum LQI values (0 and 255) should be
associated with the lowest and highest quality compliant signals, respectively, and LQI
values in between should be uniformly distributed between these two limits.
8.5.1 Overview
The AT86RF230 determines the link quality of a radio link. The radio transceiver uses
correlation results of multiple symbols within a frame to determine the LQI value. This is
done for each received frame. The minimum frame length for a valid LQI value is two
octets PSDU. LQI values are integers ranging from 0 to 255.
The LQI values can be associated with an expected packet error rate (PER). The PER
is the ratio of erroneous received frames to the total number of received frames. A PER
of zero indicates no frame error, whereas at a PER of one no frame was received
correctly.
As an example, Figure 8-3 shows the conditional packet error rate with associated LQI
values. The values are taken from received frames of length 20 octets PSDU on
transmission channels with low multipath delay spreads. Even if the transmission
channel characteristic has higher multipath delay spread than assumed for this
example, the dependency of PER to LQI values is not affected.
Since the packet error rate is a statistical value, the PER shown in Figure 8-3 is based
on a huge number of receptions.
Figure 8-3. Conditional Packet Error Rate versus LQI
1
0.9
0.8
0.7
PER
0.6
0.5
0.4
0.3
0.2
0.1
0
0
50
100
150
200
250
LQI
8.5.2 Request an LQI Measurement
The LQI byte can be obtained after a frame has been received by the radio transceiver.
One additional byte is attached to the received frame containing the LQI value. This
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information can be read as an extra byte from the Frame Buffer (see section 9.1). The
LQI byte can be uploaded after the TRX_END interrupt.
8.5.3 Data Interpretation
A low LQI value is associated with low signal strength and/or high signal distortions.
Signal distortions are mainly caused by interference signals and/or multipath
propagation. High LQI values indicate a sufficient high signal power and low signal
distortions.
Note, the received signal power as indicated by received signal strength indication
(RSSI) value or energy detection (ED) value do not characterize the signal quality and
the ability to decode a signal. As an example, a received signal with an input power of
about 6 dB above the receiver sensitivity likely results in a LQI value close to 255 for
radio channels with very low signal distortions. For higher signal power levels the LQI
value becomes independent of the actual signal strength. This is because the packet
error rate for these scenarios tends towards zero and further increase of the signal
strength, i.e. by increasing the transmission power, does not decrease the error rate
any further. In this case RSSI or ED can be used to evaluate the signal strength and the
link margin.
ZigBee networks require to determine the “best” route between two nodes. Both, the
LQI and the RSSI/ED can be used for this, depending on the optimization criteria. As a
rule of thumb RSSI/ED is useful to differentiate between links with high LQI values.
Transmission links with low LQI values should be discarded for routing decisions even if
the RSSI/ED values are high.
8.6 Clear Channel Assessment (CCA)
The main features of the Clear Channel Assessment (CCA) module are:
• All 3 modes available as defined by IEEE 802.15.4-2003 in section 6.7.9
• Adjustable threshold of the energy detection algorithm
8.6.1 Overview
The CCA is used to detect a clear channel. There are three modes available as defined
in Table 8-4.
Table 8-4. Available CCA Modes
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AT86RF230
CCA Mode
Description
1
Energy above threshold.
CCA shall report a busy medium upon detecting any energy above the ED
threshold.
2
Carrier sense only.
CCA shall report a busy medium only upon the detection of a signal with the
modulation and spreading characteristics of IEEE 802.15.4. This signal may be
above or below the ED threshold.
3
Carrier sense with energy above threshold.
CCA shall report a busy medium only upon the detection of a signal with the
modulation and spreading characteristics of IEEE 802.15.4 with energy above
the ED threshold.
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AT86RF230
8.6.2 CCA Configuration and Request
The CCA modes are configurable via register 0x08 (PHY_CC_CCA).
The 4 bit value CCA_ED_THRES of register 0x09 (CCA_THRES) defines the received
power threshold of the “energy above threshold” algorithm. The threshold is calculated
by RSSI_BASE_VAL+2•CCA_ED_THRES [dBm].
Using the Basic Operating Mode, a CCA request can be initiated manually by setting
CCA_REQUEST = 1 in register 0x08 (PHY_CC_CCA), if the AT86RF230 is in any RX
state. The CCA computation is done over eight symbol periodes and the result is
accessible 140 µs after the request.
Note, it is not recommended to initiate manually a CCA measurement when using the
Extended Operating Mode.
8.6.3 Data Interpretation
The current channel status (CCA_STATUS) and the CCA completion status
(CCA_DONE) are accessible in register 0x01 (TRX_STATUS). Note, a read access to
this register clears register bits CCA_DONE and CCA_STATUS.
The completion of a measurement cycle is indicated by CCA_DONE = 1. If the radio
transceiver detected no signal (idle channel) during the measurement cycle, the
CCA_STATUS bit is set to 1.
When using the “energy above threshold” algorithm (mode 1 and mode 3) any received
power above CCA_ED_THRES level is interpreted as a busy channel. The “carrier
sense” algorithm (mode 2 and mode 3) reports a busy channel when detecting a
IEEE 802.15.4 signal above the RSSI_BASE_VAL (see parameter 11.7.16). The radio
transceiver is also able to detect signals below this value, but the detection probability
decreases with the signal power. It is almost zero at the radio transceivers sensitivity
level (see parameter 11.7.1).
8.6.4 Register Description
Register 0x01 (TRX_STATUS)
The TRX_STATUS register signals the current state of the radio transceiver as well as
the status of the CCA measurement. Note, a read access to the register clears bits
CCA_DONE and CCA_STATUS.
Bit
7
6
5
4
CCA_DONE
CCA_STATUS
Reserved
TRX_STATUS
Read/Write
Reset value
R
0
R
0
R
0
R
0
Bit
3
2
1
0
R
0
R
0
0x01
0x01
Read/Write
Reset value
TRX_STATUS
R
0
R
0
TRX_STATUS
TRX_STATUS
• Bit 7 – CCA_DONE
This register indicates if a CCA request is completed. Each read access to register
0x01 resets the CCA_DONE bit.
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Table 8-5. Status CCA Algorithm
Register Bit
Value
Description
CCA_DONE
0
CCA calculation in progress
1
CCA calculation finished
• Bit 6 – CCA_STATUS
CCA_STATUS register bit indicates the result of a CCA request. Each read access to
register 0x01 resets the CCA_STATUS bit.
Table 8-6. Status CCA Result
Register Bit
Value
CCA_STATUS
Description
0
Channel is busy
1
Channel is idle
• Bit 5 – Reserved
• Bit [4:0] – TRX_STATUS
Refer to section 7.1.5.
Register 0x08 (PHY_CC_CCA)
The PHY_CC_CCA register contains register bits to initiate and control the CCA
measurement as well as to set the channel center frequency.
Bit
0x08
7
6
CCA_REQUEST
Read/Write
Reset value
Bit
R/W
0
R/W
0
3
2
0x08
Read/Write
Reset value
5
CCA_MODE
4
CHANNEL
R/W
1
R/W
0
1
0
R/W
1
R/W
1
CHANNEL
R/W
1
R/W
0
PHY_CC_CCA
PHY_CC_CCA
• Bit 7 – CCA_REQUEST
A manual CCA measurement is initiated with setting CCA_REQUEST = 1.
• Bit [6:5] – CCA_MODE
The CCA mode can be selected using register bits CCA_MODE.
Table 8-7. CCA Modes
Register Bit
Value
Description
CCA_MODE
0
Reserved
1
Mode 1, Energy above threshold
2
Mode 2, Carrier sense only
3
Mode 3, Carrier sense with energy above threshold
• Bit [4:0] – CHANNEL
Refer to section 9.7.5.
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Register 0x09 (CCA_THRES)
This register contains the threshold level for CCA-ED measurement.
Bit
7
6
0x09
Read/Write
Reset value
Bit
4
CCA_THRES
R/W
1
R/W
1
R/W
0
R/W
0
3
2
1
0
R/W
1
R/W
1
0x09
Read/Write
Reset value
5
Reserved
CCA_ED_THRES
R/W
0
R/W
1
CCA_THRES
• Bit [7:4] – Reserved
• Bit [3:0] – CCA_ED_THRES
The register bits CCA_ED_THRES define the threshold value of the CCA-ED
measurement. A cannel is indicated as busy when the received signal power is above
RSSI_BASE_VAL + 2 • CCA_ED_THRES [dBm].
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9 Module Description
9.1 Receiver (RX)
9.1.1 Overview
The AT86RF230 receiver is spitted into an analog radio front end and a digital base
band processor (RX BBP), see Figure 3-1.
The RF signal is amplified by a low noise amplifier (LNA) and converted down to an
intermediate frequency by a mixer. Channel selectivity is performed using an integrated
band pass filter. A limiting amplifier (Limiter) provides sufficient gain to overcome the
DC offset of the succeeding analog-to-digital converter (ADC) and generates a digital
RSSI signal with 3 dB granularity. The IF signal is sampled and processed further by
the digital base band receiver.
The RX BBP performs additional signal filtering and signal synchronization. The
frequency offset of each frame is calculated by the synchronization unit and is used
during the remaining receive process to correct the offset. The receiver is designed to
handle frequency and symbol rate deviations up to ±120 ppm, caused by combined
receiver and transmitter deviations. For details refer to section 11.5 parameter 11.5.6.
Finally the signal is demodulated and the data are stored to the Frame Buffer.
In Basic Operating Mode the start of an IEEE 802.15.4 compliant frame is indicated by
a RX_START interrupt. Accordingly it’s end is signalized by an TRX_END interrupt.
Based on the quality of the received signal a link quality indicator (LQI) is calculated
and appended to the frame, refer to section 8.5. Additional signal processing is applied
to the frame data to provide further status information like ED value (register 0x07) and
FCS correctness (register 0x06).
Beyond these features the Extended Operating Mode of the AT86RF230 supports
address filtering and pending data indication. For details refer to section 7.2.
9.1.2 Configuration
The receiver is enabled by writing the command RX_ON for the Basic Operating Mode
or RX_AACK_ON for the Extended Operating Mode to register bits TRX_CMD in
register 0x02 (TRX_STATE).
The receiver does not need any additional configuration to receive IEEE 802.15.4
compliant frames on the current selected channel when using the Basic Operating
Mode. However the frame reception in the Extended Operating Mode requires further
register configurations, for details refer to section 7.2.
9.2 Transmitter (TX)
9.2.1 Overview
The AT86RF230 transmitter consists of a digital base band processor (TX BBP) and an
analog radio front end, see Figure 3-1.
The TX BBP reads the frame data from the Frame Buffer and performs the bit-tosymbol and symbol-to-chip mapping as specified by IEEE 802.15.4 in section 6.5.2.
The O-QPSK modulation signal is generated and fed into the analog radio front end.
The fractional-N frequency synthesizer (PLL) converts the baseband transmit signal to
the RF signal, which is amplified by the power amplifier (PA). The PA output is internally
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AT86RF230
connected to bidirectional differential antenna pins (RFP, RFN), so that no external
antenna switch is needed.
9.2.2 Configuration
In Basic Operating Mode a transmission is started from PLL_ON state by either writing
TX_START to register bits TRX_CMD (register 0x02, TRX_STATE) or by raising edge
of SLP_TR.
In Extended Operating Modes a transmission is started automatically dependent on the
transaction phase of either RX_AACK or TX_ARET, refer to section 7.2.
The RF output power can be set via register bits TX_PWR in register 0x05
(PHY_TX_PWR). The maximum output power of the transmitter is typical +3 dBm. The
selectable output power range of the transmitter is 20 dB.
9.2.3 Register Description
Register 0x05 (PHY_TX_PWR)
The PHY_TX_PWR register sets the transmit power and controls the FCS algorithm for
TX operation.
Bit
0x05
7
6
5
TX_AUTO_CRC_ON
Read/Write
Reset value
R/W
0
Bit
3
R
0
PHY_TX_PWR
R
0
2
R
0
1
0
R/W
0
R/W
0
TX_PWR
0x05
Read/Write
Reset value
4
Reserved
R/W
0
R/W
0
PHY_TX_PWR
• Bit 7 – TX_AUTO_CRC_ON
Refer to sections 7.2.6 and 8.2.
• Bit [6:4] – Reserved
• Bit [3:0] – TX_PWR
The register bits TX_PWR sets the TX output power of the AT86RF230. The available
power settings are summarized in Table 9-1.
Table 9-1. PA Output Power Setting
Register Bits
TX_PWR
Value [3:0]
Output Power [dBm]
0x0
+3.0
0x1
+2.6
0x2
+2.1
0x3
+1.6
0x4
+1.1
0x5
+0.5
0x6
-0.2
0x7
-1.2
0x8
-2.2
0x9
-3.2
0xA
-4.2
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Register Bits
Value [3:0]
Output Power [dBm]
0xB
-5.2
0xC
-7.2
0xD
-9.2
0xE
-12.2
0xF
-17.2
9.3 Frame Buffer
The AT86RF230 contains a 128 byte dual port SRAM. One port is connected to the SPI
interface, the other to the internal TX/RX BBP port. For data communication both ports
are independent and simultaneously accessible. Access conflicts are indicated by a
TRX under run (TRX_UR) interrupt.
The Frame Buffer is used for the TX and RX operation of the device and can keep one
IEEE 802.15.4-2003 TX or one RX frame of maximum length at a time.
Note, a Frame Buffer access is only possible if the digital voltage regulator is turned on.
This is the case in all device states except in SLEEP and P_ON.
9.3.1 Frame Buffer Data Management
Data stored in Frame Buffer (received data or data to be transmitted) remains valid as
long as
• No new frame is written into the buffer via SPI
• No new frame is received (in any BUSY_RX state)
• No state change into SLEEP state is made
If the radio transceiver is in any RX state an incoming frame with valid SFD field
overwrites the Frame Buffer content 32 µs after the RX_START interrupt occurs, even if
the RX_START interrupt is disabled. Thus the Frame Buffer content should be
uploaded to the microcontroller before the next SFD is received. To avoid an
unintended Frame Buffer overwrite a state change to PLL_ON immediately after the
frame reception (TRX_END interrupt) is recommended.
Using the Extended Operating Mode states TX_ARET_ON or TX_ARET_ON_NOCLK,
the radio transceiver switches to RX (after successful frame transmission), if an
acknowledgement was requested in FCF. Received frames are evaluated but not
stored in the Frame Buffer in these states. This allows the radio transceiver to wait for
an acknowledgement frame and retry the data frame transmission without downloading
them again.
A radio transceiver state change, except a transition to SLEEP, does not affect the
Frame Buffer contents. If the radio transceiver is forced into SLEEP, the Frame Buffer is
powered off and the stored data gets lost.
9.3.2 User accessible Frame Content
The AT86RF230 supports an IEEE 802.15.4-2003 compliant frame format as shown in
Figure 9-1.
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AT86RF230
Figure 9-1. Frame Structure
A frame comprises two sections, the fixed internally generated SHR field and the user
accessible part stored in the Frame Buffer. The first fixed part of the frame consists of
the preamble and the SFD field. The variable frame section contains the frame length
field and the frame payload followed by the FCS field. The Frame Buffer content differs
depending on the direction of the communication (RX or TX). To access the data follow
the procedures described in sections 6.2.2 and 6.2.3.
In any of the receive states, the payload and the link quality indicator (LQI) value of a
successfully received frame are stored to the Frame Buffer. The radio transceiver
appends the LQI value to the PSDU data. The frame length information is not stored to
the Frame Buffer. When using the Frame Buffer access mode to read the Frame Buffer
content, the PHR octet is automatically prefixed to the payload during the upload
process. If the SRAM access mode is used, the frame length information cannot be
accessed. The preamble or the SFD value cannot be read.
For frame transmission, the PHR octet and the PSDU data shall be stored to the Frame
Buffer. If the TX_AUTO_CRC_ON bit is set in register 0x05 (PHY_TX_PWR), the FCS
field is replaced by the automatically calculated FCS during frame transmission. There
is no need to download the FCS field when using the automatic FCS generation.
For non IEEE 802.15.4-2003 frames, the minimum PSDU length supported by the
AT86RF230 is one byte.
9.3.3 Frame Buffer Interrupt Handling
Access conflicts may occur when reading or writing data simultaneously at the two
independent ports of the Frame Buffer, BBP and SPI. Both of these ports have its own
address counter that points to the Frame Buffer’s current address.
During Frame Buffer read access, if the SPI port’s address counter value is more than
or equal to that of TX/RX BBP port then an access violation occurs. This indicates that
the SPI transfer rate is higher than the PHY data rate.
Similar on Frame Buffer write access, an access violation occurs if the SPI port’s
address counter value is less than or equal to that of TX/RX BBP port. This access
violation can occur if the SPI transfer rate during a frame download is slower than the
PHY data rate, while having started the frame transmission already.
Both these access violations may cause data corruption and are indicated by TRX_UR
interrupt when using the Frame Buffer access mode. Access violations are not indicated
when using the SRAM access mode.
While receiving a frame, primarily the data needs to be stored to the Frame Buffer
before reading it. This can be ensured by starting the Frame Buffer read access 32 µs
after the RX_START interrupt at the earliest. When reading the frame data continuously
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the SPI transfer rate shall be lower than 250 Kbit/s to ensure no TRX_UR interrupt
occurs.
Note, during the Frame Buffer read access the TRX_UR interrupt is first valid 64 µs
after the RX_START interrupt. The occurrence of the interrupt can be disregarded when
reading the first byte of the Frame Buffer between 32 µs and 64 µs after the
RX_START interrupt.
If a received frame upload is delayed and during the upload process a new frame is
received, a TRX_UR and an RX_START interrupt occurs. Even so, the old frame data
can be read, if the SPI data rate is higher than the effective over air data rate. A
minimum SPI clock rate of 1 MHz is recommended in this special case. Finally it is
required to check the uploaded frame data integrity by a FCS using the microcontroller.
When writing data to the Frame Buffer during frame transmission, the SPI transfer rate
shall be higher than 250 Kbit/s to ensure no TRX_UR interrupt occurs. The first byte of
the PSDU data must be available in the Frame Buffer before SFD transmission has
been completed, which takes 176 µs (16 µs PA ramp up + 128 µs preamble
transmission + 32 µs SFD transmission) from the rising edge of SLP_TR pin (see
Figure 7-2).
9.4 Voltage Regulators (AVREG, DVREG)
The main features of the Voltage Regulator modules are:
• Bandgap stabilized 1.8V supply for analog and digital domain.
• Low dropout (LDO) voltage regulator
• Configurable for usage of external voltage regulator
9.4.1 Overview
The internal voltage regulators supply the low voltage domains of the AT86RF230. The
AVREG provides the regulated 1.8V supply voltage for the analog section and the
DVREG supplies the 1.8V supply voltage for the digital section. A simplified schematic
of the internal voltage regulator is shown in Figure 9-2.
Figure 9-2. Simplified Schematic of AVREG/DVREG
DEVDD / EVDD
Bandgap
voltage
reference
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AT86RF230
9.4.2 Configure the Voltage Regulators
The voltage regulators can be configured by the register 0x10 (VREG_CTRL).
It is recommended to use the internal regulators, but it is also possible to supply the low
voltage domains by an external voltage source. For this configuration, the internal
regulators need to be switched off by setting the register bits to the values
AVREG_EXT = 1 and DVREG_EXT = 1. A regulated external supply voltage of 1.8V
needs to be connected to the pins DVDD and AVDD. When turning on the external
supply, ensure a sufficiently long stabilization time before interacting with the
AT86RF230.
9.4.3 Data Interpretation
The status bit values AVDD_OK = 1 and DVDD_OK = 1 indicate an enabled and stable
internal supply voltage. Reading 0 indicates a disabled or unstable internal supply
voltage.
9.4.4 Register Description
Register 0x10 (VREG_CTRL)
This register VREG_CTRL controls the use of the voltage regulators and indicates the
status of these.
Bit
0x10
7
6
AVREG_EXT
AVDD_OK
R/W
0
R
0
R/W
0
1
Read/Write
Initial value
Bit
0x10
5
3
2
DVREG_EXT
DVDD_OK
R/W
0
R
0
Read/Write
Initial value
4
Reserved
VREG_CTRL
R/W
0
0
Reserved
R/W
0
VREG_CTRL
R/W
0
• Bit 7 – AVREG_EXT
The register bit AVREG_EXT defines whether the internal analog voltage regulator or
an external regulator is used to supply the analog low voltage building blocks of the
radio transceiver.
Table 9-2. Regulated Voltage Supply Control for Analog Building Blocks
Register Bit
Value
Description
AVREG_EXT
0
Use internal voltage regulator
1
Use external voltage regulator, internal voltage
regulator is disabled
• Bit 6 – AVDD_OK
This register bit AVDD_OK indicates if the internal 1.8V regulated supply voltage AVDD
has settled. The bit is set to logic high, if AVREG_EXT = 1.
Table 9-3 Regulated Voltage Supply Control for Analog Building Blocks
Register Bit
AVDD_OK
Value
Description
0
Analog voltage regulator disabled or supply voltage not
stable
1
Analog supply voltage has settled
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• Bit [5:4] – Reserved
• Bit 7 – DVREG_EXT
The register bit DVREG_EXT defines whether the internal digital voltage regulator or an
external regulator is used to supply the digital low voltage building blocks of the radio
transceiver.
Table 9-4. Regulated Voltage Supply Control for Digital Building Blocks
Register Bit
Value
Description
DVREG_EXT
0
Use internal voltage regulator
1
Use external voltage regulator, internal voltage
regulator is disabled
• Bit 6 – DVDD_OK
This register bit DVDD_OK indicates if the internal 1.8V regulated supply voltage DVDD
has settled. The bit is set to logic high, if DVREG_EXT = 1.
Table 9-5 Regulated Voltage Supply Control for Digital Building Blocks
Register Bit
Value
DVDD_OK
Description
0
Digital voltage regulator disabled or supply voltage not
stable
1
Digital supply voltage has settled
• Bit [1:0] – Reserved
9.5 Battery Monitor (BATMON)
The main features of the battery monitor are:
• Programmable voltage threshold range: 1.7V to 3.675V
• Battery low voltage interrupt
9.5.1 Overview
The battery monitor (BATMON) detects and indicates a low supply voltage. This is done
by comparing the voltage on the external supply pin (EVDD) with a programmable
internal threshold voltage. A simplified schematic of the BATMON with the most
important input and output signals is shown in Figure 9-3.
Figure 9-3. Simplified Schematic of BATMON
EVDD
BATMON_HR
4
+
DAC
BATMON_VTH
Threshold
Voltage
For input-to-output mapping
see control register
0x11 (BATMON)
BATMON_OK
-
„1“
clear
D
Q
BATMON_IRQ
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9.5.2 Data Interpretation
The signal bit BATMON_OK of register 0x11 (BATMON) indicates the current value of
the battery voltage:
• If BATMON_OK = 0, the battery voltage is lower than the threshold voltage
• If BATMON_OK = 1, the battery voltage is higher than the threshold voltage
After setting a new threshold, the value BATMON_OK should be read out to verify the
current supply voltage value.
Note, the battery monitor is inactive during P_ON and SLEEP states, see control
register 0x01 (TRX_STATUS).
9.5.3 BATMON Interrupt Handling
A supply voltage drop below the programmed threshold value is indicated by the
BAT_LOW interrupt, see control register 0x0E and 0x0F. The interrupt is issued only if
BATMON_OK changes from 1 to 0.
No interrupt is generated when:
• The battery voltage is under the default 1.8V threshold at power up (BATMON_OK
was never 1), or
• A new threshold is set, which is still above the current supply voltage (BATMON_OK
remains 0).
Noise or temporary voltage drops may generate unwanted interrupts when the battery
voltage is close to the programmed threshold voltage. To avoid this:
• Disable the IRQ_7 (BAT_LOW) in register 0x0E (IRQ_MASK) and treat the battery
as empty, or
• Set a lower threshold value.
9.5.4 Register Description
Register 0x11 (BATMON)
The register BATMON configures the battery monitor. Additionally the supply voltage
status at pin 28 (EVDD) is accessible by reading register bit BATMON_OK according to
the actual BATMON settings.
Bit
7
0x11
6
Reserved
Read/Write
Reset value
R
0
R
0
Bit
3
2
4
BATMON_HR
R
0
R/W
0
1
0
R/W
1
R/W
0
BATMON_VTH
0x11
Read/Write
Reset value
5
BATMON_OK
R/W
0
R/W
0
BATMON
BATMON
• Bit [7:6] – Reserved
• Bit 5 – BATMON_OK
The register bit BATMON_OK indicates the level of the external supply voltage with
respect to the programmed threshold BATMON_VTH.
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5131E-MCU Wireless-02/09
Table 9-6. Battery Monitor Status
Register Bit
Value
BATMON_OK
Description
0
VDD < BATMON_VTH
1
VDD > BATMON_VTH
• Bit 4 – BATMON_HR
The register bit BATMON_HR selects the range and resolution of the battery monitor.
Table 9-7. Battery Monitor Voltage Range Settings
Register Bit
Value
BATMON_HR
Description
0
Enables the low range, see BATMON_VTH
1
Enables the high range, see BATMON_VTH
• Bit [3:0] – BATMON_VTH
The threshold value for the battery monitor is set with register bits BATMON_VTH.
Table 9-8. Battery Monitor Threshold Voltages
Value
BATMON_VTH [3:0]
Threshold Voltage [V]
BATMON_HR = 1
Threshold Voltage [V]
BATMON_HR = 0
0x0
2.550
1.70
0x1
2.625
1.75
0x2
2.700
1.80
0x3
2.775
1.85
0x4
2.850
1.90
0x5
2.925
1.95
0x6
3.000
2.00
0x7
3.075
2.05
0x8
3.150
2.10
0x9
3.225
2.15
0xA
3.300
2.20
0xB
3.375
2.25
0xC
3.450
2.30
0xD
3.525
2.35
0xE
3.600
2.40
0xF
3.675
2.45
9.6 Crystal Oscillator (XOSC)
The main crystal oscillator features are:
•
•
•
•
66
AT86RF230
16 MHz amplitude controlled crystal oscillator
500 µs typical settling time
Integrated trimming capacitance array
Programmable clock output (CLKM)
5131E-MCU Wireless-02/09
AT86RF230
9.6.1 Overview
The crystal oscillator generates the reference frequency for the AT86RF230. All other
internally generated frequencies of the radio transceiver are derived from this unique
frequency. Therefore, the overall system performance is mainly based on the accuracy
of this reference frequency. The external components of the crystal oscillator should be
selected carefully and the related board layout should be done meticulously (refer to
section 5).
The register 0x12 (XOSC_CTRL) provides access to the control signals of the
oscillator. Two operating modes are supported. It is recommended to use the integrated
oscillator setup as described in Figure 9-4, nevertheless a reference frequency can be
fed to the internal circuitry by using an external clock reference as shown in Figure 9-5.
9.6.2 Integrated Oscillator Setup
Using the internal oscillator, the oscillation frequency strongly depends on the load
capacitance between the crystal pins XTAL1 and XTAL2. The total load capacitance CL
must be equal to the specified load capacitance of the crystal itself. It consists of the
external capacitors CX and parasitic capacitances connected to the XTAL nodes. In
Figure 9-4, all parasitic capacitances, such as PCB stray capacitances and the pin input
capacitance, are summarized to CPAR. Additional internal trimming capacitors CTRIM are
available. Any value in the range from 0 pF to 4.5 pF with a 0.3 pF resolution is
selectable using XTAL_TRIM of register 0x12 (XOSC_CTRL). To calculate the total
load capacitance, the following formula can be used
CL = 0.5•(CX+CTRIM+CPAR).
The trimming capacitors provide the possibility of reducing frequency deviations caused
by production process variations or by external components tolerances. Note that the
oscillation frequency can be reduced only by increasing the trimming capacitance. The
frequency deviation caused by one step of CTRIM decreases with increasing crystal load
capacitor values.
A magnitude control circuit is included to ensure stable operation under different
operating conditions and for different crystal types. A high current during the amplitude
build-up phase guarantees a low start-up time. At stable operation, the current is
reduced to the amount necessary for a robust operation. This also keeps the drive level
of the crystal low.
Generally, crystals with a higher load capacitance are less sensitive to parasitic pulling
effects caused by external component variations or by variations of board and circuit
parasitics. On the other hand, a larger crystal load capacitance results in a longer startup time and a higher steady state current consumption.
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5131E-MCU Wireless-02/09
Figure 9-4. Simplified XOSC Schematic with External Components
EVDD
XTAL_TRIM[3:0]
CTRIM
XTAL_TRIM[3:0]
CTRIM
AT86RF230
XTAL2
CPAR
XTAL1
16MHz
CX
CX
PCB
CPAR
9.6.3 External Reference Frequency Setup
When using an external reference frequency, the signal needs to be connected to pin
XTAL1 as indicated in Figure 9-5 and the register XTAL_MODE of register 0x12
(XOSC_CTRL) need to be set to the external oscillator mode. The oscillation peak-topeak amplitude shall be 400 mV, but not larger than 500 mV.
Figure 9-5. Setup for Using an External Frequency Reference
AT86RF230
XTAL2
XTAL1
PCB
16 MHz
9.6.4 Master Clock Signal Output (CLKM)
The generated reference clock signal can be fed to a microcontroller using pin 17
(CLKM). The internal 16 MHz raw clock can be divided by an internal prescaler. Thus,
clock frequencies of 16 MHz, 8 MHz, 4 MHz, 2 MHz or 1 MHz can be supplied by
pin CLKM.
The CLKM frequency and pin driver strength is configurable using register
0x03 (TRX_CTRL_0). There are two possibilities to change the CLKM frequency. If
CLKM_SHA_SEL = 0, changing the register bits CLKM_CTRL (register 0x03,
TRX_CTRL_0)
immediately
affects
the
CLKM
clock
rate.
Otherwise
(CLKM_SHA_SEL = 1) the new clock rate is supplied when leaving the SLEEP state
the next time.
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AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
To reduce power consumption and spurious emissions, it is recommended to turn off
the CLKM clock when not in use or to reduce its driver strength to a minimum, refer to
section 4.3.
Note:
During reset procedure, see section 7.1.4.2, register bits CLKM_CTRL are shadowed.
Although the clock setting of CLKM remains after reset, a read access to register bits
CLKM_CTRL delivers the reset value 1. For that reason it is recommended to write the
previous configuration (before reset) to the CLKM_CTRL to align the radio transceiver
behavior and register configuration. Otherwise the CLKM clock rate is set back to the
reset value (1 MHz) after the next SLEEP cycle.
For example if the CLKM clock rate is configured to 16 MHz the CLKM rate remains at
16 MHz after a reset, however the register bits CLKM_CTRL are set back to 1. Since
CLKM_SHA_SEL reset value is 1, the CLKM clock rate would change to 1 MHz after
the next SLEEP cycle if the CLKM_CTRL setting is not updated.
9.6.5 Register Description
Register 0x03 (TRX_CTRL_0)
The TRX_CTRL_0 register controls the drive current of the digital output pads and the
CLKM clock rate.
Bit
7
0x03
Read/Write
Reset value
Bit
0x03
6
5
PAD_IO
R/W
0
R/W
0
3
2
CLKM_SHA_SEL
Read/Write
Reset value
4
PAD_IO_CLKM
TRX_CTRL_0
R/W
0
R/W
1
1
0
CLKM_CTRL
R/W
1
R/W
0
R/W
0
TRX_CTRL_0
R/W
1
• Bit [7:6] – PAD_IO
Refer to in section 4.3.3.
• Bit [5:6] – PAD_IO_CLKM
The register bits PAD_IO_CLKM set the output driver current of pin CLKM.
Table 9-9. CLKM Driver Strength
Register Bit
PAD_IO_CLKM
Value
Description
0
2 mA
1
4 mA
2
6 mA
3
8 mA
• Bit 3 – CLKM_SHA_SEL
The register bit CLKM_SHA_SEL defines the commencement of the CLKM clock rate
modifications when changing register bits CLKM_CTRL.
Table 9-10. Commencement of CLKM Clock Rate Modification
Register Bit
CLKM_SHA_SEL
Value
0
Description
CLKM clock rate changes immediately
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5131E-MCU Wireless-02/09
Register Bit
Value
Description
1
CLKM clock rate changes after SLEEP cycle
• Bit [2:0] – CLKM_CTRL
The register bits CLKM_CTRL set clock rate of pin CLKM.
Table 9-11. Clock Rate at Pin CLKM
Register Bit
Value
Description
CLKM_CTRL
0
No clock, pin set to logic low
1
1 MHz
2
2 MHz
3
4 MHz
4
8 MHz
5
16 MHz
6
Reserved
7
Reserved
Register 0x12 (XOSC_CTRL)
The register XOSC_CTRL controls the operation of the crystal oscillator.
Bit
7
6
0x12
Read/Write
Initial value
Bit
R/W
1
R/W
1
3
2
4
R/W
1
R/W
1
1
0
R/W
0
R/W
0
XOSC_CTRL
XTAL_TRIM
0x12
Read/Write
Initial value
5
XTAL_MODE
R/W
0
R/W
0
XOSC_CTRL
• Bit [7:4] – XTAL_MODE
The register bit XTAL_MODE sets the operating mode of the crystal oscillator.
Table 9-12. Crystal Oscillator Operating Mode
Register Bit
Value
Description
XTAL_MODE
0x0
Crystal oscillator disabled, no clock signal is fed to the
internal circuitry.
0x4
Internal crystal oscillator disabled, use external
reference frequency
0xF
Internal crystal oscillator enabled
• Bit [3:0] – XTAL_TRIM
The register bits XTAL_TRIM control two internal capacitance arrays connected to pins
XTAL1 and XTAL2. A capacitance value in the range from 0 pF to 4.5 pF is selectable
with a resolution of 0.3 pF.
Table 9-13. Crystal Oscillator Trimming Capacitors
70
AT86RF230
Register Bit
Value
XTAL_TRIM
0x0
Description
0.0 pF, trimming capacitors disconnected
5131E-MCU Wireless-02/09
AT86RF230
Register Bit
Value
0x1
Description
0.3 pF, trimming capacitor switched on
…
0xF
4.5 pF, trimming capacitor switched on
9.7 Frequency Synthesizer (PLL)
The main PLL features are:
•
•
•
•
Generate RX/TX frequencies for all IEEE 802.15.4 - 2.4 GHz channels
Fully integrated fractional-N synthesizer
Autonomous calibration loops for stable operation within the operating range
Two PLL-interrupts for status indication
9.7.1 Overview
The synthesizer of the AT86RF230 is implemented as a fractional-N PLL. The PLL is
fully integrated and configurable by registers 0x08 (PHY_CC_CCA), 0x1A (PLL_CF)
and 0x1B (PLL_DCU).
The PLL is turned on when entering the state PLL_ON and stays on in all receive and
transmit states. The PLL settles to the correct frequency needed for RX or TX operation
according to the adjusted channel center frequency in register 0x08 (PHY_CC_CCA).
Two calibration loops ensure correct PLL functionality within the specified operating
limits.
9.7.2 RF Channel Selection
The PLL is designed to support 16 channels in the IEEE 802.15.4 – 2.4 GHz band with
a channel spacing of 5 MHz. The center frequency FCH of these channels is defined as
follows:
FCH = 2405 + 5 (k – 11) [MHz], for k = 11, 12, ..., 26
where k is the channel number.
The channel k is selected by register bits CHANNEL (register 0x08, PHY_CC_CA).
9.7.3 Calibration Loops
The center frequency control loop ensures a correct center frequency of the VCO for
the currently programmed channel.
The delay calibration unit compensates the phase errors inherent in fractional-N PLLs.
Using this technique, unwanted spurious frequency components beside the RF carrier
are suppressed, and the PLL behaves similar to an integer-N PLL.
Both calibration routines are initiated automatically when the PLL is turned on.
Additionally, the center frequency calibration is running when the PLL is programmed to
a different channel (register bits CHANNEL in register 0x08).
If the PLL operates for a long time on the same channel or the operating temperature
changes significantly, the control loops should be initiated manually. The recommended
calibration interval is 5 min.
Both calibration loops can be initiated manually by setting PLL_CF_START = 1 of
register 0x1A (PLL_CF) and register bit PLL_DCU_START = 1 of register 0x1B
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5131E-MCU Wireless-02/09
(PLL_DCU). To start the calibrations routines the device should be in state PLL_ON.
The center frequency tuning takes a maximum of 80 µs. The completion is indicated by
a PLL_LOCK interrupt. The delay cell calibration loop is completed after 6 µs. This is
typically not indicated by a PLL_LOCK interrupt.
9.7.4 PLL Interrupt Handling
There are two different interrupts indicating the PLL status (see register 0x0F). The
PLL_LOCK interrupt indicates that the PLL has locked. The PLL_UNLOCK interrupt
indicates an unexpected unlock condition. A PLL_LOCK interrupt clears any preceding
PLL_UNLOCK interrupt automatically and vice versa.
A PLL_LOCK interrupt occurs in the following situations:
• State change from TRX_OFF to PLL_ON/RX_ON
• Channel change in states PLL_ON/RX_ON
• Initiating a center frequency tuning manually
The state transition from BUSY_TX to PLL_ON can also initiate a PLL_LOCK interrupt,
due to the PLL settling back to the RX frequency.
Any other occurrences of PLL interrupts indicate erroneous behavior and require
checking of the actual device status.
9.7.5 Register Description
Register 0x08 (PHY_CC_CCA)
The PHY_CC_CCA register contains register bits to initiate and control the CCA
measurement as well as to set the channel center frequency.
Bit
0x08
7
6
CCA_REQUEST
Read/Write
Reset value
Bit
R/W
0
R/W
0
3
2
0x08
Read/Write
Reset value
5
CCA_MODE
4
CHANNEL
R/W
1
R/W
0
1
0
R/W
1
R/W
1
CHANNEL
R/W
1
R/W
0
PHY_CC_CCA
PHY_CC_CCA
• Bit 7 – CCA_REQUEST
Refer to section 8.6.4.
• Bit [6:5] – CCA_MODE
Refer to section 8.6.4.
• Bit [4:0] – CHANNEL
The register bits CHANNEL define the RX/TX channel. The channel assignment is
according to IEEE 802.15.4.
Table 9-14. Channel Assignment for IEEE 802.15.4 – 2.4 GHz Band
72
AT86RF230
Register Bit
Value
Channel Number
Center Frequency [MHz]
CHANNEL
0x0B
11
2405
0x0C
12
2410
0x0D
13
2415
0x0E
14
2420
5131E-MCU Wireless-02/09
AT86RF230
Register Bit
Value
Channel Number
Center Frequency [MHz]
0x0F
15
2425
0x10
16
2430
0x11
17
2435
0x12
18
2440
0x13
19
2445
0x14
20
2450
0x15
21
2455
0x16
22
2460
0x17
23
2465
0x18
24
2470
0x19
25
2475
0x1A
26
2480
Register 0x1A (PLL_CF)
The register PLL_CF controls the operation of the center frequency calibration loop.
Bit
0x1A
Read/Write
Reset value
Bit
7
6
4
Reserved
PLL_CF
R/W
0
R/W
1
R/W
0
R/W
1
3
2
1
0
R/W
0
R/W
1
R/W
1
R/W
1
Reserved
0x1A
Read/Write
Reset value
5
PLL_CF_START
PLL_CF
• Bit 7 – PLL_CF_START
PLL_CF_START = 1 initiates the center frequency calibration. The calibration cycle has
finished after a maximum of 80 µs. The register bit is cleared immediately after the
register write operation.
• Bit [6:0] – Reserved
Register 0x1B (PLL_DCU)
The register PLL_DCU controls the operation of the delay cell calibration loop.
Bit
0x1B
Read/Write
Reset value
Bit
7
6
4
Reserved
PLL_DCU
R/W
0
R
0
R/W
1
R/W
0
3
2
1
0
R/W
0
R/W
0
R/W
0
R/W
0
Reserved
0x1B
Read/Write
Reset value
5
PLL_DCU_START
PLL_DCU
73
5131E-MCU Wireless-02/09
• Bit 7 – PLL_DCU_START
PLL_DCU_START = 1 initiates the delay cell calibration. The calibration cycle has
finished after maximum of 6 µs. The register bit is cleared immediately after the register
write operation.
• Bit [6:0] – Reserved
9.8 Automatic Filter Tuning (FTN)
The filter-tuning unit is a separate block within the AT86RF230. The filter-tuning result is
used to provide a correct SSBF transfer function and PLL loop-filter time constant
independent of temperature effects and part-to-part variations.
A calibration cycle is initiated automatically when entering the TRX_OFF state from the
SLEEP, RESET or P_ON states.
74
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
10 Radio Transceiver Usage
This section describes basic procedures to receive and transmit frames using the
AT86RF230. For a detailed programming description refer to application note AVR2009
“AT86RF230 – Software Programming Model”.
10.1 Frame Receive Procedure
While in state RX_ON the radio transceiver searches for incoming frames on the
selected channel. A detection of a valid IEEE 802.15.4 frame is indicated by an IRQ_2
(RX_START) interrupt. The frame reception is completed when issuing the IRQ_3
(TRX_END) interrupt. Waiting for IRQ_3 (TRX_END) interrupt before uploading the
frame to the microcontroller is recommended for operations considered to be non time
critical. Figure 9-6 illustrates the frame receive procedure.
Microcontroller
AT86RF230
Figure 9-6. Frame Receive Procedure - Transactions between AT86RF230 and
Microcontroller
Critical protocol timing could require starting the frame upload as soon as possible. The
first byte of the frame data can be read 32 µs after the IRQ_2 (RX_START) interrupt.
The microcontroller must ensure to read slower than the frame is received. Otherwise,
the Frame Buffer wills under run, IRQ_6 (TRX_UR) interrupt is issued. The frame data
are not valid anymore and need to read again. The LQI byte can be uploaded to the
microcontroller after the IRQ_3 (TRX_END) interrupt was issued.
10.2 Frame Transmit Procedure
A frame transmission comprises two actions, a frame download to the Frame Buffer and
the transmission of the Frame Buffer content. Both actions can be run in parallel if
required by critical protocol timing.
Figure 9-7 illustrates the frame transmit procedure, when downloading and transmitting
the frame consecutively. After a frame download by a Frame Buffer write access, the
frame transmission is initiated by asserting pin SLP_TR or writing the TRX command
TX_START to register 0x02 (TRX_STATE), while the radio transceiver is in state
PLL_ON. The completion of the transmission is indicated by an IRQ_3 (TRX_END)
interrupt.
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5131E-MCU Wireless-02/09
Figure 9-7. Frame Transmit Procedure - Transactions between AT86RF230 and
Microcontroller
Alternatively, the frame transmission can be started before the frame data download as
described in Figure 9-8. This is useful for time critical applications. At the rising edge of
SPL_TR, the radio transceiver starts transmitting the preamble and the SFD field, which
takes about 176 µs (see Figure 7-2). The first byte of the PSDU must be available in the
Frame Buffer before this time. The SPI data rate must be higher than 250 kBit/s to
ensure that no Frame Buffer under run occurs (IRQ_6, TRX_UR).
Figure 9-8. Time Optimized Frame Transmit Procedure - Transactions between
AT86RF230 and Microcontroller
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5131E-MCU Wireless-02/09
AT86RF230
11 Technical Parameters
11.1 Absolute Maximum Ratings
Note: Stresses beyond those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional operation of
the device at these or any other conditions beyond those indicated in the operational
sections of this specification are not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
Table 11-1. Absolute Maximum Ratings
No
Parameter
Symbol
Min
-50
Typ
Max
Unit
150
°C
260
°C
11.1.1
Storage temperature
Tstor
11.1.2
Lead temperature
Tlead
11.1.3
ESD robustness
VESD
11.1.4
Input RF level
PRF
11.1.5
Voltage on all pins (except pins
4, 5, 13, 14, 29)
-0.3
VDD+0.3
11.1.6
Voltage on pins 4, 5, 13, 14, 29
-0.3
2.0
4
750
kV
V
+14
Conditions/Notes
Compl. to [2]
Compl. to [3]
dBm
11.2 Recommended Operating Range
Table 11-2. Operating Range
No
Parameter
11.2.1
Operating temperature range
11.2.2
Supply voltage
11.2.3
Supply voltage
(on pins 13, 14, 29)
Symbol
Min
Top
-40
Typ
Max
Unit
+85
°C
VDD
1.8
3.0
3.6
V
VDD1.8
1.65
1.8
1.95
V
Conditions/Notes
When using external voltage
regulators (see section 9.4).
11.3 Digital Pin Specifications
Test Conditions (unless otherwise stated):
Top = 25°C
Table 11-3. Digital Pin Specifications
No
Parameter
Symbol
Min
11.3.1
High level input voltage
VIH
VDD – 0.4
11.3.2
Low level input voltage
VIL
11.3.3
High level output voltage
VOH
11.3.4
Low level output voltage
VOL
Typ
Max
Unit
Conditions/Notes
V
0.4
VDD – 0.4
0.4
V
V
For all output driver strengths
defined in TRX_CTRL_0
V
For all output driver strengths
defined in TRX_CTRL_0
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5131E-MCU Wireless-02/09
11.4 Digital Interface Timing Specifications
Test Conditions (unless otherwise stated):
VDD = 3V, Top = 25°C
Table 11-4. Digital Interface Timing Parameters
No
Parameter
Symbol
11.4.1
SCLK frequency
(synchronous mode)
11.4.2
SCLK frequency (asynchronous
mode)
11.4.3
SEL low to MISO active
t1
11.4.4
SCLK to MISO out
t2
10
ns
11.4.5
MOSI setup time
t3
10
ns
11.4.6
MOSI hold time
t4
10
ns
11.4.7
LSB last byte to MSB next byte
t5
250
ns
11.4.8
SEL high to MISO tristate
t6
11.4.9
SLP_TR pulse width
t7
65
ns
TX start trigger
11.4.10 SPI idle time
t8
250
ns
Idle time between consecutive SPI
accesses
11.4.11 Last SCLK to SEL high
t9
250
ns
625
ns
11.4.12 Reset pulse width
Min
Typ
Max
Unit
8
MHz
7.5
MHz
180
ns
10
11.4.13 Output clock frequency (CLKM)
0
1
2
4
8
16
Conditions/Notes
data hold time
ns
MHz
MHz
MHz
MHz
MHz
MHz
≥ 10 clock cycles at 16 MHz
Programmable in register
TRX_CTRL_0
11.5 General RF Specifications
Test Conditions (unless otherwise stated):
VDD = 3V, f = 2.45 GHz, Top = 25°C, Measurement setup see Figure 5-1
Table 11-5. General RF Parameters
No
Parameter
11.5.1
Frequency range
Symbol
Min
f
2405
Typ
11.5.2
Bit rate
fbit
250
11.5.3
Chip rate
fchip
2000
11.5.4
Reference oscillator frequency
fclk
16
11.5.5
Reference oscillator settling time
11.5.6
Reference frequency accuracy
for proper functionality
11.5.7
TX signal 20 dB bandwidth
78
AT86RF230
0.5
-60
B20dB
2.8
Max
Unit
Conditions/Notes
2480
MHz
As specified in [1]
kbit/s
As specified in [1]
kchip/s As specified in [1]
MHz
1
ms
Leaving SLEEP state to clock
available at pin CLKM
+60
ppm
±40 ppm is required by [1]
MHz
RBW 100 kHz
VBW 300 kHz
5131E-MCU Wireless-02/09
AT86RF230
11.6 Transmitter Specifications
Test Conditions (unless otherwise stated):
VDD = 3V, f = 2.45 GHz, Top = 25°C, Measurement setup see Figure 5-1
Table 11-6. TX Parameters
No
Parameter
11.6.1
Output power
11.6.2
Output power range
11.6.3
Output power tolerance
11.6.4
TX Return loss
10
dB
11.6.5
EVM
8
%rms
11.6.6
Harmonics
2nd harmonic
3rd harmonic
-38
-45
dBm
dBm
11.6.7
Symbol
Min
Typ
Max
Unit
Conditions/Notes
PTX
0
3
6
dBm
Maximum configurable value
20
dB
±3
Spurious emissions
30 – ≤ 1000 MHz
>1 – 12.75 GHz
1.8 – 1.9 GHz
5.15 – 5.3 GHz
-36
-30
-47
-47
Configurable in register
PHY_TX_PWR
dB
dBm
dBm
dBm
dBm
Complies with
EN 300 328/440,
FCC-CFR-47 part 15,
ARIB STD-66,
RSS-210
11.7 Receiver Specifications
Test Conditions (unless otherwise stated):
VDD = 3V, f = 2.45 GHz, Top = 25°C, Measurement setup see Figure 5-1
Table 11-7. RX Parameters
No
Parameter
Symbol
11.7.1
Receiver sensitivity
11.7.2
RX Return loss
11.7.3
Noise figure
6
dB
11.7.4
Maximum RX input level
10
dBm
PER ≤ 1%, PSDU length of
20 octets
11.7.5
Adjacent channel rejection
-5 MHz
34
dBm
PER ≤ 1%, PSDU length of
20 octets, PRF = -82 dBm
11.7.6
Adjacent channel rejection
+5 MHz
36
dBm
PER ≤ 1%, PSDU length of
20 octets, PRF = -82 dBm
11.7.7
Alternate adjacent channel
rejection -10 MHz
52
dBm
PER ≤ 1%, PSDU length of
20 octets, PRF = -82 dBm
11.7.8
Alternate adjacent channel
rejection +10 MHz
53
dBm
PER ≤ 1%, PSDU length of
20 octets, PRF = -82 dBm
11.7.9
Spurious emissions
LO leakage
30 – ≤ 1000 MHz
>1 – 12.75 GHz
-75
dBm
dBm
dBm
NF
Min
Typ
Max
Unit
Conditions/Notes
-101
dBm
AWGN channel, PER ≤ 1%,
PSDU length of 20 octets
10
dB
100Ω differential impedance
-57
-47
79
5131E-MCU Wireless-02/09
No
Parameter
Symbol
11.7.10 TX/RX carrier frequency offset
tolerance
Min
Typ
-300
Max
Unit
Conditions/Notes
300
kHz
Sensitivity loss < 2 dB; equals
120 ppm ([1] requires 80 ppm)
11.7.11 3rd-order intercept point
IIP3
-9
dB
At maximum gain
Offset freq. interf. 1 = 5 MHz
Offset freq. interf. 2 = 10 MHz
11.7.12 2nd-order intercept point
IIP2
24
dB
At maximum gain
Offset freq. interf. 1 = 60 MHz
Offset freq. interf. 2 = 62 MHz
11.7.13 RSSI tolerance
±5
dB
11.7.14 RSSI dynamic range
81
dB
11.7.15 RSSI resolution
3
dB
11.7.16 RSSI sensitivity
-91
dBm
Defined as RSSI_BASE_VAL
11.7.17 Minimum RSSI value
0
PRF < RSSI_BASE_VAL
11.7.18 Maximum RSSI value
28
PRF ≥ RSSI_BASE_VAL + 81 dB
11.8 Current Consumption Specifications
Test Conditions (unless otherwise stated):
VDD = 3V, f = 2.45 GHz, Top = 25°C, Measurement setup see Figure 5-1
Table 11-8. Current Consumption
No
Parameter
Symbol
11.8.1
Supply current transmit state
IBUSY_TX
11.8.2
Supply current receive state
11.8.3
Supply current TRX_OFF state
11.8.4
11.8.5
Min
Typ
Max
Unit
Conditions/Notes
16.5
14.5
12.5
9.5
mA
mA
mA
mA
PTX = 3 dBm
PTX = 1 dBm
PTX = -3 dBm
PTX = -17 dBm
(At each output power level, the
supply current consumption can be
decreased by approx. 2 mA if
reducing VDD to 1.8V.)
IRX_ON
15.5
mA
State: RX_ON
ITRX_OFF
1.5
mA
State: TRX_OFF
Supply current SLEEP state
ISLEEP
0.02
µA
State: SLEEP
Supply current PLL_ON state
IPLL_ON
7.8
mA
State: PLL_ON
Unit
Conditions/Notes
11.9 Crystal Parameter Requirements
Table 11-9. Crystal Parameter Requirements
No
Parameter
11.9.1
Crystal frequency
f0
11.9.2
Load capacitance
CL
11.9.3
Static capacitance
11.9.4
Series resistance
80
AT86RF230
Symbol
Min
Typ
Max
16
8
MHz
14
pF
C0
7
pF
R1
100
Ω
5131E-MCU Wireless-02/09
AT86RF230
12 Register Reference
The AT86RF230 provides a register space of 64 8-bit registers, which is used to
configure, control and monitor the radio transceiver. The registers can be accessed in
any order.
Note: All registers not mentioned within the following table are reserved for internal use
and must not be overwritten. When writing to a register, any reserved bits shall be
overwritten only with their reset value (see Table 12-2).
Table 12-1. Register Summary – Non Reserved Registers
Addr.
Name
Bit 7
Bit 6
Bit 5
Bit 4
CCA_STATUS
Reserved
Bit 3
Bit 2
Bit 1
0x01
TRX_STATUS
CCA_DONE
0x02
TRX_STATE
0x03
TRX_CTRL_0
0x05
PHY_TX_PWR
TX_AUTO_CRC_ON
0x06
PHY_RSSI
RX_CRC_VALID
0x07
PHY_ED_LEVEL
0x08
PHY_CC_CCA
0x09
CCA_THRES
0x0E
IRQ_MASK
0x0F
IRQ_STATUS
BAT_LOW
TRX_UR
Reserved
TRX_END
RX_START
0x10
VREG_CTRL
AVREG_EXT
AVDD_OK
Reserved
DVREG_EXT
DVDD_OK
0x11
BATMON
Bit 0
TRX_STATUS
TRAC_STATUS
pg. 27, 38, 55
TRX_CMD
PAD_IO
PAD_IO_CLKM
pg. 28, 39
CLKM_SHA_SEL
CLKM_CTRL
Reserved
pg. 7, 69
TX_PWR
Reserved
pg. 49, 59
RSSI
pg. 50, 52
ED_LEVEL
CCA_REQUEST
pg. 51
CCA_MODE
CHANNEL
Reserved
MASK_BAT_LOW MASK_TRX_UR
Reserved
pg. 56, 72
CCA_ED_THRES
Reserved
BATMON_OK
Page
pg. 57
MASK_TRX_END MASK_RX_START MASK_PLL_UNLOCK MASK_PLL_LOCK pg. 20
BATMON_HR
PLL_UNLOCK
PLL_LOCK
Reserved
BATMON_VTH
XTAL_MODE
pg. 20
pg. 63
pg. 65
0x12
XOSC_CTRL
0x1A
PLL_CF
PLL_CF_START
Reserved
XTAL_TRIM
pg. 73
pg. 70
0x1B
PLL_DCU
PLL_DCU_START
Reserved
pg. 73
0x1C
PART_NUM
PART_NUM
pg. 16
0x1D
VERSION_NUM
VERSION_NUM
pg. 16
0x1E
MAN_ID_0
MAN_ID_0
pg. 17
0x1F
MAN_ID_1
MAN_ID_1
pg. 17
0x20
SHORT_ADDR_0
SHORT_ADDR_0
pg. 42
0x21
SHORT_ADDR_1
SHORT_ADDR_1
pg. 42
0x22
PAN_ID_0
PAN_ID_0
pg. 42
0x23
PAN_ID_1
PAN_ID_1
pg. 42
0x24
IEEE_ADDR_0
IEEE_ADDR_0
pg. 43
0x25
IEEE_ADDR_1
IEEE_ADDR_1
pg. 43
0x26
IEEE_ADDR_2
IEEE_ADDR_2
pg. 43
0x27
IEEE_ADDR_3
IEEE_ADDR_3
pg. 43
0x28
IEEE_ADDR_4
IEEE_ADDR_4
pg. 43
0x29
IEEE_ADDR_5
IEEE_ADDR_5
pg. 43
0x2A
IEEE_ADDR_6
IEEE_ADDR_6
pg. 44
0x2B
IEEE_ADDR_7
IEEE_ADDR_7
pg. 44
0x2C
XAH_CTRL
0x2D
CSMA_SEED_0
0x2E
CSMA_SEED_1
MAX_FRAME_RETRIES
MAX_CSMA_RETRIES
CSMA_SEED_0
MIN_BE
AACK_SET_PD
Reserved
I_AM_COORD
Reserved
pg. 40
pg. 41
CSMA_SEED_1
pg. 41
81
5131E-MCU Wireless-02/09
Notes:
• Reset values in Table 12-2 are only valid after a power on reset. After a reset
procedure ( RST = L) as described in section 7.1.4.2 the reset values of selected
registers (e.g. registers 0x01, 0x10, 0x11) can differ from that in Table 12-2.
• Read value of register 0x30 after a reset in state:
P_ON
0x11
Any other state
0x07
Table 12-2. Register Summary – Reset values
Address
Reset Value
Address
Reset Value
82
Address
Reset Value
Address
Reset Value
0x00
0x00
0x10
0x00
0x20
0x00
0x30
0x00
0x01
0x00
0x11
0x02
0x21
0x00
0x31
0x00
0x02
0x00
0x12
0xF0
0x22
0x00
032
0x00
0x03
0x19
0x13
0x00
0x23
0x00
0x33
0x00
0x04
0x00
0x14
0x00
0x24
0x00
0x34
0x00
0x05
0x00
0x15
0x00
0x25
0x00
0x35
0x00
0x06
0x00
0x16
0x00
0x26
0x00
0x36
0x00
0x07
0x00
0x17
0x00
0x27
0x00
0x37
0x00
0x08
0x2B
0x18
0x58
0x28
0x00
0x38
0x00
0x09
0xC7
0x19
0x55
0x29
0x00
0x39
0x40
0x0A
0xBC
0x1A
0x5F
0x2A
0x00
0x3A
0x00
0x0B
0xA7
0x1B
0x20
0x2B
0x00
0x3B
0x00
0x0C
0x04
0x1C
0x02
0x2C
0x38
0x3C
0x00
0x0D
0x00
0x1D
0x02
0x2D
0xEA
0x3D
0x00
0x0E
0xFF
0x1E
0x1F
0x2E
0xC2
0x3E
0x00
0x0F
0x00
0x1F
0x00
0x2F
0x00
0x3F
0x00
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Abbreviations
AACK
ACK
ADC
AGC
ARET
AVREG
AWGN
BATMON
BBP
BG
BoM
CCA
CRC
CSMA
CW
DCLK
DCU
DVREG
ED
ESD
EVM
FCS
FCF
FIFO
FTN
GPIO
ISM
LDO
LNA
LO
LQI
LSB
MAC
MFR
MHR
MSB
MSDU
MSK
NOP
O-QPSK
PA
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Auto acknowledge
Acknowledge
Analog-to-digital converter
Automatic gain control
Auto retry
Analog voltage regulator
Additive White Gaussian Noise
Battery monitor
Base-band processor
Band gap reference
Bill of material
Clear channel assessment
Cyclic redundancy check
Carrier sense multiple access
Continuous wave
Digital clock
Delay calibration unit
Digital voltage regulator
Energy detection
Electro static discharge
Error vector magnitude
Frame Check Sequence
Frame Control Field
First in first out
Automatic filter tuning
General purpose input output
Industrial, scientific, and medical
Low-drop output
Low-noise amplifier
Local oscillator
Link-quality indication
Least significant bit
Medium access control
MAC Footer
MAC header
Most significant bit
MAC service data unit
Minimum shift keying
No operation
Offset-quadrature phase shift keying
Power amplifier
83
5131E-MCU Wireless-02/09
PAN
PCB
PER
PHY
PHR
PLL
POR
PPF
PRBS
PSDU
QFN
RAM
RBW
RSSI
RX
SFD
SHR
SPI
SRAM
SSBF
TX
VBW
VCO
VREG
XOSC
84
AT86RF230
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Personal area network
Printed circuit board
Packet error rate
Physical layer
PHY Header
Phase-locked loop
Power-on reset
Poly-phase filter
Pseudo random binary sequence
PHY service data unit
Quad flat no-lead package
Random access memory
Resolution band width
Received signal strength indicator
Receiver
Start-of-frame delimiter
Synchronization Header
Serial peripheral interface
Static random access memory
Single side band filter
Transmitter
Video band width
Voltage controlled oscillator
Voltage regulator
Crystal stabilized oscillator
5131E-MCU Wireless-02/09
AT86RF230
13 Ordering Information
Ordering Code
Package
Voltage Range
AT86RF230-ZU
QN
1.8V – 3.6V
Temperature Range
Industrial (-40° C to +85° C) Lead-free/Halogen-free
Package Type
Description
QN
32QN1, 32-lead 5.0x5.0 mm Body, 0.50 mm Pitch, Quad Flat No-lead Package (QFN) Sawn
Note:
T&R quantity 5,000.
Please contact your local Atmel sales office for more detailed ordering information and
minimum quantities.
14 Soldering Information
Recommended soldering profile is specified in IPC/JEDEC J-STD-.020C.
15 Package Thermal Properties
Thermal Resistance
Velocity [m/s]
Theta ja [K/W]
0
40.9
1
35.7
2.5
32.0
85
5131E-MCU Wireless-02/09
16 Package Drawing – 32QN1
D
A
A3
E
Pin 1 Corner
A1
A2
Top View
Side View
Pin 1 Corner
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL
D2
e
E2
L
MIN
D
5.00 BSC
E
5.00 BSC
D2
3.20
3.30
3.40
3.20
3.30
3.40
A
0.80
0.90
1.00
A1
0.0
0.02
0.05
A2
0.0
0.65
1.00
L
Notes:
b
0.30
0.40
0.50
0.50 BSC
0.18
0.23
0.30
2
1. This drawing is for general information only. Refer to JEDEC Drawing MO-220, Variation VHHD-6, for proper dimensions,
tolerances, datums, etc.
2. Dimension b applies to metallized terminal and is measured between 0.15 mm and 0.30 mm from the terminal tip. If the
terminal has the optional radius on the other end of the terminal, the dimension should not be measured in that radius area.
GPC
TITLE
32QN2,
32-lead
5.0
x
5.0
mm
Body,
0.50
mm
Pitch,
Package Drawing Contact:
ZJZ
[email protected] Quad Flat No Lead Package (QFN) Sawn
86
NOTE
0.20 REF
e
Bottom View
MAX
E2
A3
b
NOM
AT86RF230
11/26/07
DRAWING NO. REV.
32QN2
A
5131E-MCU Wireless-02/09
AT86RF230
Appendix A - Continuous Transmission Test Mode
The Continuous Transmission Test Mode offers the following features:
• Continuous frame transmission
• Continuous wave signal transmission
A.1 - Overview
The AT86RF230 offers a Continuous Transmission Test Mode to support final
application/production tests as well as certification tests. Using this test mode the radio
transceiver transmits continuously a previously downloaded frame data (PRBS mode)
or a continuous wave signal (CW mode).
In CW mode three different signal frequencies can be transmitted:
f1 = fCH – 2 MHz
f2 = fCH + 0.5 MHz
f3 = fCH - 0.5 MHz
where fCH is the center frequency of the current programmed cannel in register 0x08
(PHY_CC_CCA). Note that it is not possible to transmit a CW signal on the channel
center frequency. Before starting a CW signal transmission valid data needs to be
downloaded to the Frame Buffer (refer to section 6.2.2), e.g a PHR field denotes a
frame length of 1 and one octet PSDU data.
In PRBS mode the transmission center frequency is fCH. Data downloaded to the Frame
Buffer must contain at least a valid Frame Length Field (see sections 8.1 and 9.1). It is
recommended to use a frame of maximum length (127 bytes) and arbitrary PSDU data.
In contrast to normal frame transmission here the SHR and the PHR are not
transmitted. The transmission starts with the PSDU data and is repeated continuously.
A.2 - Configuration
Before enabling the Continuous Transmission Test Mode (TST = 1) all register
configurations shall be done as follows:
• Radio transceiver initialization (TRX_STATUS = TRX_OFF)
• TX channel selection (optional)
• TX output power setting (optional)
• Frame data download (random sequence of max. length)
• Mode selection (PRBS/CW)
Setting TST = 1 enables the Continuous Transmission Test Mode. The test system or a
microcontroller has to overwrite the pull down resistor R1 connected to the TST pin (see
Figure 5-1). The pull down resistor ensures a disabled test functionality during normal
operation (TST = 0).
The transmission is started after enabling the PLL (TRX_CMD = PLL_ON) and writing
the TX_START command to register 0x02.
The detailed programming sequence is shown in Figure A-1.
87
5131E-MCU Wireless-02/09
Figure A-1. Programming Sequence - Continuous Transmission
1
RESET
2
Set IRQ_MASK register
3
Set TRX_STATE register
4
Set CLKM
5
Set channel (fCH)
6
Set TX output power
7
Verify TRX_OFF state
8
Load TX Frame to Frame Buffer
9
Configure continuous TX (1)
Write 0x01 to register 0x0E
(enable PLL_LOCK)
Write 0x03 to register 0x02
(state = FORCE_TRX_OFF)
Write 0x10 to register 0x03
Write 0x33 to register 0x08
Write 0x00 to register 0x05
(maximum TX output power)
Read register 0x01
0x08
Frame download
Write 0x0F to register 0x36
Write f_word to register 0x3D
10
Configure continuous TX (2)
11
Enable continuous TX Test Mode
12
Set TRX_STATE register
13
Interrupt: PLL_LOCK
14
Set TRX_STATE register
15
Modulated (fCH):
CW (fCH - 2.0MHz):
CW (fCH - 0.5MHz):
CW (fCH + 0.5MHz):
f_word = 0x00
f_word = 0x10
f_word = 0x80
f_word = 0xC0
Set pin TST = H
(TST = H)
Write 0x09 to register 0x02
(state = PLL_ON)
Read register 0x0F
(IRQ1)
0x01
Write 0x02 to register 0x02
(state = TX_START)
Signal Measurement
(use RFP|RFN)
16
Reset TST for Normal Operation
17
RESET
Set pin TST = L
(TST = L)
Legend:
Required setting
Optional setting
TST pin setting
Special settings for Continuous TX
A.3 - Disclaimer
The functionality of the Continuous Transmit Mode is not characterized by Atmel and
therefore not guaranteed.
The normal operation of the AT86RF230 is only guaranteed if pin TST is always logic
low.
88
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Appendix B - Errata
AT86RF230 Rev. B
No known errata.
AT86RF230 Rev. A
1. Data frames with destination address=0xFFFF is acknowledged in RX_AACK
According to IEEE 802.15.4-2003 data frames with destination address=0xFFFF
(broadcast) should not have the acknowledgment request subfield set in the frame
control field. If such a non-standard compliant data frame arrives, a device in
RX_AACK state acknowledges that frame.
Fix/Workaround
Use only standard compliant frames, i.e. do not initiate frames with destination
address=0xFFFF (broadcast) and the acknowledgment request subfield set.
2. Frame upload in RX_AACK
The following frames are not uploaded:
(1) Data frames and command frames with destination PAN ID=0xFFFF and
extended destination addressing mode
(2) Beacon frames, when the PAN ID of the receiving node is set to 0xFFFF.
Fix/Workaround
(1) Use Basic Operating Mode for orphan scanning
(2) Use Basic Operating Mode for network scanning
3. TX_ARET returns TRAC_STATUS=SUCCESS even though transaction failed
It might happen that under very special conditions (e.g. noisy network environment)
the status bit TRAC_STATUS (register 0x02) after transmission of a frame is
SUCCESS even though the transaction failed.
Example
A node transmits a frame with the acknowledgment request subfield set to logic high
and waits for an incoming ACK. If no frame is received at the end of the ACK wait
period (54 symbols), but a valid preamble is detected (e.g. jammer/interferer signal),
the TX_ARET procedure is finished immediately. A TRX_END interrupt is generated.
The TRAC_STATUS is not updated and thus shows the default value SUCCESS.
Fix/Workaround
The workaround comprises two changes:
1.
2.
Set register bits MAX_FRAME_RETRIES to 0. This prevents any
retransmissions in the TX_ARET procedure. The frame retransmission has to
be implemented in S/W. A retransmission does not require a frame download
again, only TX_START command is necessary.
Control of the TX_ARET procedure should follow these steps:
o TRX_STATUS == TX_ARET_ON
o set TRX_CMD = TX_START and download frame
o poll for TRX_STATUS == BUSY_TX_ARET
89
5131E-MCU Wireless-02/09
o set TRX_CMD = RX_ON
o wait for TRX_END IRQ
o read TRAC_STATUS
o set TRX_CMD = TX_ARET_ON
o poll for TRX_STATUS == TX_ARET_ON
Switching to RX_ON is not executed during BUSY_TX_ARET but immediately after
BUSY_TX_ARET has completed. This enables the receiver to receive a frame which
arrives shortly before the end of the ACK wait period. In this case TRAC_STATUS is
not accidentally set to SUCCESS and is still correct (NO_ACK), as long as the frame
is received. That means the software has additional time to read the
TRAC_STATUS.
Using the workaround mentioned above, the failure occurrence is considerably
reduced. A wrong TRAC_STATUS can still be observed, but very seldom (one of
million transmissions).
4. Sensitivity to continuous wave interferers
Due to the high receiver sensitivity continuous wave interferers may cause
RX_START interrupts. This may result in missed frames since the receiver is kept
busy detecting preambles and SFD. One cause of continuous wave interferers may
be due to crosstalk from clock.
Fix/Workaround
For further details see application note AVR2005 "Design Considerations for the
AT86RF230".
5. TRX_END_IRQ occurs sometimes too late in TX_ARET_ON state
This behavior can be observed, if the procedure TX_ARET performs frame
retransmissions.
Fix/Workaround
Set register bit MAX_FRAME_RETRIES = 0 (register 0x2C) and implement frame
retries by software. A frame retransmission does not require downloading the frame
again, only TX_START command is necessary.
6. TX_ARET ACK wait time too short
The maximum number of symbols waiting for an acknowledgment frame should be
54 symbols as defined in IEEE 802.15.4-2003. The implemented waiting time is
46 symbols.
Fix/Workaround
None
7. CCA Request is not executed
A requested CCA may be rejected without execution. In this case the CCA_DONE bit
indicates “CCA calculation in progress” even though the calculation must be finished
already.
Fix/Workaround
The TRX_STATUS is RX_ON. To initiate a CCA request, switch to PLL_ON state
and back to RX_ON state. Immediately after the state change initiate a CCA request.
It is not necessary to confirm the state changes.
90
AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
References
[1]
IEEE Std 802.15.4-2003: Wireless Medium Access Control (MAC) and Physical
Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks
(LR-WPANs)
[2]
ANSI / ESD-STM5.1-2001: ESD Association Standard Test Method for
electrostatic discharge sensitivity testing – Human Body Model (HBM)
[3]
ESD-STM5.3.1-1999: ESD Association Standard Test Method for electrostatic
discharge sensitivity testing – Charged Device Model (CDM)
91
5131E-MCU Wireless-02/09
Data Sheet Revision History
Rev. 5131E-ZIGB-02/04/09
1. Removed PRELIMINARY statement
2. Updated parameter 11.4.4
3. Minor editorial changes
Rev. 5131D-ZIGB-12/03/07
The AT86RF230 data sheet was fully revised and modifications of silicon revision
AT86RF230 Rev. B were incorporated. A migration note of silicon revision A to revision
B is available on www.atmel.com.
The most important modifications are:
4. Device version number in register 0x1D (VERSION_NUM) changed to 2 (section 6.3)
5. SPI Interface: MISO pin is updated on falling edge at pin SCLK (section 6.1)
6. Extended Operating Mode state diagram: State changes towards RX_AACK_ON
and TX_ARET_ON (Figure 7-5)
7. Enhanced return code of TX_ARET transaction in register bits TRAC_STATUS of
register 0x02 (section 7.2.3.2)
8. FCS check of received frames in Basic Operating Mode (section 8.2)
9. Support of pending data indication in Extended Operating Mode (sections 7.2.3.1,
7.2.3.2)
10.Update package drawing (section 16)
Rev. 5131C-ZIGB-05/22/07
1. Major revise of sections 1 to 10
2. Added “Appendix A - Continuous Transmission Test Mode”
3. Added “Appendix B - Errata”
Rev. 5131A-ZIGB-06/14/06
1. Initial release
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AT86RF230
5131E-MCU Wireless-02/09
AT86RF230
Table of Contents
1 Pin-out Diagram ..................................................................................2
Disclaimer...............................................................................................2
2 Overview ..............................................................................................2
3 General Circuit Description................................................................3
4 Pin Description....................................................................................4
4.1 Supply and Ground Pins ........................................................................................ 4
4.2 Analog and RF Pins ............................................................................................... 5
4.3 Digital Pins.............................................................................................................. 6
4.3.1 Driver Strength Settings of Digital Output Pins.............................................................. 6
4.3.2 Pull-up and Pull-down Configuration of Digital Input Pins.............................................. 7
4.3.3 Register Description ...................................................................................................... 7
5 Application Circuit ..............................................................................8
6 Microcontroller Interface ..................................................................10
6.1 SPI Timing Description......................................................................................... 11
6.2 SPI Protocol.......................................................................................................... 12
6.2.1 Register Access Mode................................................................................................. 12
6.2.2 Frame Buffer Access Modes ....................................................................................... 13
6.2.3 SRAM Access Mode.................................................................................................... 14
6.3 Radio Transceiver Identification ........................................................................... 16
6.3.1 Register Description .................................................................................................... 16
6.4 Sleep/Wake-up and Transmit Signal (SLP_TR)................................................... 17
6.5 Interrupt Logic....................................................................................................... 19
6.5.1 Overview ..................................................................................................................... 19
6.5.2 Register Description .................................................................................................... 20
7 Operating Modes...............................................................................21
7.1 Basic Operating Mode.......................................................................................... 21
7.1.1 State Control ............................................................................................................... 21
7.1.2 Basic Operating Mode Description .............................................................................. 22
7.1.3 Interrupt Handling in Basic Operating Mode................................................................ 24
7.1.4 Basic Mode Timing ...................................................................................................... 25
7.1.5 Register Description .................................................................................................... 27
7.2 Extended Operating Mode ................................................................................... 29
7.2.1 State Control ............................................................................................................... 31
7.2.2 Configuration ............................................................................................................... 32
7.2.3 Extended Operating Mode Description........................................................................ 33
7.2.4 Interrupt Handling in Extended Operating Mode ......................................................... 37
7.2.5 Register Summary....................................................................................................... 38
7.2.6 Register Description – Control Registers..................................................................... 38
7.2.7 Register Description – Address Registers ................................................................... 42
8 Functional Description .....................................................................45
8.1 Introduction - Frame Format................................................................................. 45
8.1.1 PHY Protocol Layer Data Unit (PPDU)........................................................................ 45
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8.1.2 MAC Protocol Layer Data Unit (MPDU)....................................................................... 46
8.2 Frame Check Sequence (FCS) ............................................................................ 48
8.2.2 CRC calculation........................................................................................................... 48
8.2.3 Automatic FCS generation .......................................................................................... 49
8.2.4 Automatic FCS check .................................................................................................. 49
8.2.5 Register Description .................................................................................................... 49
8.3 Energy Detection (ED) ......................................................................................... 50
8.3.1 Overview ..................................................................................................................... 50
8.3.2 Request an ED Measurement ..................................................................................... 50
8.3.3 Data Interpretation....................................................................................................... 51
8.3.4 Register Description .................................................................................................... 51
8.4 Received Signal Strength Indicator (RSSI) .......................................................... 51
8.4.1 Overview ..................................................................................................................... 52
8.4.2 Reading RSSI.............................................................................................................. 52
8.4.3 Data Interpretation....................................................................................................... 52
8.4.4 Register Description .................................................................................................... 52
8.5 Link Quality Indication (LQI) ................................................................................. 53
8.5.1 Overview ..................................................................................................................... 53
8.5.2 Request an LQI Measurement .................................................................................... 53
8.5.3 Data Interpretation....................................................................................................... 54
8.6 Clear Channel Assessment (CCA)....................................................................... 54
8.6.1 Overview ..................................................................................................................... 54
8.6.2 CCA Configuration and Request ................................................................................. 55
8.6.3 Data Interpretation....................................................................................................... 55
8.6.4 Register Description .................................................................................................... 55
9 Module Description...........................................................................58
9.1 Receiver (RX) ....................................................................................................... 58
9.1.1 Overview ..................................................................................................................... 58
9.1.2 Configuration ............................................................................................................... 58
9.2 Transmitter (TX) ................................................................................................... 58
9.2.1 Overview ..................................................................................................................... 58
9.2.2 Configuration ............................................................................................................... 59
9.2.3 Register Description .................................................................................................... 59
9.3 Frame Buffer......................................................................................................... 60
9.3.1 Frame Buffer Data Management ................................................................................. 60
9.3.2 User accessible Frame Content .................................................................................. 60
9.3.3 Frame Buffer Interrupt Handling .................................................................................. 61
9.4 Voltage Regulators (AVREG, DVREG)................................................................ 62
9.4.1 Overview ..................................................................................................................... 62
9.4.2 Configure the Voltage Regulators ............................................................................... 63
9.4.3 Data Interpretation....................................................................................................... 63
9.4.4 Register Description .................................................................................................... 63
9.5 Battery Monitor (BATMON) .................................................................................. 64
9.5.1 Overview ..................................................................................................................... 64
9.5.2 Data Interpretation....................................................................................................... 65
9.5.3 BATMON Interrupt Handling........................................................................................ 65
9.5.4 Register Description .................................................................................................... 65
9.6 Crystal Oscillator (XOSC)..................................................................................... 66
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9.6.1 Overview ..................................................................................................................... 67
9.6.2 Integrated Oscillator Setup .......................................................................................... 67
9.6.3 External Reference Frequency Setup.......................................................................... 68
9.6.4 Master Clock Signal Output (CLKM)............................................................................ 68
9.6.5 Register Description .................................................................................................... 69
9.7 Frequency Synthesizer (PLL)............................................................................... 71
9.7.1 Overview ..................................................................................................................... 71
9.7.2 RF Channel Selection.................................................................................................. 71
9.7.3 Calibration Loops ........................................................................................................ 71
9.7.4 PLL Interrupt Handling................................................................................................. 72
9.7.5 Register Description .................................................................................................... 72
9.8 Automatic Filter Tuning (FTN) .............................................................................. 74
10 Radio Transceiver Usage ...............................................................75
10.1 Frame Receive Procedure ................................................................................. 75
10.2 Frame Transmit Procedure ................................................................................ 75
11 Technical Parameters .....................................................................77
11.1 Absolute Maximum Ratings................................................................................ 77
11.2 Recommended Operating Range ...................................................................... 77
11.3 Digital Pin Specifications .................................................................................... 77
11.4 Digital Interface Timing Specifications ............................................................... 78
11.5 General RF Specifications.................................................................................. 78
11.6 Transmitter Specifications .................................................................................. 79
11.7 Receiver Specifications ...................................................................................... 79
11.8 Current Consumption Specifications.................................................................. 80
11.9 Crystal Parameter Requirements ....................................................................... 80
12 Register Reference .........................................................................81
Abbreviations .......................................................................................83
13 Ordering Information ......................................................................85
14 Soldering Information.....................................................................85
15 Package Thermal Properties..........................................................85
16 Package Drawing – 32QN1 .............................................................86
Appendix A - Continuous Transmission Test Mode .........................87
A.1 - Overview ............................................................................................................ 87
A.2 - Configuration...................................................................................................... 87
A.3 - Disclaimer .......................................................................................................... 88
Appendix B - Errata .............................................................................89
AT86RF230 Rev. B .................................................................................................... 89
AT86RF230 Rev. A .................................................................................................... 89
References............................................................................................91
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Data Sheet Revision History ...............................................................92
Rev. 5131D-ZIGB-12/03/07........................................................................................ 92
Rev. 5131C-ZIGB-05/22/07........................................................................................ 92
Rev. 5131A-ZIGB-06/14/06........................................................................................ 92
Table of Contents.................................................................................93
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Disclaimer
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