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Features
* * * * * * * *
Multiband Transceiver: 400 MHz to 950 MHz Monochip RF Solution: Transmitter-Receiver-Synthesizer Integrated PLL and VCO: No External Coil Very Resistant to Interferers by Design Digital Channel Selection 200 Hz Steps Data Rates up to 64 kbps with Data Clock and no Manchester Encoding Required High Output Power Allowing Very Low Cost Printed Antennas: - +10 dBm in the 915 MHz Frequency Band - +12 dBm in the 868 MHz Frequency Band - +14 dBm in the 433 MHz Frequency Band * FSK Modulation: Integrated Modulator and Demodulator * Power Savings: - Stand Alone "Sleep" Mode and "Wake-up" Procedures - 8 Selectable Digital Levels for Output Power - High Data Rate and Fast Settling Time of the PLL - Oscillator Running Mode "Ready to Start" - Analog FSK Discriminator Allowing Measurement and Correction of Frequency Drifts * 100% Digital Interface through R/W Registers Including: - Digital RSSI - VCC Readout
FSK Transceiver for ISM Radio Applications AT86RF211 (aka: TRX01)
Description
The AT86RF211 (aka: TRX01) is a single chip transceiver dedicated to low power wireless applications, optimized for licence-free ISM band operations from 400 MHz to 950 MHz. Its flexibility and unique level of integration make it a natural choice for any system related to telemetry, remote controls, alarms, radio modems, Automatic Meter Reading, hand held terminals, high-tech toys, etc. The AT86RF211 makes bidirectional communications affordable for applications such as secured transmissions with hand-shake procedures, new features and services, etc. The AT86RF211 can easily be configured to provide the optimal solution for the user's application: choice of external filters vs. technical requirements (bandwidth, selectivity, immunity, range, etc), and software protocol (single channel, multiple channel, FHSS). The AT86RF211 is also well adapted to battery operated systems, as it can be powered with only 2.4V. It also offers a "Wake Up" receiver feature to save power by alerting the associated microcontroller only when a valid inquiry is detected.
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General Overview
General Overview of Functioning
The AT86RF211 is a microcontroller RF peripheral: all the user has to do is to write/read registers to setup the chip (i.e. frequency selection) or have information about parameters such as RSSI level, Vbattery, PLL lock state. All these operations are carried out via a three-wire serial interface. The chip is set-up by the microcontroller: frequency and mode (Rx or Tx). Then it acts like a "pipe": any data entering DATAMSG is immediately radiated (Tx) or any wanted signal collected by the aerial is demodulated, transferred to the microcontroller by the same pin DATAMSG (Rx) as reshaped bits. No data is stored or processed into the chip. See Figure 1.
Note: In Rx mode, a clock recovery DATACLK is available on the digital interface to provide the microcontroller with a synchronization signal.
Normal Mode
Wake-up Mode
The chip is set up in a special Rx mode called sleep mode. The chip wakes up periodically thanks to its internal timer (stand alone procedure, the microcontroller is in powerdown mode), waiting for an expected message previously defined. If no correct sequence is received, the periodic scan continues. If a correct message is detected, its data field is stored into the AT86RF211 (up to 32 bits) and an interrupt is generated on the WAKEUP pin. See Figure 2 and Figure 3.
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Figure 1. Reception and Transmit Mode
F = Frequency of transmitted signal
AT86RF211 (TRX01) SLE, SCK, SDATA (for set-up) Transmit mode 3 AT86RF211 acts like a "pipe" (data is transmitted with NO processing): automatic data to frequency conversion. - DATAMSG = 0: F = F0 - DATAMSG = 1: F = F1
Companion Microcontroller
DATAMSG
F = Frequency of received signal
AT86RF211 (TRX01) SLE, SCK, SDATA (for set-up) Receive mode 3 AT86RF211 also acts like a "pipe": data (collected by the antenna) is available on pin DATAMSG: DATACLK DATAMSG
Companion Microcontroller
DATAMSG
DATACLK
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Figure 2. Wake-up Overview
Header + Address
Step 2: The chip wakes-up periodically, waiting for an expected message (stand-alone operation) Step 1: The chip is set up in sleep mode using the 3-wire interface (SLE, SCK, SDATA), then Microcontroller goes to sleep, waiting for an interrupt on WAKEUP pin Data stored 3 AT86RF211 (TRX01)
Data field
Wake-up mode
Companion Microcontroller
WAKEUP pin
Step 3: If a correct header is received (mandatory) and address matches (if any), the data field is then stored into AT86RF211 and WAKEUP pin is activated (to wake-up the Microcontroller). The Microcontroller will then read the data into one of its registers, and begin a relevant procedure. Note: Data field is optional: the chip can be simply woken-up with no dedicated data.
Figure 3. Periodical Scan
Power Consumption Reception mode Short reception window
Oscillator settling
Sleep mode Wake Up period Timing
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Block Diagram
Figure 4. AT86RF211 Block Diagram
Optional
RF FILTER
These are the only blocks that depend on the selected ISM band (433, 868 or 915 MHz): dual band applications can be done by only switching them. Synthesizer, loop filter, IF filter(s), power supply decoupling are identical.
IF1 FILTER 10.7 MHz or 21.4 MHz
IF2 FILTER 455 kHz
AERIAL MATCHING CIRCUIT
TX/RX
LNA
MIXER1
IF1 AMP
MIXER2
IF2 AMP FM DISCRIMINATOR OPTIONAL FILTER
Rx
GAIN MIN/MAX
RSSI LEVEL
BANDWIDTH CTRL
TX PA
SYNTHESIZER
DATA SLICER FREQUENCY CTRL
RPOWER CONTROL LOGIC PWR CTRL OSC WAKE-UP
10.245 MHz or 20.945 MHz
DATA DATA SLE SDATA SCK MSG CLK
WAKE-UP
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Pin Description
Table 1. Pinout
Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Notes: Name RPOWER TXGND1 RF TXGND2 TXGND3 TXGND4 TXVCC TXGND5 DIGND DIVCC DATAMSG SLE SCK SDATA WAKEUP DATACLK - EVCC1 EGND1 - CGND1 CVCC1 XTAL1 XTAL2 Comments Full scale output power resistor GND RF input/output GND GND GND VCC GND GND VCC Input/output digital message Serial interface enable Serial interface clock Serial interface data Wake-up output Data clock recovery Test pin: do not connect VCC GND Test pin: do not connect GND VCC Crystal input Crystal output Pin 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Name SKFILT DSIN DISCOUT IF2VCC IF2GND IF2IN IF2DEC DISCFILT IF2OUT IF1DEC IF1IN IF1OUT AGND AVCC CVCC2 CGND2 FILT1 VCOIN EVCC2 EGND2 RXIN RXVCC RXGND SWOUT Comments Threshold for data slicer Data slicer input Discriminator output VCC GND IF2 amplifier input 2.2 nF to ground Discriminator bypass IF2 mixer output 4.7 nF to ground IF1 amplifier input IF1 mixer output GND VCC VCC GND Synthesizer output Synthesizer input (VCO) VCC GND LNA input from SAW filter VCC GND Switch output
1. All VCC pins must be connected in each functional mode (Tx, Rx, wake-up, PDN) 2. To be connected: Rx mode only, all but: 1, 3, 17, 20, 48 Tx mode only, all but: 15 to 17, 20, 25 to 27, 30 to 36, 45, 48 3. Pin 20 must remain unconnected or connected to ground
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Detailed Description
Frequency Synthesis
Crystal Reference Oscillator The reference clock is based on a classical Colpitts architecture with three external capacitors. An XTAL with load capacitor in the range of 10 pF - 20 pF is recommended. The bias circuitry of the oscillator is optimized to produce a low drive level for the XTAL. This reduces XTAL aging. Any standard, parallel mode 10.245 MHz or 20.945 MHz crystal can be used.
Note: The PLL is activated only when the oscillator is stabilized.
Figure 5. Crystal Oscillator Inputs
XTAL1
XTAL2
Figure 6. Typical Networks
XTAL1 C1 = 82 pF XTAL2 XTAL1 C1 = 68 pF XTAL2
CL = 16 pF (1) C2 = 56 pF 15 pF 6.5/30 pF (2)
CL = 20 pF
(1) C2 = 68 pF
33 pF
6.5/30 pF
(2)
Notes:
1. Various load capacitance (CL) crystals can be used. In case CL differs of 16 pF or 20 pF, the surrounding network (C1, C2) must be re-calculated. 2. Thanks to the fine steps of the synthesizer (200 Hz), the trimmer capacitor can be replaced by a software adjustment.
Synthesizer
A high-speed, high-resolution multi-loop synthesizer is integrated. The synthesizer can operate within two frequency bands: 400 MHz to 480 MHz and 800 MHz to 950 MHz. All channels in these two bands can be selected through software programming (registers F0 to F3). All circuitry is on-chip with the exception of the PLL loop filter. The phase comparison is made thanks to a charge pump topology. Typical charge pump current is 225 A.
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Figure 7. Synthesizer Loop Filter Schematic
VCO PFD & CHP Fref
FILT1
VCOIN
Note:
The PLL loop filter can be designed to optimize the phase noise around the carrier. Three configurations can be suggested, regarding the application and channel spacing: - Narrow band: (14.7 k + 2.2 nF) // 220 pF - Typical: (3.3 k + 5.6 nF) // 560 pF - High datarates: (10 k + 1 nF) // 100 pF
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Receiver Description
Figure 8. Typical Expected Currents in Rx Mode
Supply Current - Rx Mode
32.00
868 or 915 MHz
Isupply (mA)
30.00
433 MHz
28.00
26.00 2.25 2.50 2.75 3.00 3.25 Vsupply (V) 3.50 3.75 4.00 4.25
Detailed Current - Rx Mode
10.00 EVCC2
Supply Currents (mA)
8.00
6.00 EVCC1 RXVCC 4.00 CVCC2 CVCC1 AVCC DIVCC IF2VCC TXVCC 4.25
2.00
0.00 2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
Vsupply (V)
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Overview and Choice of Intermediate Frequencies
For selectivity and flexibility purpose, a classical and robust 2 IF superheterodyne architecture has been selected for the AT86RF211. In order to minimize the external components cost, the most popular IF values have been chosen. The impedances of the input/output of the mixing stages have been internally matched to the most usual ceramic filter impedances. Two typical IF values are suggested: * * 10.7 MHz is the most popular option. 21.4 MHz: the image frequency is far enough from the carrier frequency to enable the use of a front-end ceramic filter instead of a SAW filter. It is also noticeable that 21.4 MHz quartz filters usually have more abrupt slopes than 10.7 MHz ceramic filters.
Rx - Tx Switch
A SPST switch is integrated. In the transmission mode, it protects the LNA input from the large voltage swings of the PA output (up to several volts peak-to-peak), which is switched to a high impedance state. It is automatically turned ON or OFF by the RX/TX control bit. The insertion loss is about 2 dB and the reverse isolation about 30 dB in a 300 environment. The immunity of the AT86RF211 can be improved with an external band-pass filter. For example, when using a SAW Filter, this device must be matched with the LNA input and the switch output. The following scheme gives the typical implementation for an 868 MHz application with a 50/50 SAW filter.
Image Rejection and RF Filter
Figure 9. Typical 50 SAW Filter Implementation in the 868 MHz Band
These inductors can be printed
SWOUT (pin 48) SPST Switch
2.2 nH SAW
50
12 nH RXIN (pin 45)
See Table 2 for precise matching information. The SAW filter can be replaced by a TEM ceramic, helicoidal or a ceramic coax /4 resonator designed as a narrow band-pass filter. For instance, with an IF selected at 10.7 MHz, a -3 dB bandwidth of 5 MHz, with an insertion loss of 1 dB and an image rejection of 12 dB can be achieved with the following:
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Figure 10. TEM Filter
1 pF 1 pF
/4 TEM
Zc = 7 l = 0.75 (19 mm)
Such a filter also provides an out-of-band interference rejection greater than 20dB, 40 MHz away from 433 MHz. First LNA/Mixer The main characteristics of the LNA/Mixer are typically: * * * * Voltage gain: 17 dB for the LNA/Mixer; 11 dB if gain min. is selected Bandwidth: 1.2 GHz Noise figure of LNA alone: 3 dB at 900 MHz, best matching Noise figure of LNA + mixer: 8 dB at 900 MHz, with maximum gain and best matching 12 dB at 900 MHz, with minimum gain and best matching 1 dB compression point: -20 dBm at the input of LNA Matching:
* *
Table 2. Matching Information
Frequency Band 433 MHz 868 MHz 915 MHz Notes: RXIN(1) 35 + j 170 37 + j 85 30 + j 85 SWOUT(2) 24 - j 43 50 - j 42 50 - j 42
1. RXIN: impedance to be seen by LNA input for NF optimization purpose 2. SWOUT: output impedance of the RF switch
The gain is programmable through bit 25 of CTRL1 register (6dB attenuation when min gain is selected). The choice for the matching between the SWITCH and the LNA depends mainly on the chosen SAW filter. Usually in/out impedance of SAW filters is 50, but other ones can be implemented and the matching network recalculated thanks to the previous impedance table. The LNA is directly coupled to the first mixer. Input and output of the LNA/Mixer must be connected through a capacitive link because of their internal DC coupling. A SAW or ceramic filter provides such a link.
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Figure 11. Schematic Input of the LNA
RXIN
Figure 12. Schematic Output of the Mixer
IF1OUT
The first mixer translates the input RF signal down to 10.7 MHz or 21.4 MHz as chosen by the user. The local oscillator is provided by the same synthesizer which will generate a local frequency 10.7 MHz or 21.4 MHz away from the Tx carrier frequency. The output impedance of the mixer is 330 with a 20% accuracy, so that low cost, standard 10.7 MHz ceramic filters can be directly driven. Other IFs may be chosen thanks to the high bandwidth (50 MHz) of the mixer. IF1 filtering A popular ceramic filter is used to reject the second image frequency and provide a first level of filtering. The IF1 filter can however be removed; it leads to a sensitivity reduction of about 3 dB (the substitution coupling capacitor should be > 100 pF). IF1 Gain and Second Mixer The input impedance of the IF1 amplifier is naturally 330 to match the input filter. The voltage gain, i.e. gain at 10.7 MHz or 21.4 MHz added to the conversion gain at 455 kHz is typically 14 dB when loaded by 1700. The second mixer operates at a fixed LO frequency of 10.245 MHz or 20.945 MHz. Its output impedance is 1700 in parallel with 20 pF.
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Figure 13. IF1 Filtering
IF1 Filter IF1OUT (pin 36) "or" 330 330 IF1IN (pin 35)
C > 100 pF
Figure 14. Schematic Input of IF1 Amplifier
IF1IN
330
20 k IF1DEC
Figure 15. Schematic Output of the Second Mixer
1600
IF2OUT
IF2 Filtering and Gain
IF2 filtering achieves a narrow channel selection. In case it is not used, it should be replaced by a > 1 nF coupling capacitor, thus the IF1 filter is the only part achieving the channel selection. Available commercial filters with a 35 kHz BW allow data rates up to 19.6 kbps if crystal temperature drifts are very low. For faster communications and/or wider channelization, this ceramic filter can be replaced by an LC band-pass filter as proposed hereafter.
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Figure 16. LC Band-pass Filter
10 nF 10 nF
F1
F2
Filter gain global response
Frequency ~ F1 ~ F2
40 kHz or higher
* * * IF2 Amplifier Chain
10 nF capacitors cut DC response forward and backward. The first network has the low cut-off frequency. The second network has the high cut-off frequency.
The input impedance of the IF2 amplifier is 1700. This value enables the use of popular filters with impedance between 1500 and 2000. It is directly connected to the FSK demodulator. The bandwidth is internally limited to 1 MHz to minimize the noise before the discriminator. It acts like a band pass filter centered at 455 kHz with capacitive coupling between stages of amplifier and mixer. Total voltage gain is typically 86 dB. Thanks to the capacitive coupling, no slow DC feedback loop is needed enabling a fast turn on time. IF2DEC has to be decoupled with at least 2.2 nF. Figure 17. Input of the IF2 Amplifier Schematic
IF2IN
1900
IF2DEC
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RSSI Output The RSSI value can be read as a 6 bits word in the STATUS register. Its value is linear in dB as plotted below:
Figure 18. Typical RSSI output (board implementation, T = 25C, VCC = 3V)
RSSI Output
70 60 50
RSSI Code
Dispersion: +/-5dB
40 30 20 10 0 -110 -100 -90 -80 -70 -60 -50 -40 -30 Power Level at Antenna Input Port (dBm)
Dynam ic Range: 50dB
Note:
Should the RSSI be required for accurate measurement purpose (precision better than 5 dB), then it is possible to measure one value with a calibrated RF source and store it into the microcontroller, during the production testing.
The RSSI dynamic range is 50 dB from -95 dBm to -45 dBm RF input signal power, over temperature and power supply ranges. The RSSI LSB's value weighs about 1.3 dB in the linear area. The RSSI value is measured from the IF2 chain. The RSSI is periodically measured thanks to a successive approximation ADC with a 12 s clock. Thereafter, the time needed to complete the right code depends on the power step: a 10 dB step on the aerial leads to a 10/1.3 = 8 clock cycles, i.e. 96 s (full range from code 0 to 63 = 756 s). Its value can be compared with a user predefined value (TRSSI), so that the demodulated data is enabled only if the RSSI value is above this threshold. Some hysteresis effect may be added (see CTRL1 register's content). The AT86RF211 also has the possibility to measure another voltage. The ADC measuring the RSSI can be turned into voltage or discriminator output DC level measurement.
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Figure 19. ADC Converter Input Selection
STATUS register RSSI M U Voltage X ADC M U X MVCC MRSSI
Vcc supply DISCOUT (MOFFSET)
M U X
CTRL1[1] CTRL1[24]
Note: For voltage measurement, the LSB weighs 85 mV and the reference voltage is 1.25V.
The ADC measuring the RSSI can be turned into voltage or discriminator output DC level measurement. FSK Demodulator Its structure is based on an oscillator: Figure 20. Schematic of the FSK demodulator
Fin oscillator A
RBW
B FD
C
The oscillator's natural frequency is FD and it actually oscillates at the Fin frequency. The signal at the output of the oscillator (point A) is proportional to the frequency difference between Fin and FD. The XOR function translates the difference into a pulse duty cycle (point B).Thereafter by low-pass filtering of the signal is obtained a mean voltage of the signal (point C). The architecture of this demodulation is thereby analog and allows the transmission of continuous data stream of the same value as the output voltage is proportional to the input frequency. Thus it is not mandatory to use Manchester encoding and the first bit is correctly demodulated. The oscillator feedback resistor controls the center frequency FD. It is adjusted according to the output of a dummy FSK demodulator driven by a 455 kHz internal reference frequency which is a division of the reference crystal. The discrete components connected to pin 32 DISCFILT are the loop filter of the PLL stabilizing the 455 kHz signal.
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The input RBW resistor controls the discriminator bandwidth. This bandwidth is selected by CTRL1[6]. The default value is "standard discriminator BW". The slope of the discriminator increases by 5 mV/kHz/V with VCC and is 14 mV at 2.4V. Example: VCC = 3V implies +17 mV/kHz sensitivity for the demodulator VCC = 3.6V implies +20 mV/kHz sensitivity for the demodulator Data Slicer The analog signals at the output of the discriminator (DISCOUT, pin 27) are converted into CMOS level data by a high resolution comparator called a Data Slicer. The Data Slicer has a reference for its comparator which can be chosen thanks to CTRL1[4]. The reference sets the comparison level of the comparator. One option is to extract the average value of the demodulated signal on the SKFILT pin (25), this is the external mode. The other option is to set an absolute value for this reference (internal mode). * External mode:
The external mode uses the average value of the demodulated signal as the comparison level for the comparator. Thus there must be enough transitions in the message to ensure that the average value remains between the "0" level and the "1" level. Manchester encoding can be used in this mode as well as DC-free encoding schemes. The choice for SKFILT capacitor is a trade-off between the maximum duration of a constant bit (whatever "0" or "1") and the max allowed settling time to charge this capacitor after powering up.
Note: The SKFILT pin is in high impedance state during the "sleep" period of the Wake Up mode, so that the level is kept constant and there is no need to charge again this tank.
*
Internal mode:
The internal mode uses the output of a DAC as the comparison level. Once this threshold has been correctly set, an "absolute" data slicing of the demodulated signal is possible: no need for DC-free modulation scheme (it is possible to send a "0" or "1" infinitely). Figure 21. Schematic of the Data Slicer
DISCOUT
+ -
DATAMSG
+ + -
DSIN 4 bits
+
+
Choice of internal or external reference for the data slicer
Vdd/2
100 k
SKFILT
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To operate this way, the user must make sure that the "0" and "1" level at the output of the discriminator are "on both sides" of the comparison level in order for the decision to be made properly. Figure 22. How to Set Up the Data Slicing Parameters
DISCOUT: demodulated data OK Time
Not OK Comparator threshold
To set the discriminator and the Data Slicer accordingly: - - It is possible to measure the output DC level of the discriminator DISCOUT (thanks to the A/D embedded converter) DTR[1:0] make it possible to shift (up or down) the DC level at the output of the discriminator : - DTR[1] = 1: +180 mV + 77x (VCC - 2.4V) - DTR[0] = 1: -180 mV - 77x (VCC - 2.4V) DTR[5:2] make it possible to tune the comparison threshold around VCC/2. 16 levels are possible, with a LSB = 15 mV per Volt of supply voltage. VCC/2 corresponds to DTR[5:2] = 0111, and the RESET value is 1000.
-
These procedures can be made automatically by software. Please refer to the application note.
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Transmitter Description
Figure 23. Typical Expected Currents in Tx Mode
Supply Current - Tx Mode
65.00 60.00 55.00 50.00 433MHz 915MHz 868MHz
Isupply (mA)
45.00 40.00 35.00 30.00 25.00 20.00 15.00 2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
Vsupply (V)
Detailed Current - Tx Mode
30.00
PA
25.00 Supply Currents (mA)
20.00
TXVCC
15.00
EVCC2
10.00
EVCC1
5.00
0.00 2.25 2.50 2.75 3.00 3.25 Vsupply (V) 3.50 3.75 4.00
CVCC2 CVCC1 RXVCC DIVCC
4.25
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Power Amplification
The Power Amplifier has been built to deliver more than +10 dBm, i.e. 10 mW in the three popular frequency bands. This power level is intended to be measured on the aerial port with a correct output matching network. Note that a correct calculation of the matching network guarantees an optimal power efficiency. Naturally, the greater the PA output voltage swing, the better the power efficiency. As the PA output is supplied through an inductor, a swing of 2 x VDD is possible. In practice, due to saturation effects, the voltage swing is limited to approximately (2 x VDD) - 1V. With a power supply voltage of 3V, the PA output voltage is 5V peak-to-peak, or 1.77 VEFF. Figure 24. Output of the Power Amplifier
The PA must be correctly matched to deliver the best efficiency in terms of output power and current consumption. Here is an example of the typical recommended output network in the 868 MHz band: Figure 25. Output Matching at 868 MHz
Power supply filtering Vcc
12 nH RF PA output 1.5 nH
Supply inductor aerial
~ 50 matched filtering 50
Note: The filter is designed to meet relevant regulations. Please refer to application note for details.
A benefit of this network is to filter the output signal harmonic levels; hence it can be designed to meet a particular regulation. It is mandatory to implement low impedance grounding techniques. Excessive inductor values to ground will not only limit the PA output voltage swing, but may also trigger RF instability. Board design is vital to avoid parasitic loss when high output power is needed (direct short connection to a single low impedance ground plane).
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An automatic level control loop (ALC) is integrated, in order to minimize the sensitivity of the PA to the temperature, process and power supply variations. For instance, at +85C, the output power is about 2 dB less than at 25C. At -40C, the output power is higher than at 25C. The ALC is controlled by a current which is generated in the following way: Figure 26. ALC of the Power Amplifier
V RPOWER IOUT To ALC DAC RPOWER
18 k
(v) U 1.25 V I
iref =
3 bits
digital power control
Figure 27. Typical Output Power of the PA for T = 25C and VCC = 3V
Output Power
14 433MHz 12 868MHz 10 915MHz
Pout (dBm)
8 6 4 2 0 -2 26 31 36 41 46 51 56 61
Isupply (mA)
Hardware Control
The max output power is determined by RPOWER and the maximum output power is obtained with RPOWER = 10 k. 18 k is the nominal value for a +10 dBm output in the 868 MHz frequency band. Decreasing this value to 10 k will lead to +14 dBm at 433 MHz, +12 dBm at 868 MHz, +10 dBm at 915 MHz (typical values for conducted output power).
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Figure 28. RPOWER Input Schematic
100
RPOWER
Note:
Keeping the PA output matched guarantees maximum power efficiency.
Software Control
The power can then be adjusted, from the value set by RPOWER down to a maximum of 12 dB below, by programming the bits 6 to 8 of the CTRL1 register. So, 8 levels are digitally selectable with a variation of the output power. The minimum regulated output power is set to -10 dBm. Table 3. Software Control of the Power Level
TXLVL (CTRL1) 000 001 010 011 100 101 110 111 Note: Pout at 433 MHz (dBm) 0 4 6 8 10 11 12 13 Pout at 868 MHz (dBm) -2 0 3 5 7 8 9 10 Pout at 915 MHz (dBm) -3 0 2 4 5 7 8 9
Unless otherwise specified, typical data given for RPOWER = 18 k, T = 25C, VCC = 3 V
Control Logic
Serial Data Interface The application microcontroller can control and monitor the AT86RF211 through a synchronous, bidirectional, serial interface made of 3 wires: * * * SLE: enable input SCK: clock input SDATA: data in/out
When SLE = `1', the interface is inhibited, i.e. the SCK and SDATA (in) values are not propagated into the IC, reducing the power consumption and preventing any risk of parasitic write or read cycle. A "read" or "write" cycle starts when SLE is set to `0' and stops when SLE is set to `1'. Only one operation can be performed in one access cycle: only one register can be either read or written.
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* Register Interface Format A message is made of 3 fields: - - - address A[3:0]: 4 bits (MSB first) R/W: read/write selection data D[31:0]: up to 32 bits (MSB first)
ADDRESS A[3] A[2] A[1] A[0]
R/W R/W MSB
DATA up to 32 bits (variable length) D[nbit-1:0] LSB
Variable register length and partial read or write cycles are supported. In case of partial read or write cycles, the first data (in or out) is always the MSB of the register. * WRITE Mode (R/W = 1) The address, R/W and data bits are clocked on the rising edge of SCK. If the number of data bits is lower than the register capacity, the LSB bits keep their former value allowing safe partial write. If the number of data bits is greater than the register capacity, the extra bits are ignored. The data is actually written into the register on the rising edge of SLE when the data length is less or equal to the register length. When trying to write more data than the register length, data field is written on the first extra rising clock edge regarding register length. Figure 29. Write Chronogram: Complete Write Cycle in a 10 bits Register
SLE
SCK
SDATA
A[3]
A[2]
A[1]
A[0]
R/W
D[9]
D[8]
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
The complete register of 10 bits is updated on a rising edge of SLE. Figure 30. Write Chronogram: Partial Write Cycle, Writing 2 bits
SLE
SCK
SDATA
A[3]
A[2]
A[1]
A[0]
R/W
D[31] D[30]
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Only the 2 MSBs are updated on the rising edge of SLE; other register bits are unchanged. * READ Mode (R/W = 0) The address and R/W bits are clocked on the rising edge of SCK. The data bits are changed on the falling edge of SCK. The MSB of the register is the first bit read. SDATA I/O pin is switched from input to output on the edge following the "1" clocking the R/W bit. It is possible to stop reading a register (SLE back to "1") at any time. If an attempt to read more bits than the register capacity is detected, SDATA is clamped to "0". If the address of a register is not valid, SDATA is set to "1" during the first 32 SCK periods, then to "0" during all the extra periods. SDATA is switched back to the input state when SLE is back to "1". Figure 31. Read Chronogram: Complete Read Cycle from a 10 bits Register
SLE
SCK
SDATA SDATA direction
A[3]
A[2 ]
A[1]
A[0]
R/W
D[9 ]
D[8]
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
INPUT
OUTPUT
INPUT
Figure 32. Read chronogram: Partial Read Cycle, Reading 2 bits
SLE
SCK
SDATA SDATA mode
A[3] A[2] A[1] A[0] R/W D[31] D[30] INPUT OUTPUT INPUT
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Figure 33. Chronogram with Timing
tdle tdle
SLE T tw tw
SCK tsd thd tpzon tpd tpzd
SDATA
A[3]
A[2]
A[1]
A[0] R/W
D[9 ]
D[8] D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
SDATA direction
INPUT
OUTPUT
INPUT
Note:
For the timing specification, please refer to the timing table "Digital CMOS DC Characteristics" on page 42.
Registers Table 4. Registers Overview
Name F0 F1 F2 F3 CTRL1 STAT DTR WUC WUR WUA WUD RESET CTRL2 Note: Address A[3:0] (0000)2 (0001)2 (0010)2 (0011)2 (0100)2 (0101)2 (0110)2 (0111)2 (1000)2 (1001)2 (1010)2 (1011)2 (1100)2 (1101)2 (1110)2 (1111)2 32 R-W Nbits 32 32 32 32 32 31 6 32 18 25 32 1 Read-Write R-W R-W R-W R-W R-W R R-W R-W R-W R-W R W Comments F0 Frequency Code F1 Frequency Code F2 Frequency Code F3 Frequency Code Main Control Register Status Register Data Slicer Reference/Discriminator offset adjusting Wake-up Control Register Wake-up Data Rate Register Wake-up Address Register Wake-up Data Register Reset Reserved Reserved Reserved Control Register (Lock Detect - Clock Recovery)
All the registers must be reprogrammed after the voltage supply has been removed, otherwise they will be in the default state
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Reset Register (RESET)
Name nbit RESET 0
Writing in this register (0 or 1) triggers an asynchronous reset. This register can only be written. All registers return to reset state. The chip returns in power-down. So all the following blocks are reset: * * * * * * * * * * Control Register (CTRL1) Table 5. CTRL1 Overview
Name nbit init Name nbit init PDN 31 0 TXLVL 14-12 (000)2 RXTX 30 0 TXFS 11 0 10 0 DATACLK 29 0 RXFS 9-8 (10)2 TXLOCK 28 1 XTALFQ 7 0 PAPDN 27 0 FSKBW 6 1 WUEN 26 0 FSKPOL 5 1 LNAGSEL 25 0 DSREF 4 1 MVCC 24 0 3 0 2 0 TRSSI 23-18 (000000)2 HRSSI 17-15 (000)2 0 0
All registers to default value Wake-up function. Clock recovery function. Synthesizer dividers. Clock recovery function. PLL lock detect. From powering up the supplies, it takes about 10 s or at least 1.8V before the reset state is established (Power-on Reset). From reseting the device, one should wait about 10 s before re-programming RSSI detection block. Discriminator clock (455 kHz).
And with the power-down state, reset is applied to the following blocks:
MOFFSET 1 0
Register reset value = (10000270)16
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Table 6. CTRL1 Detailed Description(1)(2)(4)(3)
Name PDN Number of Bits 1 Comments General power-down 0: power down mode; only the serial interface is active 1: AT86RF211 activated reset value: 0 RXTX 1 Reception or transmission selection 0: Rx mode 1: Tx mode reset value: 0 DATACLK 1 DATA clock recovery selection 0: no signal on DATACLK output pin 1: Clock recovery active: DATACLK activated reset value: 0 TXLOCK 1 Transmission on PLL lock 0: transmission enabled, regardless of the PLL lock status 1: transmission only when the PLL is locked reset value: 1 note: the PLL status is stored in the PLLL bit of the STATUS register PAPDN 1 Power amplifier power down 0: Tx Power Amplifier power down mode 1: Tx Power Amplifier activated (only if PDN = 1) reset value: 0 WUEN 1 Wake-up function enable 0: Wake-up function disabled, whatever the content of the wake-up control registers 1: Wake-up function activated, depending on the content of wake-up control registers reset value: 0 LNAGSEL 1 LNA gain selection 0: maximum gain 1: minimum gain reset value: 0 MVCC 1 RSSI or VCC power supply measurement selection 0: RSSI voltage measurement, value is stored in STAT register: MRSSI bits 1: VCC voltage measurement, value is stored in STAT register: MVCC bits reset value: 0 TRSSI 6 RSSI value threshold DATAMSG validated if RSSI TRSSI + HRSSI (high RSSI level) DATAMSG inhibited if RSSI < TRSSI - HRSSI (low RSSI level) reset value: (000000)2 HRSSI TXLVL 3 3 Value RSSI hysteresis reset value: (000)2 Tx PA output power selection (000)2: minimum transmission level (111)2: maximum transmission level reset value: (000)2 TXFS 1 Tx frequency selection 0: F0 & F1 1: F2 & F3 reset value: 0
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Table 6. CTRL1 Detailed Description(1)(2)(4)(3) (Continued)
Name - RXFS Number of Bits 1 2 Comments reserved, must be kept to reset value: 0 RX frequency selection (00)2: F0 (01)2: F1 (10)2: F2 (11)2: F3 reset value: (10)2 XTALFQ 1 Crystal frequency 0: 10.245 MHz (when IF1 = 10.7 MHz) 1: 20.945 MHz (when IF1 = 21.4 MHz) reset value: 0 FSKBW 1 Discriminator range 0: Narrow Discriminator BW 1: Standard Discriminator BW reset value: 1 FSKPOL 1 Polarity of DATAMSG 0: inverted signal 1: direct signal reset value: 1 DSREF 1 Data Slicer reference voltage 0: external reference: SKFILT pin voltage 1: internal reference: DAC level voltage reset value: 1 - - MOFFSET 1 1 1 reserved, must be kept to reset value: 0 reserved, must be kept to reset value: 0 0: internal ADC sets to VCC measurement 1: internal ADC sets to DISCOUT DC level measurement reset value: 0 - Notes: 1 reserved, must be kept to reset value: 0
1. The same ADC is used to measure RSSI or VCC voltage. When the VCC voltage is measured, the RSSI measurement is stopped (previously measured RSSI is kept into STATUS Register). This can disturb the reception process (if a threshold is used for DATAMSG validation). So, it is not recommended to measure VCC in reception mode. 2. VCC measurement can not be done when the AT86RF211 is in power-down mode. 3. While in VCC measurement, it is possible to measure the DC output of the discriminator. 4. Description of RSSI measurement with hysteresis mechanism: if the RSSI measurement is higher than the high RSSI level, DATAMSG is validated (high RSSI level = TRSSI + HRSSI). If the RSSI measure is lower than the low RSSI level, DATAMSG is inhibited (low RSSI level = TRSSI - HRSSI). Between these two levels, DATAMSG validation depends on the previous measurement. Example: TRSSI = 32 and HRSSI = 4 implies High RSSI level = 26 and Low RSSI level = 28
MRSSI sequence RSSI level DATAMSG
27 NOK
32 NOK
35 NOK
36 OK valid
35 OK valid
32 OK valid
29 OK valid
28 OK valid
27 NOK
25 NOK
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Control Register (CTRL2) Table 7. CTRL2 Overview
Name nbit init DATARATE 31-18 (0000)16 DATATOL 17-10 (00)16 LDCK 9 0 N0LD1 8-5 (0010)2 N1LD2 4-0 (10111)2
Register reset value = (00000057)16 Table 8. CTRL2 Detailed Description
Name DATARATE Number of bits 14 Comments Received DATAMSG rate This value must be programmed to have the DATACLK activated. (selected with DATACLK bit in CTRL1 register). Value from 1 kbps to 50 kbps reset value: (0000)16 DATATOL 8 Tolerance for DATACLK, clock recovery Recommended value = 2% of the rate. reset value: (00)16 LDCK 1 Clock frequency is doubled to increase precision of PLL lock detection 0: 10 MHz clock frequency 1: doubled clock frequency reset value: 0 N0LD2 4 PLL unlock condition trigger Recommended values are reset values reset value: (0010)2 N1LD2 5 PLL lock condition trigger Recommended values are reset values reset value: (10111)2
* Clock Recovery Function The clock recovery function is activated by setting to `1' the DATACLK bit of the CTRL1 register. The clock recovery function provides on DATACLK pin the data clock, synchronized on the received data flow. The targeted position for the rising edge of the clock is the middle of the data bit. It is then easy for the microcontroller to read without synchro troubles. Clock recovery mechanism is based on the generation of a basic data clock with a period given by DATARATE of CTRL2 with a step of about 100 ns. This basic clock is synchronized on the received data flow with a phase correction step fixed by DATATOL of CTRL2 register (step of about 100 ns also). So, DATATOL can - - - compensate for the difference between the read data rates from transmitter and receiver (fixed by DATARATE). allow fast initial synchronization of data clock, avoiding bit transition times and converge toward the middle of the bit. keep the right data rate (no additional and no removed bit) when a noisy data with bad bit transition position arrives.
The best value of DATATOL is a trade-off between these considerations. The typical recommended value of RATETOL is 2% of DATARATE.
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If the tolerance is too high, the rate value is reached earlier, and the rate value could be unstable (too big step). If the tolerance is too low, it could be difficult to catch up the DATA and the function could get lost. Notice that maximum acceptable distance between two data transitions depends on the precision of DATARATE versus transmitter actual data rate. Synchronization mechanism is explained with the chronogram hereafter. The synchronization is done for the first bit. In worst case conditions, when data and clock arrive at the same time, it begins at the second bit. Notice that the DATACLK signal is available as soon as the DATACLK bit is programmed, whatever the state of DATAMSG pin. The programmed data rate allows the creation of a basic clock at the programmed DATARATE frequency at the beginning of the reception. Then, the clock is shifted if necessary from the tolerance value, depending on the previous DATA transition: the clock is moved later or sooner, depending on the gap between CLOCK and DATA. For example: if DATARATE = 50 kbps, which is equivalent to a duration of 200 x T for 1 bit, with T = 100 ns = base clock period. if DATATOL = 2% x DATARATE = 4 x T. Figure 34. Clock Recovery
DATAMSG 200T DATACLK Expected value Synchronized values with DATAMSG Expected value Tol = 4T Tol = 4T
* DATARATE Programming This value must be programmed only when the DATA clock is needed on DATACLK output pin of the chip. The DATA rate can be programmed from 1 kbps to 64 kbps with 14 bits of CTRL2 register. DATARATE is the period of the data rate and can be programmed with a resolution given by the crystal oscillator period: * * 10.245 MHz oscillator, period = T = 97.6 ns 20.945 MHz oscillator, period = T = 95.5 ns
Some datarate values with the 10.245 MHz oscillator given for example:
DATARATE[13:0] (160)10 (205)10 (vv)10 (534)10 (1024)10 Rate 64 kbps 50 kbps ...... 19.2 kbps 10 kbps Period 1 bit ~ 160 x T 1 bit ~ 205 x T 1 bit ~ vv x T 1 bit ~ 534 x T 1 bit ~ 1024 x T
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DATARATE[13:0] (1067)10 (2135)10 (4269)10 (10246)10 Rate 9.6 kbps 4.8 kbps 2.4 kbps 1 kbps Period 1 bit ~ 1067 x T 1 bit ~ 2135 x T 1 bit ~ 4269 x T 1 bit ~ 10246 x T
* Datatol Programming The tolerance for the extraction of DATA rate must be nearly 2% of the RATE. The tolerance represents the step for the calculation of the rate. If the tolerance is too high, rate value is reached earlier but the rate value could be unstable (step too big). If the tolerance is too low, it could be difficult to catch up the DATA and the clock recovery could get lost. Some tolerance values given for example, with tolerance = 2% x DATARATE:
DATATOL[7:0] (3)10 (4)10 (vv)10 (20)10 (21)10 (43)10 (85)10 (205)10 Rate 64 kbps 50 kbps ...... 10 kbps 9.6 kbps 4.8 kbps 2.4 kbps 1 kbps Period 1 bit ~ 3 x T 1 bit ~ 4 x T 1 bit ~ vv x T 1 bit ~ 20 x T 1 bit ~ 21 x T 1 bit ~ 43 x T 1 bit ~ 85 x T 1 bit ~ 205 x T
* PLL Lock Detect The PLL lock function uses UP and DOWN signals from the internal phase detector. These signals are analyzed synchronously with a clock frequency, depending of LDCK bit programming (10 MHz or 20 MHz sampling). LDCK is set to `1' to double the clock frequency of the function PLL lock detect, to increase the precision of the function. N0LD2 triggers the unlock condition of the PLL. N0LD2 = number of consecutive edges of the sampling clock with UP and DOWN active before considering PLL unlocked. This value must not be set to 0 or 1. The recommended value is default value, i.e. 2. N1LD2 triggers the lock condition of the PLL. N1LD2 = number of cycle at the PLL reference frequency, without any unlock condition before considering PLL locked. This value must not be set to 0. It is recommended to use default values indicated in the table.
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Frequency Registers
Table 9. Frequency Registers
Name nbit F0, F1, F2, F3 31-0
Name F0
Number of bits 32
Comments Frequency code value F0 default register in TX mode ("0" code in FSK modulation). Frequency code value F1 default register in TX mode ("1" code frequency in FSK modulation). Frequency code value F2 default register in RX mode. Frequency code value F3
F1
32
F2
32
F3 Note:
32
1. F0, F1, F2 and F3 registers must be programmed before using the device.
There is no simple relationship between frequency registers and the exact frequency. Atmel provides a tool to program them on a production bench.
* Frequency Registers Selection The FSK modulation is completely integrated. Two registers have to be programmed (default F0 and F1) to allow "0" and "1" transmission. The frequency register selection depends on the control register programming and on the DATAMSG pin:
RXTX 0 0 0 0 1 1 1 1 RXFS 00 01 10 11 XX XX XX XX TXFS X X X X 0 0 1 1 DATAMSG X X X X 0 1 0 1 Mode Receive LO is F0 Receive LO is F1 Receive LO is F2 Receive LO is F3 Transmit "0" on F0 Transmit "1" on F1 Transmit "0" on F2 Transmit "1" on F3
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In reception mode, only one frequency needs to be programmed. In transmission mode, two different registers (F0 & F1), or (F2 & F3) must be programmed for "0" code and "1" code transmission. The DATAMSG pin value actually selects the used register. The four registers can also be set to define two channels, so that the AT86RF211 may switch quickly from a channel to the other.
Mode RX TX Programmed Frequency FCHANNEL IF1 FCHANNEL deviation
Example: FCHANNEL = 868.3 MHz IF1 = 10.7 MHz Deviation = 4 kHz
Mode RX TX Notes: FSK 868.3 10.7 = 879 MHz or 857.6 MHz programmed in F2 868.3 0.004 = 868.304 MHz programmed in F1 when DATAMSG = "1" and 868.296 MHz programmed in F0 when DATAMSG = "0" 1. In reception mode, one of the two frequencies (879 MHz or 857.6 MHz) can be chosen, taking into account external parameters (for example, the noise that brings the image frequency). 2. Two frequencies are used to transmit data: 868.304 MHz for "1" transmission and 868.296 MHz for "0" transmission. The polarity of DATAMSG can be swapped using bit 5 of CTRL1.
Status Register
The STATUS register is used to read the status of internal functions (including the wake-up function) or the output value of the internal ADC. This register can only be read. Table 10. Status Register Overview
Name nbit Name nbit PLLL 30 MRSSI 29-24 MSGDATL 14-10 MVCC 23-18 WAKEUP 17 16 MSGMRATE 9-0 MSGERR 15
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Table 11. Status Register Detailed Description
Name PLLL Number of bits 1 Comments PLL Lock flag 0: PLL unlocked 1: PLL locked reset value: 0 MRSSI MVCC 6 6 Measured RSSI level reset value: (00)16 Measured VCC power supply voltage or discriminator output when MOFFSET = 1 reset value: (00)16 WAKEUP flag Copy of the WAKEUP pin, but not affected by polarity selection. 0: no wake-up message received 1: wake-up message received reset value: 0 Reserved reset value: 0 MSGERR 1 Wake-up message error in test message mode 0: no error detected in the received message 1: message received with error reset value: 0 MSGDATL 5 Wake-up message data length length of the data stored in WUD (received message). reset value: 0 Wake-up message measured data rate bit period extracted from message header of the wake-up message. Measured as a multiple of 1.56 s (like RATE in WUR register). 0: 1 x 1.56 s (vv)10: vv x 1.56 s (3ff)16: 1024 x 1.56 s reset value: (000)16
WAKEUP
1
-
1
MSGMRATE
10
DTR Register
The DTR register allows the user to precisely adjust the offset of the data slicer input. Table 12. DTR Overview
Name nbit init DSREF[3:0] 5-2 (1000)2 DISCHIGH 1 0 DISCLOW 0 0
Register reset value = (20)16
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Table 13. DTR Detailed Description
Name DSOFFSET Number of bits 4 Comments Data Slicer reference tuning (0000)2 to (1111)2 reset value: (1000)2 DISCHIGH 1 Discriminator offset shift (high) 0: no shift 1: output level increased reset value: 0 DISCLOW 1 Discriminator offset shift (low) 0: no shift 1: output level decreased reset value: 0
Wake-up Control Register Table 14. WUC Overview
Name nbit init Name nbit init WUE 31 0 WL2 5-3 (010)2 DATA 30 1 STOP 29 1 DATL 28-24 (11111)2 ISTU 2 0 ADD 23 1 - 1 0 - 22 0 WPER 21-13 (001011111)2 - 0 0 WL1 12-6 (0000100)2
Register reset value = (7f8be110)16 Table 15. WUC Detailed Description
Name WUE Number of bits 1 Comments Wake-up function enable Returns to "0" when a valid message is received. 0: wake-up disable 1: wake-up enable reset value: 0 DATA 1 Data content 0: message without data field 1: message with data field reset value: 1 STOP 1 STOP field usage 0: fixed data length: data length set from 1 to 32 by DATL 1: variable data length: data length given by the STOP field location; DATL must be set to (11111)2 reset value: 1
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Table 15. WUC Detailed Description (Continued)
Name DATL Number of bits 5 Comments Data length Valid in fixed data length mode (STOP = 0). (00000)2: 1 bit (min data length value) ------------------(11110)2: 31 bits (11111)2: 32 bits (max data length value) reset value: (11111)2 ADD 1 Address content 0: message without address field 1: message with address field reset value: 1 MSGTST 1 Message error test 0: no error detection mode 1: error detection enabling for debugging reset value: 0 WPER 9 Wake-up period Variable from 10 ms to 328 sec with an accuracy of 20%.(on-chip RC oscillator) reset value: 960 ms reset value: (5f)16 WL1 7 Minimum delay before TEST1 (check of RSSI level) Variable from 1ms to 1.024 sec Delay calculation starts when the reference oscillator starts reset value: 5 ms reset value: (04)16 WL2 3 Minimum delay between TEST 1 and TEST 2 (check of header detection) Variable as multiple of WL1 from 0 to 31 x WL1 reset value: 2 x WL1 reset value: (2)10 ISTU 1 Inhibit stuff mechanism 0: stuff is used for wake-up message 1: no stuff used in the wake-up message reset value: 0 2 Reserved, must be kept to reset value reset value: 0
* WPER Programming WPER can be set from 10 ms to 328 sec with an accuracy of 20%. A 10 ms period clock is used for this period generation. Bit 8 and 7 give a period multiplication factor of 1, 16 or 256 (with two serial by 16 clock prescalers). Bit 6 to 0 give the number of cycles of the divided clock from 1 to 128 (counter).
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Table 16. Wake Up Period Programming
WPER[8:0] (000)16 (001)16 - (07e)16 (07f)16 WPER[8:7] (00)2 (00)2 (00)10 (00)2 (00)2 WPER[6:0] (00)16 (01)16 (vv)10 (7e)16 (7f)16 Period 10 ms 20 ms - 1270 ms 1280 ms Prescaler 1 1 1 1 1 Comments 1 x 10 ms (1+1) x 10 ms (vv +1) x 10 ms 1 x 1270 ms 1 x 1280 ms
(101)16 or (081)16 (102)16 or (082)16 - (17e)16 or (0fe)16 (17f)16 or (0ff)16
(10)2 or (01)2 (10)2 or (01)2 (10)2 or (01)2 (10)2 or (01)2 (10)2 or (01)2
(01)16 (02)16 (vv)10 (7e)16 (7f)16
170 ms 330 ms - 20.2 sec 20.3 sec
16 16 16 16 16
((16 x 1)+1) x 10 ms ((16 x 2)+1) x 10 ms ((16 x vv)+1) x 10 ms ((16 x 126)+1) x 10 ms ((16 x 127)+1) x 10 ms
(181)16 (182)16 - (1fe)16 (1ff)16
(11)2 (11)2 (11)2 (11)2 (11)2
(01)16 (02)16 (vv)10 (7e)16 (7f)16
2.57 sec 5.13 sec - 323 sec 325 sec
256 256 256 256 256
((256 x 1)+1) x 10 ms ((256 x 2)+1) x10 ms ((256 x vv) +1) x 10 ms ((256 x 126)+1) x 10 ms ((256 x 127)+1) x 10 ms
* WL1 Programming WL1 can be set from 1 ms to 1.024 sec. A 1 ms period clock is used for this delay generation. Bit 6 gives a period multiplication factor of 1 or 16 (by 16 clock prescaler). Bits 5 to 0 give the number of cycles of the divided clock from 1 to 64 (counter). Table 17. WL1 Programming
WL1[6:0] (00)16 (01)16 (vv)10 (3e)16 (3f)16 WL1[6] 0 0 0 0 0 WL1[5:0] (00)16 (01)16 (vv)10 (3e)16 (3f)16 Period 1 ms 2 ms vv + 1 ms 63 ms 64 ms Prescaler 1 1 1 1 1 Comments 1 x 1 ms (1+1) x 1 ms 1x (vv +1) ms 1 x 63 ms 1 x 64 ms
(40)16 (41)16 - (7e)16 (7f)16
1 1 1 1 1
(00)16 (01)16 (vv)10 (3e)16 (3f)16
16 ms 32 ms - 1.008 sec 1.024 sec
16 16 16 16 16
16 x 1 ms 16 x 2 ms 16 x (vv +1) ms 16 x 63 ms 16 x 64 ms
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* WL2 programming WL2 can be set as a multiple of WL1 from 0 to 31 WL1. Table 18. WL2 Programming
WL2[2:0] (000)2 (001)2 (010)2 (011)2 (100)2 (101)2 (110)2 (111)2 Period 0 1 x WL1 2 x WL1 3 x WL1 4 x WL1 8 x WL1 16 x WL1 31 x WL1 Comments Simultaneous test of the RSSI and the header
Wake-up Data Rate Register (WUR) Table 19. WUR Overview
Name nbit init WUOP 17-16 (01)2 RATECHK 15 0 RATE 14-5 (0000010000)2 RATETOL 4-0 (01000)2
Table 20. WUR Detailed Description
Name WUOP Number of bits 2 Comments WAKEUP output polarity (00)2: WAKEUP pin active low (01)2: WAKEUP pin active high (1x)2: WAKEUP pin open drain (active low, inactive tri-state) reset value: (01)2 RATECHK 1 Data rate check the data rate is automatically extracted from the HEADER field. the data rate can be compared to RATE with a tolerance of plus or minus RATETOL. Data rate is computed from a unit of 1.56 s (Reference clock divided by 16). 0: data rate not checked. 1: data rate check done (header ignored if check fails). reset value: 0 Data rate value 0d: min value = 1 x 1.56 s (1023)10: max value = 1024 x 1.56 s reset value: 64 x 1.56 s reset value: (63)10 RATETOL 5 Data rate tolerance 0d: min value = 0 x 1.56 s (31)10: max value = 31 x 1.56 s reset value: 8 x 1.56 s reset value: (8)10
RATE
10
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The data rate (in bps) and the decimal value to be coded in the register are related by the equation: 640000 RATE = -----------------------rate (bps) The following table gives the programming values of commonly used rates:
Rate 1200 bits/sec 2400 bits/sec 4800 bits/sec 9600 bits/sec WUR RATE (533)10 (267)10 (133)10 (67)10
Wake Up Address Register (WUA) Table 21. WUA Overview
Name nbit init ADDL 24-20 (01001)2 ADD 19-0 (0f0f0)16
Table 22. WUA Detailed Description
Name ADDL Number of bits 5 Comments Wake-up address length 0: wake-up address length = 1 bit 1: wake-up address length = 2 bits .......... (19)10: wake-up address length = 20 bits >(19)10: forbidden reset value: 10 bits ADD 20 Wake-up address If wake-up address length is less than 20 bits, MSB bits are ignored reset value: (0f0f0)16
Concerning this register, attention should be paid to the fact that the last bit of the address field is not taken into account when testing the address field that is received. Thus the last bit must be programmed and counted in the address length but it can be either "0" or "1".
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Wake-up Data Register (WUD) Table 23. WUD Overview
Name nbit WUD (data length -1) - 0
Table 24. WUD Detailed Description
Name WUD Number of bits Length Comments Wake-up message data Warning: The length of this register is variable: * case fixed data length (STOP = 0 of WUC) data length is given by DATL of WUC. * case variable data length (STOP = 1 of WUC) data length is given by MSGDATL of STAT register. Warning: The first bit of received data is the LSB: WUD[0].
Note:
To use this mode, please refer to the corresponding application note.
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Electrical Specification
Absolute Maximum Ratings
Temperature Storage temperature Supply voltage Digital input voltage RXIN input power Note: +95C -65 to +150C 0 to 3.95V -0.3 to VCC + 0.3V 0 dBm
ESD sensitive device: storage or handling of the device must be carried out according to usual protection rules.
Stresses beyond the conditions listed above may cause permanent damage to the device. Exposure to Absolute Maximum Ratings conditions for an extended period may affect device reliability.
DC Characteristics
Unless otherwise specified, data is given for T = 25C, VSUPPLY = 2.7V
Parameter Supply voltage Supply current Supply current Supply current Supply current Supply current Operating temperature Note: -40 Min 2.4 0.5 3 29 35 20 +85 Typ Max 3.75 Unit V A A mA mA mA C Comment
(1)
Power-down Sleep mode Rx mode Tx mode, Pout = +10 dBm at 433 MHz Tx mode, PDN-PA on
1. The allowed supply voltage of the AT86RF211 is higher than 3.75V. However, we strongly recommend not to exceed 3.75V from now on, to be compliant with future versions of the device.
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Digital CMOS DC Characteristics
Name Vil Parameter
Unless otherwise specified, data is given for T = 25C, VSUPPLY = 2.7V
Conditions
Min
Typ
Max 0.3*Vcc 0.2*Vcc
Units V V V V
CMOS low level input voltage - Normal input(2) - Schmitt trigger input(3) CMOS high level input voltage - Normal input(2) - Schmitt trigger input(3) CMOS low level output voltage(1) CMOS high level output voltage(1) 2. For digital CMOS pins: SLE, SCK, SDATA 3. For digital CMOS pins: DATAMSG Iol = 1 mA Ioh = - 1 mA 0.8*Vcc 0.7*Vcc 0.85*Vcc
Vih
Vol Voh Note:
0.2*Vcc
V V
1. For digital CMOS pins : SDATA, DATAMSG, DATACLK, WAKEUP.
* Timings
Name tr = tf F T tw tsd thd tpd tpzon tdle tpzd CL(1) Note: Parameter CMOS rise/fall times SCK frequency SCK period SCK low or high time SDATA setup before SCK rising SDATA hold after SCK rising SDATA output propagation delay after SCK falling (read mode) (CL = 30 pF) Delay to switch SDATA to output after SCK falling (read mode) Minimum delay between an edge of SLE and an edge of SCK Delay to switch SDATA to input (tri-state) after SLE rising (read mode) Max load for CMOS output pins These timings refer to the Figure 33 on page 25. Conditions CL = 50 pF ; 20% to 80% 0 200 60 40 40 2 3 40 40 50 50 50 Min Typ Max 30 5 Units ns MHz ns ns ns ns ns ns ns ns pF
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AT86RF211
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AT86RF211
Synthesizer Specification
Unless otherwise specified, data is given for T = 25C, VSUPPLY = 2.7V
ii
Parameter Frequency Range Frequency Range Crystal Frequency Crystal Frequency Oscillator Settling Time Lock Time(2) Lock Time(2) Phase Noise 400 to 480 MHz Phase Noise 800 to 950 MHz Phase Noise 400 to 480 MHz Phase Noise 800 to 950 MHz Notes:
Min 400 800 10.235 20.925 5
Typ
Max 480 950
Unit MHz MHz MHz MHz ms s s dBc/Hz dBc/Hz dBc/Hz dBc/Hz
Comments Digital programming Digital programming IF 1 = 10.7 MHz(1) IF 1 = 21.4 MHz(1) Depending on crystal specifications From oscillator settling 100 kHz shift At 10 kHz from the carrier At 10 kHz from the carrier At 100 kHz from the carrier At 100 kHz from the carrier
10.245 20.945 8 300 30 -80 -75 -91 -86
10.255 20.965
1. Crystal frequency can be slightly changed but since IF2 = IF1 - Crystal frequency, IF2 will shift and must remain within the IF2 filter and discriminator bandwidth. 2. With the "typical implementation" loop filter.
Receiver Specification
Parameter IF1 IF1 Filter Impedance IF2 IF2 Filter Impedance FSK Sensitivity Min
Unless otherwise specified, data is given for T = 25C VSUPPLY = 2.7V
Typ 10.7 330 455 1700 -105 Max Unit MHz kHz dBm Typical performance with a BER of 1% at input pin RXIN (45). BW = 10 kHz, F = 7.5 kHz; Brate = 4800 bps(1) Input matched, complete RX chain Comments 21.4 MHz also possible
Noise Figure Input IP3
15 -15
dB dBm
Max Input Power -5 dBm BER < 10% Note: 1. The overall sensitivity depends on measurements conditions and external components, i.e.: -100 dBm for BW = 10 kHz, F = 7.5 kHz, Brate = 4800 bps with RF switch used and external SAW filter
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1942C-WIRE-06/02
Transmitter Specification Unless otherwise specified, data is given for T = 25C, VSUPPLY = 2.7V,
RPOWER = 18 k.
Parameter Output Power Output Power Output Power Output Power Dynamic Range Automatic Level Control Accuracy Automatic Level Control Accuracy FSK Data Rate RX to TX Toggle Time Notes: 200 Min +10 +10 +8 Typ +14 +12 +10 12 1 2 64 Max Unit dBm dBm dBm dB dB dB kbps s Typical loop filter implementation Comments 433 MHz band(1) 868 MHz band(1) 915 MHz band(1) Digital programming(2) Constant conditions Against VCC, T(3)
1. Output power for Rpower = 10 k and TXLVL = "111" 2. The maximum power is set by an external resistor, connected to pin RPOWER. The output power can be digitally programmed/re-programmed, up to -12 dB below this limit, by means of a 3-bit word: TXLVL of CTRL1 register. 3. The output power is regulated against process, temperature and power supply variations by an internal ALC loop.
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AT86RF211
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AT86RF211
Typical Application
Implementation
Optional SAW Filter
SAW
VCC
VCC
VCC
VCC
VCC
Rpower
IF1 Filter: 10.7 MHz or 21.4 MHz
ANTENNA
AT86RF211
VCC
IF2 Optional Ceramic Filter (455 kHz)
Optional RC Filter
VCC
10.245 MHz or 20.945 MHz
Note:
Accurate information about parts and values of components to be used around AT86RF211 are described in our application notes. "RF Bill-of-Material/cost for 868-915 MHz applications".
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1942C-WIRE-06/02
Layout
Reference Design Top Layer
Each unused area must be filled with copper and connected to the bottom side ground plane
Decoupling capacitors remain close to the supply pins
Reference Design Bottom Layer
One-block ground plane with no slot under the whole RF area This small slot is allowed as it is under the RF211: thus there is no track above
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AT86RF211
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AT86RF211
Packaging Information
48 lead TQFP
Dimension A A1 A2 D D1 E E1 L e b ccc
Nominal Value (mm) 1.60 0.05 min/0.15 max 1.40 9.00 7.00 9.00 7.00 0.60 0.50 0.22 0.1
Tolerance max
Dimension A A1
Nominal Value (inch) 0.063 0.002 min/0.06 max 0.055 0.354 0.275 0.354 0.275 0.024 0.020 0.009 0.004
Tolerance max
0.05 0.20
0.10 0.20 0.10 +0.15/-0.10 basic 0.05 max
A2 D D1 E E1 L e b ccc
0.002 0.008
0.004 0.008 0.004 +0.006/-0.004 basic 0.002 max
Ordering information
Full Part Number AT86RF211 DAI AT86RF211 DAI-R
Package TQFP48 TQFP48
Conditionning Tray Tape & reel
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1942C-WIRE-06/02
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(c) Atmel Corporation 2002. Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in Atmel's Terms and Conditions located on the Company's web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel's products are not authorized for use as critical components in life support devices or systems. ATMEL (R) is the registered trademark of Atmel. Other terms and product names may be the trademarks of others. Printed on recycled paper.
1942C-WIRE-06/02 0M

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