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
V

Readout

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 bidirec-
tional 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 exter-
nal 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 micro-
controller only when a valid inquiry is detected.

FSK
Transceiver for
ISM Radio
Applications

AT86RF211
(aka: TRX01)

Rev. 1942CWIRE06/02

AT86RF211

1942CWIRE06/02

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 parame-
ters such as RSSI level, Vbattery, PLL lock state. All these operations are carried out via
a three-wire serial interface.

Normal Mode

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.

Wake-up Mode

The chip is set up in a special Rx mode called sleep mode. The chip wakes up periodi-
cally thanks to its internal timer (stand alone procedure, the microcontroller is in power-
down 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.

AT86RF211

1942CWIRE06/02

Figure 1. Reception and Transmit Mode

F = Frequency of
transmitted signal

AT86RF211 acts like a "pipe"
(data is transmitted with NO
processing): automatic data
to frequency conversion.
- DATAMSG = 0: F = F0
- DATAMSG = 1: F = F1

AT86RF211 (TRX01)

Transmit mode

Companion Microcontroller

DATAMSG

SLE, SCK, SDATA

(for set-up)

F = Frequency of
received signal

AT86RF211 also acts like a "pipe":
data (collected by the antenna)
is available on pin DATAMSG:

AT86RF211 (TRX01)

Receive mode

Companion Microcontroller

DATAMSG

SLE, SCK, SDATA

(for set-up)

DATACLK

DATAMSG

DATACLK

AT86RF211

1942CWIRE06/02

Figure 2. Wake-up Overview

Figure 3. Periodical Scan

Header + Address

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.

AT86RF211 (TRX01)

Wake-up mode

Companion Microcontroller

WAKEUP pin

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

Data field

Reception mode

Short reception window

Oscillator settling

Sleep mode

Wake Up period

Timing

Power

Consumption

AT86RF211

1942CWIRE06/02

Block Diagram

Figure 4. AT86RF211 Block Diagram

SYNTHESIZER

FREQUENCY

CTRL

CONTROL LOGIC

WAKE-UP

DATA SLICER

BANDWIDTH CTRL

RSSI LEVEL

FM DISCRIMINATOR

OPTIONAL

FILTER

IF2

FILTER

455 kHz

PWR
CTRL

Optional

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.

GAIN MIN/MAX

AERIAL

MATCHING

CIRCUIT

DATA

MSG

DATA

CLK

SDATA

WAKE-UP

SLE

SCK

IF2

AMP

IF1

AMP

MIXER2

IF1

FILTER

10.7 MHz

21.4 MHz

LNA

MIXER1

TX/RX

FILTER

RPOWER

OSC

10.245 MHz

20.945 MHz

Part Number AT86RF211

Document Outline