Atmel AT86RF230 2.4GHz 收发方案

Atmel 公司的AT86RF230是低功耗2.4 GHz无线电收发器，是真正的SPI到天线的解决方案，具有业界最好的RF性能，连接预算为104 dB，是同类产品的三倍，采用Raven板内的高增益天线室外的通信距离可达700米，而工作模式的耗电仅为15mA，而睡眠模式则下降为20nA。AT86RF230非常适合ZigBee/IEEE 802.15.4如无线传感器网络，工业控制，家庭和建筑物自动化，消费类电子以及PC外设。本文介绍AT86RF230的主要性能，方框图，典型应用电路以及评估板AVRRAVEN的详细电路图和材料清单（BOM）。

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:

Wireless sensor networks
Industrial control
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”.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 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.
The RZRAVEN is a development kit for the AT86RF230 radio transceiver and the AVR microcontroller. It serves as a versatile and professional platform for developing and debugging a wide range of RF applications; spanning from: simple point-to-point communication through full blown sensor networks with numerous nodes running complex communication stacks. On top of this, the kit provides a nice human interface, which spans from PC connectivity, through LCD and audio nput and output.

The RZRAVEN 2.4 GHz Evaluation and Starter kit enables development, debugging and demonstration of a wide range of lowpower wireless applications including IEEE 802.15.4, 6LoWPAN and ZigBee networks. The RZRAVEN kit comprises two AVR Raven boards (AVRRAVEN) with 2.4 GHz transceiver, on board picoPower AVR application processors and LCD display, and one USB stick (AVRRZUSBSTICK) with a 2.4 GHz transceiver for USB connection to your PC. A PC SW package is included enabling wireless network setup and control, a wireless network analyzer and over-the-air programming.

The kit utilizes the AVR picoPower™ technology in combination with the superior RF performance offered by the AT86RF230 2.4 GHz ISM transceiver.

The RZ Raven kit comprises two Raven boards, one USB Stick and a selection of firmware application and software that will dramatically reduce time to market for designers considering short range wireless ISM band applications based on IEEE802.15.4™, ZigBee® or 6LoWPAN.

The Raven board can be used as a multi application wireless node with a LCD graphical user interface. It has two AVR picoPower microcontrollers: an ATmega1284P that can be used to control RF application stacks, and an ATmega3290P that controls the display and user interfaces. The Raven contains a custom LCD display, a 5 position joystick, a microphone and a speaker allowing the evaluation of a variety of user interactions that are appropriate in the target wireless applications. To support application development the following functionalities are available: graphical user interface, communication ports, ATmega1284P port pins available on headers, on-board temperature sensor, voltage sensor, relay driver, boot loader and ISP support for programming.