ATMEL ATAVRRZ502 User Manual

AVR414: User Guide - ATAVRRZ502 -

Accessory Kit

Features

• Introduction to the ATAVRRZ502 hardware.

• Includes evaluation application that uses the IEEE

• An example on how to establish a peer-to-peer connection.

• Supports both the IAR® compiler and GCC.

1 Introduction

This application note describes the ATAVRRZ502 Accessory Kit (RZ502). The RZ502 is designed for evaluation of the Atmel AT86RF230 2.4 GHz radio transceiver. This radio transceiver fully complies with the IEEE 802.15.4™ standard and targets low-power wireless technologies within home, building and industrial automation such as ZigBee™.

An evaluation application is available together with this document. This application shows how to set up a peer-to-peer network, with two nodes, and send data using the wireless link.

802.15.4 library from Atmel.

8-bit Microcontrollers

Application Note

Figure 1-1. ATAVRRZ502 Accessory Kit

Rev. 8051A-AVR-11/06

2 Getting Started with the ATAVRRZ502 Accessory Kit

This section gives an introduction to what the ATAVRRZ502 Accessory Kit contains and its system requirements. At the end brief instructions are given on how to get the Accessory Kit up and running in the shortest amount of time.

2.1 Unpacking the System

Kit contents:

• (2 pcs) RZ502 Radio boards with SMA stub antennas.

• (2 pcs) ATmega1281V AVR

• Technical Library CD.

2.2 System Requirements

The minimum hardware and software requirements are:

• (2 pcs) STK®500

• (2 pcs) STK501

• (2 pcs) 9 pin RS-232 cable

• (2 pcs) 6-wire cable

• (2 pcs) 2-wire cable

• Power Supply for STK500.

• PC running AVR Studio

to-RS232 bridge).

microcontroller in TQFP Package.

and with two available RS-232 ports (COM port or USB-

2.3 Quick Start Guide

This section goes through how to get the RZ502 kit and evaluation application up and running in the shortest amount of time.

1. Unpack the ATAVRRZ502 Accessory Kit and ensure that it contains all components listed in subsection

2. Ensure that all the components listed in subsection

3. Go through the steps in section to build both peers.

4. Generate EEPROM file for each peer in the network using the HEXMaker application. How to use this application is described in subsection

5. Program the ATmega1281 microcontroller by following the instructions in subsection

6. Finally, a chat client is available to interface with the evaluation application just programmed into the AVR microcontroller. Go through the instructions in section on how to setup and use the chat client.

5.2. Repeat this step on both peers.

2.1.

2.2 is available.

4 to assemble the hardware. Repeat this step twice

5.1.

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3 Hardware Description

Figure 3-1 ATAVRRZ502 Components

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3.1 Description of AT86RF230

The AT86RF230 is a 2.4 GHz radio transceiver from Atmel. It is specially designed for IEEE 802.15.4 and ZigBee applications. Main features are:

• Low power consumption.

• Large link budget (104 dBm).

• True 1.8 volts operation.

• Minimized number of external components needed.

The only required external components are antenna, 16 MHz crystal and four decoupling capacitors. An easy-to-use Serial Peripheral Interface (SPI) is defined for accessing the radio’s register file. Please consult the AT86RF230 radio transceiver’s datasheet for further information about its specifications, operating modes, registers etc.

3.2 Description of Antenna and Balun Circuit

The antenna output of the AT86RF230 is differential. This configuration is beneficial because:

• Immunity to electromagnetic interference.

• Immunity to power-supply noise.

• Immunity to ground noise.

• Suppression of even-order harmonic.

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• Better tolerance to less than perfect RF ground.

However, the RZ502 has a typical single ended SMA stub antenna mounted. A special circuit is required to convert the 100Ω differential RF input/output pins of the AT86RF230 to a 50Ω single ended RF port. This is solved by a BALUN circuit on the RZ502 top module. A BALUN (a compound term meaning “BAlanced-UNbalanced”) is a passive component that transforms impedance. Two capacitors are added as a DC

Figure 3-2 depicts the BALUN circuit described above.

block.

Figure 3-2 BALUN Circuit

RFN

BALUN

Balanced 1

Unbalanced

SMA Connector

RFP

3.3 Description of Power and Filter Circuit

Figure 3-3 shows the power and filter circuit connected to the AT86RF230. The power circuit is built from three components; a SMD fuse (F1), a Zener diode (D1) and a jumper (JP1). D1 is a 3.9 Volts Zener diode connected in series with the thermal fuse. This connection prevents excessive voltages on the DVTG (Digital Voltage) and AVTG (Analog Voltage) ports when JP1 is closed, and potentially harm the AT86RF230. JP1 can also be used for current measurements.

The rightmost part of inductor) filter used to suppress noise and harmonics to enter the analog/RF part of the radio transceiver.

Figure 3-3 Power and Filter Circuit

Balanced 2

Figure 3-3 is a PI-type LC (two shunt capacitors and one series

3.4 Description of STK500 Interface

The STK500 board has two expansion connectors, one on each side of the programming module. All AVR I/O ports, programming signals and control signals are routed to these connectors. This connector is used by the RZ502 top module to mount itself to the STK500/STK501 board stack. And ultimately connect the AT86RF230 radio

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Figure 3-4 depicts the pin-out of expansion connector 1.

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transceiver to the AVR microcontroller. Only a few of the available pins are used to control the radio transceiver. The reminder of this subsection describes the interface necessary to control the radio transceiver.

Figure 3-4 Expansion Connector 1 Pin-out

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3.4.1 SPI Lines

3.4.2 IRQ Line

3.4.3 SLP_TR Line

The SPI is used to program control registers as well as to transfer data frames between the AVR and the AT86RF230. Each access is initiated with the SPI master (AVR) pulling the slave select (SS/SEL) line low. Both master and slave (AT86RF230) will now prepare the data to be sent, and the master generates the necessary clock pulses on the SCLK line to interchange the data. Data is always transferred from master to slave on the Master Out – Slave In, MOSI line, and from slave to master on the Master In – Slave Out, MISO line. When a packet has been transmitted, the master will pull high the slave select line to synchronize the slave.

The AT86RF230 has six different interrupts defined. However, all these interrupt signals are combined internally via a logical “OR” operation to one external interrupt line. An interrupt is indicated to the AVR microcontroller whenever the IRQ line is pulled high (logical 1). The controller must poll the AT86RF230 to determine the interrupt source and to clear the IRQ line.

The SLP_TR signal is a multi-functional pin. It can be used as either a transmit start or a sleep signal. Pin functionality is dependant upon the transceiver’s internal state. Please consult the datasheet of the AT86RF230 for more information.

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3.4.4 Reset Line

3.4.5 Pins used by the RZ502

This line is used to reset the AT86RF230 radio transceiver. The reset line is controlled by one of the AVR pins and not connected to the reset button on the STK500 board.

Table 3-1 lists the 17 pins used by the RZ502 top module and their usage. This information can be used to run the Accessory Kit on alternative platforms. Remaining pins of the expansion connector 1 is not connected.

NOTE: Be sure that none of the pins used by the RZ502 top module is connected to other circuitry. I.e. no additional circuitry can be connected to the SPI pins of the PORTB connector on the STK500 etc.

Table 3-1

Expansion Connector 1 Pin Name Usage

Notes: 1. Pins connected to the same net. Only one required if number of pins is scarce.

. Pins used by the RZ502 board

1,2,21,22,39,40

19,20

25 PB5

26 PB4

27 PB3 MISO line. 28 PB2 MOSI line. 29 PB1 SCK line. 30 PB0 SEL line. 32 PD6

34 PD4

2. Not connected by default. Requires de-soldering R1 (0 Ω) and soldering onto the R2 pads.

(1)

(2)

GND Used for analog and digital ground.

VTG

XT1

Target voltage. Must be within the operating range of the AT86RF230 [1.8 to

3.6 Volts]. Can be used to connect the CLKM pin on

the AT86RF230 to the AVR’s XT1 pin. Reset line. Connected to the RST pin on

the AT86RF230. Connected to the SLP_TR pin on the

AT86RF230.

Used to connect the CLKM pin of the AT86RF230 to the Timer1 module on the AVR.

Connected to the IRQ pin on the AT86RF230.

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4 Hardware Assembly

The following steps walk the reader through how to assemble and prepare the STK500 board and the STK501 top module to be used with the RZ502. Then finally how to mount the RZ502 board and configure it to run the evaluation application.

NOTE: The following steps must be completed successfully to ensure correct operation of the hardware.

Step A. Assemble and configure the STK500 board

The jumpers and operating voltage of the STK500 board must be set up correct in advance of mounting the STK501 and radio board.

1. Carefully remove any AVRs from the target sockets on the STK500.

2. Place jumpers on the following headers as shown in

• VTARGET

• AREF

• RESET

• BSEL2

3. Connect a serial cable to the connector marked RS232CTRL on the STK500 to a COM port on the PC.

4. Apply power to the STK500 by moving the power switch toward the edge of the board.

5. Start AVR Studio and press “Cancel” in the Welcome dialog window.

6. From the Tools menu, select “Program AVR” and “Connect…”.

7. Select “STK500 or AVRISP” as platform and then press “Connect…”. Verify that a window named “STK500” appears.

8. Open the Board tab. Adjust the VTarget voltage and ARef voltage to 3 Volts. Press the Write Voltages button. Close the STK500 window.

Figure 4-1:

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