Atmel AVR2016 User Manual

AVR2016: RZRAVEN Hardware User's Guide

Features

• Development kit for the AT86RF230 radio transceiver and AVR® microcontroller.

• CE, ETSI and FCC approved.

• LCD module (AVRRAVEN):

- AT86RF230 radio transceiver with high gain PCB antenna.

- Dual AVR microcontrollers.

- Dynamic Speaker and microphone.

- Atmel Serial Dataflash®.

- User IO section:

• USART

• GPIO

• Relay Driver

- Powered by battery or external supply:

• 5V to 12V external supply.

• USB module (RZUSBSTICK):

- AT86RF230 radio transceiver with miniature PCB antenna.

- AVR microcontroller with integrated Full Speed USB interface.

- External memory interface.

1 Introduction

8-bit Microcontrollers

Application Note

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 input and output.

Figure 1-1. The RZRAVEN Kit Modules

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2 General

The RZRAVEN kit is built from one RZUSBSTICK module and two AVRRAVEN modules. See

The complete schematics and Gerber files are available from the compressed archive accompanying this application note.

Figure 2-1 Assembly drawing AVRRAVEN - front view.

Figure 2-1 to Figure 2-4 for further details.

Figure 2-2 Assembly drawing AVRRAVEN - back view.

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Figure 2-3 Assembly drawing RZUSBSTICK - front view.

Figure 2-4 Assembly drawing RZUSBSTICK - back view

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3 The AVRRAVEN Module

Figure 3-1 AVRRAVEN overview

Joystick and user I/O

MCU #1: ATmega3290P, User I/O

Realtime

Clock oscillator

32kHz Xtal

The AVRRAVEN hardware is based on 2 microcontroller and one radio transceiver chip. The ATmega3290P handles the sensors and the user interface and the ATmega1284P handles the AT86RF230 radio transceiver and the RF protocol stacks. The MCUs and the radio communicate via serial interfaces.

For hardware details please refer to Appendix A for the complete AVRRAVEN schematics.

Audio I/O

On-chip MCU RC oscillator,

Set to 4MHz

LCD display

2-way async Serial comm

MCU #2: ATmega1284P, RF Stacks

Realtime

Clock oscillator

32kHz Xtal

On-chip MCU RC oscillator,

Set to 4MHz

2-way sync

Serial comm

PCB Antenna

Radio chip

AT86RF230

16MHz Xtal

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3.1 AVR Microcontrollers

Two AVR microcontrollers are found on the AVRRAVEN module. An ATmega1284P is connected to the AT86RF230 radio transceiver, and an ATmega3290P is driving the LCD. Both these devices are selected from the AVR picoPower family, something that ensures minimal power consumption and operation down to 1.8 Volts. Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is used as an inter processor communication bus.

3.2 Atmel Radio Transceiver

The AT86RF230 is a 2.4GHz radio transceiver that is tailored for a wide range of wireless applications. Low power consumption and market leading RF performance makes it an excellent choice for virtually any type of networking device. Support for IEEE 802.15.4 channel access) type of applications is available through an enhanced layer of functionality on top of the basic radio transceiver.

3.3 Antenna description

The antenna on the AVRRAVEN is a 100 loop antenna with a net peak gain of about 5dB.

3.4 LCD

(Automatic acknowledge of packets, address filtering and automatic

The LCD found on the AVRRAVEN module is a full custom 160-segment display tailored for the RZRAVEN kit (See segments text area; four segment number area and numerous handy symbols. In particular pay attention to the bird looking symbol. It is symbolizing the two black scouting ravens of Norse god Odin; Hugin (Thought) and Munin (Memory). The saga says that they flew around the world and reported news back to Odin at night. Underneath the raven segment’s “eye” there is a red LED capable of soft-blinking; this may be used to indicate the AVRRAVEN’s search for “news” on the air interface.

A full segment map can be found in Appendix C and in the schematics folder in the compressed archive file accompanying this application note. The LCD is driven directly from the connected ATmega3290P.

Figure 3-2 AVRRAVEN - LCD Segments

Figure 3-2 for a quick reference). It contains a 7

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3.5 Speaker

3.6 Microphone

3.7 Serial Dataflash®

An 8  speaker is provided. The ATmega3290P controls all audio. The signal source is the TIMER1’s PWM output and the signal is shaped via a low-pass filter and amplified by a Class-D amplifier. Pulling PORTE7 low activates the active filter and providing a PWM signal on PORTB5 activates the amplifier.

The AVRRAVEN’s microphone is connected to the ATmega3290P ADC channel 0. The signal is amplified and low-pass filtered. Pulling PORTE7 low activates the microphone circuit.

A 16-Mbits Atmel Serial Dataflash (AT45DB161D) is connected to the ATmega3290P’s Serial Peripheral Interface (SPI). This storage is used for safe firmware images, sounds and general-purpose parameters. See the firmware documentation for an overview of occupied sectors, and those available to the end user. Even with a couple of safe firmware images for the two microcontrollers there is plenty space left for the end user. Please note that the serial Dataflash will operate properly when the voltage is above 2.5 Volts while the rest of the design will operate down to 1.8Volts

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3.8 Serial EEPROM

3.9 Real Time Clock

3.10 NTC

A 2-Kbits Atmel Serial EEPROM (AT24C02B) is connected to the ATmega1284P’s two-wire interface (TWI). This storage is write protected by hardware and can only be read. The storage contains important configuration and calibration data that should not be unintentionally overwritten. Information such as a unique EUI 64-bit address can be found her-in. A rich set of access functions and the parameter map is given in the RZRAVEN firmware documentation.

Separate 32768 Hz clock crystals are connected to the ATmega3290P’s and the ATmega1284P’s asynchronous timer interfaces. This allows an application to implement a real time clock (RTC) to keep track of time when sleep modes are used to reduce the power consumption. This is especially important for battery-operated nodes.

A NTC is connected to the ATmega3290P’s Analog to Digital Converter (ADC) channel 4. This NTC can be used to measure the temperature in the surroundings of the AVRRAVEN. The NTC can be found below the joystick, close to J401. The JTAG interface must be disabled when using the temperature sensor. When running the AVRRAVEN from an external power source the onboard voltage regulator may heat the temperature sensor giving faulty reading. To avoid this the sensor NTC may be soldered off and relocated using short wires. If a higher level of accuracy is required the users may also calibrate the sensor by adjusting the temperature lookup table in firmware.

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3.11 Power Supply

The AVRRAVEN can be powered either from batteries or an external 5 to 12 Volts DC source. The power source is selected by the position of the jumper located immediately to the right of the LCD (See the figure below for a reference). Polarity protection is provided when using an external power source.

The AVRRAVEN has been designed to run from two 1.5V LR44 battery cells.

An onboard voltage regulator makes it possible to run power the AVRRAVEN from a 5 to 12 Volts DC source. The external voltage is applied to the two leftmost pins in the user IO area (J401). The ATmega3290P’s ADC channel 2 is connected to a voltage divider and the external voltage supply interface. This way it is possible for the application to monitor the external operating voltage.

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3.12 Interfaces

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The AVRRAVEN module has multiple interfaces that can be used for serial communication, interaction with external sensors and control units such as relays and of course programming and debugging.

Figure 3-3 AVRRAVEN User Interfaces

Table 3-1

Pin number Function Comment

1 Ext. power supply, 5-12V input External power input

2 Ext. power supply 0V Connected to internal 0V

3 Relay coil positive Relay driver circuit positive

4 Relay coil negative Relay driver circuit negative

5 Voltage measure input, 0-Vcc*5 Analog input via 47k/10k voltage divider

6 Voltage measure input, 0-Vcc Analog input directly to ADC input.

7 Vcc Connected to the VCC net directly

8 User IO #1

9 User IO #2

10 User IO #3

11 User IO #4

12 Common Connected to internal 0V

. Interfaces available on J401

Digital I/O, may interface an LED or a switch directly. On-board 470 series resistors and 10k pull-ups are provided.

Pin change interrupts, TWI and USI is also available on these pins.

Care should be taken when connecting to the AVRRAVEN’s interfaces, since there is no protection circuitry provided. Damage to the MCUs or other circuits may be the result of ESD spark, short circuits, polarity or over-voltage faults.

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3.12.1 Programming Interface

Both the ATmega3290P and ATmega1284P can be programmed using either the JTAG or ISP interface. JTAG programming can be facilitated by connecting a JTAG ICE mkII to the 50-mil pin header J301 (ATmega3290P) and J204 (ATmega1284P). A total of 5 50-mil pin headers and one 50-mil to 100-mil converter are supplied with the RZRAVEN kit.

ISP programming can be performed by connecting an ISP enabled AVR programming tool to the pin header J302 (ATmega3290P) and J205 (ATmega1284P). AVR tools like STK500, AVRISP mkII and JTAGICE mkII can be used for this.

The AVRRAVEN does not come with these headers mounted. So it is up to the user populating these. Wires could also be soldered in instead of the dual row headers.

3.12.2 Relay Interface

A relay interface (Relay Positive and Negative) is available through J401. This interface can be used with the AVRRAVEN running from external power. A switching transistor is connected to PB6 on the ATmega3290P so that sufficient current can be provided to the relay being driven. An external power source must be used if the relay option is required. The AVRRAVEN must then be supplied with the rated voltage of the relay.

3.13 Voltage Measurement Interface

3.13.1 GPIO

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Two of the pins in header J401 can be used for external voltage measurements, however only one at the time. The possible voltage ranges are 0 to VCC or via a voltage divider giving an approximate range of 0 to five times VCC. A simple voltage divider is implemented to scale the measurement voltage. A diode bridge is also used to prevent reverse polarity and to protect the ATmega3290P’s ADC channel 3.

Both the ATmega3290P and ATmega1284P are high pin count devices, and a number of these are not used. These pins are available through the user IO headers; J401, J201, J202 and J203. See

Table 3-2 and Table 3-3 for further details.

Be aware that these pins do not have level converters and should thus not be connected directly to an application board running on a different voltage level than the AVRRAVEN.

Table 3-2

ATmega3290P Port Pin PCB Connection Comment

PE3 J401 –8

PE4 J401-9

PE5 J401-10

PE6 J401-11

. ATmega3290P User IO

Via 470 series resistor and10k pull-up

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Table 3-3. ATmega1284P User IO

ATmega1284P Port Pin PCB Connection Comment

PC0 J201-1

PC1 J201-2

PC2 J201-3 JTAG TCK.

PC3 J201-4 JTAG TMS.

PC4 J201-5 JTAG TDO.

PC5 J201-6 JTAG TDI.

N.C. J201-7

N.C. J201-8

PD0 J202-1

PD1 J202-2

PD2 J202-3 DIO or RXD1.

PD3 J202-4 DIO or TXD1.

PD4 J202-5 DIO.

PD5 J202-6 DIO.

PB2 J202-7 DIO. NB: NOT PD6!

PD7 J202-8 DIO.

PA0 J203-1 DIO or ADC Channel 0.

PA1 J203-2 DIO or ADC Channel 1.

PA2 J203-3 DIO or ADC Channel 2.

PA3 J203-4 DIO or ADC Channel 3.

PA4 J203-5 DIO or ADC Channel 4.

PA5 J203-6 DIO or ADC Channel 5.

PA6 J203-7 DIO or ADC Channel 6.

PA7 J203-8 DIO or ADC Channel 7.

Additional interfaces PCB Connection Comment

External power J201-10

J202-10 J203-10

0V J201-9

J202-9 J203-9

TWI SCL. Connected to serial EEPROM

TWI SDA. Connected to serial EEPROM

Populate R204 to connect to PC6. RTC Xtal XC202 must then be removed.

Populate R205 to connect to PC6. RTC Xtal XC202 must then be removed.

RXD0 Inter processor communication.

TXD0 Inter processor communication.

Connected to J401-1

Connected to J401-2

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