Atmel AVR2016, User Manual

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Atmel AVR2016: RZRAVEN Hardware User’s Guide [APPLICATION NOTE]
8117E − AVR − 07/12
5
2.1
Atmel AVR Microcontrollers
Two AVR microcontrollers are found on the Atmel AVRRAVEN module. An Atmel ATmega1284P is connected to the
Atmel AT86RF230 radio transceiver, and an Atmel 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 1.8V.
Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is used as an inter processor
communication bus.
2.2
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 TM (Automatic acknowledge of packets, address filtering and automatic channel
access) type of applications is available through an enhanced layer of functionality on top of the basic radio transceiver.
2.3
Antenna description
The antenna on the AVRRAVEN is a 100 Ω loop antenna with a net peak gain of about 5dB.
2.4
LCD
The LCD found on the AVRRAVEN module is a full custom 160-segment display tailored for the Atmel RZRAVEN kit
(See
Figure 2-2 for a quick reference). It contains a seven 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 2-2. AVRRAVEN – LCD Segments.
2.5
Speaker
An 8 Ω 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.