We wanted the following features for the board:
- All thru-hole construction for easy assembly
- Easy port connections to breadboards for prototyping
- 2 serial ports. Lots of memory (> 32k Flash).
- JTAG connector for debugging
Some of the other features of the board are:
- all headers are on a 0.1" grid to allow accessory proto-boards to span multiple connectors if needed
- the power input connector can be a coaxial barrel connector, a 2-pin terminal block, or a MTA-100 connector or 0.1" spacing header
- LCD displays can be connected using 1x16, 2x7 or 2x8 connectors.
This photo shows some of the key board features:
Each port connector has +5V power, ground, and the 8 port bits. A DIL16-to-DIP16 ribbon cable can be used to carry the signals, power, and ground to a breadboard. The DIP16 connector on the ribbon cable plugs directly into the breadboard. There are 6 uncommitted lines on the headers if you want to add additional signals to the ribbon cable.
The AVR1284-3U board uses removable UART interfaces called ComBoards. It is easy to switch between different connectors and interface types. Presently there are modules for RS323-DCE (DB9F), RS232-DTE (DB9M), and RS485 interfaces. The RS485 interface can use RJ45 jacks for CAT-5 cable or a terminal block. We will be adding USB and other module options in the future.
There are 4 different DIP40 AVRs that can be used with this board depending on how much memory you want:
ATMEGA164PA-PU, 16k Flash, 1K SRAM, 512 EEPROM
ATMEGA324PA-PU, 32k Flash, 2K SRAM, 1K EEPROM
ATMEGA644PA-PU, 64k Flash, 4K SRAM, 2K EEPROM
ATMEGA1284P-PU, 128k Flash, 16K SRAM,4K EEPROM
All parts feature 2 USARTS, 1 two-wire interface (TWI), JTAG debug, in-system programming (ISP), 8 channel 10-bit ADC, 20 MHz max. clock, and 1.8 to 5.5 Volt operation. All parts have two 8-bit timers and a 16-bit timer, except that the 128k part has two 16-bit timers.
The 'P' in the part number is for PicoPower, which means the chip can be operated at low voltages and set up to draw minimal amounts of power.
Either P or the PA version of the 16k, 32k, or 64k parts can be used. The PA parts use a smaller die size and are slightly cheaper. There isn't a PA version of the 128k part yet.
The AVR1284-3U development board will be available as a bare PCB with a parts list, a parts kit (solder it yourself), and a fully assembled board.
Please send your comments and suggestions for AVR dev boards to firstname.lastname@example.org