JED AVR595 Single Board Computer using the ATmega2561

Dimensioned drawing: AVR595 dimensions

Parts locations: AVR595 parts.jpg

Port allocations: AVR595 ports

Colour schematic: AVR595 schematic

CPU Data sheet: ATMega2561

JED AVR595 "Little ozzy logger"

In summary:

CPU is AVR2561, with 256 Kbyte of FLASH, 8 Kbyte RAM, 4 Kbyte EEPROM;
LCD interface to drive Hitachi controller 2 x 40 or 4 x 20 LCD text display. Board actually can mount on back of small 4 x 20 LCD;
Keyboard scanner interface;
Back-to-back clamp diodes are placed on all user lines for ESD protection;
Series resistors for current and EMC limiting on all inputs;
Eight input ports with voltage divider resistor pairs for setting input thresholds and voltage ratios and full-scale ranges for all analog and digital inputs. Analog input is 10-bit resolution by up to 8 channels. Basic input range is 0 … 4.096 volts;
Two RS232 Serial ports have ESD protection and EMC filters. One port can be RS485 or V-drive USB memory port interface;
Ultra-stable Real Time Clock with Temperature Compensated Crystal Oscillator (TXCO) for +/- 3.5 minutes/year max error. Clock device also has a 3 degree accuracy temperature sensor as board internal temperature readout;
Four low level analog inputs for thermocouples, feeding a 20 bit delta-sigma ADC using LTC2492;
DataFlash memory providing 8 Mbyte of data storage for datalogging. Also byte-writable 32 Kbyte FRAM from Ramtron;
Eight N-FET output ports;
Four input ports to interrupts;
One port is a 1-Wire port for device expansion or operator certification/identification;
All devices used are full industrial temperature range and board is designed for lead-free manufacture.