ATMEGA644A-AU [Microchip]

The high-performance Microchip 8-bit AVR® RISC-based microcontroller combines 64 KB ISP Flash memory with read-while-write capabilities, 2 KB EEPROM, 4 KB SRAM, 32 general purpose I/O lines, 32 general purpose working registers, a real-time counter, three flexible timer/counters with compare modes and PWM, two USARTs, a byte-oriented Two-Wire serial interface, an 8-channel 10-bit A/D converter with optional differential input stage with programmable gain, programmable watchdog timer with internal oscillator, SPI serial port, a JTAG (IEEE® 1149.1 compliant) test interface for on-chip debugging and programming, and six software selectable power saving modes. The device operates between 1.8-5.5 volts.

By executing powerful instructions in a single clock cycle, the device achieves throughputs approaching one MIPS per MHz, balancing power consumption and processing speed.