Microchip ATMEGA644A-AU, 8bit AVR Microcontroller, ATmega644A, 20MHz, 64 kB Flash, 44-Pin TQFP

The Microchip ATmega48PA CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. It operates on 1.8V to 5.5V voltage range. The AVR core combines a rich instruction set with 32 general purpose working registers. It features 64Kbytes of in-system programmable flash with read-while-write capabilities, 2Kbytes EEPROM, 4Kbytes 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.

Up to 20MIPS throughput at 20MHz
On-chip 2-cycle multiplier
Programming Lock for Software Security
Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes
One/two 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode
Real Time Counter with Separate Oscillator
Master/Slave SPI Serial Interface
Programmable Watchdog Timer with Separate On-chip Oscillator
On-chip Analog Comparator
Interrupt and Wake-up on Pin Change
Power-on Reset and Programmable Brown-out Detection
Internal Calibrated RC Oscillator
External and Internal Interrupt Sources
44-lead TQFP package