The ATMEGA644P-20MU is a low-power CMOS 8-bit Microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega644P achieves throughputs approaching 1MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. The ATmega644P provides 64kB of in-system programmable flash with Read-While-Write capabilities, 2kB EEPROM, 4kB SRAM, 32 general purpose I/O lines, 32 general purpose working registers, real time counter (RTC), three flexible timers/counters with compare modes and PWM, 2 USARTs, a byte oriented 2-wire Serial Interface, a 8-channel, 10-bit ADC with optional differential input stage with programmable gain, programmable Watchdog Timer with Internal Oscillator, an SPI serial port, IEEE std. 1149.1 compliant JTAG test interface.
● Advanced RISC architecture
● Power-on reset and programmable brown-out detection
● Internal calibrated RC oscillator
● External and internal interrupt sources
● Six sleep modes - idle, ADC noise reduction, power-save, power-down, standby and extended standby
● 131 Powerful instructions-most single clock cycle execution
● 32 x 8 General purpose working registers
● Fully static operation
● Up to 20MIPS throughput at 20MHz
● On-chip 2-cycle multiplier
● JTAG (IEEE std. 1149.1 compliant) interface
● Programmable watchdog timer with separate on-chip oscillator
● On-chip analog comparator
● Interrupt and wake-up on pin change
● Two 8-bit timers/counters with separate prescalers and compare modes
● One 16-bit timer/counter with separate prescaler, compare mode and capture mode
● Real-time counter with separate oscillator
● Six PWM channels
● Two programmable serial USART
● Master/Slave SPI serial interface
