The ATMEGA644-20AU is a 8-bit high-performance, low-power AVR RISC-based Microcontroller Unit combines 64kB ISP flash memory with read-while-write capabilities, 2kB EEPROM, 4kB SRAM, 32 general purpose I/O lines, 32 general purpose working registers, real time counter, three flexible timer/counters with compare modes and PWM, 2 USARTs, byte oriented 2-wire serial interface, 8-channel/10-bit A/D converter with optional differential input stage with programmable gain, programmable watchdog timer with internal oscillator, SPI serial port, JTAG test interface for on-chip debugging and six software selectable power saving modes. All the 32 registers are directly connected to the Arithmetic Logic Unit, allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.
Advanced RISC architecture
131 Powerful instructions
Fully static operation
Up to 20MIPS throughput at 20MHz
High endurance non-volatile memory segments
Optional boot code section with independent lock bits
In-system programming by on-chip boot program
True Read-While-Write operation
Programming lock for software security
JTAG interface
Power-on reset and programmable brown-out detection
