The Microchip ATMEGA644PA-AU is a low-power 8-bit AVR® megaAVR MCU running up to 20 MHz, with 64 KB Flash, 4 KB SRAM, and 2 KB EEPROM. It provides 32 GPIOs, 6 PWM channels, an 8-channel 10-bit ADC, dual USARTs, SPI, I²C, and JTAG debugging. Operating from 1.8–5.5 V across –40 °C to +85 °C, this 44-pin TQFP package is ideal for embedded and industrial control applications.