ATMEL ATmega1284P Preliminary Summary Manual

This datasheet mainly introduces the characteristics and functions of the AVR® ATmega128A 8-bit microcontroller, including 131 powerful instructions, 32 x 8 general purpose registers, 20 MHz clock frequency at 20 MIPS throughput, 128K bytes of In-System Self-Programmable Flash, 4K bytes of EEPROM, 16K bytes of Internal SRAM and so on.