ATTINY25-20PU – picoPower 8-bit AVR RISC Microcontroller 2KB Flash 8-Pin PDIP

Datasheet
The ATtiny25/45/85 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 ATtiny25/45/85 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.