ATtiny2313

The high-performance, low-power Microchip 8-bit AVR® RISC-based microcontroller combines 2 KB ISP Flash memory, 128B ISP EEPROM, 128B internal SRAM, universal serial interface (USI), full-duplex UART, and debugWIRE for on-chip debugging. The device supports a throughput of 20 MIPS at 20 MHz and operates between 2.7-5.5 volts. By executing powerful instructions in a single clock cycle, the device achieves throughputs approaching one MIPS per MHz, balancing power consumption and processing speed.

See also the picoPower® version: ATtiny2313A