This is the famous Atmel ATtiny85 microcontroller, specifically the 20MHz Attiny85-20PU. This is a popular AVR microcontroller based on RISC architecture, and packs a decent set of functions despite its size and low number of pins.
Check out the SparkFun Tiny AVR Programmer for using with this IC.
- Atmel 8-bit AVR RISC-based microcontroller
- 8KB ISP flash memory
- 512B EEPROM
- 512-Byte SRAM
- 6x general-purpose I/O lines
- 32x general purpose working registers
- 1x 8-bit timer/counter with compare modes
- 1x 8-bit high speed timer/counter
- Internal and external Interrupts
- 4-channel 10-bit A/D converter
- Programmable watchdog timer with internal oscillator
- 3x Software selectable power saving modes
- DebugWIRE for on-chip debugging
- Achieves a throughput of 20 MIPS at 20 MHz and operates between 2.7-5.5 volts.