The ATtiny2313 is the last version of a whole series of AVR microcontrollers made by Atmel. Predecessors were for example the AT89C2051, the AT89S2051 and the AT90S1200. It is despite it's small size a very complete microcontroller and it's equipped with a serial port which is also suitable for USB. The MEEPS ATtiny2313 board is equipped with reset circuitry, an external 20MHz crystal and a 6 pin ISP connection to program the microcontroller. A mere 13 I/O pins are free for several purposes. Is the serial port unused the total of free pins is 15, very impressive for such a small microcontroller. The ATtiny2313 is easily programmable in assembly, C en also the powerful BASIC compiler BASCOM AVR is very suitable for this chip. This board is also suited for the recent ATtiny4313, this microcontroller is identical to the ATtiny2313 but has 4K program memory.