Optimised STK200/300 Programmer

The STK200/300 programmer is found in nearly every programmer software for Atmel AVR microcontrollers. The programmer shown here differs from other, similar, circuits in not requiring any extra power supply for itself, while still offering STK200 as well as STK300 programmer functionality.

In case you did not know, AVR microcontrollers can be programmed in-circuit with only five wires: Clock, MOSI, MISO, Reset and Ground. To these should be added the +5 V supply voltage taken from the microcontroller on the target board.