ATtiny2313 based PC/AT Keyboard Synthesizer

This video demonstrates a simple 2 voice square wave synthesizer I made from an ATtiny2313 chip and an old PC/AT keyboard. Simplified schematic (no 7-seg LED): http://alex.starspirals.net/wp-content/uploads/2010/08/ATtiny2313_music_player.pdf Source code: http://starspirals.net/prj/ATtiny2313XBoard/ATtiny2313XBoard_KeyboardOrgan.asm Article (in Russian): http://alex.starspirals.net/?p=1269