The making of a classic - this blog follows my progress as I construct and build a TR-909 drum machine clone from scratch.
Monday, 5 November 2007
After some debugging of the controller PCB I've come to the conclusion that I've done a tiny but crucial error. When both mCU's are connected, the crystal won't oscillate. The reason, it seems, is because pin 9 on mCU 1 and pin 10 on mCU 2 are connected to the same pin on the crystal. On my prototype card I get oscillation when the same pin on both mCU's go to the same pin on the crystal.
I will update the circuit to accomodate the change. Guess I'll have to bring out the knife and cut some paths on the etched cards.. *sigh*