Expand your PSIM!
2004-12-22 by djbrow54
I was sitting here looking at my latest module which is a conversion of the PAiA MIDI2CV to a MOTM format. I had it left over and thought it would get more use installed in my synth. Then it dawned on me ... I could use this for a PSIM expansion. Mode4 in the PAiA is a MIDI Control Change to CV for all 8 channels. I can expand the PSIM by up to 8 CV channels out by using the MIDI output capability of the PSIM to send Control Change messages to the PAiA. The PAiA only uses 7 bit data so the outputs have less resolution over the 0 to 10 volt range. The PAiA implements running status so it's only two bytes of data per channel which takes ~615 uS to transmit in polled mode. This may be that excuse for me to update my MIDI drivers with interrupt driven transmit. Right now I have the PSIM looping all 4 inputs to outputs and generating an 22 Hz 5 volt ramp output on the PAiA output with additional 5 mS triggers on output 2 and output 3 that occur at 33% and 66% of the duty cycle. Neat! Dave