To be able to use the synth for sequencing, I need some way to control the synth from the computer. The standard way for doing this is midi. Right now, midi is the only way to play the Bergfotron, as I don't have a CV keyboard.
Because the serial digital nature of midi, a microprocessor is required to decode the midi messages. I didn't want to be bothered with programming, and everything that goes with a microcontroller design. Therefore I opted for a midi to CV converter kit.
The Oakley MidiDAC fulfilled my specifications. It outputs CVs for pitch, gate, velocity, aftertouch and a few more things. What else is available depends on what mode the unit is in. Oakley sell the MidiDAC as an unpopulated circuit board, along with a programmed PIC processor. They can supply the DAC too.
The Bergfotron is dimensioned for bitimbral operation. Therefore two MidiDAC boards were purchased. They are mounted together, in the same module.
One thing the MidiDAC doesn't have is a midi sync output. Therefore a Blacet midi to sequencer interface chip have been aquired. It can output 24 ppqn clock and start/stop commands. I'm also planning a LFO that is controlled by the chip and therefore synced to midi tempo. This will all be in a future module.
The midi module seen from the side.
The same module seen from below.
The midi connectors are on a separate panel. The jacks are for inserting other signals on the pitch CV and gate buses. This way another controller can be accessed from all modules, without running patchcords to each of them. Ideal if you want to connect an analog sequencer or a CV keyboard, instead of midi control.
The connector module seen from the back.