Single chip VC-ADSR idea

[Jeremy Brookes]

> Assuming you want midi control over your synth as well as 'knob'
> control, I
> would think you could do the same job with a PIC or other microcontroller
> with a UART for midi input - use CC's for ADSR parameters, and use an
> external DAC to generate the output voltages.
> The serial bus only needs a couple of lines, so if the processor
> has enough
> oomph, you could use the remaining i/o lines to select
> demultiplexed outputs
> for multiple EGs. One of those 20MIPs ATMEL jobs should handle 8 EGs.
> Not quite a single chip solution, but still a very low parts count.

I wasn't initially thinking about MIDI control - it was going to a single
chip that has a TTL gate input and a number of 0-5V control voltage inputs
for the ADSR times and levels. I was planning on making it a sort of
replacement for a CEM type of ADSR chip.

But as you point out, MIDI is an option. The PIC 16C7x have onboard UARTS
that should handle MIDI.

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   MIDI, SYNTHS, CIRCUITS, STUFF