[sdiy] dsPIC fun board

[Seb Francis]

Eric Brombaugh wrote:
>
> Also, don't forget Seb Francis' Digi-Mod dsPIC project - it's very 
> similar to this one with some nice extras - decent audio codec, sample 
> memory, more CV inputs, etc. Last he mentioned it he had a layout done 
> but I haven't heard more from him about it since then and he pulled 
> the schematics & board plots from his site. I don't recall if it had 
> CV outs though...
>

Just got back from holiday and am now happily in possession of a couple 
of Digi-Mod PCBs.  So once I've got my suitcase unpacked and emails 
read, it's time for some soldering :)

Final schematics and details will be back up soon enough, and PCBs will 
be available for sale once I get the prototype fully tested.

I did end up laying a footprint for some CV outputs in the end.  Can't 
remember which DAC I spec'ed, but was 4x 12bit I think.

Feature overview is:

- dsPIC33FJ128GP708 (40 MIPS)
- High quality audio CODEC (2 channels in, 2 channels out), with 
switchable sample rate
- 4Mbit SRAM (5.6s sample time at full sample rate)
- Analog feedback loop with CV control (using THAT2162 VCAs)
- 14 CV inputs (2 to VCAs, 12 to DSP)
- 4 CV outputs
- 8 Analog Gate inputs
- 10 Digital I/O pins (3.3V logic levels, including 2xSPI, 1xI2C)
- MIDI In/Thru/Out
- 8Mbit EEPROM to save samples, etc.
- ICSP/ICD connection

All features are optional and can be omitted if not required (except for 
the dsPIC of course!)

Seb