[sdiy] Pots vs Encoders, was Re: [sdiy] dave smith *instruments*

[Eric Brombaugh]

On 02/02/2010 08:06 AM, Jason Tribbeck wrote:
>
>> Interesting thread for me because I'm in the thinking stage for a digital
>> (FPGA) synth design that I want to be "knobby".
>
> Oddly enough, I'm doing the same, although it'll be an ARM instead of PIC for the controller.
>
> I'm using the ARM for MIDI decoding and oscillator assignment as well (it communicates with the FPGA via SPI - or will be once I've debugged an issue with it).

Last year I put together an ARM & FPGA synth board where the ARM loads 
the FPGA configuration from SD flash, then starts parsing MIDI and 
driving the parameters into the FPGA via SPI. Works pretty well. I've 
got a 2x16 LCD and a bunch of spare I/O that could be used for things 
like pots, buttons & encoders, but I found that simply using MIDI CCs 
from the pots on my keyboard worked very nicely. I've 16 knobs on the 
controller and those mapped nicely into many of the functions (FM 
parameters, ADSR, delay, mix, etc.

I'd hoped to take the next step and go polyphonic, but then something 
shiny distracted me...

Eric