[sdiy] General Audio DSP PCB

[Seb Francis]

Andre Majorel wrote:
> On 2006-06-10 11:30 +0100, Seb Francis wrote:
>
>   
>> What I'm building is a quad delay/flanger, but the design & PCB will be 
>> suitable as a general lightweight DSP platform for playing around with 
>> any audio effects processing ideas ...
>>
>> From the UI point of view there's connectors for:
>> 7 continuous rotary encoders
>> 2 switches (in my case 1 toggle, 1 momentary push)
>> 3 digit LED display
>> 4 clip LEDs
>>
>> There's also MIDI in and out so you can extend the UI with your 
>> favourite MIDI controller.
>>     
>
> Is it voltage controllable ?
>   

It could quite easily be ...

The rotary encoder and switch connections go directly to the PIC16F877A 
I/O pins.  8 of these pins can be configured in software as analog 
inputs (10-bit ADC).  The only modification to the circuit you would 
need to make is omitting the pull-up resistors for any analog input pins.

Even more usefully, the 2 main DSP PICs have many spare I/O pins, of 
which 7 can be configured as analog inputs (12-bit ADC).  I was thinking 
of routing these spare I/O pins to PCB headers - seems like this would 
be very helpful for direct voltage control of the DSP.

Seb