[sdiy] Which programable chip?

[Jason Proctor]

oh right we're talking about Ian's routing project.

IMHO, things get gnarly very quickly going the adc -> mcu -> dac 
route. unless the analogue signals are happily in the 0-5v range, 
there's going to have to be some scaling stuff in there to allow 
negative voltages etc. i did this for my module, and it works, but 
it's not very precise. i doubt that just using the module as a pass 
through wouldn't distort the signal somehow.

4051s etc do seem like a good solution in this case. the mcu can be 
used to implement patch memories and other stuff that it's good at.



>Why would you need to run the audio through the processor?
>
>If I'm not mistaken, are you wanting to route one input (of 8 total) 
>to one output (of 8 total)?  You can do that with 2 4051 
>multiplexers, and not have to worry about any ADCs or DACs or high 
>speed processors or anything.  You only need to send 6 bits to 
>control everything.
>
>And if you want to be able to route multiple signals simultaneously, 
>it may be slightly more complicated (depending on whether you want 
>arbitrary routings, etc.)- you may need a crosspoint matrix, even 16 
>4066 chips (or similar), but it's the same basic idea to use analog 
>switches to do the work.