[sdiy] Microchip DSP kit $60 > AVR32

Roy J. Tellason rtellason at verizon.net
Fri Mar 21 18:51:13 CET 2008


On Friday 21 March 2008 13:13, Tom Wiltshire wrote:
> On 21 Mar 2008, at 16:35, Julian wrote:
> > Do either of you, or anyone else, know a good place to start
> > reading about on this area (sparkfun gives me hardware, but very
> > little in the way of knowlege to even make choices)  Google (or at
> > least my search terms) isnt getting me very far.
> >
> > Again, what im looking for is some sort of development platform
> > where i can (hopefully) implament some audio processing, with
> > sufficient facilities to let me concentrate soely on the
> > programming side, rather than having to learn the hardware specifics
> > (dacs/adc/busses etc) before i even start.
> >
> > A kind of 'dummies guide to microprocessor driven effects boxes' if
> > you like!
> >
> > Thanks, Julian
>
> Depends a bit how comfortable you feel with this sort of stuff or how
> much previous experience you've got. Have you done any assembly
> language? Do you write C programs?

I have,  and have in the past,  but not lately.  I don't think I'd have a 
problem with the software end of it,  much.

> I've been playing with the dsPICs for about a year, and found them
> pretty easy to learn. The board that started this thread would
> probably be a reasonable option to build a basic in/out digital
> effects box.

What I can't get into at this point is anything particularly spendy.  Maybe 
later on,  perhaps,  but not now...

> I've recently bought the Freescale Soundbite board that a few others
> on this list are using. It's a much more serious DSP, and would make
> a rackmount digital effects processor with the addition of just a
> power supply and a rack case. It has 4 stereo ins and four stereo
> outs, and optical digital in/out if you want it.

Is that last one for MIDI?

> The only problem would be controlling it, for which you need a front panel
> with knobs and switches connected to another processor which then talks to
> the DSP via SPI or I2C.

Those protocols are also on my list to deal with getting into one of these 
days.  Thinking about some of the commercial gear I've seen schematics of and 
worked on to some limited extent,  I remember some two-wire and three-wire 
interfaces and am wondering if those mfrs. used either of those,  or just 
their proprietary stuff.  Anyone know?

> That last point makes the dsPIC more appealing. You can simply
> connect the A/D inputs to pots to give a 0-5V CV and then use the ADC
> values to control parameters. This makes life easier. I used the
> 30F4013, which has 13 12-bit A/D channels for control CVs and
> includes the Codec interface to talk to an output audio DAC.
>
> I can't comment on the ARM chips, as I haven't used them since the
> Acorn Archimedes! I'm sure they're at least as good.

Lots of fun tech out there to play with,  never enough hours in a day...

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
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Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin




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