Re: DSP System


"David L. Jones" <altzone@xxxxxxxxx> wrote in message
news:1184928750.929663.117500@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jul 20, 6:05 pm, "Jon Slaughter" <Jon_Slaugh...@xxxxxxxxxxx> wrote:
"David L. Jones" <altz...@xxxxxxxxx> wrote in
messagenews:1184912759.591055.253980@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx



On Jul 20, 1:55 pm, "Jon Slaughter" <Jon_Slaugh...@xxxxxxxxxxx> wrote:
How hard is it to actually implement a DSP system?

I've been looking at the TMS320C6720 and some conversion devices and
it
seems I can gather all the components needed but I really don't have a
good
idea about how to go and implement something like that. The pdf's I've
looked at on TI's don't really go into detail about how to actually
put
something together(atleast the one's I've seen).

All I want to do is take an analog signal, add some digital
filtering(well,
whatever I want once I get into the software side), and output the
signal.

The digital conversion's seems pretty straight forward and I was plan
on
using something like the PCM1741 and PCM1807 or something similar for
the
conversion(although I ultimately want to go to 192khz).

I think all I'll need is the converters, memory, and the dsp? (I don't
think
I'll need a controller?) Is it going to be much harder than just
hooking
all
these up together and then downloading some code to the dsp?

At this point I do not need anything fancy and just want to apply some
effects like reverb and chorus to a signal for a start. The biggest
problems
at this point is the IC packaging for these devices as most are out of
my
reach(BGA, for example) for prototyping.

Is such a conceptually simple project out of my ability as a hobbyist?
Do
I
need to come up with some prototyping schematic and get some pcb's
made
for
prototyping? I'm really not sure how to go about this and I can't
find
any
documents online that can give me some details about the process ;/

Any ideas?
Thanks,
Jon

What you need is a DSP development board. They will usually contain
all you need to get a project like this off the ground - the DSP chip,
any required memory, a few ADC inputs and DAC outputs etc, many are
targeted specifically for audio use. It's already done for you.
TI have a complete range of them:
http://focus.ti.com/dsp/docs/dspsupporttnp.tsp?sectionId=3&tabId=2079...

They aren't particularly cheap, but it can save you weeks of mucking
around with hardware, when really a project like this is all about the
software.

There is nothing really special about DSP's, they are essentially just
a microprocessor with specilised hardware making them faster at math
and signal processing functions than a regular microprocessor or
microcontroller.

I've looked at that but I can justify the expense. Its got, what, about
20-30$ worth of components and another 20-30$ for the pcb (if that) yet
they
want 400 for just a starter? If theres something I'm missing that makes
it
worth it then please let me know about it but it seems like its not worth
it.

Jon

You are paying for the convenience, it's called "starter" for reason,
it gets you started with no with fuss and no wasted effort, productive
from day one.
You might be able to build it for less, but how much is your time
worth?
You have to design your board and get it made, and all the research
that goes along with that. Get the parts in one-off qty that aren't
always available as such. Then you have to sort out the software tools
and libraries etc etc


Isn't that part of the fun though? I'll eventually have to do that anyways.
The only reason I would want the board is so I have some guide lines on how
all the components fit together(since I can't seem to find any documentation
to help) and because if/when I do it myself I know I'll *** it up and spend
days or weeks if not months on some stupid little thing.

There are others available, but prices are similar, try this Blackfin
DSP audio kit:
http://www.analog.com/processors/platforms/ask.html
http://www.analog.com/en/prod/0,2877,BF537%252DHARDWARE,00.html

It's got everything you need for audio DSP development, tons of memory
and I/O etc, plus all a whole bunch of software tools.
Digikey have it for $371.


I was just looking at that. It was about 300$ direct. The Blackfin seems
pale in comparison to the TMS series though. The Shark seems to be decent
though.

I think I'm just going to try and design a board myself. It may or may not
work but I suppose I can post my results here and get a little help. It just
seems it will be a few months before I can even start unless I can find some
good documentation. The EVM is pretty nice in that it has a bunch of stuff
but I don't think I need it all and most likely its overkill. Its nice to
have but I wouldn't want to waste 500$(min since I'll need software stuff
too) if I don't follow through with the project I have in mind(although it
would be nice to have around but not for the price).

I'll see what I can come up with though. Trying to gather some info on it
now. The TMS data*** just didn't give me much hope for finding good info.

Thanks,
Jon



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