Hello!

I am doing a project for my final year in college that will use a
(hopefully) dsp based PIC microcontroller to implement a multi effects
processor. From looking at the site, i see that analog's and texas ins.
chips seem to be at the fore. Unfortunately the resources aren't available
for me to use these chips or any boards associated with them for
development. What i'd like to do is send in a simple .wav file, some simple
note, then perform a few different delay based effects on it, for example,
delay with feedback, phase, echo/reverb. So, my question is, is it possible
to do what i'm talking about on a PIC, and if so, what would be the correct
PIC to go for and the correct board also? From looking at a few algorithms
it doesn't seem tremendously difficult to do, but then again assumption is
the mother of all screw ups, hence why i need you guys' help!!
I really appreciate any help you could provide, including code, software,
hardware advice, whatever you might think would be useful!

Thanks in advance!

On Sep 9, 10:43=A0am, "rotabeast" <gmenac...@gmail.com> wrote:
> Hello!
>
> I am doing a project for my final year in college that will use a
> (hopefully) dsp based PIC microcontroller to implement a multi effects
> processor. From looking at the site, i see that analog's and texas ins.
> chips seem to be at the fore. Unfortunately the resources aren't availabl=
e
> for me to use these chips or any boards associated with them for
> development. What i'd like to do is send in a simple .wav file, some simp=
le
> note, then perform a few different delay based effects on it, for example=
,
> delay with feedback, phase, echo/reverb. So, my question is, is it possib=
le
> to do what i'm talking about on a PIC, and if so, what would be the corre=
ct
> PIC to go for and the correct board also? From looking at a few algorithm=
s
> it doesn't seem tremendously difficult to do, but then again assumption i=
s
> the mother of all screw ups, hence why i need you guys' help!!
> I really appreciate any help you could provide, including code, software,
> hardware advice, whatever you might think would be useful!
>
> Thanks in advance!

I've had pretty good luck doing simple audio effects using the
Microchip dsPIC33F family of parts. If you get the ones with the 'DCI'
peripheral then you can connect them directly to inexpensive audio
codecs. I'm not aware of any commercially available development boards
which are tailored for this sort of application though - Microchip has
an audio board, but my understanding is that it's fairly limited. I've
built my own boards for personal use though - more info on that here:

http://members.cox.net/ebrombaugh1/synth/dsPIC_sp/index.html

Eric

>I've had pretty good luck doing simple audio effects using the
>Microchip dsPIC33F family of parts. If you get the ones with the 'DCI'
>peripheral then you can connect them directly to inexpensive audio
>codecs. I'm not aware of any commercially available development boards
>which are tailored for this sort of application though - Microchip has
>an audio board, but my understanding is that it's fairly limited. I've
>built my own boards for personal use though - more info on that here:
>
>http://members.cox.net/ebrombaugh1/synth/dsPIC_sp/index.html
>
>Eric
>

Hi eric,

Thanks very much for that information, its very useful. Just one more
thing..did you find it difficult to write the programs for the effects that
you needed? all i want to do is delay, with variable parameters, tremolo
and phaser. As far as i know they dont seem hard in theory, but in practice
it might be a different deal!

thanks again!

On Sep 10, 1:47=A0am, "rotabeast" <gmenac...@gmail.com> wrote:
> >I've had pretty good luck doing simple audio effects using the
> >Microchip dsPIC33F family of parts. If you get the ones with the 'DCI'
> >peripheral then you can connect them directly to inexpensive audio
> >codecs. I'm not aware of any commercially available development boards
> >which are tailored for this sort of application though - Microchip has
> >an audio board, but my understanding is that it's fairly limited. I've
> >built my own boards for personal use though - more info on that here:
>
> >http://members.cox.net/ebrombaugh1/synth/dsPIC_sp/index.html
>
> >Eric
>
> Hi eric,
>
> Thanks very much for that information, its very useful. Just one more
> thing..did you find it difficult to write the programs for the effects th=
at
> you needed? all i want to do is delay, with variable parameters, tremolo
> and phaser. As far as i know they dont seem hard in theory, but in practi=
ce
> it might be a different deal!
>
> thanks again!

Those sort of effects are very easy to design. Go to this site for
lots of detail on how to implement them:

http://www.spinsemi.com/knowledge_base.html

These folks also make a fairly nice effects chip and development kit.
If you can't build your own you might consider this.

Eric

You can find some examples of audio effects implementation in
http://www.analog.com/static/imported-files/application_notes/21065L_Audio_Tutorial.pdf
The examples in this document are for the other architecture but
nevertheless they might be useful to get an idea of how the audio effects
are implemented in HW/SW.

--
Alexander