AVR-Chat

If you don't need a DsPic, look at these low end devices;
18F23K20 series  28pin, 64MHz , about $1.60        or
18F14K50 series, 20pin 48MHz  similar price

I'm not saying they're suited to the app, but they're budget micros' with
oomph

Roland


2009/11/9 syberraith <syberraith@yahoo.com>

>
>
>
>
> --- In AVR-Chat@yahoogroups.com <AVR-Chat%40yahoogroups.com>, BobGardner@...
> wrote:
> >
> > Guitar amps aint real hifi. The speakers dont get much above 3.5KHz, so I
> think a 20MHz AVR might do a respectable job of a 10bit 9KHz transfer table
> lookup function and echo chorus type effects.
> >
> >
> > -----Original Message-----
> > From: syberraith <syberraith@...>
> > To: AVR-Chat@yahoogroups.com <AVR-Chat%40yahoogroups.com>
> > Sent: Sat, Nov 7, 2009 12:46 pm
> > Subject: [AVR-Chat] Looking for the Right AVR for my Project
> >
> >
> >
> > I am designing a guitar pedal effect and need a MCU to sample the signal,
>
> > erform a non-linear function, then generate a control current.
> > The project requires one ADC and one DAC these can be separate devices.
> > The non-linear function can be performed without a FPU using CORDIC
> routines.
> > hese would take a significant number instruction cycles to perform.
> > The function could also be performed with a look up table, which would
> require
> > ignificant memory.
> > I would like to have a sample rate as high as possible, 200K samples per
> second
> > ould be the highest desired, with 46K being the absolute lowest required.
>
> > I have been looking at 16 bit devices in the 30 MIPS range and up. Most
> of the
> > nes I have seen with sufficient speed have been excessive elaborate.
> > So, does anybody know on a simple device with enough speed for my
> project?
> > Regards,
> > Fred
> >
> >
> > ------------------------------------
> > Yahoo! Groups Links
> > Individual Email | Traditional
> > http://docs.yahoo.com/info/terms/
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
> I see I need to clarify some things.
>
> This is a compression only effect, It has two states, on an off. The lookup
> table would be for a transcendental function, which could also be done with
> a iterative process that would take up less memory but more instruction
> cycles.
>
> Yes, dsPICs look promising. I've been looking at PIC30s and PIC33s, which
> run at up around 30MHz. The trouble with them is that they come with a lot
> of communication peripherals that I lack any need for such as Ethernet or
> USB etc. The basic MCU for those is a PIC24 that I think only runs at 16MHz.
>
> I could just as well use a 32 bit device. Lots of AVR models there with the
> the same selection problem.
>
> Being new to MCU and out of practice with coding. I do need to look at
> what's been done before in similar projects.
>
> Thanks,
>
> Fred
>
>  
>


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