[sdiy] Freescale Soundbuite

[Johannes Öberg]

;-( But thanks for your answer, cleared some things up for me.

Wasn't really thinking of a sampler, but a synth with looped (but long
as in multicycle) samples for waveforms, like the Korg DSS-1. So it
would need all the usual "virtual analog" features, and preferably
internal FX. Isn't a dedicated DSP faster for that?

And why are people using the Spartan 3E instead of the 3A, the latter
supposed to be optimized for DSP instead of logic? Btw, can't find
that Spartan based sampler on the google, have a URL?

What attracted me to the SoundBite is that's it seems like a
ready-to-go dev board for audio, with many I/O:s and no FPGA/hardware
learning curve as I'm already somewhat familiar with the 56k DSPs and
assembler programming. I get the feeling that doing something FPGA
based takes considerably more skill.

BTW, that's 88k-words as in 88k x 24 bits isn't it?

/J

On Feb 3, 2008 4:21 PM, Eric Brombaugh <ebrombaugh at earthlink.net> wrote:
>
> 88kB is the internal RAM. There are several schemes by which you can
> allocate it between program and data space, but that's all you get for
> direct access. If you want additional memory for sampling then your
> only option for this particular processor is to hook up an external RAM.
>
> Since most of the DSP56371 I/O pins are already committed on the
> SoundBite board,  that means you'll have to warm up the soldering iron
> and start hacking. There isn't enough GPIO to use a parallel RAM chip
> though, so you'll either have to design a serial/parallel RAM
> controller, or you need to buy a serial RAM chip. Serial RAM is not
> very common, but you might be able to use FRAM which is a high
> endurance non-volatile technology that is available with SPI
> interface. Unfortunately, the sizes are somewhat limited (32kx8 max in
> DIY-compatible packages) so you'd need 16 of them for your target
> sample size, and at ~$5.00 each that's going to get expensive pretty
> quick.
>
> It seems to me that if a sampler is what you're trying to do, the
> SoundBite really isn't the right platform to start with.  Any other
> microcontroller out there with a large GPIO complement would probably
> do - you can use ARM, PIC, AVR, dsPIC, etc, coupled with a good-sized
> parallel SRAM. For sampling you don't need a whole lot of DSP power
> either, so that opens up the field a lot. Or, try the Xilinx Spartan
> 3e Starter kit - it's also only $150 and includes ADC/DAC, a huge
> DRAM, etc. There's even a sampler design available online for it
> already, which would give you a good start.
>
> Eric