[sdiy] Serial EPROM, sample playback

[Johannes Öberg]

Hi list!

I'm making another sample-playback thingy. This time it's longer and
reprogrammable (>=20 times) samples and better quality (>=3 secs, >=6bit
15khz or equiv.). It's a PIC 16F84 in the middle, and everything will run on
batteries.

What would be the best way to store the sample? I'm considering an SPI Flash
EPROM, but it seems quite cumbersome to interface them with bitbanging. The
I2C ones seems even worse. What's worse is I can only find surface-mount
flash eproms. Therefor the programming would have to be in-circuit, and
adding a PC interface on the PIC seems very difficult, not to mention it
eats PIC legs. But maybe I'm wrong?

What simple diy SPI Flash programmers exists? Preferably with DOS/Win
software.

What's done already that I should look at? How about trying to interface a
parallell (E)EPROM with some help from a shiftregister? Would this eat alot
of power?

Also, would perhaps I2C be better? It does seem terrible for bitbanging,
especially since I lack proper test equipment (I only have a slow scope and
a DMM).

I'm also concerned about the DAC. Since I'm low on free PIC pins, Roman
Black's 1.5 bit DAC seems to be the most suitable. Anybody have any other
suggestions I should look at?

Any tips welcome!
/Johannes
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20051207/29a46d33/attachment.htm>