[sdiy] Serial EPROM, sample playback

[James Patchell]

Hmmm....

I interfaced up an ATMega128 to an SPI flash memory.  Writing a windows 
based app to download data to the slave via RS232 is not that bad... (I 
used actually an FTDI245 usb chip on the AVR for the com port...REAL fast)....

Also, it is not that difficult to interface to Compact Flash Cards.  That 
way, you can load them up on your PC and then read the data out with the 
PIC....

For the PC program, I do have an example for a windows program that 
interfaces to a COM port on my website below...

http://www.oldcrows.net/~patchell/Windows/WindowsProgramming.html

See the section on Overlapped RS232.

All you need to do is add the code for sending the data...somehow...

I can't post the C code for the SPI flash, however.  Wrote that code for a 
client...and he would not appreciate it if I published it :-(

At 06:57 AM 12/7/2005 +0100, Johannes Öberg wrote:
>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

         -Jim
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http://www.oldcrows.net/~patchell

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