pic microcontroller discussion list wrote:
> Hello all
>
> I'm working on a PIC16F877 IDE hard drive interface
> and I was wondering if someone could suggest a good
> type of parallel RAM that I could put right on the IDE
> bus to hold the next 512 bytes of info that I'm
> reading/writing to the hard drive.  I've never used
> parallel ram before, but I think this should work
> right?
>
> I have 2 or 3 spare pins on the F877 so I would be
> able to control the CS pin of the ram or whatever it
> uses.  What about pulling some RAM from an oldschool
> video card (it's in sockets)?
>
> Any help/info/ideas would be appreciated.
>


That's not difficult. It might be more difficult finding
them. DigiKey and Mouser never seem to have the size I
want in stock. Any of the parallel RAM chips you can
find/salvage should be useable. You might have better
luck at jameco if you want a small quantity of DIP
versions.

most of the SRAM chips have parallel address and data
lines. To control, there is typically a /CE (chip enable)
and a /WE (write enable). Some also have /OE (output
enable - used to tristate the data lines for bus systems)

If you're wanting to put it on the IDE bus, you probably
want a version that has the /OE signal such as CY62256.
It's rather large for only using 512 bytes, but it's
typical of the interface used by other chips.

hope that gets you started in the right direction.

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