Hi Matthew,

        Have a boo at the following links, there's enough info to
give you a good handle on how DRAMs work.


http://www.sxlist.com/techref/mem/dram/olmstead.html

        The timing considerations is a nice overview.


http://www.tech-tools.com/hwt12.htm

        Much explanation, and code for a 1-bit DRAM.


http://www.massmind.org/techref/microchip/picsimm.htm

        PIC Microcontoller Memory Method

The 16C74A to 256KB SIMM interface (can easily adapt up to 4 MB)

        Working code for a PIC 16C74A micro

....<snip>....

>
>
>Anyway, if anyone knows where I could find some docs
>for these SIMMs or ICs I would greatly appreciate it.

        See if you can find a cross reference for the memory chips
you have on the
SIMM, and check on data sheets from all available manufacturers.

>
>If I can't find any docs, I'll have to go at it
>blindfolded.  I've found some time specs of similar
>parts and I'll try the old CAS before RAS refresh
>thing to see if it's compatible first.


        It seems to come down to how many and how often you need to
refresh, but what I found as Herb said, the refresh timing is quite
conservative.


Heinz Czychun

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