Date   : Fri, 14 Jul 1989 21:18:02 GMT
From   : uop!nsayer@ucdavis.ucdavis.edu (Nick Sayer)
Subject: AAARRRRGGGGHHHH! Ram chip hassles

Forgive the widespread post, but I am being driven quite insane by
this nagging problem.

I am in the process of upping the speed on a PCPI Applicard for a friend
of mine. I was able to do this successfully on my Applicard, with parts
in my toolbox, but now my toolbox is empty, and I need to buy some more
RAMs. 

I need 64Kx1 dynamic RAM chips, like 4164's. They need to be 100 ns.
They need to work with 7 bit (128 cycle) refresh. I have called 20
different people (really! I counted!). Every single person I talked
to apparently didn't know what I was talking about. As I talked to
them, I could see (even through the phone!) this strange blank look
come across their face.

Am I the only one in the world who understands the difference between
7 and 8 bit refresh??? Am I going to have to buy 256K RAM chips and
waste 192K of RAM to make this project go???

This project is for a Z-80. When the Z-80 refreshes, it puts a 7 bit number
out on the high 7 bits of the address bus and generates a special refresh
read signal. Some RAM chips will work just fine when only every second
row is refreshed. These are called 7 bit refresh cycle RAMs.

P-P-P-P-P-Please, eddie!!!!

Nick Sayer  |  nsayer@uop.edu  | ...ucbvax!ucdavis!uop!nsayer
Packet radio: N6QQQ @ WB6V | FredMail: NSAYER@MADERA%NORCAL
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