Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!fox!portal!cup.portal.com!Ordania-DM
From: Ordania-DM@cup.portal.com (Charles K Hughes)
Newsgroups: sci.electronics
Subject: DRAM & Speeds needed...
Message-ID: <26414@cup.portal.com>
Date: 30 Jan 90 04:38:32 GMT
Organization: The Portal System (TM)
Lines: 16


  I am having a bit of trouble with processor speeds versus DRAM speeds.
I am working on an 8MHz 6502/65816 design and I need to know what speed 
of DRAM I need.  The spec sheets for the 6502 list a 60ns access time,
but I am having trouble believing this when there are 33MHz '386 machines
using 80ns drams.  Could somebody explain how this works and what speed 
I would need to use?
  That was the first part - now for the second.  Along the same lines I need
to perform a great deal of address decoding for addresses $000000-$00FFFF
and I cannot figure out how to do them without introducing wait states.  Does
anyone know of any general purpose memory mappers/decoders that work at high
speeds? (8/16Mhz - real clock speed - 1 read/write per cycle)

Thanks
 Charles_K_Hughes
@cup.portal.com