Path: utzoo!attcan!uunet!ginosko!gem.mps.ohio-state.edu!apple!noah
From: noah@Apple.COM (Noah Price)
Newsgroups: comp.sys.mac
Subject: Re: Mac IIci SIMMs
Summary: More on fast-page-mode on the Mac IIci
Keywords: fast page mode Mac IIci
Message-ID: <35381@apple.Apple.COM>
Date: 9 Oct 89 06:29:35 GMT
References: <10730@phoenix.Princeton.EDU> <35341@apple.Apple.COM>
Followup-To: comp.sys.mac
Organization: Apple Computer Inc, Cupertino, CA
Lines: 21

Just a minor correction...

In article <35341@apple.Apple.COM> marc@Apple.COM (Mark Dawson) writes:
>(2) As I understand it, a 1 meg chip only has 10 address lines, but you need
>20 bits to address the full 1 meg.  So what you do (for a read) is to put the
>low 10 bits of the address on the address lines, and strobe the CAS line.  You
 ^^^^^^^^^^^--not really, but ok in theory                 RAS~--^^^
>then but the upper 10 bits of the address on the address lines, and strobe the
              ^^^^^^^^^^^^^--again, not really
>RAS line.  Now you have given the chip the "full" address, and it will output
 ^^^--CAS~
>the data you want.

So, RAS~ is asserted first with the address of the row, followed by CAS~ with
the address of the column within that row.  CAS~ can be asserted repeatedly to
get other columns from that row.

noah price                                        Mac IIci Hardware Design Team
                                                  Apple Computer, Inc.
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noah@apple.com                                      ...!{sun,decwrl}!apple!noah