The 64KZ is organized as two 32K Blocks (not 16); the A15
switches control whether that block is in the lower or upper
half of the 64K range.
Reset out disables that block after a reset to allow the boot
ROM to use that space on power up.
Override & DMA are only relevant for DMA operations.
Bank switching is done by outputting a byte to 40H
(this address is set by a jumper block/PROM):
bit 0 = bank 0, etc., and each block's bank(s) are of
course set with SW2 & SW3.
Good luck; I've got a manual somewhere that I could scan
if you haven't already gotten one elsewhere, but probably
not this weekend. Email me off-list if I can help.
m
-----------------Original Message----------------
From: "Mike Davis" <ipscone_at_msdsite.com>
To: cctalk_at_classiccmp.org
Date: Wed, 21 Aug 2002 21:48:17 -0700
Subject: Cromemco 64KZ Info Needed
Reply-To: cctalk_at_classiccmp.org
Hope this is not a duplicate. The first one did not show up.
I have just obtained a Cromemco 64KZ board. This has 64K of RAM and
I'd like to test this out this weekend. Unfortunately, I don't have
any documentation.
There are 4 banks of RAM (16K x 8) Each bank is labeled "page0",
"page1", "page2" and "page3". There are also 3 8-pin dip switches:
I have a couple of photos at:
http://www.msdsite.com/vcomp/cromemco/photos.html
Since this is a 64K board and since there is other memory in my
system. I'm hoping this allows some sort of bank switching. But
without docs, I don't know how to use it.
I assume the Bank A/B allow setting which bank a particular 16K might
reside but am not sure. And the address lines of A15, A14 are a
mystery.
Is there a way to switch banks by writing to an I/O port? Location?
Can any of you help with an explanation how this works and how I might
use the switches?
Thanks in advance,
Mike
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Received on Fri Aug 23 2002 - 14:33:05 BST