Re: info cpm board for cbm 8032

From: Mike Naberezny <>
Date: Thu, 15 Sep 2011 19:12:36 -0700
Message-ID: <>
Hi Ruud & Didier,

On 8/10/11 12:42 PM, wrote:
> Is it possible to say what belongs in the smaller empty socket? I
> must be a ROM because there isn't one on the board But OTOH the
> pinout is weird, certainly not like any (EP)ROM I know.

Some mysteries of the CP/M board are now solved.  Didier was correct, the 
empty socket is for an AM9511A math coprocessor.

Recently an 8032 sold on eBay USA and the buyer found a Z-RAM board inside. 
He found my page on the board with Google and contacted me.  He had the manual 
and sent me photocopies of it.  He did not have the disk.

The buyer said the seller also sold an 8050 drive, so I contacted that buyer 
as well.  He received a handful of disks with the drive.  Luckily, the CP/M 
boot disk was one of them and he sent it to me.

I've scanned the manual and made a disk image:

This is an interesting board.  It functions as a configurable 64K RAM expander 
for the PET, similar in ways to the 8096 board.  To run CP/M, the PET loads 
CP/M into the expansion RAM and then switches on the Z80.  The expansion RAM 
is then only accessible to the Z80.  The board adds a 6520 PIA to the PET 
memory map and a special terminal program communicates with the Z80 side 
through I/O lines.


Mike Naberezny (

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Received on 2011-09-16 03:00:08

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