RE: info cpm board for cbm 8032

From: Didier Derny <>
Date: Tue, 17 Nov 2009 20:36:36 +0100
Message-ID: <000001ca67bd$46f80660$d4e81320$@org>

I don't know if it's  the same board but it looks similar
I think there were a sort memory in $9000/$A000 to communicate
With the cpm board.  Perhaps with a jumper to choose between both

I had 2 8050 disks, one was a standard cbm disk with
A program,  a large part of basic and a small part of 6502 assembler

In fact, apparently, the cp/m bios was redirected to the 6502
- signaling with the PIO
- memory block (I can't remember where)
- a small 6502 assembler program charged of the transfers
- then a "quite" large basic program was processing the bios request
- then the small assembler program sent the response to the request.

It was also probably possible to map some sections of the cp/m memory 
Into the 6502 address space ($a000 ???)

To boot the cp/m board board was probably using the following scheme

- z80 stopped 
- cp board loaded block by block with the cp/m code
- z80 started

I don’t remember the details on how the pio worked.

I'm not sure if it was with this board but I think that the cp/m disks
Where stored in cbm files.

I worked a few days with this board, trying to attach a hard disk driver
But when  I saw how dirty the software was we just stopped using it.

Perhaps that the 24 pin socket was for a numeric processor

-----Message d'origine-----
De : [] De la part de
Envoyé : mardi 17 novembre 2009 18:36
À :
Objet : Re: info cpm board for cbm 8032

Hallo Didier,

As promised:

The unpopulated socket is meant for a 6502. As the you can see there 
is no EPROM onboard. The unpopulated 24 pins socket is NOT meant for 
an ERPOM. Pin 1 and 3 are connected to ground, pin 12 isn't. Pin 2 
is connected to +5V, pin 24 isn't. I have no idea at all what could 
fit there.

The Z80 communicates with the 6502 through the 6821/PIO combination. 
And even there are anomalies; the pins are connected to each other 
in a weird way (or I did something wrong). That rules out that the 
Z80 could address the $A000 expansion for example.

   / __|__
  / /  |_/     Groetjes, Ruud Baltissen
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Received on 2009-11-17 20:00:11

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