Re: More on 8280

From: William Levak <wlevak_at_SDF.ORG>
Date: Thu, 9 Jul 2015 03:36:54 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.1507090331280.7679@sdf.lonestar.org>
There are two sets of DOS ROMs for the 8280 on zimmers.net, 30054x-001 and 
30054x-revA.  Comparing these two sets, there are a total of seven 
differences between them.  Where they are different, the -001 ROMs are one 
higher than the -revA ROMs.  This includes two locations where there are 
$AA fill bytes and the -001 ROMs have two $AB amongst all the $AA.
It appears that the -001 ROMs are defective.

On Tue, 7 Jul 2015, William Levak wrote:

>
> On zimmers.net there are two 8280 300541 files: 300541-001.bin and 
> 300541-revB.bin.  If you compare the two files, everywhere they are 
> different, 300541-001.bin is 2 higher than 300541-revB.bin.  If you 
> disassemble them, 300541-revB.bin makes sense; 300541-001.bin does not.
>
> Therefore:  300541-001.bin is a version of 300541-revB.bin with a bad d1 
> line.
>
> The schematics do not show a GCR ROM.
>
> The schematics are available at:
>
>      www.cbmhardware.de/floppy/cbm8280.php
>
> They are very fuzzy and hard to read.  I am working on cleaning up a copy. 
> When it is ready, I will send it to zimmers.net. Don't expect much.  It was 
> scanned at a very low resolution.
>
> wlevak@sdf.lonestar.org
> SDF Public Access UNIX System - http://sdf.lonestar.org
>
>      Message was sent through the cbm-hackers mailing list
>

wlevak@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org

       Message was sent through the cbm-hackers mailing list
Received on 2015-07-09 04:00:07

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