Re: identifying an unknown eprom content

From: didier_at_aida.org
Date: Thu, 27 Aug 2020 22:59:43 +0200
Message-ID: <00724962-2927-fe14-792c-a35d221628f2_at_aida.org>
this is the file to boot a station
the station board has a an eprom and a mc6854 + rs422 drivers
the software boot the operating system via the mc6854
the last character of the last line of the screen is used to have an 
indication of network activity
it loads 1 track of the hard disk and then starts executing the code
the code is then moved into the 64k extension

I'm also looking to the content of the eprom on the scsi board
but nobody seemed to have seen it
in fact the project started as SASI board but the name changed to SCSI

the network for the cbm 8032 was based on this system
http://www.brutaldeluxe.fr/products/france/memsoft/memsoft_pub_sicob_1981.pdf
same hard disk unit, different box, different interface
their multiplexer was an apple II motherboard in an industrial box
our multiplexer was a commodore 8032 in an industrial box

I think the chip in $8000 is a z80sio (not absolutely sure, I rarely 
programme this chip)
our board were all based on mc6854


On 27/08/2020 18:45, Martin Hoffmann-Vetter wrote:
> Hello,
>
>> The bytes at $e000 & $e001 are used as data, but also the irq/brk
>> vector points to $e000 so any irq or brk will go into an infinite
>> loop.
> No, $e000 ist only used as defaut value for $0059 and $e001 as defaut value for $006a.
>
> All hardware vectors (reset, irq and nmi) points to $e002.
>
>> Reset or nmi will start execution at $e002.
> There is a brk at $e864 that is called as error after timeout. So the reset routine is called via irq routine.
>
> I think this is an eprom for a single mpu system with small address decoding: $0000-$3fff for ram, $4000-$7fff for io1, $8000-$bf00 for io2 and $c000-$ffff for rom. Only first four bytes are used for io1 and io2.
>
>>> I have 2 eproms labeled: pc-central-26-4.bin (8k) and
>>> boot-poste-3.bin (4) the boot-post-3.bin contains the good
>>> content... [the copyright is present]
>> Are the two roms related? It might help to have them both
> Yes, that's a very good idea. Is it possible to post the other rom, too?
>
> Regards
> Martin
>
>
>
>


Received on 2020-08-28 00:00:03

Archive generated by hypermail 2.3.0.