Re: identifying an unknown eprom content

From: didier_at_aida.org
Date: Thu, 27 Aug 2020 13:14:05 +0200
Message-ID: <9acded7d-54ad-1337-e501-9e6862d07786_at_aida.org>
I know very little about this eprom
it was given to be by commodore maintenance about 30 years ago
according to the label it was supposed to work on a network board 
installed in a 8032 motherboard
obviously it's not the case
I'm thinking to a c64 cartridge in ultimax mode (booting in $E000)
I'm trying to get a better disassembly and some clue to go further




On 27/08/2020 12:56, Francesco Messineo wrote:
> Hi,
> just a suggestion: when you reverse engineer some unknown firmware,
> you NEED also to have a complete schematic of the system before you
> start.
> So if you don't have a schematic, you need to first reverse engineer a
> good schematic.
> I tell you that from my own experience on reverse engineering these
> kind of old and undocumented boards.
> The code starts to make sense (and you can start making sense of it)
> once you know where RAM/ROM and whatever else (I/O) is mapped.
>
> HTH
> Frank IZ8DWF
>
> On Thu, Aug 27, 2020 at 12:49 PM <didier_at_aida.org> wrote:
>> I'm trying to identify an eprom with an unknown content
>> I was thinking it was the eprom booting the server (a commodore mother
>> board without screen nor keyboard in an industrial box)
>> (on the commodore we had a network composed of a server and up to 16
>> stations)
>> 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]
>> what I know on the pc-central-26-4.bin:
>> - it's a 8k eprom, starts at $E000, the code starts at $E002 before
>> there are 2 bytes  $00 $BF
>> - it's 6502 code  (seems written by an amateur)
>> - there is some code between $E800 and $E8FF so it's not a 8032
>> - they are writing something around $8000  and also around $0400
>>
>> I was thinking that perhaps it was something for a vic20 or a c64 but
>> I've not really used this 2 machines
>> any idea of what I can do to identify the machine ?
>>
>> I'm thinking to try to check the use of I/O area but I need a better
>> disassembly
>>
>>
Received on 2020-08-27 14:01:09

Archive generated by hypermail 2.3.0.