Re: Second Opinion on unknown PET option roms

From: William Levak <wlevak_at_SDF.ORG>
Date: Wed, 8 Sep 2021 05:11:43 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.2109080500060.27839_at_sdf.org>
My notes say that 901447-30 is diagnostic 320350  for the test fixture for 
PETs without a 6545 CRTC. It resides at $9800 in memory. It requires a 
jumper block in place of the keyboard and another jumper block on the user 
port. The test fixture has a clip that is clipped over the 6502. The reset 
button is then pressed and a diagnostic begins.

I think I have a description of the jumper blocks on zimmers.net, but I 
don't remember exactly where.

On Tue, 7 Sep 2021, Hans Liss wrote:

> I padded 901447_30_2001diag_0000.bin out with a 2k block and loaded it in 
> VICE at $9000, so that the ROM ended up at $9800, and then ran "sys 38912". 
> This happened:
>
> PET
>
> So, clearly it's the Diagnostic Clip 901447-30 for PET 2001.
>
> /Hans
>
>
> On 2021-09-06 22:35, Hans Liss wrote:
>> 
>> I used the VICE monitor to load that block into PET video RAM:
>> 
>> diagnostic 320350g
>> 
>> a8-a11 bad
>> 
>> tv ram ok
>> 
>> i-ram bad
>> 
>> z-page ok
>> 
>> a8-adr bad
>> 
>> stack ok
>> 
>> remove clip
>> 
>> /Hans
>> 
>> On 2021-09-06 22:14, Hans Liss wrote:
>>> 
>>> 901447-30_2001diag_0000.bin seems to disassemble nicely at $9800, and 
>>> http://mhv.bplaced.net/cbmroms/cbmroms.php lists "901447-30" as a 
>>> "Diagnostic Clip" for PET 2001, to be located at 9800-9FFF. Incidentally, 
>>> the code around $9979 seems to load bytes from $99ce to $99d8 to screen 
>>> memory, so maybe someone more patient than I can figure out what it says? 
>>> I suspect the entire block between $9985 and $99d8 is screen text, 
>>> actually.
>>> 
>>> 901484-03-2031ro_c000.bin seems to match "901484-03" on the same page, 
>>> which describes it as DOS 2.6 Low for the 2031 drive, to load at c000. 
>>> There's a copy of that ROM on 
>>> http://www.zimmers.net/anonftp/pub/cbm/firmware/drives/old/2031/index.html, 
>>> however, which seems to have nothing in common with this one. So that's 
>>> strange.
>>> 
>>> /Hans
>>> 
>>> On 2021-09-06 21:39, Hans Liss wrote:
>>>> 
>>>> Better link: 
>>>> http://www.zimmers.net/anonftp/pub/cbm/firmware/misc/unknown/
>>>> 
>>>> The low count of "a9" bytes in several of these is a sure sign it's not 
>>>> 6502 code. I took a quick look at a few:
>>>>
>>>>   * 8in-cpm-trbdos.bin is definitely Z80 code (or 8085, perhaps?). A
>>>>     CPM "driver" for 8-inch floppies, perhaps?
>>>>   * 740turbo1-1.bin is also Z80 code.
>>>>   * I suspect ultima-ii-v1-73.bin is also Z80 code.
>>>>   * create-new-base.bin and 40-80-60h.bin seem to be something else,
>>>>     like not program code at all.
>>>> 
>>>> I found a fairly useful disassembler at 
>>>> https://onlinedisassembler.com/odaweb/, by the way. I tend to use wfdis 
>>>> for 6502 code, but this one has many other architectures and accepts 
>>>> small hex dumps as input.
>>>> 
>>>> /Hans
>>>> 
>>>> On 2021-09-06 19:23, Bo Zimmerman wrote:
>>>>> Hello all,
>>>>> 
>>>>> Dave McMurtrie contributed a nice pile of PET option rom images to the 
>>>>> funet/zimmers archive _at_ 
>>>>> http://www.zimmers.net/.../computers/pet/other/index.html
>>>>> 
>>>>> I had no trouble identifying and classifying most of them. However, 
>>>>> there were several that I could either not get working, properly 
>>>>> disassembled,, or just couldn't identify. This is fairly new to me, so I 
>>>>> created a special place for them here:
>>>>> http://www.zimmers.net/ano.../pub/cbm/firmware/misc/unknown/
>>>>> 
>>>>> If anyone out there enjoys digital archeology, I'd ask you to give a 
>>>>> second or third opinion on some of those unknown roms. It's possible the 
>>>>> eproms were just corrupt or unreadable, but I'd sure like someone else 
>>>>> to concur before I throw any of the images out.
>>>>> 
>>>>> - Bo Zimmerman
>>>>> 
>>>>> 
>

wlevak_at_sdf.org
SDF Public Access UNIX System - http://sdf.org
Received on 2021-09-08 08:00:03

Archive generated by hypermail 2.3.0.