Re: 8050 ROM dump

BTW while we're at it, the *third* 8050 ROM, a 2316 (901467-01 aka 901467, 
same in all DOS versions AFAIK) also matches the image on Zimmer's.

And it also has a gotcha:

It's programmed for an active LOW on pin 21 (Vpp) and connected to GND in
the 8050, but a 2716 needs Vcc on pin 21.

mike

----- Original Message ----- 
From: "MikeS" <dm561@torfree.net>
To: <cbm-hackers@musoftware.de>
Sent: Thursday, April 14, 2011 3:00 PM
Subject: Re: 8050 ROM dump


> Well, I dumped all 4 ROMs that I have and they match Zimmer's images
> perfectly.
>
> ***BUT***
>
> These ROMs are programmed with an active-HIGH chip select (pin20), so a
> 2764
> (or even a 68764/6) would presumably need to have CS inverted. I think
> this
> issue has also come up in the C64/C128 world somewhere...
>
> If he didn't account for that then I'm surprised he read anything at all,
> not just "substantially different" code ;-).
>
> mike
>
> ----- Original Message ----- 
> From: "Jim Brain" <brain@jbrain.com>
> To: <cbm-hackers@musoftware.de>
> Sent: Thursday, April 14, 2011 12:14 PM
> Subject: Re: 8050 ROM dump
>
>
>>
>> On Thu, April 14, 2011 10:05 am, Steve Gray wrote:
>>> This doesn't seem right. Surely commodore used EPROMs while developing
>>> the
>>> drives, before they made masked roms. Perhaps it's a matter of selecting
>>> the correct speed EPROM? Afaik the two CPUs don't access the same rom
>>> anyway. I'm sure I've seen drives with EPROMs direct from commodore.
>>
>> The user contacted me to state that he was able to rig up a way to read
>> the 2364 onto his programmer.  He notes the code is substantially
>> different from the Zimmers ROMs.  I don't have a copy yet, so I cannot
>> verify this information (yes, it is possible he messed up the wiring on
>> his reader interface, but I can't confirm either way).
>>
>> He notes he cannot continue working on it this week, but will try next
>> week or so.  I will keep the group updated.
>>
>> Jim
>>
>>
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>
>
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