Re: need help with identifying some ROMs

I opened up my MPS-801, the EPROM is labeled HN467432G and has a sticker
over the window labeled 5JW.

On Mon, May 2, 2022 at 11:11 AM Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
wrote:

> On 5/2/22 19:36, groepaz_at_gmx.net wrote:
> > Am Montag, 2. Mai 2022, 19:26:11 CEST schrieb Gerrit Heitsch:
> >> On 5/2/22 19:00, groepaz_at_gmx.net wrote:
> >>> Hy!
> >>>
> >>> In order to specify better what ROMs come with VICE and/or which the
> user
> >>> needs to provide, i have started renaming them to, and listing them in
> the
> >>> documentation with, their actual part numbers. For some i could not
> find
> >>> them - it would be cool if those of you who own these devices - or know
> >>> the part numbers - could provide them. Perhaps you can also point me to
> >>> another archive than zimmers (a list of part numbers doesnt really
> help).
> >>>
> >>> In particular:
> >>>
> >>> - mps801.bin (MPS 801 charset)
> >>> - mps803.bin (MPS 803 charset)
> >>
> >> Isn't the MPS803 using a controller with an internal ROM? The controller
> >> can use an external ROM, but according to the service manual, that
> >> feature is not used and the internal 4K ROM runs the printer.
> >
> > Thats what i thought too - however, the .bin that comes with VICE
> contains 4k
> > (3.5k for 803) of charset data. Perhaps the actual internal ROM keeps
> only
> > half of this and the revers mode is done in software? In any case, the
> part
> > number would be interesting :) Perhaps we can have a real dump soonish,
> see
> > https://csdb.dk/forums/?roomid=11&topicid=155739#155808 (That probably
> means
> > the part number is something with 78C11 in it? or did they label them
> > differently?)
>
> I remember peeking into my MPS803 back then and vaguely remember that
> there was just 7811 printed on the chip. Maybe there was a part number
> too, but it would have been a much smaller print which I couldn't read.
>
> And I would expect the reverse being done in software. Saves a lot of
> ROM space that can be put to better use. And the code for it should be a
> simple test whether reverse is wanted and then an EOR #$FF (or
> equivalent) on the bit pattern about to be send to the print head.
>
> Looking at the datasheet, it looks like Z80-based controller.
>
>   Gerrit
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