Re: Copying ROMS ?

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Is there a manufacturers mark on these ROMs? Is it possible they are
Motorola? Motorola had some ideas about Eprom/Rom compatibility that wasn't
shared by Intel and others and Motorolas' design did not catch on. Motorola
was (it seems) more aligned with TI in those days (both from Texas?) and
were also making 2564's that have a different select pinout than 2764s. Do
the 2764 Eproms work in the board that has these mystery ROMs?

On another note, I hope it isn't too hot where you are - you mention
swaying the ROMs and I'd hate to think you were succumbing to the
weather... ;-) Heatstroke? (going back into hiding...)

John:-#)#

At 08:12 AM 22/06/2002 -0700, Mike Davis wrote:

>Like I said below:
>EPSON BASIC1R0 M64020AA
>EPSON BASIC1R0 M64021AA
>EPSON BASIC1R0 M64022AA
>EPSON BASIC1R0 M64023AA
>
>The other writing is simply date code information.
>
>The thing is, like I have said, I have a 2nd HX-20 that has 27C64s
>installed. So, I was going to copy the BASIC to 27c64s and use in
>the 2nd unit to have a BASIC machine.
>
>Someone suggested that the masked ROMs might have some sort of
>special non-standard select method within the ROMs. But if that was
>the case, the 27C64 wouldn't work, unless there was some difference
>in the board (No PALs on this board). I'm going to disassemble it
>today and see if the 2nd unit has some rewired ROMs.
>
>But, I have a 2nd problem that I'm trying to work off of this board.
>I pulled the BASIC ROMs from the 1st unit and performed a hard reset,
>clearing RAM. Still ran BASIC and the monitor program that were
>supposed to be in ROM (ROMs were completely out of the system).
>
>I was going to simply sway ROMS and see if they worked in the other
>system but for some reason, the systems behave the same, regardless
>of which set of ROMs is in either machine.
>
>I thought perhaps the program is loaded into resident memory but the
>manuals don't mention this and I don't know how to force a reload. I
>know their other machine, PX-8, behaved this way.
>
>
> > Is there any common numbering on the masked parts that might give a
> > clue as to what they REALLY are?
> >
> >
> > Mike Davis wrote:
> > >
> > > That was the first thing I tried. It read in all blank. That is
> > > the problem that I'm trying to resolve.
> > >
> > > > If 2764s are known to work just read the ROMs as 2764s.
> > > >
> > > >
> > > > Mike Davis wrote:
> > > > >
> > > > > I have verified that I can read and write other 27c64s and I
> > > > > also tried swapping ROMS however there is another small glitch.
> > > > >
> > > > > Apparently the HX-20 runs the programs out of RAM. I guess it
> > > > > loads from PROM and runs from RAM. I removed all of the BASIC
> > > > > ROMs and performed a hard reset and when it comes back, it's
> > > > > still running BASIC, without the BASIC ROMs even installed.
> > > > > Wierd!
> > > > >
> > > > > I have looked through the manuals to try and find a way to force
> > > > > a reload but no go (so far). I might try removing the internal
> > > > > batteries and see what happens.
> > > > >
> > > > > The manual also mentions that one can use 27C64s in the HX-20.
> > > > > There may also be one other thing that is causing the problem.
> > > > > I am trying to read the ROMS using family/pin codes for other
> > > > > ROMS. I don't find that part number and have tried a number of
> > > > > other 8K ROM fam/pin codes and none give me anything but blank
> > > > > loads.
> > > > >
> > > > > Perhaps that is part of the problem?
> > > > >
> > > > > Mike
> > > > >
> > > > > >
> > > > > > Verify that you can read another 2764 (incase you have reader
> > > > > > problems).
> > > > > >
> > > > > > Can you swap the 2764 for the Masked ROMs & work without
> > > > > > changing jumpers/settings/wiring?
> > > > > >
> > > > > > I see there are a few HX-20 collectors on the net, they may be
> > > > > > more informed.
> > > > > >
> > > > > > Kev
> > > > > >
> > > > > > >
> > > > > > > I think I understand what you are saying. I'm sure they are
> > > > > > > Masked ROMS or at least that would make sense. They are a 4
> > > > > > > chip chipset with numbers: EPSON BASIC1R0 M64020AA to
> > > > > > > M65023AA.
> > > > > > >
> > > > > > > The thing is however, that in identical machines, the other
> > > > > > > EPROMS are 27C64 so the pinout would seem to have to be the
> > > > > > > same or the EPROMS would not work right in the other
> > > > > > > identical machines, would they?
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > >
> > > >
> >
> >

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Received on Sat Jun 22 09:46:14 2002