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| CX5M II msx2 conversion problem
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grit
msx novice
Berichten: 25 |  Geplaatst: 03 November 2007, 01:03 |
I am in the process of upgrading my CX5M II (us version) and am running into a little problem. I have to put the MSX2 ROM somewhere... There is a 16K eprom available on the mainboard which originally holds some sort of 80 columns display extension, but it maps to address $4000 instead of $0 on which it should be for the MSX2 ROM.
I put in a 32KB rom, the two 16K parts on the eprom programmed with the same data (so doubled) and it only shows one 16K block when put in the computer,
Does anyone know how to get this rom to map at address $0?
Thanks,
Gerrit
http://www.rgp.nl/cx5m
http://www.cx5m.net
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Jipe
msx freak
Berichten: 185 | Geplaatst: 03 November 2007, 16:05 |
search a cutting wire on PCB and restore connection
search a strap on PCB and remove it
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dicksch
msx friend
Berichten: 6 | Geplaatst: 11 November 2007, 11:23 |
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grit
msx novice
Berichten: 25 | Geplaatst: 11 November 2007, 23:17 |
yes, seen the doc, no good, I have a different mainboard. scratching and connectin pin 20 hasn't worked as of yet...
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dicksch
msx friend
Berichten: 6 | Geplaatst: 12 November 2007, 04:17 |
I found that I had to lift both pin 20 and 22 on the subrom. Pin 20 was then wired to MREQ-B and pin 22 to the NOT SLT30 as in the diagram. I made no changes to the board but just bent the 2 pins out slightly when reinserting into the socket and then wired the bent pins to the needed signals.
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grit
msx novice
Berichten: 25 | Geplaatst: 12 November 2007, 08:58 |
Aha, I'll try that, let you know what happens.
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