NMS 8220 Replace the application rom

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By gdx

Enlighted (4386)

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18-05-2021, 11:20

This depends on the program in ROM.

By Caliostro

Resident (54)

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18-05-2021, 11:28

An example?

By Caliostro

Resident (54)

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19-05-2021, 00:35

To update:
I copied 2 16K games
8000 -> Kings Valley
C000 -> Pac Man
I disconnected pin 27 "A14" and connected to pin 28 with 1K resistor and Pac Man start, I connect pin 27 (without disconnecting resistor) to GND and Kings valley start ...
In this way then, the eprom 27C512 is used as a 27C256, I am a little closer

By Caliostro

Resident (54)

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19-05-2021, 09:26

Update 2:
I copied 2 32K games
The goonies
0000 --> 3FF0 second section
4000 --> 7FF0 first section
Catboy
8000 --> BFF0 second section
C000 --> 0FFF first section
Pin 27 --> A14
Pin 28 --> 1K resistor to Pin 1 and The goonies start
pin 1 (without disconnecting resistor) to GND and Catboy start

By gdx

Enlighted (4386)

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19-05-2021, 09:40

You did not say that you wanted to put several Roms in it. I understand why you are having trouble making this work. It's complicated to put multiple 16K games on a 64K ROM without mapper. You have to either recompile the games to place them in the right addresses, or modify the MSX hardware even more.
Anyway, it's a shame to modify this MSX just to put some games. You can do the same with a cartridge and even put more games if it's a megarom. The principle is the same. A utility or the Basic-Kun compiler seems more interesting to me to put into this MSX.

I made a patch for that the internal Designer runs by pressing the Select key while starting the MSX in case you can't find an interesting replacement software.

Donwload: https://mon-partage.fr/f/kZ9bzIor/

By Caliostro

Resident (54)

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19-05-2021, 10:01

I didn't start with the idea of inserting multiple roms, I'm just experimenting.
rest assured, everything is positioned on DIP, nothing is destructive. thanks for the file

By Caliostro

Resident (54)

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19-05-2021, 10:32

ok, now a 48K rom also works, I am satisfied .... now I also try on Fenner SPC-800 and study the next project ...

By Caliostro

Resident (54)

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19-05-2021, 12:05

doesn't work in SPC-800, is there a reason why 27C512 doesn't work on MSX1?

By gdx

Enlighted (4386)

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19-05-2021, 12:27

SPC-800 use all slots, only half of slot 0 is free, so there must be a jumper somewhere to switch the slot from the location to another. Otherwise, this ROM location is for the one that is free in half of slot 0 (8000h-FFFFh).

https://www.msx.org/wiki/Fenner_SPC-800

By Caliostro

Resident (54)

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19-05-2021, 12:33

Ah OK thank you very much

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