Dumping/reverse engineering MSX models thread

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By xesco

Rookie (19)

xesco's picture

07-02-2020, 20:16

Any reason why it's not emulated in OpenMSX? Or it's just not worth it? Just wondering.
My idea was to learn about the tools and play arround with the software and harware so I will still do it for the fun of it.
If not needed then I won't post it here thoough.

Thanks!

By rderooy

Paladin (683)

rderooy's picture

07-02-2020, 20:40

A Check and some high-res pictures of the internals are always welcome I think. Especially a picture of the bottom of the mainboard, which is missing from the wiki for the /40.

I don't know if it is worthwhile emulating the /40. According to the wiki, the only difference with the /20 is a few fixes on the mainboard, but I don't know what those fixes are and if they can or need to be emulated.

By Grauw

Ascended (8927)

Grauw's picture

07-02-2020, 20:43

Everything is worth emulating Smile.

If the machine XML is identical, then you know, which is useful info by itself.

By xesco

Rookie (19)

xesco's picture

07-02-2020, 21:45

Grauw wrote:

Everything is worth emulating Smile.

If the machine XML is identical, then you know, which is useful info by itself.

That is a good point. As a starter here the photos of internals, external and ports.

Thanks for your comments!

By xesco

Rookie (19)

xesco's picture

15-02-2020, 00:55

Dumps of System ROMs can be found here

Added many photos of internals and screenshots of execution results for all the tools. Only missing part is keyboard matrix which requires pressing combinations of keys and taking pictures at the same time which is not possible by myself :)

By dproldan

Supporter (15)

dproldan's picture

11-03-2020, 22:02

I have access to a japanese Yamaha YIS-805/256. It's having some problems booting, but I'm confident I'll be able to repair it. I'l dump everything as soon as I can as post internal pictures. Anything else you'd like to see or document?

By Manuel

Ascended (16432)

Manuel's picture

11-03-2020, 23:38

See the readme of the zip file in the first post of this thread for all tests you can do and the tools to execute them.

By dproldan

Supporter (15)

dproldan's picture

09-04-2020, 00:43

Unfortunately, I haven't been able to spend time with the Yamaha YIS805/256 for repairs, but I have the EEPROM ICs on hand and have made a protoboard cartridge to try and read them in another MSX.
I need your help to find which software I should use for dumping the EEPROMs, and some instructions about pages and rom sizes, as I have no experience wih this stuff.

I have tested the protoboard cartridge with a konami rom, dumped the rom using rom-x.bin and then I was able to run the rom in an emulator. So looks like this method should work.

There are 4 x 27C256 EEPROMS.

I have extracted them using the default settings in ROM-X.BIN and got the files dumped, but I feel like I'm missing something. I put these files here: https://drive.google.com/drive/folders/1Ef9jW-BWeVFqd_SlMz24aiiUfynn99nS?usp=sharing

I have also tried using a program called SaveROM v1.2, when I turn on the MSX with one of these EEPROMS connected, It's found on slot 1 Pages 1 2. If I want to save that, what start and end addresses should I enter?

Any advice?

By sdsnatcher73

Paladin (882)

sdsnatcher73's picture

09-04-2020, 07:21

You can always dump entire 64kB (0-FFFF) and trim the file later using a hex editor. That is what I do (no good at calculating in HEX either Wink)

But it would be 4000-BFFF for pages 1 and 2 (every page is 4000 hex), page 0 starts at 0000, then page 1 on 4000, page 2 on 8000 and page 3 on C000.

By dproldan

Supporter (15)

dproldan's picture

09-04-2020, 08:12

Got it, thanks! I dumped the ROMS as 64KB files and put them here: https://drive.google.com/drive/folders/1_4Tvv1YcH99fyE8MnQuZrTJE3MhYicwI?usp=sharing

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