Does anyone have a good write up of how the Ms. Pac-man daughter board works?

souzilla

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Does anyone have a good write up of how the Ms. Pac-man daughter board works?

I did the high score save for just Pac-man and some pople are asking for Ms Pac-man as well. Updating the bootleg roms is easy enough, but I think some people want drop in roms for the real Ms. Pac-man.

Dumping the encrypted roms in an unencrypted format is not a big deal, I could do this with a Fluke 9010a. But updating them and re-encrypting is what I have not figured out yet. Could I run the un-encrypted roms through the daughter board somehow and dump the encrypted version out? I have not done that much research yet, but could use some tips.

The other options is to mod the daughter board to NOT overlay some sections of the original program roms, but I think that is probably more work. Can anyone provide me tips into how the roms are encrypted? Maybe I could write program to do the encrypting (unless someone has done this already and can give me a link).

Thanks in advance
 
The MAME driver has some good info in it, but what I really would like to know if someone can layout how the pals do address decoding. That would be useful. Even knowing which roms correlate with the overlayed addresses would be nice :)

Edit: I figured it out... thanks for letting me think outloud :)
 
Last edited:
I wrote a little app to encrypt and decrypt roms for use on the Ms Pac-man daughter board. I know some may not think it is encryption, but if something changes the data in a way which scrambles it up... well you get the picture.

Shoot me a PM if you would like a copy of it
 
File attached

Here you go.
To run it use the following syntax from a command prompt

To Decrypt
cscript.exe mspac_enc.vbe -d U7.bin

To Encrypt
cscript.exe mspac_enc.vbe -e updated_U7.bin
 

Attachments

  • mspac_enc.zip
    5.1 KB · Views: 8
Here is an update... the first version just decrypted the data.
This version encrypts/decrypts the addresses too.

Just to be clear this is used to modify U5, U6 or U7 on the Ms Pac daughter board.

To Decrypt
cscript.exe mspac_enc.vbe -d U7.bin

To Encrypt
cscript.exe mspac_enc.vbe -e updated_U7.bin
 

Attachments

  • mspac_enc.zip
    7.2 KB · Views: 8
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