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Miscellaneous WIP: Sussing out cdimono2 #106685 07/29/16 03:46 PM
Joined: May 2009
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J
Just Desserts Offline OP
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We currently have dumps of both 68HC05 microcontrollers used on a Mono-II CD-i motherboard, one of SERVO, one of SLAVE. SERVO apparently controls the mechanics in the CD drive itself, and SLAVE manages the front panel and a few other miscellaneous tasks.

I'm banking on the idea that by emulating the two 68HC05s properly as well as their hookups, then the cdimono2 driver should boot far enough that we can figure out if there are any remaining issues in the DSP56k core that it uses for audio.

In the meantime, I'm tasking myself with coming up with a C-like decompilation of the 68HC05 programs. I'm starting on SERVO, and will post updates as I figure out more and more of the program code.

Here's what I've got so far: https://gist.github.com/MooglyGuy/4a0276e66c36e2ad8c4842c3b0b8c749

Re: Miscellaneous WIP: Sussing out cdimono2 [Re: Just Desserts] #106697 07/30/16 06:55 PM
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Do you have schematics of a Mono-II player electronics surrounding these chips? I have service manuals for both players using this board, I could scan in the relevant parts.

What are you using for decompilation?

Re: Miscellaneous WIP: Sussing out cdimono2 [Re: Just Desserts] #106698 07/30/16 07:06 PM
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Stiletto Offline
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Since December we have service manuals for:
- CDI210/00/05
- CDI210/40/41/45
- CDI210/60/65
- CDI220/00
- CDI220/20/25/31/37/39
- CDI220/40/41/45/47
- CDI220/60/61/65/77
- CDI220/80/85/97
- CDI350/00/05/11/17
- CDI360/00/05/11/17
- CDI450/00/05/11/17
- CDI470/00/05/06

Re: Miscellaneous WIP: Sussing out cdimono2 [Re: Stiletto] #106699 07/30/16 07:26 PM
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Posts: 1,862
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Just Desserts Offline OP
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Updated disassemble/decompile of SERVO here: https://gist.github.com/MooglyGuy/73fbb9a17c6d46ec818e3dd15b6e8876

I'm using MAME's integrated debugger and disassembler to look at a disassembly of the 68HC05 code, then I just jot a more high-level pseudocode version of it in notepad as I go through it. At the moment I'm concentrating on getting all of the code mapped out, at which point I intend to go through and infer proper names for all the various RAM locations and bit flags.

The service manuals that I got off the MAME team's dev FTP provide both schematics and PCB layouts for a large number of different CD-i players, in particular the 220/40/41/45/47, which was the model that the current SERVO and SLAVE dumps in the "cdimono2" ROM set in MAME were dumped from.


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