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 Post subject: Susoft 5a clone?
PostPosted: Fri Sep 18, 2015 4:30 pm 
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Hello!
I've got a very cheap Batman cartridge to try to make an MMC3 repro on it.
When I opened it, instead of MMC3 clone I found this 23c269 and some more chips (glue logic?).
Could this be a pirate Sunsoft 5a clone?
The stage 1 and 2 music are swapped, just as said happens on the japanese game.
I found that the game slows down a lot more than I remember.
Does this happen on the original Batman J?
Does someone have information about this clone?
Could I do a repro of Batman 2 or Mr Gimmick with this board?
Thanks in advance!!


Attachments:
Batman j Pirata.png
Batman j Pirata.png [ 1.07 MiB | Viewed 3033 times ]
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 Post subject: Re: Susoft 5a clone?
PostPosted: Fri Sep 18, 2015 8:49 pm 
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Location: Brasilia, Brazil
Dump the ROMs and try to load them on a emulator. If they work as a mapper 69 .nes file then you might have it work for what you want.

But considering it's a NTDEC cartridge it could be a "customized" mapper and your game is hacked to run on a different mapper. If you try what I suggested above and it doesn't work that's the likely cause.


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 7:45 am 
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Looks like it's a custom mapper :-(
This explains the slowdown!!
Could be possible to hack the games to use it?
I think not, I have no idea where are the SRAM control pins and PRG/CHR A17...
I have compared both PRG files, first half is almost identical, but the second half is almost all different.
I'm putting the ROMs here, just if someone is interested.
Should I disassemble the board, scan it and share the scans?
Thanks in advance.


Attachments:
File comment: Pirate Batman J PRG
BAT_NTD.PRG [128 KiB]
Downloaded 112 times
File comment: Pirate Batman J CHR
BAT_NTD.CHR [128 KiB]
Downloaded 117 times
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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 8:30 am 
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Fisher wrote:
I have compared both PRG files, first half is almost identical, but the second half is almost all different.
I'm putting the ROMs here, just if someone is interested.

These are bad dumps! It looks like A16 wasn't connected properly.

Fisher wrote:
Should I disassemble the board, scan it and share the scans?

Good documentation is always appreciated. Of course, it's up to you - you're the one who would have to put it back together to re-use it!


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 10:16 am 
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I'll redump it later... Thanks to pointing this!
Looks like A16 is in /OE, I thought my "dumper" would notice this...
I think will be better to wire the pin to the top of the slot, or is better to dump it twice, once with A16 low and after with A16 high?
If a scan of the board will help the community to better understand the mapper (or the new mapper), count on it!! It's a little effort to help make emulation better!!


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 1:56 pm 
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Redumped!
Have pulled a wire to pin2 from /OE on both ROMs at the 32 pin socket, got very different results!!
CHR's md5sum is the same as the original. I'll assume they're the same. Not posting here.
PRG is very different. Still no luck running them on an emulator :-(
Nestopia only gives me a noise. Both FCEUltra and Mednafen just quit!
Maybe I messed up and fried the PRG? Is it still a bad dump?
I'm thinking in flashing the original PRG on a FlashROM and test if it works.
Have scanned both sides of the board. Hope it helps someone, specially me :-)
It's 600dpi. Although only 8bpp... Is this enough?
Looking quickly I saw 4 unused pins... maybe they're the SRAM control pins and PRG/CHR A17, just have no idea of how to find who is who :-(
Again, many thanks!! I'm learning a ton and having lots of fun too!!


Attachments:
File comment: Pirate Batman J PRG
BAT-NTD.PRG [128 KiB]
Downloaded 88 times
File comment: Pirate Batman J component side
Batman J Pirata - Comp (8b).png
Batman J Pirata - Comp (8b).png [ 1.08 MiB | Viewed 2965 times ]
File comment: Pirate Batman J solder side
Batman J Pirata - Solda (8b).png
Batman J Pirata - Solda (8b).png [ 1.23 MiB | Viewed 2965 times ]
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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 2:19 pm 
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The chip on your cart is a VRC2 clone.

The game plays fine as mapper 23.

edit: Well, not so fine due to the extra logic chips on the board as it uses them to extend the mapper capabilities. Graphics glitch slightly without the extra chips.


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 3:22 pm 
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Cool!!
So, I can do a Contra J repro with this Batman!!
Any idea of what to do with the added logic??
What about the mapper pinout?? Is it similar to the VRC2?
Many thanks!!


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 3:27 pm 
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You likely will have to mod the board heavily...

I can't really help you with that part. :)

But I am sure you will learn a lot about this from doing it.


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sat Sep 19, 2015 3:42 pm 
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Took a quick look at the the pinouts, seems just like this one:
http://wiki.nesdev.com/w/index.php/VRC2_pinout
Gotta check all the pins to have sure, if it's consistent, I'll have the guidelines to mod.
Now I need to leave, real life is calling!!
Many thanks!! That was great!!


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sun Sep 20, 2015 2:00 am 
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Fisher wrote:
CHR's md5sum is the same as the original. I'll assume they're the same. Not posting here.

That means the CHR is still a bad dump...

Now that I have a good dump of the PRG and very nice scans of the PCB, I can start to analyze the mapper.


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sun Sep 20, 2015 4:25 am 
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Joe wrote:
Fisher wrote:
CHR's md5sum is the same as the original. I'll assume they're the same. Not posting here.

That means the CHR is still a bad dump...

Now that I have a good dump of the PRG and very nice scans of the PCB, I can start to analyze the mapper.



VRC4,MAPPER25
but F000-F003 is IRQ change.


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sun Sep 20, 2015 4:54 am 
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Real machine, Is the blood flashing?


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sun Sep 20, 2015 6:44 am 
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The mapper is your standard pirate VRC2-with-IRQ board, using VRC2b wiring.

The IRQ circuit uses two counters, one that counts 2048(?) cycles of M2, and another that counts a programmable multiple, up to 16(?), of that 2048 cycles and generates an IRQ. The control registers are mapped to $F000, $F001, and $F003 (mask $F003). Writes to $F000 halt and clear the 2048-step counter, halt the 16-step counter, and acknowledge the IRQ. Writes to $F001 start both counters. The high four bits of writes to $F003 will be loaded into the 16-step counter.

I'm not sure if it's just the pictures, but I don't see anything connected to 74191 pin 5. The connection to that pin controls the direction of the 16-step counter, but I'm not sure what it will do if it's not connected at all...

I'll see if I can draw some schematics for this, so others can more easily follow the IRQ circuit.


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 Post subject: Re: Susoft 5a clone?
PostPosted: Sun Sep 20, 2015 8:44 am 
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Done!

I wonder if there's already a mapper number assigned for this configuration.


Attachments:
batman pirate irq.png
batman pirate irq.png [ 25.31 KiB | Viewed 2873 times ]
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