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1. NO BLATANT PIRACY. This includes reproducing homebrew less than 10 years old, with the exception of free software.
2. No advertising your reproductions, with the exception of free software.
3. Be nice. See RFC 1855 if you aren't sure what this means.



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 Post subject: iNES Mapper 15 Repro
PostPosted: Thu Mar 17, 2016 3:41 pm 
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Joined: Fri Jul 04, 2014 2:34 pm
Posts: 335
Location: Germany
Hey there,
I'm trying to find out how to make a mapper 15 repro for Bio Hazard.
I've already found this topic: viewtopic.php?t=4088
But it doesn't help as all sources seem lost and the author doesn't seem to reply an e-mails. :'(

Anyone have a backup or know how to make one?

Thanks!


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 Post subject: Re: iNES Mapper 15 Repro
PostPosted: Thu Mar 17, 2016 6:06 pm 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 7519
Location: Seattle
The web archive does have an old copy of the schematic (e.g. http://web.archive.org/web/200605010000 ... 168in1.pdf ) but I guess I may as well attach it here:
Attachment:
168in1.pdf [31.11 KiB]
Downloaded 105 times


Note that most of the functionality is inside the GAL16L8. Based on sdm's comment that "I think Biohazard dont use PAL/GAL chip", that would imply that the only PRG layout supported is 32 KiB mode, making Bio Hazard just want an ≈oversize BNROM. i.e. you could try just a board with a 74'377 and an inverter (to prevent bus conflicts). (Or a 74'139 and a 74'176, if the register needs to be cleared on powerup)

IF that is true, and the GAL is not used, then the connectivity would be:
(shared)
CPU D1…D5 → latch → PRG A15…A19
(variant 1)
CPU R/W → inverter → ROM /OE
CPU R/W → 74'377 /LATCHENABLE
CPU /ROMSEL → ROM /CE + 74'377 ↑LATCH
(variant 2)
CPU R/W → 74'139 1A + 1B
CPU /ROMSEL → 74'139 1G
74'139 1Y0 → 74'176 ↑LATCH
74'139 1Y3 → ROM /OE + /CE


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 Post subject: Re: iNES Mapper 15 Repro
PostPosted: Fri Mar 18, 2016 9:07 am 
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Joined: Fri Jul 04, 2014 2:34 pm
Posts: 335
Location: Germany
Ah, thanks alot!


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