iNES Mapper 15 Repro

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Ice Man
Posts: 547
Joined: Fri Jul 04, 2014 2:34 pm

iNES Mapper 15 Repro

Post by Ice Man »

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!
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: iNES Mapper 15 Repro

Post by lidnariq »

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:
168in1.pdf
(31.11 KiB) Downloaded 249 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
Ice Man
Posts: 547
Joined: Fri Jul 04, 2014 2:34 pm

Re: iNES Mapper 15 Repro

Post by Ice Man »

Ah, thanks alot!
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