Making BIOHAZARD cartridge

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Making BIOHAZARD cartridge
by sdm on 2008-05-03 (#33219)
I try build BIOHAZARD game cartridge. Its works, but i dont know how to connect WRAM/SRAM to it. Any ideas??

Schematics:
http://www.slanina.pl/gfx/168in1/168in1.pdf (mapper 15 - Contra 100in1 / Contra 168in1). I think Biohazard dont use PAL/GAL chip (its used only to control VRAM on 100in1/168in1 only)

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by kyuusaku on 2008-05-04 (#33230)
The PAL doesn't determine the A13 and A14 outputs to ROM? Only if they are simply passed through does the PAL not matter, not to say the same logic could be implemented with another discrete chip.

Since you already have /RD and /WR for the SRAM, you just need to decode the enable with a 3 input NAND gate: Image

by sdm on 2008-05-05 (#33245)
connect to A13/A14 cart connector or to PAL/ROM A13/A14??

by kyuusaku on 2008-05-05 (#33249)
Connect them to the cart connector, ROM A13/A14 change with bankswitching.

by sdm on 2008-05-05 (#33252)
sorry, but.. :) Where /ROMSEL , PHI2 and RW?? Cart connector? Please give me best famicom cart pinout scheme (i have probably old and simply version).

by kyuusaku on 2008-05-05 (#33256)
See P1 here: http://nesdev.com/Ntd_8bit.jpg