I'm looking to build a repro of the new Tengai Makyou translation and I hit a snag on some wiring. The game has 2 roms that need swapped out. The new translation has a 2MB program rom and a 5MB data rom. I can swap out the chips without issue, but the cart needs a couple wires to allow the last half of the expanded program rom to work. I found some descriptions of how to do this, but I half understand it. I have a ISL84544 switch, unsure of the wiring. Working with a 2MB chip which I directly wired a A21 to the SPC7110 chip. It will turn on, just won't pass the rom check screen.
1) Force the A23 input to the address decoder to be permanently high, and now feed A23 into a switch (eg ISL84544)
to select between the two 1MB ROM chips -or- invert it and add to address for 2MB ROM chip address bus value.
2) Tengai Makyou Zero is also compatible with the real cart adding two wires. 90-9f:8000-FFFF.
Tengai Makyou PCB pinout
https://wiki.superfamicom.org/spc7110
This is what I have so far.