CHA 42G-1

Been playing with this board set lately.

Figured out that on the PB output from the Neo-273 P14 and P15 are flipped compared to the CHA 256.

So I flipped them which cleared up the C rom problems I was having BUT now fix layer has a problem.

I swapped A2 and A4 on the S1 and now everything plays clear.

So would the easiest fix be to just swap A20 and A19 from C rom?

P bus is shared for C and S addressing so yes, swap lines after the 273, not before.

Pedrobear said:

P bus is shared for C and S addressing so yes, swap lines after the 273, not before.

Click to expand...

Sucky thing is that if I swap them after the 273 (P14 and P15) then I have to swap A2 and A4 (S1) before the 273 to fix the fix layer after the swap of the P14 and P15 output.

Looks like I'm gonna try it at the eprom level and just swap halves.

Well you got something wrong because there's no P bus after the 273 latch. Before being cart edge side, after being rom side.

If you want to swap C A19<->A20 to linearise ROM data, swap 273's pins 45 & 46.

http://wiki.neogeodev.org/index.php?title=NEO-273