MaarioS wrote:Hey there people, I've read the entire topic but I still have not found the exact plain solution how to make Star Ocean cart. Well maybe there were some theories and debates but nothing 100% confirmed to be working on real hardware so.... has anyone figured out which portions of the code goes where?? How EXACTLY roms should be connected on the cart and which part of the code goes where?? Which part should be connected like normal and which part should be interleaved or connected different?? How about if I want to use combination of 8MB+4MB memories or even one 16MB memory?? I got kind of lost and now I have no idea what I'm supposed to do after reading all of this. I'd be so grateful if anyone made it very clear how to do the cart and provided me with confirmed & verified information. That would be so much appreciated!! Many thanks in advance!!
The decompressed star ocean is a combination of lo rom and extended Hi rom mappers. Roms 1&2 are extended hi rom mapped just like Crimson echos and tales of phantasia. Rom 3 is mapped as lo rom where A15 is skipped. A22 determines when the decoder is active for the ex hi rom and lo rom mappings. When A22 is low, it activates the decoder (139) to enable rom 3 and when it's high, it deactivates rom 3 and enables the decoder to run as extended hi rom where A23 determines which rom is selected between Rom1 and Rom2.
Here are some examples:
Star ocean using the "cart creation" pcb. http://youtu.be/vMVl1shH_50
Star ocean using donor snes cart http://youtu.be/_gnYuvCplE4
You could have star ocean in 1 big rom but you'd need to do some address shifting (because of A15). It it could fit in a single rom, but without additional circuitry, it wouldn't work.