I started on an experimental PowerPak mapper with a coprocessor I made (Chipmunk) that allows the NES to upload code for the coprocessor to run and get an interrupt when it finishes. I'm using mapper slot 248 currently since it's meant for mappers in development.
The architecture is almost a 6502.
I made a test ROM (included, with source) and it has the coprocessor run the test from here except for some extra stores at the end to put the tests passed variable and "1337d00d" at the start of RAM. In the test ROM, press Start to run the coprocessor program.
I tried to make an extremely fast Conway's Life but I ran into issues where the RAM used for the playfield was getting corrupted instead and I don't know why. I made an edited version of the Life that just constantly toggled all the cells on the grid instead and occasionally the first byte would fail to write. I think it's probably incorrect interfacing with the block RAM or some sort of weird timing problem, and I've included the source if someone wants to try look at that.
I have a mapper I want to implement, allowing the programmer to swap PRG banks and change the mirroring, and to add a scanline counter but I'll probably only do that if I can get this fixed. In its place currently is just CNROM.
The architecture is almost a 6502.
I made a test ROM (included, with source) and it has the coprocessor run the test from here except for some extra stores at the end to put the tests passed variable and "1337d00d" at the start of RAM. In the test ROM, press Start to run the coprocessor program.
I tried to make an extremely fast Conway's Life but I ran into issues where the RAM used for the playfield was getting corrupted instead and I don't know why. I made an edited version of the Life that just constantly toggled all the cells on the grid instead and occasionally the first byte would fail to write. I think it's probably incorrect interfacing with the block RAM or some sort of weird timing problem, and I've included the source if someone wants to try look at that.
I have a mapper I want to implement, allowing the programmer to swap PRG banks and change the mirroring, and to add a scanline counter but I'll probably only do that if I can get this fixed. In its place currently is just CNROM.