I took a NES ELROM board and removed the PRG and CHR ROM.
I patched a copy of megaman 1 per the readme and the resulting patched rom plays ok on an emulator.
I removed the header and burned it to an AM27C040-120DC, installed that eprom and rewired pins 1,2, 24,30 and 31.
I installed some 62256 RAM in place of the CHR-ROM (Sony CXK58256P-10L), installed it offset pin 1 to maskrom hole 3 alignment, and rewired it:
Pin 1 to hole 29 (A14)
Pin 22 (OE) to hole 31 (/CE)
Pin 27 (/WE) to Pin 56 on the NES cart (PPU /WR)
Pin 28 to Pin 32 (Vcc, +5V)
The resulting game boots but I get alternating horizontal lines in the screen at the title screen and the colors in the game are off.
Any ideas on where I might be off?
I patched a copy of megaman 1 per the readme and the resulting patched rom plays ok on an emulator.
I removed the header and burned it to an AM27C040-120DC, installed that eprom and rewired pins 1,2, 24,30 and 31.
I installed some 62256 RAM in place of the CHR-ROM (Sony CXK58256P-10L), installed it offset pin 1 to maskrom hole 3 alignment, and rewired it:
Pin 1 to hole 29 (A14)
Pin 22 (OE) to hole 31 (/CE)
Pin 27 (/WE) to Pin 56 on the NES cart (PPU /WR)
Pin 28 to Pin 32 (Vcc, +5V)
The resulting game boots but I get alternating horizontal lines in the screen at the title screen and the colors in the game are off.
Any ideas on where I might be off?