Programming MMC1
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MMC1 was Nintendo's first ASIC mapper for the NES.
Quick setup for UNROM style
To get an environment similar to UNROM, with 8 KB of CHR RAM, a fixed PRG ROM bank at $C000, and a 16 KB switchable PRG ROM bank at $8000, do this:
lda #$80 ; reset the mapper sta $E000 lda #$0E ; vertical mirroring, fixed $C000, 8 KB CHR pages sta $8000 ; (use $0F instead for horizontal mirroring) lsr a sta $8000 lsr a sta $8000 lsr a sta $8000 lsr a sta $8000
