The actual PRG/CHR/etc. mapping logic for the VRC7 can be found in Goroh's KONAMI document. Overall, this is how it works:
$8000 - Select 8KB PRG bank at $8000-$9FFF
$8010 - Select 8KB PRG bank at $A000-$BFFF
$9000 - Select 8KB PRG bank at $C000-$DFFF
$9010/$9030 - sound
$A000 - Select 1KB CHR bank at $0000-$03FF
$A010 - Select 1KB CHR bank at $0400-$07FF
$B000 - Select 1KB CHR bank at $0800-$0BFF
$B010 - Select 1KB CHR bank at $0C00-$0FFF
$C000 - Select 1KB CHR bank at $1000-$13FF
$C010 - Select 1KB CHR bank at $1400-$17FF
$D000 - Select 1KB CHR bank at $1800-$1BFF
$D010 - Select 1KB CHR bank at $1C00-$1FFF
$E000 - Set mirroring (bottom 2 bits = V/H/S0/S1) and SRAM enable (D7:1=enabled, D7:0=disabled)
$E010 - IRQ latch register
$F000 - IRQ control register (D0=$F010 mode, D1=enable, D2=single-cycle vs scanline count)
$F010 - IRQ reset register (sets IRQ enable to $F000 D0)
Note that Lagrange Point uses CHR RAM and that it IS banked.
Tiny Toon Adventures 2 also uses this mapper, though with a few differences - expansion sound is not used, CHR ROM is used rather than CHR RAM, and registers are selected via $X000/$X008 rather than $X000/$X010.
_________________ Quietust, QMT Productions
P.S. If you don't get this note, let me know and I'll write you another.
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