INES Mapper 038
iNES Mapper 038
| Company | Bit Corp. |
| Games | 1 in NesCartDB |
| Boards | UNL-PCI556 |
| PRG ROM capacity | 128K |
| PRG ROM window | 32K |
| PRG RAM capacity | None |
| CHR capacity | 32K |
| CHR window | 8k |
| Nametable arrangement | V(hardwired) |
| Bus conflicts | No |
| IRQ | No |
| Audio | No |
| iNES mappers | 038 |
NESCartDB
| iNES 038 |
iNES Mapper 038 represents the board used for Bit Corp.’s Crime Busters. It is another mapper almost identical to GNROM (66) except the bits and writeable port moved around.
7 bit 0
---- ----
xxxx CCPP
||||
||++- Select 32 KB PRG ROM bank for CPU $8000-$FFFF
++--- Select 8 KB CHR ROM bank for PPU $0000-$1FFF
Writes to $F000-$FFFF are very likely to also trigger a bankswitch, but well behaved code has no reason to. The 74138 used by this board uses /ROMSEL and R/W on its enable inputs, but /ROMSEL is 1 while M2 is low, not just while M2 is high and and A15 is low. As a result, before M2 is high, if the 2A03’s A14, A13, and A12 lines are 1 and R/W is 0, the 74161’s /LOAD line will still load from the data bus.