Pirate game "Mario Baby" Mapper #42 Info ---------------------------------------- 05.29.2000 Mapper info by The Mad Dumper Thanks to Thomas Steen for testing help. --- This game is really "Bio Miracle Boukette Upa"; a Konami FDS game that was turned into a cartridge by some enterprising pirates and rebadged "Mario Baby". The label on the cartridge is actually the artwork for the original game. There is only a small paper label glued to the top of the cart which says "Mario Baby". If you like the original game, this is for you since only the opening screen was slightly modified. The sprites, etc. are all intact. The cart proper is a regulation famicom cart case, however inside there is a whopping 11 chips- 9 TTL/CMOS, 1 8K RAM, and 1 128K ROM. The back of the cart has the usual funny inscription: "The unique manufacturer adopting high class IC and processed by not oxidized gold plate on the apparatus, to protect protect your IPU." I couldn't have said it better myself. --- This mapper has been assigned the number 42. (that's 42 decimal) The ROM is mapped in from 6000-FFFF. It is broken up into 16 8K banks. Bank #0 is 0000-1FFF of the ROM, bank #1 is 2000-3FFF of the ROM, etc. Reads: 6000-7FFF: Selectable 8000-9FFF: bank #0Ch A000-BFFF: bank #0Dh C000-DFFF: bank #0Eh E000-FFFF: bank #0Fh Writes: E000 : Select bank E001 : Select mirroring E002 : IRQ Control E003 : --not used-- These writes are mirrored from E000-FFFF, every 4 bytes. E000 is the same as E004, E008, E00C, etc. --- Writes to the ROM area control the bankswitching and other features of this cart. When writing to the ROM area, it is disabled to prevent bus contention. Writing to E000 selects the desired 8K bank that will appear at 6000-7FFF. Only the lower 4 bits of the written value are used. Writing to E001 selects mirroring like so: (x = not used) xxxx 0xxx = V mirroring xxxx 1xxx = H mirroring Writing to E002 turns the IRQ counter on/off. xxxx xx0x = Counter turned off and reset back to 0000h xxxx xx1x = Counter enabled This counter is very simple. It counts M2 clock ticks. After 24576 M2 ticks, an /IRQ is fired off. This is about 215 or so scanlines. It is most likely used to split the screen for the status bar.