One guy asked me to analyze this cartridge. Fortunatelly there were photos of PCB on the web so I give a chance.
There is one think I cannot agree with the Mapper 105 description:
Because the MMC1-PRG-A14 is directly connected to both EPROMS, if MMC1 is switched into 16K+16K mode and MMC1 PRG's bank is modified, $8000 might stop pointing to first 32k even without rising edge on `I` bit.
There is one think I cannot agree with the Mapper 105 description:
Quote:
On powerup and reset, the first 32k of PRG (from the first PRG chip) is selected at $8000 *no matter what*.
PRG cannot be swapped until the mapper has been "initialized" by setting the 'I' bit to 0, then to '1'. This
toggling will "unlock" PRG swapping on the mapper.
PRG cannot be swapped until the mapper has been "initialized" by setting the 'I' bit to 0, then to '1'. This
toggling will "unlock" PRG swapping on the mapper.
Because the MMC1-PRG-A14 is directly connected to both EPROMS, if MMC1 is switched into 16K+16K mode and MMC1 PRG's bank is modified, $8000 might stop pointing to first 32k even without rising edge on `I` bit.