|Mickey in Letterland/Numberland IRQs
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|Author:||Zepper [ Tue Apr 24, 2018 6:01 pm ]|
|Post subject:||Mickey in Letterland/Numberland IRQs|
I added Acclaim's IRQ timing, of IRQ counter clocking on falling edges of A12. This way, Mickey games work much better. From my attempts of getting this game working fine, I'd like some advice on it. Ages ago, someone said that the only difference is about Acclaim's IRQ triggered 4 cycles later if compared to MMC3. That's NOT the only difference from my attempts.
Is Numberland the same board/IRQ system of Letterland?
If I ignore $2006 writes, there's no scorebar shaking.
If I fix Numberland, Letterland is the glitched one, but I believe it's what a NES console does.
EDIT: it was a mistake in my code.
|Author:||NewRisingSun [ Tue Apr 24, 2018 9:58 pm ]|
|Post subject:||Re: Mickey in Letterland/Numberland IRQs|
Mickey's Safari in Letterland uses Acclaim's MC-ACC chip (mapper 4 submapper 3), Mickey's Adventures in Numberland uses a regular MMC3C chip (mapper 4 submapper 0). Implement MC-ACC by raising IRQ four PPU cycles after PA12 goes high (versus 0 on MMC3) and by ignoring further PA12 rises for 35 PPU cycles (versus 8 on MMC3). Mickey's Safari in Letterland's scorebar seems to depend on the latter aspect.
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