Multi-slot cart recognition

shadowkn55

Genbu's Turtle Keeper
15 Year Member
Joined
Dec 9, 2006
Posts
2,386
I always wondered about this. How do multi-slot mvs boards recognize when there is a cartridge in a slot? I suppose this applies to 1-slot boards also since it needs to know when to cross-hatch.
 

Kyuusaku

B. Jenet's Firstmate
Joined
Mar 26, 2003
Posts
419
AFAIK software detection only, they select a slot and check for coherent data instead of open bus.
 

smkdan

Galford's Armourer
Joined
Dec 30, 2009
Posts
452
There's some detail on the the coherent data the BIOS expects on the wiki . Off the top of my head, it checks the "NEO-GEO" string @ $100, a non zero NGH value @ $108 and a valid security pointer @ $182. If any of those don't check out then it considers the slot empty.
 
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