z80 ram in sms mode (genesis)

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KRIKzz
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z80 ram in sms mode (genesis)

Post by KRIKzz » Fri Feb 04, 2011 10:50 am

i make a dump of z80 ram in sms mode and i detected code of everdrive OS in this memory. WTF i was thinking (: so now i know that z80 in sms mode not use own 8kb ram, it use m68k ram begining from upper 32k.

i always was assured that z80 use own ram in sms mode. by this reason i have had a problems with some sms games which require ram initialization. they just stop working after randomly changes in OS code :oops:

but if thinking logical, then all should work exactly as is worked - z80 switched to m68k bus, so it should use m68k ram and cart

TmEE co.(TM)
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Post by TmEE co.(TM) » Fri Feb 04, 2011 4:12 pm

Yes, in SMS mode the RAM for Z80 is the 68K RAM, sepecifically the higher byte. Lower byte goes to cart, higher to RAM.
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maksevrod

Post by maksevrod » Fri Feb 25, 2011 7:06 pm

64 k? Its too small :)

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