Posted By
Twinspirit32
on 2016-12-28
05:11:32
|  Re: Porting to Commodore Plus 4 of my game Genius, memory/bitmap mode questions..
As JamesC stated:
"Plus/4 has various I/O at $FD00 and above. It's a LOT easier to stay below this address, than to see the RAM underneath."
I've mapped my game code and for addressing reasongs I would like to use $E000-$FFFF for hires page 3 used as background copy for restoring pixels during the animation.
I'm having trouble writing/reading from the area $FD00-$FFFF, when I write there the systems crashes due to I/O registers changing etc..
I'm using the $FF3F and $FF3E to enable and disable RAM bank $8000-FFFF, but apparently writing to $FD00-$FFFF ram causes crashes.
Is there a way to read/write correctly RAM in that particular range of address without messing with I/O, and being the RAM/ROM switch in that area too, when I write to $FF3F first time I activate the RAM, when I write for the second time I store the byte in that location?
Before making changes to the addressing mode look up table to foward that $FD00-$FFFF area to another specific RAM space I would like to check it there's a way to use that memory...
Thanks for any tip in advance!
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