On the DTV Rev2 the $01 ROM / I/O mapping is performed on the linear
memory map before segment mapping.
i.e if $00c000-$00ffff is mapped onto $4000-$7fff, I/O will appear
mirrored at $5000-5fff and kernal will appear at $6000-7fff depending
on
$01. This makes the linear addressing routines using the segment
mapper a
bit more complex as they have to change $01 aswell as the segment
register to access ram.
Was this intended? (i.e will it change in a possible future
revision?)
Regards
/Daniel Kahlin <tlr>
http://www.kahlin.net/daniel/dtv/
Actually the 6510 $01 decoding(PLA) is done after the mapper. To maintain compatibitly with the good-ole c64 it was necessary to keep the PLA decoding active anywhere in the Segment = "000000XX" and Mode = "01" (RAM) range. Anything outside of that will not have Kernal, Basic or I/O mirrors.
FWIW. At the moment there will be no other revisions and likely no more production runs.