[#FFFF]
> It's accessed using MREQ# rather than IORQ#.
> Are you saying you don't have
> to select slot 3 in order to change it?Yes > In which case, does it affect other expanded slots also? Yes, but since you have the *primary* slot (I/O port #A8) set toa certain slot, switching expanded slots in other primary slots doesn't make a difference. > ie. is it possible to have more than one > secondary slot register, on a per slot basis, No. > or does writing to the same register affect all slots? Yes :-) > Presumably when the RAM at #C000 - #FFFF is enabled, writing to this > register will also "write through" to the RAM at location #FFFF, so that > reading from this location will return the last value written to the > register. (?) Reading #FFFF will return the *inverse* of what you've written into it (don't ask ;-)). I guess it will depend on the hardware whether the byte written to #FFFF will ever land in RAM... (AFAIK, all of this should be in the MSX Red Book, by the way, which is available from ftp://ftp.funet.fi/pub/txt/tech/tredbook.arj) Eric -- For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
