Hi Richard, ] 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. (?) Writes to a secundairy slot register are not propagated to the subslots controlled by that secundairy slot register. The address decoder does not do a 'write select' or whatsoever on the subslots when accessing the 0xffff address. This is also useless, since reading 0xffff will return the reverse value of the secundairy slot anyway.
See also my other message for more details. Kind regards, Alex Wulms -- Visit The MSX Plaza (http://www.inter.nl.net/users/A.P.Wulms) for info on XelaSoft, Merlasoft, Quadrivium, SD-Snatcher on fMSX, the MSX Hardware list, XSA Disk images, documentation, Japanese MSX news from Ikeda and lots more. -- For info, see http://www.stack.nl/~wynke/MSX/listinfo.html
