I'm more familiar with the Acorn BBC range of machines but have recently been making improvements to other machines in MAME such as Dragon, Camputers Lynx, Z88, and am now looking at the MTX range.
I started this discussion over on Facebook, and appreciate the replies from Dave and Andy, and will continue to seek technical assistance here.
So I currently have both ROM and RAM based memory maps implemented, and can optionally load a ROM extension board containing either Pascal or NewWord, both of which seem to work so the ROM 2 subpages are also working.
I'm now trying to add floppy support with either the FDX or SDX boot ROMs. Whilst booting the FDX ROM (in ROM 3) it's trying to write, what look like vectors, to the ROM area 3FFC-3FFF, then jumps to D140 where no code exists. The SDX ROM that I tried also wants to write to the ROM region.
Here's some logging, where bankswitch are writes to IOBYTE, the rest should be self explanatory. If the memory map should be RAM based at this point then I'd expect to see a bankswitch 8x. Anyone any idea what could be wrong?
Code: Select all
[:exp:fdx:fdc] cmd: seek 1 0 (track=0)
[:] bankswitch 00
[:] bankswitch 01
[:] bankswitch 20
[:] bankswitch 30
[:z80] ':z80' (FD52): unmapped program memory write to 3FFE = 52 & FF
[:z80] ':z80' (FD52): unmapped program memory write to 3FFF = FD & FF
[:z80] ':z80' (FDD0): unmapped program memory write to 3FFC = D0 & FF
[:z80] ':z80' (FDD0): unmapped program memory write to 3FFD = FD & FF
[:z80] Z80 ill. opcode $ea $ff ($d140)
[:z80] Z80 ill. opcode $ea $ff ($d144)
[:z80] Z80 ill. opcode $ea $ff ($d148)
[:z80] Z80 ill. opcode $ea $ff ($d14c)