Thank you for this important hint.Silvester wrote:Unfortunately that would clash with SGC/GC: I/O at $1C000-$1C1FF, Eprom is copied to RAM at $10000-$17FFF & $1C200-$1FFFF.
Are you sure that $1C200-$1FFFF is not again mapped to the QL bus later?
What is the source of your information?
It is not a nice thing to use an area explicitely marked "internal" for the QL. It is unclear how exactly GC/SGC access $18100-$1BEFF. This has probably never been used, and the PLD sources do not exist. There might even be version differences.Silvester wrote:That only leaves QL internal I/O area, and to avoid ZX8301/2, and possibly Qimi, leaves $18100-$1BEFF free for use (via DSMC).
I won't shift address ranges by $100. Also not above $19000. As I wrote, this is start of a Q68 internal 12 KB ROM/RAM area. But we could consider:Silvester wrote: $18100-$188FF <slot 0> Ethernet CP2200
$18900-$190FF <slot 1> Q68 compatible external I/O (*)
$18400-$187FF Ethernet CP2200 (uses only 8 address lines anyway)
$18800-$18FFF Q68 compatible extension bus
Requires that we can make absolutely sure there is no issue with the internal I/O area. Somehow I don't have a good feeling.