ZX PROFI 1024 - paging via one OUT
This is adressation of ZX PROFI ports:
ZX PROFI 1024 kB
port 7FFD: (adressation - 0xxxxxxx xxxxxx0x )
D0 = bank 0 ;128 kB memory
D1 = bank 1 ;128 kB memory
D2 = bank 2 ;128 kB memory
D3 = videoram
D4 = rom
D5 = disable paging
D6 = unused
D7 = unused
port DFFD: (adressation - xx0xxxxx xxxxxx0x )
D0 = bank 3 ;256 kB memory
D1 = bank 4 ;512 kB memory
D2 = bank 5 ;1024 kB memory
Both ports use D0-D2 for set memory pages. As I see uncomplette ports adressation then is possible reset/set both ports via one OUT to port adress 0x0xxxxx xxxxxx0x . For example: OUT 1FFD,0 reset paging bits on both ports (set page 0 and disconnect extra memory). OUT 1FFD,4 set ram page 4 + extra memory block(128kB) 4. Software using write to port 1FFD for SCORPION machines or ZX128+2A/+3 can set incorrect memory page in high 16kB on ZX PROFI. Where can I find schematic of different versions ZX PROFI computer ? Last ZX PROFI versions use identical ports adressation ?