Difference between revisions of "Z80 port map"
|Line 32:||Line 32:|
Revision as of 16:55, 18 December 2013
|$00||Read sound code from 68k||Clear sound code buffer|
|$08||Set $F000~$F7FF bank||Enable NMI|
|$09||Set $E000~$EFFF bank|
|$0A||Set $C000~$DFFF bank|
|$0B||Set $8000~$BFFF bank|
|$0C||Reply to 68k|
Bank selection is made by reading ports. SNK used an obscure feature of the Z80: when accessing ports, the entire address bus is set, not only the lower 8 bits.
The banks can then be chosen by putting the bank number in B, the port number in C and doing IN A,(C). Or by putting the bank number in A and doing IN A,(Port). (to verify)