See [[Installing Vortex Expansion RAM]].
== Technical (very incomplete) ==
* This section describes how you can access the RAM of the SP512.
* The exact decoding (e.g. complete or partial) of I/O port addresses is not confirmed at this time.
* The port addresses given are recommended and are those used by B.O.S..
I/O port &FBBD:
Bit Function
7 Unknown
6 Unknown (Discology utility uses it - does it choose RAM in 32K blocks instead of 64K blocks??)
5 Ramcard - Ram disabled : When 1, allow mapping byte in 7Fxx to access BANK selected by byte 2..0 (Paging ok 32K). When 0, 7Fxx has not effect (note DK'Tronic 64K for CPC 464 may work in this case).
4 When 1, disable all internal and external RAM. Reserved for future use
3 Ram expansion - Rom disable when 1
2..0 Used to choose the 64K block of the SP512 to select
I/O port &7F00:
Bit Function
7 Set to 1
6 1 = make RAM visible in range &8000-&FFFF, 0 = make RAM visible in range &0000-&7FFF
5 Set to 1 to activate SP512. If bit 5 of &FBBD is 1 will select SP512 ram, otherwise select RAM of CPC464.
3 1 = Upper ROM disable, 0 = Upper ROM enable
2 1 = Lower ROM disable, 0 = lower ROM enable
1,0 Screen mode
* When bit 5 is 0, then bit 6 is ignored.
* When reading, ROM has priority over the RAM.
== Manual ==
