Plus 3 Memory Paging Control

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Number $1FFD
Short desc. Controls ROM paging and special paging options from the +2a/+3.
Bit Mask %0001 ---- ---- --0-
Readable No
Writable Yes
Subsystem Memory map

Bit mapped to control paging options.

Bit Effect
5-7 Undocumented, may be used for extra bits of slot 4 bank select (see Memory Paging Control ($7FFD / 32765))
4 Printer Port Strobe
3 Disk motor enable
2 Normal mode: High bit of ROM selection.

Special mode: High bit of memory configuration number (see Memory map).

1 Special mode: Low bit of memory configuration number.
0 Paging mode. 0=Normal, 1=Special.

Any values written to this port should also be stored in $5B67 if you intend to use any OS routines.