Plus 3 Memory Paging Control

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Revision as of 17:23, 18 August 2017 by wiki>Hyphz
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Number $1FFD
Decimal
Short desc. Controls ROM paging and special paging options from the +2a/+3.
Bit Mask
Readable No
Writable Yes
Subsystem Memory map

Bit mapped to control paging options.

Bit Effect
5-7 Undocumented
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 $5X67 if you intend to use any OS routines.