Difference between revisions of "Plus 3 Memory Paging Control"

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|Number=$1FFD
 
|Number=$1FFD
 
|ShortDesc=Controls ROM paging and special paging options from the +2a/+3.
 
|ShortDesc=Controls ROM paging and special paging options from the +2a/+3.
|PortMask=%0001 ---- ---- --0-
 
 
|Readable=No
 
|Readable=No
 
|Writable=Yes
 
|Writable=Yes
 
|Subsystem=Memory map
 
|Subsystem=Memory map
 +
|PortMask=%0001 ---- ---- --0-
 
}}
 
}}
 
Bit mapped to control paging options.
 
Bit mapped to control paging options.

Revision as of 23:05, 19 April 2019

Number $1FFD
Decimal
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.