Difference between revisions of "Plus 3 Memory Paging Control"
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(Created page with "{{Port |Number=$1FFD |ShortDesc=Controls ROM paging and special paging options from the +2a/+3. |Readable=No |Writable=Yes |Subsystem=Memory Map }} Bit mapped to control pagin...") |
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| Line 4: | Line 4: | ||
|Readable=No | |Readable=No | ||
|Writable=Yes | |Writable=Yes | ||
| − | |Subsystem=Memory | + | |Subsystem=Memory map |
}} | }} | ||
Bit mapped to control paging options. | Bit mapped to control paging options. | ||
| Line 19: | Line 19: | ||
| 2 || Normal mode: High bit of ROM selection. | | 2 || Normal mode: High bit of ROM selection. | ||
| − | Special mode: High bit of memory configuration number. | + | Special mode: High bit of memory configuration number (see [[Memory map]]). |
|- | |- | ||
| 1 || Special mode: Low bit of memory configuration number. | | 1 || Special mode: Low bit of memory configuration number. | ||
| Line 25: | Line 25: | ||
| 0 || Paging mode. 0=Normal, 1=Special. | | 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. | ||
Revision as of 17:23, 18 August 2017
| 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.