Difference between revisions of "83:Ports:02"
From WikiTI
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== Credits and Contributions == | == Credits and Contributions == | ||
* created by CoBB | * created by CoBB | ||
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| + | [[Category:83:Ports:By Address|02 - ROM and RAM pager]] | ||
| + | [[Category:83:Ports:By Name|ROM and RAM pager]] | ||
Revision as of 03:25, 30 March 2005
Synopsis
Port Number: 02h
Function: ROM and RAM Pager
This port controls what page is swapped into the 4000h to 7FFFh range.
Read Values
Always the last value output is read back.
Write Values
- Bits 0 to 2: The lower 3 bits of the desired ROM page (bit 3 can be set through bit 4 of the link port)
- Bit 3: Must be 1, otherwise the the calculator crashes
- Bit 4: 0 - the specified ROM page is swapped in, 1 - the RAM page specified by bit 0 swapped in (0 causes it to mirror the page at C000h, 1 mirrors the page at 8000h)
- Bit 5: Unknown, harmless
- Bit 6: Unknown, harmless
- Bit 7: Must be 1, otherwise the the calculator crashes
Credits and Contributions
- created by CoBB
