Difference between revisions of "86:Ports:06"
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Latest revision as of 02:08, 20 September 2021
Synopsis
Port Number: 06h
Function: Upper Memory Bank Port
This port controls which memory bank is accessible in the 8000-BFFFh range. See Memory Mapping for the interpretation of the banks & pages.
Read Values
- Bit 0-7: Reads last value written.
Write Values
- Bit 0-5: Page select (external address bits 14-19).
- Bit 6-7: Bank select.
Comments
- This port is set to 41h when the OS passes control to a program. Its value at program exit is ignored.
