https://wikiti.brandonw.net/index.php?action=history&feed=atom&title=86%3APorts%3A0686:Ports:06 - Revision history2026-04-06T08:12:30ZRevision history for this page on the wikiMediaWiki 1.23.5https://wikiti.brandonw.net/index.php?title=86:Ports:06&diff=11819&oldid=prevZeroko: Created page with "06 - Upper Memory Bank Upper Memory Bank == Synopsis == '''Port Number:''' 06h '''Function:''' Upper Memory Ban..."2021-09-20T09:08:52Z<p>Created page with "<a href="/index.php?title=Category:86:Ports:By_Address" title="Category:86:Ports:By Address">06 - Upper Memory Bank</a> <a href="/index.php?title=Category:86:Ports:By_Name" title="Category:86:Ports:By Name">Upper Memory Bank</a> == Synopsis == '''Port Number:''' 06h '''Function:''' Upper Memory Ban..."</p>
<p><b>New page</b></p><div>[[Category:86:Ports:By_Address|06 - Upper Memory Bank]] [[Category:86:Ports:By_Name|Upper Memory Bank]]<br />
== Synopsis ==<br />
'''Port Number:''' 06h<br />
<br />
'''Function:''' Upper Memory Bank Port<br />
<br />
This port controls which memory bank is accessible in the 8000-BFFFh range. See [[86:Memory_Mapping|Memory Mapping]] for the interpretation of the banks & pages.<br />
<br />
=== Read Values ===<br />
* Bit 0-7: Reads last value written.<br />
<br />
=== Write Values ===<br />
* Bit 0-5: Page select (external address bits 14-19).<br />
* Bit 6-7: Bank select.<br />
<br />
== Comments ==<br />
* This port is set to 41h when the OS passes control to a program. Its value at program exit is ignored.</div>Zeroko