Difference between revisions of "83Plus:Ports:22"
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[[Category:83Plus:Ports:By_Address:Protected|22 - Flash Lower Limit]] [[Category:83Plus:Ports:By_Address|22 - Flash Lower Limit]] [[Category:83Plus:Ports:By_Name|Flash Lower Limit]] | [[Category:83Plus:Ports:By_Address:Protected|22 - Flash Lower Limit]] [[Category:83Plus:Ports:By_Address|22 - Flash Lower Limit]] [[Category:83Plus:Ports:By_Name|Flash Lower Limit]] | ||
{{SE-Only Port|02}} | {{SE-Only Port|02}} | ||
| + | {{Protected Port}} | ||
== Synopsis == | == Synopsis == | ||
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=== Read Values === | === Read Values === | ||
| − | * [00h - FFh]: Flash Pages | + | * [00h - FFh]: Flash Pages strictly below this value have execution permission. This is always set to 08 in TIOS. |
=== Write Values === | === Write Values === | ||
| Line 16: | Line 17: | ||
== Comments == | == Comments == | ||
| − | This port does not exist on the standard 83 Plus. See ports [[83Plus:Ports:05|5]] and [[83Plus:Ports:16|16]] instead. Execution of code from a page above this port's value and below the value in [[83Plus:Ports:23|Port 23]] will cause the calculator to reset. | + | This port does not exist on the standard 83 Plus. See ports [[83Plus:Ports:05|5]] and [[83Plus:Ports:16|16]] instead. Execution of code from a page at or above this port's value and at or below the value in [[83Plus:Ports:23|Port 23]] will cause the calculator to reset. |
| + | |||
| + | For some reason, page 00 seems to always be executable. | ||
| + | |||
| + | This port can be completely overridden by [[83Plus:Ports:24|port 24]]. | ||
| + | |||
| + | If port 23h is less than 22h, all pages will be executable. | ||
Latest revision as of 13:58, 20 January 2021
| This port only exists as a distinct port on the TI-83 Plus Silver Edition, the TI-84 Plus, and the TI-84 Plus Silver Edition. On the standard TI-83 Plus, it acts as a shadow of port 02. |
| This port is protected, which means user programs cannot ordinarily write to it directly. |
Synopsis
Port Number: 22h
Function: Flash Execution Lower Limit
This port controls the first of two flash page execution limits.
Read Values
- [00h - FFh]: Flash Pages strictly below this value have execution permission. This is always set to 08 in TIOS.
Write Values
- [00h - FFh]: The new execution limit. You must enable flash access through port 14 first.
Comments
This port does not exist on the standard 83 Plus. See ports 5 and 16 instead. Execution of code from a page at or above this port's value and at or below the value in Port 23 will cause the calculator to reset.
For some reason, page 00 seems to always be executable.
This port can be completely overridden by port 24.
If port 23h is less than 22h, all pages will be executable.
