Difference between revisions of "83Plus:Ports:16"
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| − | [[Category:83Plus:Ports:By_Address:Protected|16 - Flash Sector Exclusion]] [[Category:83Plus:Ports:By_Address|16 - Flash | + | [[Category:83Plus:Ports:By_Address:Protected|16 - Flash Sector Exclusion]] [[Category:83Plus:Ports:By_Address|16 - Flash Page Exclusion]] [[Category:83Plus:Ports:By_Name|Flash Page Exclusion]] |
{{Protected Port}} | {{Protected Port}} | ||
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'''Port Number:''' 16h | '''Port Number:''' 16h | ||
| − | '''Function:''' Flash Sector Exclusion | + | '''Function:''' Flash Sector/Page Exclusion |
| − | This port controls which sectors of Flash may contain executable code. | + | This port controls which sectors or pages of Flash may contain executable code. |
=== Read Values === | === Read Values === | ||
| Line 13: | Line 13: | ||
=== Write Values === | === Write Values === | ||
| + | * Each bit maps to a page, as determined by [[83Plus:Ports:05|port 5]]. Set a bit to disallow execution on that page. | ||
| + | |||
| + | == Comments == | ||
| + | The above only applies to the 83+ basic. It does nothing on other models. | ||
| + | |||
| + | This port is protected, just as [[83Plus:Ports:14|port 14]] is; it is the only other protected port in the original hardware. Note that as with most protected ports, Flash must be write-enabled for writing to have any effect. | ||
| + | |||
| + | It is used, as are ports [[83Plus:Ports:22|22]] and [[83Plus:Ports:23|23]] on the SE, to prevent code in the archive from executing, thus theoretically limiting Flash execution privileges to FlashApps. | ||
| + | |||
| + | === An alternate version? === | ||
| + | The TI-73 uses this port differently. Instead of controlling individual pages, each bit corresponds to a Flash ''sector:'' | ||
| + | |||
* Bit 0: Set if execution is not allowed in sector SA2 (pages 08-0B.) | * Bit 0: Set if execution is not allowed in sector SA2 (pages 08-0B.) | ||
* Bit 1: Set if execution is not allowed in sector SA3 (pages 0C-0F.) | * Bit 1: Set if execution is not allowed in sector SA3 (pages 0C-0F.) | ||
* Bit 2: Set if execution is not allowed in sector SA4 (pages 10-13.) | * Bit 2: Set if execution is not allowed in sector SA4 (pages 10-13.) | ||
* Bit 3: Set if execution is not allowed in sector SA5 (pages 14-17.) | * Bit 3: Set if execution is not allowed in sector SA5 (pages 14-17.) | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | == | + | == Credits and Contributions == |
| − | + | * '''Tijl Coosemans:''' Documentation [http://tijl.ulyssis.be/83phwinfo.txt here]. | |
| − | + | == See Also == | |
| − | + | * [[83Plus:Ports:05#Synopsis (TI-83 Plus)|Port 5]] | |
| − | + | * [[83Plus:Ports:22|Port 22]] | |
| + | * [[83Plus:Ports:23|Port 23]] | ||
Latest revision as of 17:25, 3 March 2020
| This port is protected, which means user programs cannot ordinarily write to it directly. |
Contents
Synopsis
Port Number: 16h
Function: Flash Sector/Page Exclusion
This port controls which sectors or pages of Flash may contain executable code.
Read Values
- Nothing useful (mirror of port 14, I think.)
Write Values
- Each bit maps to a page, as determined by port 5. Set a bit to disallow execution on that page.
Comments
The above only applies to the 83+ basic. It does nothing on other models.
This port is protected, just as port 14 is; it is the only other protected port in the original hardware. Note that as with most protected ports, Flash must be write-enabled for writing to have any effect.
It is used, as are ports 22 and 23 on the SE, to prevent code in the archive from executing, thus theoretically limiting Flash execution privileges to FlashApps.
An alternate version?
The TI-73 uses this port differently. Instead of controlling individual pages, each bit corresponds to a Flash sector:
- Bit 0: Set if execution is not allowed in sector SA2 (pages 08-0B.)
- Bit 1: Set if execution is not allowed in sector SA3 (pages 0C-0F.)
- Bit 2: Set if execution is not allowed in sector SA4 (pages 10-13.)
- Bit 3: Set if execution is not allowed in sector SA5 (pages 14-17.)
Credits and Contributions
- Tijl Coosemans: Documentation here.
