83Plus:Ports:16

Synopsis

Port Number: 16h

Function: Flash Sector Exclusion

This port controls which sectors of Flash may contain executable code.

Read Values

• Nothing useful (mirror of 83Plus:Ports:14, I think.)

Write Values

• 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.)
• Bit 4: Unknown.
• Bit 5: Unknown.
• Bit 6: Unknown.
• Bit 7: Unknown.

Comments

The above only applies to the 83+ basic; the port's function on the SE and 84+ is not known.

This port is protected, just as 83Plus:Ports:14 is; it is the only other protected port in the original hardware.

It is used, as are ports 83Plus:Ports:22 and 83Plus:Ports:23 on the SE, to prevent code in the archive from executing, thus theoretically limiting Flash execution privileges to FlashApps.