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 port 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 port 14 is; it is the only other protected port in the original hardware.

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.