83Plus:Ports:24 - Revision history

Fghsgh: this was making no sense

2021-01-20T21:52:26Z

this was making no sense

KermMartian: /* Synopsis */

2013-03-15T05:36:14Z

‎Synopsis

KermMartian: /* Write Values */

2013-03-15T05:35:48Z

‎Write Values

KermMartian at 05:20, 15 March 2013

2013-03-15T05:20:00Z

Dr. D'nar: Found true purpose of bits 0 and 1

2013-02-20T21:20:33Z

Found true purpose of bits 0 and 1

Thepenguin77: Created page with '24 - Flash Execution Override 24 - Flash Execution Override [[Category:83Plus:Ports:By_Name|Fl…'

2011-08-21T04:35:14Z

Created page with '24 - Flash Execution Override 24 - Flash Execution Override [[Category:83Plus:Ports:By_Name|Fl…'

New page

[[Category:83Plus:Ports:By_Address:Protected|24 - Flash Execution Override]] [[Category:83Plus:Ports:By_Address|24 - Flash Execution Override]] [[Category:83Plus:Ports:By_Name|Flash Execution Override]]
{{SE-Only Port|04}}
{{Protected Port}}

== Synopsis ==
'''Port Number:''' 24h

'''Function:''' Flash Execution Override

This port overrides [[83Plus:Ports:23|port 23]] and is overridden by port [[83Plus:Ports:22|port 22]].

=== Write Values ===
* Bit 0: Set to allow execution on any flash page
* Bit 1: Set to disable execution on every page except privileged pages, bit 0 and [[83Plus:Ports:22|port 22]] override this function.
* Bits 2-7: Toggleable, but no effect is apparent

=== Read Values ===
* Bit 0: Set if execution is allowed on any flash page
* Bit 1: Set if execution is disabled on every page except privileged pages, and pages allowed by bit 0 and [[83Plus:Ports:22|port 22]].
* Bit 2-7: Reads whatever was last written

== Comments ==
This port is very strange and not well understood. Bits 2-7 can be toggled so they probably have a use.

This port does not exist on the standard 83 Plus. See ports [[83Plus:Ports:05|5]] and [[83Plus:Ports:16|16]] instead.

== See Also ==
* [[83Plus:Ports:26|Port 26]]
* [[83Plus:Ports:21|Port 21]]
* [[83Plus:Ports:26|Port 22]]
* [[83Plus:Ports:26|Port 23]]

@@ Line 10: / Line 10: @@
 Bit 0 of this port forms the high bit of page number for port 22. Bit 1 of this port forms the high bit of the page number for port 23. Therefore, this port supports 8 MB flash chips.
-Since no 8 MB flash chip exists, this port in effect overrides [[83Plus:Ports:23|port 23]] and is overridden by port [[83Plus:Ports:22|port 22]].
+Since no 8 MB flash chip exists, this port in effect overrides both [[83Plus:Ports:22|port 22]] and [[83Plus:Ports:23|port 23]].
 === Write Values ===

@@ Line 8: / Line 8: @@
 '''Function:''' Flash Execution Limits High Bit
-Bit 0 of this port forms the high bit of page number for port 23. Bit 1 of this port forms the high bit of the page number for port 24. Therefore, this port supports 8 MB flash chips.
+Bit 0 of this port forms the high bit of page number for port 22. Bit 1 of this port forms the high bit of the page number for port 23. Therefore, this port supports 8 MB flash chips.
 Since no 8 MB flash chip exists, this port in effect overrides [[83Plus:Ports:23|port 23]] and is overridden by port [[83Plus:Ports:22|port 22]].

@@ Line 13: / Line 13: @@
 === Write Values ===
-* Bit 0: High bit (bit 8) of port 23
+* Bit 0: High bit (bit 8) of port 22
-* Bit 1: High bit (bit 8) of port 24
+* Bit 1: High bit (bit 8) of port 23
 * Bits 2-7: Toggleable, but no effect is apparent. These bits are currently unused.

@@ Line 15: / Line 15: @@
 * Bit 0: High bit (bit 8) of port 23
 * Bit 1: High bit (bit 8) of port 24
-* Bits 2-7: Toggleable, but no effect is apparent
+* Bits 2-7: Toggleable, but no effect is apparent. These bits are currently unused.
 === Read Values ===
@@ Line 21: / Line 21: @@
 == Comments ==
 This port does not exist on the standard 83 Plus.  See ports [[83Plus:Ports:05|5]] and [[83Plus:Ports:16|16]] instead.

@@ Line 1: / Line 1: @@
-[[Category:83Plus:Ports:By_Address:Protected|24 - Flash Execution Override]] [[Category:83Plus:Ports:By_Address|24 - Flash Execution Override]] [[Category:83Plus:Ports:By_Name|Flash Execution Override]]
+[[Category:83Plus:Ports:By_Address:Protected|24 - Flash Execution Limits High Bit]] [[Category:83Plus:Ports:By_Address|24 - Flash Execution Limits High Bit]] [[Category:83Plus:Ports:By_Name|Flash Execution Limit High Bit]]
 {{SE-Only Port|04}}
 {{Protected Port}}
@@ Line 6: / Line 6: @@
 '''Port Number:''' 24h
-'''Function:''' Flash Execution Override
+'''Function:''' Flash Execution Limits High Bit
-This port overrides [[83Plus:Ports:23|port 23]] and is overridden by port [[83Plus:Ports:22|port 22]].
+Bit 0 of this port forms the high bit of page number for port 23. Bit 1 of this port forms the high bit of the page number for port 24. Therefore, this port supports 8 MB flash chips.
 === Write Values ===
-* Bit 0: Set to allow execution on any flash page
+* Bit 0: High bit (bit 8) of port 23
-* Bit 1: Set to disable execution on every page except privileged pages, bit 0 and [[83Plus:Ports:22|port 22]] override this function.
+* Bit 1: High bit (bit 8) of port 24
 * Bits 2-7: Toggleable, but no effect is apparent
 === Read Values ===
-* Bit 0: Set if execution is allowed on any flash page
+* Bit 0-7: Reads whatever was last written
-* Bit 1: Set if execution is disabled on every page except privileged pages, and pages allowed by bit 0 and [[83Plus:Ports:22|port 22]].
-* Bit 2-7: Reads whatever was last written
 == Comments ==
-This port is very strange and not well understood. Bits 2-7 can be toggled so they probably have a use.
+Bits 2-7 can be toggled so they may have a use, too.
 This port does not exist on the standard 83 Plus.  See ports [[83Plus:Ports:05|5]] and [[83Plus:Ports:16|16]] instead.