84PCE:Ports:0028 - Revision history

Jacobly: Fix flash unlock sequence.

2021-07-08T23:29:17Z

Fix flash unlock sequence.

Jacobly: /* Bit [0] */

2019-06-29T05:17:50Z

‎Bit [0]

Jacobly at 20:37, 1 February 2018

2018-02-01T20:37:32Z

Jacobly at 19:42, 8 August 2017

2017-08-08T19:42:52Z

Jacobly at 04:48, 8 August 2017

2017-08-08T04:48:43Z

Jacobly: /* Synopsis */

2017-08-08T04:42:53Z

‎Synopsis

MateoConLechuga: Created page with "0028 - Unknown == Synopsis == '''Port Number:''' 0028 '''Function:''' Unknown == Details == This port's function is unknown. === Bit [0..."

2017-08-06T11:31:57Z

Created page with "0028 - Unknown == Synopsis == '''Port Number:''' 0028 '''Function:''' Unknown == Details == This port's function is unknown. === Bit [0..."

New page

[[Category:84PCE:Ports:By_Address|0028 - Unknown]]
== Synopsis ==
'''Port Number:''' 0028

'''Function:''' Unknown

== Details ==

This port's function is unknown.

=== Bit [0] ===
Latches value written, no apparent effect.

=== Bit [1] ===
Always 0, writes do not latch.

=== Bit [2] ===
Latches value written, no apparent effect.

=== Bits [7:3] ===
Writes do not latch, no apparent effect.

@@ Line 23: / Line 23: @@
 Can be cleared by writing a 0.
 Gets cleared any time unprivileged code is executed or port 6 bit 2 is reset.
-Fetching a flash unlock sequence (F31800F3F3ED7EED56ED3928ED3828CB57) that ends in privileged flash while port 6 bit 2 is set is the only way to set it.
+Fetching a flash unlock sequence (F31800F3ED7EED56ED3928ED3828CB57) that ends in privileged flash while port 6 bit 2 is set is the only way to set it.
 === Bits [7:4] ===
 Writes do not latch, no apparent effect.

@@ Line 16: / Line 16: @@
 === Bit [2] ===
-Can be written freely (under the usual protected port constraints).
+Can be written freely (under the usual privileged port constraints).
 === Bit [3] ===

@@ Line 20: / Line 20: @@
 === Bit [3] ===
 Can be cleared by writing a 0.
-Gets cleared any time unprivileged code is executed.
+Gets cleared any time unprivileged code is executed or port 6 bit 2 is reset.
-Fetching a flash unlock sequence (F31800F3F3ED7EED56ED3928ED3828CB57) that ends in privileged flash is the only way to set it.
+Fetching a flash unlock sequence (F31800F3F3ED7EED56ED3928ED3828CB57) that ends in privileged flash while port 6 bit 2 is set is the only way to set it.
 === Bits [7:4] ===
 Writes do not latch, no apparent effect.

@@ Line 1: / Line 1: @@
-[[Category:84PCE:Ports:By_Address|0028 - Unknown]]
+[[Category:84PCE:Ports:By_Address|0028 - Flash Protection Status]] [[Category:84PCE:Ports:By_Name|Flash Protection Status]]
 == Synopsis ==
 '''Port Number:''' 0028
-'''Function:''' Flash locked status
+'''Function:''' Flash Protection Status
-−
-Flash is unlocked iff bits 2 and 3 of this port are both set.
-−
-bit 2: can be modified freely (under the usual protected port constraints)
-−
-bit 3: can be cleared by writing a 0 or any time unprivileged code is executed, fetching the flash unlock sequence (F31800F3F3ED7EED56ED3928ED3828CB57) ending in privileged flash is the only way to set it
 == Details ==
-This port's function is unknown.
+Flash is unlocked if both bits 2 and 3 of this port are set.
 === Bit [0] ===
@@ Line 22: / Line 16: @@
 === Bit [2] ===
-Latches value written, no apparent effect.
+Can be written freely (under the usual protected port constraints).
-=== Bits [7:3] ===
+=== Bits [7:4] ===
 Writes do not latch, no apparent effect.