Port Number: 0028
Function: Flash Protection Status
Flash is unlocked if both bits 2 and 3 of this port are set.
Latches value written, no apparent effect.
Used by OS on Python Edition.
Always 0, writes do not latch.
Can be written freely (under the usual privileged port constraints).
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 (F31800F3ED7EED56ED3928ED3828CB57) that ends in privileged flash while port 6 bit 2 is set is the only way to set it.
Writes do not latch, no apparent effect.