XC2200 Derivatives
System Units (Vol. 1 of 2)
Memory Organization
User’s Manual
3-43
V2.1, 2008-08
MemoryX2K, V1.3
•
A successful “
” sets WPRODIS and clears WPA.
•
“
Re-Enable Read/Write Protection
” clears RPRODIS and WPRODIS and sets RPA
and WPA according to
depending on PROIN, PROINER and RPRO.
Double indirect by changing security pages. After executing a command sequence that
changed the content of a security page the IMB Core immediately reads back the pages
and determines all resulting security data as described for system startup in
“Initialization of the Effective Security Level” on Page 3-42
. The examples in
“Protection Handling Examples” on Page 3-45
will show how this can be used for
installing and removing protection or changing passwords.
3.9.6.4
Reaction on Protection Violation
If software tries to violate the protection rules the following happens:
•
Reading data when read protection is effective: The bit IMB_FSR.PROER is set and
the Flash access trap can be triggered via the SCU if IMB_INTCTR.DPROTRP is 0.
Default data is delivered.
•
Fetching code when read protection is effective: the trap code “TRAP 15
D
” is
delivered instead.
•
Programming or erasing memory ranges when they are write protected: PROER is
set.
3.9.6.5
Layout of the Security Pages
The previous sections just mentioned the content of the security pages. This section
depicts their exact layout.
depicts symbolically the layout of the security
pages 0 and 1.