Motorola MPC823e - Page 231

Memory Management Unit
MOTOROLA MPC823e REFERENCE MANUAL 11-13
MEMORY MANAGEMENT
11
UNIT
PP4—Protection for the Fourth 1K Subpage in a 4K Page
This field contains protection code for the fourth subpage in a 4K page. Depending on the
encoding mode, this field has different meanings.
PAGES OVER 4K WITH 4K RESOLUTION PROTECTION
PP3 SETTING CASE: Mx_CTR (PPCS) = 1
00 No hit for any state
01 Hit only for problem accesses
10 Hit only for privilege accesses
11 Hit for both problem and privilege accesses
4K PAGES WITH 1K RESOLUTION PROTECTION
PP4
SETTING
INSTRUCTION PAGES DATA PAGES
PRIVILEGED MODE PROBLEM MODE PRIVILEGED MODE PROBLEM MODE
00 No access No access No access No access
01 Executable No access Read/Write No access
10 Executable Executable Read/Write Read-only
11 Executable Executable Read/Write Read/Write
PAGES OVER 4K WITH 4K RESOLUTION PROTECTION
PP4 SETTING CASE: Mx_CTR (PPCS) = 0
0x Third subpage not valid
1x Third subpage valid
x0 Fourth subpage not valid
x1 Fourth subpage valid