mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 227

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

Memory Management Unit
V—Valid
11.5.2 Level Two Descriptor
The following table describes the hardware-assisted level two descriptor format that
minimizes the software tablewalk routine.
RPN—Real Page Number
This field contains the physical address of the page mapped in by this entry.
PP1—Protection for the First 1K Subpage in a 4K Page
This field contains protection code for the first subpage in a 4K page. Depending on Bit 22
of the PP2 field, the same protection code has different protection schemes.
LEVEL TWO DESCRIPTOR FORMAT
NOTE: — = Undefined. The default values depend on the state of system memory.
SETTING
RESET
RESET
FIELD
ADDR
FIELD
ADDR
R/W
R/W
BIT
BIT
PP1
00
01
10
11
0 = Segment is not valid.
1 = Segment is valid.
16
0
PRIVILEGED MODE
17
Executable
Executable
Executable
No access
1
RPN
R/W
—
18
INSTRUCTION PAGES
2
Freescale Semiconductor, Inc.
For More Information On This Product,
4K PAGES WITH 1K RESOLUTION PROTECTION
19
3
20
MPC823 REFERENCE MANUAL
4
PP1
R/W
PROBLEM MODE
—
Go to: www.freescale.com
Executable
Executable
21
No access
No access
5
22
6
SYSTEM MEMORY
SYSTEM MEMORY
PP2
R/W
—
23
7
RPN
R/W
—
24
8
PRIVILEGED MODE
PP3
R/W
—
Read/Write
Read/Write
Read/Write
No access
25
9
10
26
PP4
R/W
—
DATA PAGES
11
27
R/W
LPS
12
28
—
PROBLEM MODE
Read/Write
R/W
No access
No access
Read-only
SH
13
29
—
MOTOROLA
R/W
14
30
CI
—
R/W
15
31
—
V