LM3S818 Datasheet, PDF (140/572 Pages) Bookham, Inc. – Microcontroller

Cortex-M3 Peripherals
Register 39: MPU Region Attribute and Size (MPUATTR), offset 0xDA0
Register 40: MPU Region Attribute and Size Alias 1 (MPUATTR1), offset 0xDA8
Register 41: MPU Region Attribute and Size Alias 2 (MPUATTR2), offset 0xDB0
Register 42: MPU Region Attribute and Size Alias 3 (MPUATTR3), offset 0xDB8
Note: This register can only be accessed from privileged mode.
The MPUATTR register defines the region size and memory attributes of the MPU region specified
by the MPU Region Number (MPUNUMBER) register and enables that region and any subregions.
The MPUATTR register is accessible using word or halfword accesses with the most-significant
halfword holding the region attributes and the least-significant halfword holds the region size and
the region and subregion enable bits.
The MPU access permission attribute bits, XN, AP, TEX, S, C, and B, control access to the
corresponding memory region. If an access is made to an area of memory without the required
permissions, then the MPU generates a permission fault.
The SIZE field defines the size of the MPU memory region specified by the MPUNUMBER register
as follows:
(Region size in bytes) = 2^(SIZE+1)
The smallest permitted region size is 32 bytes, corresponding to a SIZE value of 4. Table
3-9 on page 140 gives example SIZE values with the corresponding region size and value of N in
the MPU Region Base Address (MPUBASE) register.
Table 3-9. Example SIZE Field Values
SIZE Encoding
Region Size
Value of N^a
Note
00100b (0x4)
32 B
5
Minimum permitted size
01001b (0x9)
1 KB
10
-
10011b (0x13)
1 MB
20
-
11101b (0x1D)
1 GB
30
-
11111b (0x1F)
4 GB
No valid ADDR field in MPUBASE; the Maximum possible size
region occupies the complete
memory map.
a. Refers to the N parameter in the MPUBASE register (see page 138).
MPU Region Attribute and Size (MPUATTR)
Base 0xE000.E000
Offset 0xDA0
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
reserved
XN reserved
AP
Type RO
RO
RO
R/W
RO
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
SRD
Type R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
23
22
reserved
RO
RO
0
0
7
6
reserved
RO
RO
0
0
21
20
19
18
17
16
TEX
S
C
B
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
5
4
3
2
1
0
SIZE
ENABLE
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
140
July 14, 2014
Texas Instruments-Production Data