Functional Peripherals Registers
104
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
Cortex-M4F Peripherals
2.4.2.5
RASR Register (Offset = DA0h) [reset = 00000000h]
RASR is shown in
and described in
.
MPU Region Attribute and Size Register. Use the MPU Region Attribute and Size Register to control the
MPU access permissions. The register is made up of two part registers, each of halfword size. These can
be accessed using the individual size, or they can both be simultaneously accessed using a word
operation. The sub-region disable bits are not supported for region sizes of 32 bytes, 64 bytes, and 128
bytes. When these region sizes are used, the subregion disable bits must be programmed as 0.
Figure 2-13. RASR Register
31
30
29
28
27
26
25
24
RESERVED
XN
RESERVED
AP
R/W-0h
R/W-0h
R/W-0h
R/W-0h
23
22
21
20
19
18
17
16
RESERVED
TEX
S
C
B
R/W-0h
R/W-0h
R/W-0h
R/W-0h
R/W-0h
15
14
13
12
11
10
9
8
SRD
R/W-0h
7
6
5
4
3
2
1
0
RESERVED
SIZE
ENABLE
R/W-0h
R/W-0h
R/W-0h
Table 2-18. RASR Register Field Descriptions
Bit
Field
Type
Reset
Description
31-29
RESERVED
R/W
0h
28
XN
R/W
0h
Instruction access disable bit
0b = enable instruction fetches
1b = disable instruction fetches
27
RESERVED
R/W
0h
26-24
AP
R/W
0h
Data access permission field
0b = Priviliged permissions: No access. User permissions: No
access.
1b = Priviliged permissions: Read-write. User permissions: No
access.
10b = Priviliged permissions: Read-write. User permissions: Read-
only.
11b = Priviliged permissions: Read-write. User permissions: Read-
write.
101b = Priviliged permissions: Read-only. User permissions: No
access.
110b = Priviliged permissions: Read-only. User permissions: Read-
only.
111b = Priviliged permissions: Read-only. User permissions: Read-
only.
23-22
RESERVED
R/W
0h
21-19
TEX
R/W
0h
Type extension field
18
S
R/W
0h
Shareable bit
0b = not shareable
1b = shareable
17
C
R/W
0h
Cacheable bit
0b = not cacheable
1b = cacheable