Memory Protection Unit (MPU) Register Descriptions
1653
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
Cortex-M3 Peripherals
Figure 25-51. MPU Region Attribute and Size (MPUATTR) Register
31
29
28
27
26
24
Reserved
XN
Reserved
AP
R-0
R/W-0
R-0
R/W-0
23
22
21
19
18
17
16
Reserved
TEX
S
C
B
R-0
R/W-0
R/W-0
R/W-0
R/W-0
15
8
SRD
R/W-0
7
6
5
1
0
Reserved
SIZE
ENABLE
R-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 25-59. MPU Region Attribute and Size (MPUATTR) Field Descriptions
Bit
Field
Value
Description
31-29
Reserv ed
Reserved
28
XN
Instruction Access Disable
0
Instruction fetches are enabled.
1
Instruction fetches are disabled.
27
Reserved
Reserved
26-24
AP
Access Privilege
0
For information on using this bit field, see
23-22
Reserved
Reserved
21-19
TEX
Type Extension Mask
0
For information on using this bit field, see
18
S
Shareable
0
For information on using this bit field, see
17
C
Cacheable
0
For information on using this bit field, see
16
B
Bufferable
0
For information on using this bit field, see
15-8
SRD
Subregion Disable Bits
0
The corresponding subregion is enabled.
1
The corresponding subregion is disabled.
Region sizes of 128 bytes and less do not support subregions. When writing the attributes for such
a region, configure the SRD field as 0x00. See
for more information.
7-6
Reserved
Reserved
5-1
SIZE
Region Size Mask
0
The SIZE field defines the size of the MPU memory region specified by the MPUNUMBER register.
Refer to
for more information
0
ENABLE
Region Enable
0
The region is disabled.
1
The region is enabled.