Table 3-3. TEX, S, C, and B Bit Field Encoding (continued)
Other Attributes
Shareability
Memory Type
B
C
S
TEX
Outer and inner
write-through. No write
allocate.
Not shareable
Normal
0
1
0
000
Shareable
Normal
0
1
1
000
Not shareable
Normal
1
1
0
000
Shareable
Normal
1
1
1
000
Outer and inner
non-cacheable.
Not shareable
Normal
0
0
0
001
Shareable
Normal
0
0
1
001
-
-
Reserved encoding
1
0
x
a
001
-
-
Reserved encoding
0
1
x
a
001
Outer and inner
write-back. Write and
read allocate.
Not shareable
Normal
1
1
0
001
Shareable
Normal
1
1
1
001
Nonshared Device.
Not shareable
Device
0
0
x
a
010
-
-
Reserved encoding
1
0
x
a
010
-
-
Reserved encoding
x
a
1
x
a
010
Cached memory (BB =
outer policy, AA = inner
policy).
See Table 3-4 for the
encoding of the AA and
BB bits.
Not shareable
Normal
A
A
0
1BB
Shareable
Normal
A
A
1
1BB
a. The MPU ignores the value of this bit.
Table 3-4 on page 141 shows the cache policy for memory attribute encodings with a
TEX
value in
the range of 0x4-0x7.
Table 3-4. Cache Policy for Memory Attribute Encoding
Corresponding Cache Policy
Encoding, AA or BB
Non-cacheable
00
Write back, write and read allocate
01
Write through, no write allocate
10
Write back, no write allocate
11
Table 3-5 on page 141 shows the
AP
encodings in the
MPUATTR
register that define the access
permissions for privileged and unprivileged software.
Table 3-5. AP Bit Field Encoding
Description
Unprivileged
Permissions
Privileged
Permissions
AP
Bit Field
All accesses generate a permission fault.
No access
No access
000
Access from privileged software only.
No access
RW
001
Writes by unprivileged software generate a
permission fault.
RO
RW
010
Full access.
RW
RW
011
Reserved.
Unpredictable
Unpredictable
100
Reads by privileged software only.
No access
RO
101
141
June 18, 2014
Texas Instruments-Production Data
Tiva
™
TM4C1294NCPDT Microcontroller