B1.105 System Control Register
The SCTLR characteristics are:
Purpose
Provides the top level control of the system, including its memory system.
Usage constraints
The SCTLR is accessible as follows:
EL0
(NS)
EL0
(S)
EL1
(NS)
EL1
(S)
EL2 EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
-
RW
RW RW RW
RW
Control bits in the SCTLR that are not applicable to a VMSA implementation read as the value
that most closely reflects that implementation, and ignore writes.
Some bits in the register are read-only. These bits relate to non-configurable features of an
implementation, and are provided for compatibility with previous versions of the architecture.
Configurations
SCTLR (NS) is architecturally mapped to AArch64 register SCTLR_EL1. See
If EL3 is using AArch32, there are separate Secure and Non-secure instances of this register.
If EL3 is using AArch32, write access to SCTLR(S) is disabled when the
CP15SDISABLE2
signal is asserted HIGH.
Attributes
SCTLR is a 32-bit register.
31 30 29 28 27 26 25 24
14 13 12 11
3 2 1 0
M
I
RES
0
V
C A
EE
TRE
AFE
TE
18
21 20 19
UWXN
WXN
9
17 16 15
RES
1
nTWE
RES
0
nTWI
RES
0
8 7 6 5 4
CP15BEN
THEE
ITD
SED
RES
0
RES
0
23 22
RES
0
RES
1
RES
1
RES
0
Figure B1-58 SCTLR bit assignments
[31]
Reserved,
RES0
.
TE, [30]
T32 Exception enable. This bit controls whether exceptions are taken in A32 or T32 state:
0
Exceptions, including reset, taken in A32 state.
1
Exceptions, including reset, taken in T32 state.
The input
CFGTE
defines the reset value of the TE bit.
AFE, [29]
B1 AArch32 system registers
B1.105 System Control Register
100236_0100_00_en
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Summary of Contents for Cortex-A35
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