System Control
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
4-6
ID073015
Non-Confidential
4.2.2
c1 registers
shows the CP15 system control registers you can access when CRn is c1.
4.2.3
c2 registers
shows the CP15 system control registers you can access when CRn is c2.
4.2.4
c3 registers
shows the CP15 system control registers you can access when CRn is c3.
Table 4-3 c1 register summary
Op1
CRm
Op2
Name Type
Reset Description
0
c0
0
SCTLR
RW
-
a
1
ACTLR
b
RW
0x00000000
2
CPACR
RW
-
c
Coprocessor Access Control Register
c1
0
SCR
de
RW
0x00000000
Secure Configuration Register
1
SDER
RW
0x00000000
2
NSACR
RW
f
-
g
Non-secure Access Control Register
3
VCR
RW
0x00000000
Virtualization Control Register
a. Depends on input signals. See
.
b. RO in Non-secure state if NSACR[18]=0 and RW if NSACR[18]=1.
c. The reset value depends on the VFP and NEON configuration.
If VFP and NEON are implemented, and NEON is powered up, the reset value is
0x00000000
If VFP is implemented, and NEON is not implemented or powered down, the reset value is
0x80000000
If VFP and NEON are not implemented, the reset value is
0xC0000000
.
d. No access in Non-secure state.
e. SCR[6] is not implemented, RAZ/WI.
f. RW in Secure state and RO in the Non-secure state.
g.
0x00000000
if NEON present and
0x0000C000
if NEON not present.
Table 4-4 c2 register summary
Op1
CRm
Op2
Name Type
Reset
Description
0
c0
0
TTBR0
RW
-
1
TTBR1
RW
-
Translation Table Base Register 1
2
TTBCR
RW
0x00000000
a
a. In Secure state only. You must program the Non-secure version with the required value.
Translation Table Base Control Register
Table 4-5 c3 register summary
Op1
CRm
Op2
Name Type
Reset Description
0
c0
0
DACR
RW
-
Domain Access Control Register