Table B2-7 CPUPWRCTLR Retention Control Field (continued)
Encoding Number of counter ticks
Minimum retention entry delay
(System counter at 50MHz-10MHz)
010
8
160ns-800ns
011
32
640ns – 3,200ns
100
64
1,280ns-6,400ns
101
128
2,560ns-12,800ns
110
256
5,120ns-25,600ns
111
512
10,240ns-51,200ns
Configurations
There are no configuration notes.
Usage constraints
Accessing the CPUPWRCTLR_EL1
This register can be read using MRS with the following syntax:
MRS <Xt>,<systemreg>
This register can be written using MSR with the following syntax:
MSR <systemreg>, <Xt>
This syntax is encoded with the following settings in the instruction encoding:
<systemreg>
op0 op1 CRn CRm op2
S3_0_C15_C2_7 11
000 1111 0010 111
Accessibility
This register is accessible in software as follows:
<systemreg>
Control
Accessibility
E2H
TGE
NS
EL0
EL1
EL2
EL3
S3_0_C15_C2_7
x
x
0
-
RW
n/a
RW
S3_0_C15_C2_7
x
0
1
-
RW
RW
RW
S3_0_C15_C2_7
x
1
1
-
n/a
RW
RW
'n/a' Not accessible. The PE cannot be executing at this Exception level, so this access is not possible.
Traps and enables
For a description of the prioritization of any generated exceptions, see
Synchronous exception
prioritization
in the
Arm
®
Architecture Reference Manual Armv8, for Armv8-A architecture
profile
for exceptions taken to AArch64 state.
Write access to this register from EL1 or EL2 depends on the value of bit[7] of ACTLR_EL2
and ACTLR_EL3.
The number of system counter ticks required before the core signals retention readiness on PACTIVE to the power controller. The core does not accept a retention
entry request until this time.
B2 AArch64 system registers
B2.31 CPUPWRCTLR_EL1, Power Control Register, EL1
100798_0300_00_en
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reserved.
B2-189
Non-Confidential
Summary of Contents for Cortex-A76 Core
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