Functional Description
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
2-13
ID021414
Non-Confidential
Figure 2-7 CNTCLKEN with CLKIN:CNTCLK ratio changing from 3:1 to 1:1
Note
Figure 2-7
shows the timing relationship between the system counter clock,
CLKIN
and
CNTCLKEN
, where
CNTCLKEN
asserts one clock cycle before the rising edge of
CLKIN
.
It is important that the relationship between
CLKIN
and
CNTCLKEN
is maintained.
2.3.2
Input synchronization
The Cortex-A53 processor synchronizes the input signals:
•
nCORERESET
.
•
nCPUPORESET
.
•
nFIQ
.
•
nIRQ
.
•
nL2RESET
.
•
nMBISTRESET
.
•
nPRESETDBG
.
•
nREI
.
•
nSEI
.
•
nVFIQ
.
•
nVIRQ
.
•
nVSEI
.
•
CLREXMONREQ
.
•
CPUQREQn
.
•
CTICHIN
.
•
CTICHOUTACK
.
•
CTIIRQACK
.
•
DBGEN
.
•
EDBGRQ
.
•
EVENTI
.
•
L2FLUSHREQ
.
•
L2QREQn
.
•
NEONQREQn
.
•
NIDEN
.
•
SPIDEN
.
•
SPNIDEN
.
CNTCLK
CNTCLKEN
asserts one
CLKIN
cycle before the rising edge of
CNTCLK
1
CLKIN
cycle
CLKIN
:
CNTCLK
= 3:1
CLKIN
:
CNTCLK
= 1:1
CNTCLKEN
CLKIN
1
CLKIN
cycle