The
System Control Processor
(SCP) configures the PLLs, muliplexers, and dividers in the clock system
during bootup.
The following table shows the N1 SoC clocks.
Note
The default clock frequencies in this table represent an example clock configuration which enables
correct operation of the N1 SoC. Further SoC testing and measurement, by Arm or by other developers,
might result in other default frequencies.
Table 2-1 N1 SoC clocks
Clock
Source
Default
frequency
Description
SWCLKTCK
External debugger
-
Combined P-JTAG and
Serial Wire Debug
(SWD) clock.
CPU0REFCLK
OSC1
50MHz
Reference clock for CPU0PLL. Generates
CPU0PLLCLK
for cluster 0.
CPU1REFCLK
OSC2
50MHz
Reference clock for CPU1PLL. Generates
CPU1PLLCLK
for cluster 1.
CLUSREFCLK
OSC3
50MHz
Reference clock for CLUSPLL. Generates
CLUSPLLCLK
,
a common cluster clock for cluster 0 and cluster 1.
DMCREFCLK
OSC6
50MHz
Reference clock for DMCPLL. Generates
DMCPLLCLK
for the DDR subsystem.
INTREFCLK
OSC4
50MHz
Reference clock for INTPLL. Generates
INTPLLCLK
for
the CMN
‑
600 Coherent Mesh Network.
SYSREFCLK
OSC0
50MHz
Reference clock for SYSPLL. Generates the main system
clock
SYSPLLCLK
, and other clocks through
programmable dividers.
REFCLK
OSC5
50MHz
Always
‑
On reference clock.
CPU0PLLCLK
CPU0PLL
2.4GHz
Cluster-specific clock for cluster 0.
CPU1PLLCLK
CPU1PLL
2.4GHz
Cluster-specific clock for cluster 1.
CLUSPLLCLK
CLUSPLL
1.6GHz
Clock for cluster 0 and cluster 1.
DMCPLLCLK
DMCPLL
1.6GHz
Clock for DDR4 subsystem.
INTPLLCLK
INTPLL
1.6GHz
CMN
‑
600 Coherent Mesh network clock.
SYSPLLCLK
SYSPLL
2.4GHz
Main system clock.
2 Hardware description
2.4 Clocks
101489_0000_02_en
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