21.8.13. DPLL Control A
Name:
DPLLCTRLA
Offset:
0x28
Reset:
0x80
Property:
PAC Write-Protection, Write-Synchronized (ENABLE)
Bit
7
6
5
4
3
2
1
0
ONDEMAND
RUNSTDBY
ENABLE
Access
R/W
R/W
R/W
Reset
1
0
0
Bit 7 – ONDEMAND: On Demand Clock Activation
The On Demand operation mode allows the DPLL to be enabled or disabled depending on peripheral
clock requests.
If the ONDEMAND bit has been previously written to '1', the DPLL will only be running when requested by
a peripheral. If there is no peripheral requesting the DPLL’s clock source, the DPLL will be in a disabled
state.
If On Demand is disabled the DPLL will always be running when enabled.
In standby sleep mode, the On Demand operation is still active.
Value
Description
0
The DPLL is always on, if enabled.
1
The DPLL is enabled when a peripheral is requesting the DPLL to be used as a clock
source. The DPLL is disabled if no peripheral is requesting the clock source.
Bit 6 – RUNSTDBY: Run in Standby
This bit controls how the DPLL behaves during standby sleep mode:
Value
Description
0
The DPLL is disabled in standby sleep mode if no peripheral requests the clock.
1
The DPLL is not stopped in standby sleep mode. If ONDEMAND=1, the DPLL will be running
when a peripheral is requesting the clock. If ONDEMAND=0, the clock source will always be
running in standby sleep mode.
Bit 1 – ENABLE: DPLL Enable
The software operation of enabling or disabling the DPLL takes a few clock cycles, so the
DPLLSYNCBUSY.ENABLE status bit indicates when the DPLL is successfully enabled or disabled.
Value
Description
0
The DPLL is disabled.
1
The DPLL is enabled.
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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