18.7.7 DFLL48M Control A

Name: DFLLCTRLA
Offset: 0x1C
Reset: 0x82
Property: PAC Write-Protection

Bit 76543210 
 ONDEMANDRUNSTDBY    ENABLE  
Access R/WR/WR/W 
Reset 101 

Bit 7 – ONDEMAND On Demand Control

The On Demand operation mode allows the DFLL to be enabled or disabled depending on peripheral clock requests.

If On Demand is set, the DFLL will only be running when requested by a peripheral and enabled (DFLLTRLA. ENABLE=1). If there is no peripheral requesting the DFLL’s clock source, the DFLL will be in a disabled state.

If On Demand is disabled the DFLL will always be running when enabled (DFLLTRLA.ENABLE=1). In standby sleep mode, the On Demand operation is still active.

0: The DFLL is always on.

1: The DFLL is running when a peripheral is requesting the DFLL to be used as a clock source. The DFLL is not running if no peripheral is requesting the clock source.

Bit 6 – RUNSTDBY Run in Standby

This bit controls how the DFLL behaves during standby sleep mode:

0: The DFLL is not running in standby sleep mode if no peripheral requests the clock.

1: The DFLL is running in standby sleep mode. If ONDEMAND is one, the DFLL will be running when a peripheral is requesting the clock. If ONDEMAND is zero, the clock source will always be running in standby sleep mode.

Bit 1 – ENABLE DFLL Enable

0: The DFLL oscillator is disabled.

1: The DFLL oscillator is enabled.

Note: This bit is write-synchronized: Due to synchronization, there is delay from updating the register until the peripheral is enabled/disabled. The value written to DFLLCTRLA.ENABLE will read back immediately after written.