18.7.12 DPLL Control A
| Name: | DPLLCTRLA |
| Offset: | 0x30 + n*0x14 [n=0..1] |
| Reset: | 0x80 |
| Property: | PAC Write-Protection, Write-Synchronized Bits, Enable-Protected Bits |
| 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 Control
The On Demand operation mode allows the DPLLn to be enabled or disabled, depending on peripheral clock requests.
If On Demand is set, the DPLLn will be running only when requested by a peripheral and enabled (DPLLnCTRLA. ENABLE=1). If there is no peripheral requesting the DPLLn’s clock source, the DPLLn will be in a disabled state.
If On Demand is cleared, the DPLLn will always be running when enabled (DPLLnCTRLA.ENABLE=1).
In standby sleep mode, the On Demand operation is still active.
0: The DPLLn is always running.
1: The DPLLn is running when a peripheral is requesting the DPLLn to be used as a clock source. The DPLLn is not running if no peripheral is requesting the clock source.
Bit 6 – RUNSTDBY Run in Standby
This bit controls how the DPLLn behaves during standby sleep mode:
0: The DPLLn is not running in standby sleep mode if no peripheral requests the clock.
1: The DPLLn is running in standby sleep mode. If ONDEMAND is one, the DPLLn 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 DPLL Enable
0: The DPLLn is disabled.
1: The DPLLn is enabled.
The software operation of enabling or disabling the DPLLn takes a few clock cycles, so the DPLLnSYNCBUSY. ENABLE status bit indicates when the DPLLn is successfully enabled or disabled.