16MHz Internal Oscillator (OSC16M) Control

  0x18 8 PAC Write-Protection 0x82  

16MHz Internal Oscillator (OSC16M) Control

Bit  7 6 5 4 3 2 1 0  
Access  R/W R/W     R/W R/W R/W    
Reset  1 0     0 0 1    

Bit 7 – ONDEMAND: On Demand Control

On Demand Control

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

If the ONDEMAND bit has been previously written to '1', the oscillator will only be running when requested by a peripheral. If there is no peripheral requesting the oscillator’s clock source, the oscillator will be in a disabled state.

If On Demand is disabled the oscillator will always be running when enabled.

In standby sleep mode, the On Demand operation is still active.

0 The oscillator is always on, if enabled.
1 The oscillator is enabled when a peripheral is requesting the oscillator to be used as a clock source. The oscillator is disabled if no peripheral is requesting the clock source.

Bit 6 – RUNSTDBY: Run in Standby

Run in Standby

This bit controls how the OSC16M behaves during standby sleep mode.

0 The OSC16M is disabled in standby sleep mode if no peripheral requests the clock.
1 The OSC16M is not stopped in standby sleep mode. If ONDEMAND=1, the OSC16M will be running when a peripheral is requesting the clock. If ONDEMAND=0, the clock source will always be running in standby sleep mode.

Bits 3:2 – FSEL[1:0]: Oscillator Frequency Selection

Oscillator Frequency Selection

These bits control the oscillator frequency range.

0x00 4MHz
0x01 8MHz
0x10 12MHz
0x11 16MHz

Bit 1 – ENABLE: Oscillator Enable

Oscillator Enable

0 The oscillator is disabled.
1 The oscillator is enabled.