23.8.8 16MHz Internal Oscillator (OSC16M) Control

Name: OSC16MCTRL
Offset: 0x18
Reset: 0x82
Property: PAC Write-Protection

Bit 76543210 
 ONDEMANDRUNSTDBY  FSEL[1:0]ENABLE  
Access R/WR/WR/WR/WR/W 
Reset 10001 

Bit 7 – ONDEMAND 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.

ValueDescription
0The oscillator is always on, if enabled.
1The 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

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

ValueDescription
0The OSC16M is disabled in standby sleep mode if no peripheral requests the clock.
1The 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

These bits control the oscillator frequency range.

ValueDescription
0x004MHz
0x018MHz
0x1012MHz
0x1116MHz

Bit 1 – ENABLE Oscillator Enable

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