12.1.3 Oscillator Status and Manual Enable

The Oscillator Status (OSCSTAT) register displays the Ready status for each of the following oscillators:
  • External oscillator
  • HFINTOSC
  • MFINTOSC
  • LFINTOSC
  • SOSC
  • ADCRC
The OSCSTAT register also displays the Ready status for the 4xPLL.

The HFINTOSC Oscillator Ready (HFOR) and MFINTOSC Oscillator Ready (MFOR) Status bits indicate whether the respective oscillators are ready for use. Both clock sources are available for use at any time but may require a finite amount of time before they have reached the specified accuracy levels. When the HFINTOSC or MFINTOSC are ready and achieved the specified accuracy, module hardware sets the HFOR/MFOR bits, respectively.

When a new value is loaded into the OSCFRQ register, the HFOR and MFOR bits are cleared by hardware and will be set again once the respective oscillator is ready. During pending OSCFRQ changes, the MFINTOSC will stall at either a high or a low state until the HFINTOSC locks in the new frequency and resumes operation.

The Oscillator Enable (OSCEN) register can be used to manually enable the following oscillators:
  • External oscillator
  • HFINTOSC
  • MFINTOSC
  • LFINTOSC
  • SOSC
  • ADCRC
Important: OSCEN cannot be used to manually enable the 4xPLL.