4.5.3 RC Oscillator Calibration

Both the RCOSC_HF and RCOSC_LF frequency shift when the temperature changes and the oscillators age. Calibrate these oscillators periodically against the XOSC_HF.

Calibrating the RCOSC_HF gives more accurate timing when running the system off this clock and starts up the XOSC_HF faster. Calibrating the RCOSC_LF gives more accurate timing for the RTC when in standby. If the RCOSC_LF is unused by the application, calibrating this oscillator is unnecessary.

The auxiliary domain contains a TDC you can use to calibrate these oscillators against the XOSC_HF. TI-RTOS contains an implementation of calibrating both the RCOSC_HF and RCOSC_LF and can be a reference for those who must calibrate RC oscillators without TI-RTOS. The following implementation is in the TI-RTOS installation:

C:\ti\tirtos_cc13xx_cc26xx_#_##_##_##\products\tidrivers_cc13xx_cc26xx_#_##_##_##\packages\ti\drivers\power\Power_calibrateRCOSC.c.