How to restore default RC Calibration values

This feature is present on certain ST devices having an Internal RC oscillator as clock selection.

RC Calibration values are used to get a good frequency accuracy on internal RC oscillator.

Some ST devices have the default RC Calibration values factory programmed in the ST Mcu's Program and Data memory.

Restoring the default RC Calibration values in the ST Mcu's Program and Data memory can be done by enabling and then disabling Read-Out Protection.

If Read-Out Protection is already disabled, set it to ON in the option byte settings and program the option byte.

Then set Read-Out Protection back to OFF and reprogram the option byte.

The default RC Calibration values are then automatically written to the appropriate addresses in Program and Data memory.

Note: This feature is working only in specific programming modes: "Socket" or "ICP OPT Disable".

Refer to your STxxxx Datasheet for the default values and addresses.

CAUTION: Any Program or Data in the ST Mcu memory are lost when Read-Out Protection is disabled.