If the device is configured to use the external LF oscillator (as below), and the external oscillator is physically removed, will the device automatically switch to use the internal oscillator? That seems to be the case via experimentation:
#define SET_CCFG_MODE_CONF_SCLK_LF_OPTION 0x2
We are seeing an issue where we are using the external oscillator as above, but sometimes our devices become unresponsive in our cooking and calibration process of the device. It looks to be UART overrun, perhaps due to the device relying on the internal oscillator for UART system communication. If we remove the external oscillator, the device still advertises and communicates via UART. But it is unable to be connected to as the advertisement/connection interval times become slightly off..suggesting that perhaps that internal oscillator needs to be calibrated for consistent / robust communication in UART, BLE.
The chip revision is 2.3, and we do not have the calibration of the internal oscillator enabled. But we are going to experiment with calibration enabled. Thank you.