21.6.2.8.1 Function system_main_clock_set_failure_detect()

Enable or disable the main clock failure detection.

void system_main_clock_set_failure_detect( const bool enable)

This mechanism allows switching automatically the main clock to the safe RCSYS clock, when the main clock source is considered off.

This may happen for instance when an external crystal is selected as the clock source of the main clock and the crystal dies. The mechanism is to detect, during a RCSYS period, at least one rising edge of the main clock. If no rising edge is seen the clock is considered failed. As soon as the detector is enabled, the clock failure detector (CFD) will monitor the divided main clock. When a clock failure is detected, the main clock automatically switches to the RCSYS clock and the CFD interrupt is generated if enabled.