Introduced a configuration for uninterruptible task source event.
Now, by default, HRTIM will be the source of the uninterruptible task trigger. However, as this require HRTIM to be initialized, Timer 6 is kept as an option for uses that do not involve HRTIM.
Also:
- Introduced a function to obtain HRTIM period in µs, and corrected a misleading comment on the existing function.