3.4 Clock – Component 3

Purpose of the test: Detect unexpected deviations in system clock frequency.

For the MCU to operate correctly and with correct timing, the frequency of the system clock must be verified to be within specification.

Acceptable measures for Fault detection are frequency or time-slot monitoring. The requirement is to detect that it is not oscillating at a frequency that will cause problems for proper application execution.

The tinyAVR® 1-series event system allows for timer/counter captures to be triggered by an external clock signal or the RTC (Real-Time Counter), allowing for frequency comparison between a reference clock and the system clock.