8.4.4 Reset or Wake-up from Sleep

The FSCM is designed to detect an oscillator failure after the Oscillator Start-up Timer (OST) has expired. The OST is used after waking up from Sleep and after any type of Reset. The OST is not used with the EC Clock modes so that the FSCM will be active as soon as the Reset or wake-up has completed. Therefore, the device will always be executing code while the OST is operating when using one of the EC modes.

Figure 8-10. FSCM Timing Diagram
Note: The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in this example have been chosen for clarity.