The following table summarizes the different watchdog timeout periods which could beavailable, as an example.Table 21-2. Watchdog timeout availabilityReference clock Prescaler Watchdog time-out availabilityREF_CLK Pass through 1×RCP to 65535×RCP 1Enable 256×RCP to 16776960×RCP1. RCP means Reference Clock Period.NOTEWhen the programmer switches clock sources duringreconfiguration, the watchdog hardware holds the counter atzero for 2.5 periods of the previous clock source and 2.5periods of the new clock source after the configuration timeperiod ( 128 bus clocks) ends. This delay ensures a smoothtransition before restarting the counter with the newconfiguration.21.4.2 Watchdog refresh mechanismThe watchdog resets the MCU if the watchdog counter is not refreshed. A robust refreshmechanism makes it very unlikely that the watchdog can be refreshed by runaway code.To refresh the watchdog counter, software must execute a refresh write sequence beforethe timeout period expires. In addition, if window mode is used, software must not startthe refresh sequence until after the time value set in the WIN register. See the followingfigure.Functional descriptionMWCT101xS Series Reference Manual, Rev. 3, 07/2019464 NXP Semiconductors
