ZHCSIK0A July 2018 – October 2021 TPS3430
PRODUCTION DATA
To achieve the 200 ms Watchdog Reset Delay requirement, this design simply leaves CRST pin floating (NC - No Connect) to set the Watchdog Reset Delay (tRST) to the factory-programmed delay of 200 ms. Refer to section 8.1.1 CRST Delay to learn more about the factory-programmed timing options and how to program the Watchdog Reset Delay using an external capacitor.
In Figure 8-4 below, the Watchdog Reset Delay of 200 ms is shown by causing a watchdog timing fault. No watchdog pulse comes on WDI within the Watchdog Timeout so WDO activates for tRST of 200 ms. Then after three watchdog faults, a watchdog pulse at 1Hz and 20% duty cycle arrives on WDI causing WDO to deactive and remain high.