Hi,
in a current project I've used a TPS3820-3.3 watchdog which is connected to the micro controller RESET line. To test the functionality of the watchdog circuitry I've disconnected the WDI input during operation. The RESET stayed high.
In this forum I read that the watchdog is not enabled if WDI is left floating or toggled within the first 120 - 200 ms. This leads me to the assumption that the watchdog is not enabled after start up.
Checking the waveforms:
- WDI is toggled within 13ms for the first time after RESET transitions to high for the first time.
- WDI pulse width is 16.6 µs and toggled every 10 ms
This values seem to be well within the specified limits.
Circuit and waveforms added for reference.
Any ideas?
Regards, Martin
Not triggering:
Start up:
Pulse Width