Maximum Reload time for WDT

[Shagan]

Hi Guys, 

We have a need to send data every 4 hours. 

In order to do this, we sleep 1 hour at a time (1-hour timer - single shot) and increment counter, and when the count is 4 we send the data. This is working well. 

Due to unknown reasons the device sometimes can get hung when trying to send the data. 

Our plan was to set the WDT_CONFIG_RELOAD_VALUE to 120000000, to make sure we reset the device after 1 hour if it got stuck. 

But we are unable to provide values more than 600000 (which triggers at 100 seconds). 

Can u suggest a way to configure such a large interval? 

regards

Shankar

[Kenneth]

I am not sure what is the problem here, but there is watchdog example in the SDK that should be possible to use as reference. 

As a side comment, have you done any calculation on the current consumption?

The system ON idle current with an RTC running is ~1.7uA depending on how much RAM you retain during sleep.

If you wakeup every 100 seconds for ~50us then the average increase is ~0.002uA. In other words there is no difference in battery life whether you wakeup every 100 seconds or 1hour, because the idle current is about ~1000x larger.

Best regards,
Kenneth

[Shagan]

Hi Kenneth, 

I did use the example as a reference. Please look at my comment on the previous reply. I did try using the example as a reference. 

The reason why we are trying to do 1 hour, is to make sure the device indeed wakes up after 1 hour, in case the timer for 1 hour was not set right after sending data to server. I have seen some conflicts in running multiple timers at the same time. so this is just a catchall watchdog. 

regards

Shankar