Im working on a project which requires the Ndogo to wake up from power-down-mode every 3 hours.
What can I use to trigger to Ndogo to wake up?
I read something about a watchdog timer, but that one only lasts 8 seconds max. before interrupt.
Ive also seen people use a ‘RTC’, can I use this for my problem with a Ndogo?
I remember something about that library that the prescaler /divider was set in the library.
you can alter it. it should increase the time past 8 seconds.
For how many seconds do you want it to sleep?
Unlike the Mbili, the Ndogo does not have an external RTC onboard.
You could use an DS3231 on an external break out board.
The library supports both periodic and a single scheduled interrupt (up to 24 hours in adavance).
You could either use a regular shorter term interrupt and test and then execute what tasks are due, or you could schedule a longer term interrupt for specific time between the tasks.
So that means my best options is to use a watchdog interrupt, keeping up a counter?
Yes, that might be a good way to start.
Just a note, if you were planning on using the millis() function, in some sleep modes the timer which increments that value is turned off.