Unusual App Timer Problem

[Hein]

Hi there,

I've got something usual happening with the App Timers in my application, hopeing for some advice on how to track this one down.

There is one part in my code where an external event (handler) powers up and external IC, then starts a single shot app timer, after 200ms the app timer times out and I configure the external IC. This normally works fine, but every now and then the app timer somehow gets into a state where the timer event handler is run immediately after starting the timer (instead of 200ms later)

This 'fault' condition occurs for some time, then it all goes back to working properly.

I have printed out the timer ticks and first interval values from the app_timer.c file and it does not look like the problem is related to the value of the timer ticks, and the interval value is always consistent. I will add some of the debug outputs tomorro when I get to work.

It surely must be something in my application otherwise many people would see this ?

Any ideas appreciated!

[Jørgen Holmefjord]

Hi,

Are you running multiple timers in your application? Your symptoms sound like they could be caused by this known bug in app_timer (it is mentioned in SDK 15.x.0 known issues thread).

I don't know which SDK version you are using, but in SDK 15.x.0, there is a new implementation of app_timer, app_timer2. You can try changing to this new version and see if this solve the issue.

Best regards,
Jørgen

[Hein]

Awesome, thanks Jorgen, yes, that certainly sounds like the same problem! Yes, this is a fairly large application with many app timers, it is likely that I am starting at least 1 timer with a timerout > 256 seconds. I will try the app_timer2 implementation first. Will report back with my results tomorrow morning. Thanks!

[Hein]

Hi Jorgen, just to confirm, switching all code as-is to app_timer2.c looks to have completely fixed the problem, thanks!