timer can not trigger by right ticks

[ghost]

Hi all,

I create 4 timer in APP, and there seem only one timer (work in single shot mode) can not trigger by right ticks.

I add some log and find that:

1. First I start this timer, timeout_ticks is 229376 (7s), then I get the current time by app_timer_cnt_get, it show the current time is 4 .
2. When time out of this timer get the current time is 229382, it seem right.
3. Then I start this timer against, timeout_ticks is 16384 (0.5s), the current time is 229386.
4. But something wrong, I wait almost 7s, then it get timeout handler. And I also print the current time, it is 229393, it seems wrong, 229393 -229382 = 11,it is not 16384, but I wait almost 7s.
5. Finally I start this timer against, timeout_ticks is 196608(6s),current time is 229398.
6. But also get wrong current time of 229405 when the time out, but I think I wait about 6s to get this time out which seem right.

What's wrong? Please help me, thank you very much.

What I use is NRF52, and the SDK is nRF5_SDK_11.0.0, softdevice is s132.

[ghost]

I find that there is only step 3 and 5 would start the timer in the timeout_handler funchtion of this timer, and when I start the timer I will stop the timer first. Does it mean I can not start or stop a timer in the timeout handler function of itself?

[tesc]

Hi,

All the values you print from your timeout handler (229382, 229386, 229393, 229390, 229405) are slightly larger than your initial timeout value (229376). This is because the timer continues to run (although it has triggered an interrupt on the timeout value) and there is some variation in how long it takes before getting to those places in the interrupt handler.

As far as I can see, the timer triggers on the first value (229376) every time.

When you call app_timer_stop() and app_timer_start() from interrupt context (APP_LOW or higher) the corresponding operations will be queued and run later in APP_LOW.

Are you checking the return values of app_timer_stop() and app_timer_start()?

[ghost]

Hi， Thanks for your answer. I have already checked the return values of app_timer_stop and app_timer_start is NRF_SUCCESS. And you are right, the the timer will triggers on the first value (229376) every time. Do you mean that the timer no really stop when I stop it by app_timer_stop in the interrupt since all the values of current_timer are slightly larger than the initial timeout value?

[ghost]

I found that it will be sometime OK when the timeout_ticks is 0.5s and 6s, but it seems more often work in NG

[tesc]

I think I would need to see your code to know exactly what you are doing and why you see what you see. Can you provide code where you are seeing the issues?