NRF_TIMER_TASK_CAPTURE4 of timer4 is permanent at the same value

[Constantin]

I am facing a problem. Two sensors are triggering with data_ready pins and a timer value is captured upon the event. But the value can be stored only in RAM if a context switch happens. But this depends on the processor usage. Therefore, it can happen that one sensor triggers a capture event, but the interrupt routine is delayed due to softdevice processing etc. and in the meantime the other sensor triggers a more recent capture. In this case the timing is screwed.

I've tried to use another capture channel of the same timer but somehow the NRF_TIMER_TASK_CAPTURE4 of timer4 is permanent at the same value. But I have to admit that I am not sure if the event is correctly configured since the code in the header is always greyed out . And I do not know where TIMER_INTENSET_COMPARE4_Msk is defined.

/** @brief Timer tasks. */
typedef enum
{
    NRF_TIMER_TASK_START    = offsetof(NRF_TIMER_Type, TASKS_START),      ///< Task for starting the timer.
    NRF_TIMER_TASK_STOP     = offsetof(NRF_TIMER_Type, TASKS_STOP),       ///< Task for stopping the timer.
    NRF_TIMER_TASK_COUNT    = offsetof(NRF_TIMER_Type, TASKS_COUNT),      ///< Task for incrementing the timer (in counter mode).
    NRF_TIMER_TASK_CLEAR    = offsetof(NRF_TIMER_Type, TASKS_CLEAR),      ///< Task for resetting the timer value.
    NRF_TIMER_TASK_SHUTDOWN = offsetof(NRF_TIMER_Type, TASKS_SHUTDOWN),   ///< Task for powering off the timer.
    NRF_TIMER_TASK_CAPTURE0 = offsetof(NRF_TIMER_Type, TASKS_CAPTURE[0]), ///< Task for capturing the timer value on channel 0.
    NRF_TIMER_TASK_CAPTURE1 = offsetof(NRF_TIMER_Type, TASKS_CAPTURE[1]), ///< Task for capturing the timer value on channel 1.
    NRF_TIMER_TASK_CAPTURE2 = offsetof(NRF_TIMER_Type, TASKS_CAPTURE[2]), ///< Task for capturing the timer value on channel 2.
    NRF_TIMER_TASK_CAPTURE3 = offsetof(NRF_TIMER_Type, TASKS_CAPTURE[3]), ///< Task for capturing the timer value on channel 3.
#if defined(TIMER_INTENSET_COMPARE4_Msk) || defined(__NRFX_DOXYGEN__)
    NRF_TIMER_TASK_CAPTURE4 = offsetof(NRF_TIMER_Type, TASKS_CAPTURE[4]), ///< Task for capturing the timer value on channel 4.
#endif
#if defined(TIMER_INTENSET_COMPARE5_Msk) || defined(__NRFX_DOXYGEN__)
    NRF_TIMER_TASK_CAPTURE5 = offsetof(NRF_TIMER_Type, TASKS_CAPTURE[5]), ///< Task for capturing the timer value on channel 5.
#endif
} nrf_timer_task_t;

[Vidar Berg]

Hello,

Capture register 4 and 5 should be available if you use TIMER4 as you can see from the table here:

I've tried to use another capture channel of the same timer but somehow the NRF_TIMER_TASK_CAPTURE4 of timer4 is permanent at the same value

What value do you see?

Best regards,

Vidar

[Constantin]

I always see the same value. It seems to be a random value.

[Vidar Berg]

Can you take a screenshot of the TIMER4 peripheral registers when you see this random value?

[Constantin]

Okay I did a bit more investigation and found out that it only happens when I start  our timesync routine which calls:

		APP_ERROR_CHECK(sd_radio_session_open(radio_callback));

		APP_ERROR_CHECK(request_next_event_earliest());

The code is from here:
https://github.com/wiesener/nRF5-ble-timesync-demo

If I comment these lines out and start a measurement everything works fine. But when I call these lines the capturing is stopped. Any guesses why?

[Vidar Berg]

Yes, I guess the timesync code and you application may be trying to use the same timer instance.