Reading the timer counter value using the Capture Task

[soumil]

Hi,

Is this the right way of reading the timer value using the capture task. In this code i am trying to read the updated value of counter for every event generated in the interrupt handler.

> int main() {
>     NRF_CLOCK->TASKS_HFCLKSTART = 1;
>         NRF_TIMER2->BITMODE = 03ul << 0ul;
>         NRF_TIMER2->MODE = 0ul << 0ul;
>         NRF_TIMER2->TASKS_CLEAR = 1;
>         NRF_TIMER2->CC[0] = 1000;
>         NRF_TIMER2->PRESCALER = 9;
>         NRF_TIMER2->INTENSET = 1ul << 16;
>         NVIC_EnableIRQ(TIMER2_IRQn); 
>        
>         NRF_TIMER2->TASKS_START =1;
>         NRF_TIMER2->TASKS_CAPTURE[1] =1;
>         NVIC_SetPriority(TIMER2_IRQn, 3);
>     }
>     void TIMER2_IRQHandler(void)
>         {
>             if (NRF_TIMER2->EVENTS_COMPARE[0] !=0)
>             {
>                
>                 NRF_TIMER2->EVENTS_COMPARE[0] = 0;
>                
>                 count =  NRF_TIMER2->CC[1];  
>                        
>             }
>           
>               
>         }

What i am getting is the same count value everytime the interrupt is called. Is this the right behavior or am i missing anything?

[RK]

No, the value in the CC[] register is only updated once each time you trigger the TASK_CAPTURE task. You're only triggering it once in the setup, so you'll get the same value every time.

[soumil]

So after i read the value in the interrupt handler should i again do this NRF_TIMER2->TASKS_CAPTURE[1] =1;

[RK]

no - you should do the task capture before you read the value, else you will get the previous value.

[soumil]

Thanks RK.