NRF52840 used Timer2 to detect count

Question

I used

condition:

const nrf_drv_timer_t m_timer2 = NRF_DRV_TIMER_INSTANCE(2);

nrf_drv_timer_config_t timer_config = {.frequency = NRF_TIMER_FREQ_1MHz,
.mode = NRF_TIMER_MODE_TIMER,
.bit_width = NRF_TIMER_BIT_WIDTH_16,
.interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,
.p_context = NULL};

err_code = nrf_drv_timer_init(&m_timer2, &timer_config, NULL);

void in_pin_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
int Counter;
switch(pin)
{
case 31:
Timer_Counter++;
if(Timer_Counter == 1)
{
nrf_drv_timer_enable(&m_timer2);
if(Enter_Flag == 1)
{
read_sensor_data();
}
}
else if(Timer_Counter == 2)
{
nrfx_timer_pause(&m_timer2);
Counter = (int)nrf_drv_timer_capture(&m_timer2,NRF_TIMER_CC_CHANNEL2);
NRF_LOG_INFO("Current cout: %d \n\r", Counter);
nrf_drv_timer_disable(&m_timer2);
nrf_drv_timer_clear(&m_timer2);
Timer_Counter = 0;
}
else
{
Timer_Counter = 0;
}
break;
default:
break;
}
}

But the Counter data distortion.

<info> app: Current cout: 5001
<info> app: Current cout: 5000
<info> app: Current cout: 4999
<info> app: Current cout: 4999
<info> app: Current cout: 5014 <==distortion
<info> app: Current cout: 4999
<info> app: Current cout: 5000
<info> app: Current cout: 5000

MartinBL · Accepted Answer

Hi, 
 If you are using BLE you can expect to see distortion like this. The Softdevice does timing critical processing in high priority interrupts that will delay your timer application interrupts. Please refer to the Softdevice Specification: Bluetooth Low Energy Advertiser (Broadcaster) processor usage . As you can see, you can expect tens and hundreds of micro seconds delays when the Softdevice is active.

NRF52840 used Timer2 to detect count

Top Replies