Ble advertising and timer conflict

[Folny]

Hi

I would like to ask you for advice on how to solve my problem with Ble and the timer I have nRf52840 and I am trying to add a timer to examples\ble_peripheral\ble_app_uart timer works properly unless advertising_start(); and then the timer conflict with Ble begins. Does anyone have a solution to this problem ? I am adding part of the timer code and also photos where to see my problem.

#define GPIO_24       NRF_GPIO_PIN_MAP(0,24)

void timer_init(void)
{
    NRF_TIMER2->TASKS_STOP = 1;

    NRF_TIMER2->SHORTS    = (TIMER_SHORTS_COMPARE0_CLEAR_Enabled << TIMER_SHORTS_COMPARE0_CLEAR_Pos);
    NRF_TIMER2->MODE      = TIMER_MODE_MODE_Timer;
    NRF_TIMER2->BITMODE   = (TIMER_BITMODE_BITMODE_24Bit << TIMER_BITMODE_BITMODE_Pos);
    NRF_TIMER2->PRESCALER = 1;  
    NRF_TIMER2->INTENSET  = (TIMER_INTENSET_COMPARE0_Set << TIMER_INTENSET_COMPARE0_Pos);

    NRF_TIMER2->CC[0]       = 100;

    NRF_TIMER2->TASKS_START = 1;
	NVIC_EnableIRQ(TIMER2_IRQn);
} 

void TIMER2_IRQHandler(void)
{
    if (NRF_TIMER2->EVENTS_COMPARE[0])
    {
       nrf_gpio_pin_toggle(GPIO_24);
	   NRF_TIMER2->EVENTS_COMPARE[0] = 0;
    }
}

not start advertising

start advertising

[haakonsh]

The SoftDevice has execution priority during timing-critical radio events. That means that your TIMER's ISR is blocked from executing during advertisements. 

If you need to toggle a GPIO based on a TIMER, you should use the PPI and GPIOTE peripherals. That way do not even need the TIMER interrupt at all.

[Folny]

Thank you for your answer but I don't want to switch only GPIO I need it to read and sample data with AD7691.

[haakonsh]

At what sample rate?
And for how long, continuously?

[Folny]

The frequency will be about 40-80 kHz and must run continuously.

Here is part of the code

int32_t AD7982_Read_GPIO(void){

  int16_t  AD_Data = 0;
  char BitCounts = 0;

  NRF_GPIO->OUTSET = (1UL << ADC_CNV_PIN);
  Delay_ADC(40);
  NRF_GPIO->OUTCLR = (1UL << ADC_CNV_PIN);
  Delay_ADC(10);
	
for(BitCounts = 0; BitCounts < 18; BitCounts++)
{
  AD_Data = AD_Data << 1;
	NRF_GPIO->OUTSET = (1UL << ADC_CLK_PIN);
  AD_Data |= nrf_gpio_pin_read(ADC_MISO_PIN);
  NRF_GPIO->OUTCLR = (1UL << ADC_CLK_PIN);
}
  return AD_Data;
}

void TIMER2_IRQHandler(void){

  if (NRF_TIMER2->EVENTS_COMPARE[0]){
			
  ctr++;
  ticks++;
	
  int32_t AD_Read = AD7982_Read_GPIO();
  bins[ctr] = AD_Read;
	
  if (ctr == SAMPLES -1)
  {
    ++numSamples;
    if (numSamples == numSamplesToAverage)
    {
      numSamples = 0;
      if (!sampleReady)     
      {
        memcpy((void*)averages, bins, sizeof(averages));
        sampleReady = true;
      }
      memset(bins, 0, sizeof(bins));
    }
		ctr = -1;
   } 
    NRF_TIMER2->EVENTS_COMPARE[0] = 0;
  }
}

[Folny]

The code will be based on this principle but an external 18bit ADC AD7691 will be used.

https://github.com/dc42/arduino/blob/master/MetalDetector/MetalDetector.ino