app_time and nrf_delay_ms

[samo]

Hi

I would like to read values from three AD channels where I use different sampling frequencies and different number of samples are captured at each sampling frequency. To be clear I will explain my problem in the case of one channel. Every 10s I would like to capture five values from the actual channel and subsequently the averaging is performed. The time between each sample should be around 10ms. At this stage I do not know what is the best programming solution for my problem to be the sofware as efficient as possible. Here is my current code, where I used nrf_delay_ms(10) function for waiting between two samples. I know that this is not the most efficient way because of that I will appreciate for any advice how I can improve my code.

Best regards

Samo

static void adc_lpg_timer_handler(void * p_context) // timer executed every 10s
{ 	
	
	int i;
	nrf_adc_value_t adc_value;
	uint8_t err_code;
	uint16_t ave_adc = 0;
	
	nrf_gpio_pin_toggle(LPG_PIN);	
	
	for(i=0; i < 5; i++)
	{
		nrf_delay_ms(10);
		while(nrf_drv_adc_is_busy())
		{
		}	
		err_code = nrf_drv_adc_sample_convert(&adc_lpg,&adc_value);
		APP_ERROR_CHECK(err_code);
	
	  ave_adc = ave_adc + adc_value;
  }
	 ave_adc = ave_adc/5;
	 ave_adc = 1200*ave_adc/1023;	 	 	
	 err_code = ble_adcs_2_update(&m_adcs,ave_adc);	 
	 APP_ERROR_CHECK(err_code);
	 ave_adc = 0;	   		
	 
	 nrf_gpio_pin_toggle(LPG_PIN);	
}

[Øyvind Karlsen]

Hi,

Have a look at the application timer tutorial. It describes how to set up energy efficient timers and interrupts in which you can perform your measurements. For example you can use one timer instance to trigger interrupts every 10 s and then every 10 ms after that. The reason you do not want to use nrf_delay_ms is that it implements waiting by calling a sequence of NOP__ to the processor core, keeping it active and thus drawing current.

Best regards,

Øyvind