Issue with IMU Sensor (LSM6DSV16X) Sample Rate in Sensor Hub Mode

[SaeedZadeh]

I am using an IMU sensor in sensor hub mode (LSM6DSV16X, LIS2MDL) with the FIFO interrupt interval set at 30 Hz. The data is sent over BLE. It works perfectly when using RTT, but when I disable debug mode, the sample rate drops to around 1 Hz.

Could someone please help me resolve this issue?

Thank you.

[Edvin]

Do you mean the nRF's ADC? In that case, what triggers the ADC interrupts?

BR,

Edvin

[SaeedZadeh]

Yes, it is nRF's ADC. Whenever the conversion is finished, the interrupt will occur.

static void analog_sample_work_handler(struct k_work *work)
{
	int ret = 0;
	
	
	/* Start ADC */
	ret = analog_read();
	if (ret) {
		LOG_ERR("Cannot read analog signals(err: %d)", ret);		
	} else {
		for(uint8_t i = 0; i < 4; i++) {
			ret = analog_get_raw(i, &adc_raw[i]);
			if (ret) {
				LOG_ERR("Cannot get raw analog values(err: %d)", ret);
				break;
			}
		}
	}
	
	
		
	if(!ret) {		
			
		memset(tx_ble_buffer, 0, sizeof(tx_ble_buffer));  
		sprintf((char *)tx_ble_buffer, "ADC:A1=%d,A2=%d,A3=%d,A4=%d\r\nLED:L1=%d,L2=%d,L3=%d,L4=%d\r\n",
      	adc_raw[0],adc_raw[1],adc_raw[2],adc_raw[3],led_state[0],led_state[1],led_state[2],led_state[3]);
				
		LOG_INF("BLE Tx data : %s", tx_ble_buffer);	
			
		ret = ble_send(tx_ble_buffer, strlen(tx_ble_buffer));	
		if (ret) {
			LOG_ERR("Cannot send ADC/LED data via BLE");	
		}		
	}

	k_work_reschedule(k_work_delayable_from_work(work), K_MSEC(ANALOG_SAMPLE_INTERVAL));
}

static void on_nus_connect(struct k_work *item)
{
	ARG_UNUSED(item);	

	
	
#if !(IMU_SIMULATION)

	gpio_pin_interrupt_configure_dt(&tap_int, GPIO_INT_EDGE_TO_ACTIVE);
	gpio_pin_interrupt_configure_dt(&fifo_int, GPIO_INT_EDGE_TO_ACTIVE);
	

	/* IMU out of low power mode */
	int ret = imu_set_low_power(false);
	if (ret) {
		LOG_ERR("Cannot get IMU out of low power(err: %d)", ret);		
	}
#endif	
	
	
	/* Schedule analog signal processing */
	k_work_schedule(&analog_sample_work, K_MSEC(ANALOG_SAMPLE_INTERVAL));
		
}

[Argus]

Hi Edvin, 

I am currently working on lsm6dsv16x sensor and my IDE platform is VS code nRF connect SDK v2.2.0.

I am unable detect the sensor. 

Could you please share your sensor working details or any suggestion on the same.

Thanks in advance! 

[Edvin]

Can you set up the application so that it shows the issue that you are seeing without the actual sensor, then .zip it and upload it here?

Best regards,

Edvin

[SaeedZadeh]

Please find attached your requested file. If you run and connect to the BLE central, you can see the data rate difference on the BLE central's output on the terminal when RTT is connected and disconnected.

Thank you,

Saeed

nrf5340_imu_adc_led_ble_Apr5.zip