TWI Low power mode

[Murugan]

Dear Nordic Team,

Thanks for support

Currently i am work with VL53L0X in ble_uart_app example. it working fine , but its take 5ma current. How can i use TWI in low power mode. Please suggest anyone.

SDK =12.3.0 , SD=s132. 

My Code :  

Fullscreen TWI.txt Download

void twi_init (void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = DEVICE_SCL_PIN,
       .sda                = DEVICE_SDA_PIN,
       .frequency          = NRF_TWI_FREQ_400K,
       .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
       .clear_bus_init     = false
    };

    err_code = nrf_drv_twi_init(&m_twi, &twi_config, NULL, NULL);  //twi_handler
    APP_ERROR_CHECK(err_code);

    nrf_drv_twi_enable(&m_twi);
}


int main(void)
{
    uint32_t err_code;
    bool erase_bonds;
     uint8_t LI8u_Buffer[50]={0};
		static uint8_t data_array[20]={"Distance===>0000MM\n"};
    // Initialize.
    APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);
    //uart_init();
	   //==============================================================
	
//			twi_init();
//			if(VL53L0X_init(1)){VL53L0X_Init_flag=1;}
//			else VL53L0X_Init_flag = 0;	

//			VL53L0X_setSignalRateLimit(0.1);
//			VL53L0X_setVcselPulsePeriod(VcselPeriodPreRange,18);
//			VL53L0X_setVcselPulsePeriod(VcselPeriodFinalRange,14);
//			VL53L0X_setMeasurementTimingBudget(220000);
			
			//============================================================
    buttons_leds_init(&erase_bonds);
    ble_stack_init();
    gap_params_init();
    services_init();
    advertising_init();
    conn_params_init();

   // printf("\r\nUART Start!\r\n");
    err_code = ble_advertising_start(BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);

    // Enter main loop.
    for (;;)
    {
			 // nrf_delay_ms(5000);
        power_manage();
			  if(m_conn_handle != BLE_CONN_HANDLE_INVALID)
				{	
					Read_Sensor();
						data_array[12]='0'+(Distance/1000);
						data_array[13]='0'+(Distance/100)%10;
						data_array[14]='0'+(Distance/10)%10;
						data_array[15]='0'+(Distance%10);
					if(VL53L0X_Init_flag){
					err_code=ble_nus_string_send(&m_nus,(uint8_t *)"INIT OK",7);			
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
							}
					  err_code=ble_nus_string_send(&m_nus,data_array,sizeof(data_array));			
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
									nrf_delay_ms(500);
				}					
    }
}
void Read_Sensor(void){
				twi_init();nrf_delay_ms(5);
			if(VL53L0X_init(1)){VL53L0X_Init_flag=1;}
			else VL53L0X_Init_flag = 0;	nrf_delay_ms(5);
//VL53L0X_Init_flag=1;
			VL53L0X_setSignalRateLimit(0.1);
			VL53L0X_setVcselPulsePeriod(VcselPeriodPreRange,18);
			VL53L0X_setVcselPulsePeriod(VcselPeriodFinalRange,14);
			VL53L0X_setMeasurementTimingBudget(220000);
	nrf_delay_ms(500);
						 Distance = VL53L0X_readRangeSingleMillimeters();
						 if( Distance<=2000 && Distance>0 )
						 {	
							 Dist_Values=Distance;
						//	 printf("Distance=%d\r\n",Dist_Values);
						 }else{
							 if(Distance!=0&&Distance!=65535){
								    if(Distance>=2000 &&Distance <=8000){
											Dist_Values=1999;
										}
										else if(Distance>=8000 && Distance <=9000){
											Dist_Values=1999;
										}
							 }
					//		printf("Distance Error=%d\r\n",Distance);
						 }
						 						 	nrf_drv_twi_disable(&m_twi);	nrf_delay_ms(5);
							nrf_drv_twi_uninit(&m_twi);nrf_delay_ms(5);
	
	*(volatile uint32_t *)0x40003FFC = 0;
	*(volatile uint32_t *)0x40003FFC;
	*(volatile uint32_t *)0x40003FFC = 1;
						 
}

[haakonsh]

you need to take care when using the drivers in blocking mode as the nrf_delay_ms() functions are implemented as asm NOP instructions and it will therefore not put the CPU to sleep. If you want to sleep while waiting you need to set up an RTC to time out after the given timout period and put the CPU to sleep with the following calls:
__WFE();

__SEV();

__WFE();.  

[Murugan]

Thanks for reply. My ADC part also take 5ma but it is going to disabled and consume low current. But i cant disable the TWI module.

[haakonsh]

Do you mind sharing the configuration of the SAADC driver? 
Are you putting the CPU to sleep whenever you're not using it?

[Murugan]

When i need battery value i call this function . That time only take 5 ma Current. After few seconds going to 50uA.

void Read_Battery_Volt(void){
uint32_t err_code;
adc_configure();nrf_delay_ms(10);
err_code = nrf_drv_saadc_sample();
APP_ERROR_CHECK(err_code);nrf_delay_ms(10);
err_code = nrf_drv_saadc_sample();
APP_ERROR_CHECK(err_code);nrf_delay_ms(10);
err_code = nrf_drv_saadc_sample();
APP_ERROR_CHECK(err_code);nrf_delay_ms(10);
nrf_drv_saadc_uninit();
}

[Murugan]

 Problem solved. I am just add few lines in  power manage function  "static void power_manage(void) " . Anyway thank you @haakonsh.

 static void power_manage(void)
{
#if (__FPU_USED == 1)
__set_FPSCR(__get_FPSCR() & ~(0x0000009F));
(void) __get_FPSCR();
NVIC_ClearPendingIRQ(FPU_IRQn);
#endif
__WFE();

uint32_t err_code = sd_app_evt_wait();
APP_ERROR_CHECK(err_code);
}