nrf52 with LDO setup consum 10 uA

[Amigo]

I set up my nrf52 self board with internal LDO using reference schematics  with internal LDO setup. 

Im entering the power safe mode using __WFE instruction

if(lpm_flag)
			{
				nrf_gpio_pin_clear(LED_0);
				retry_cnt = 0;
				
				nrf_esb_disable(); // останавливаем
				while(!nrf_esb_is_idle());
				NRF_RADIO->POWER = RADIO_POWER_POWER_Disabled << RADIO_POWER_POWER_Pos;
				
				// Уходим в спящий режим если ничего не приняли	
				clocks_set(XTAL_LF, true);
				clocks_set(XTAL_HF, false);
				
				// разрешаем прерывания от кнопки и геркона
				NVIC_EnableIRQ(GPIOTE_IRQn);
								
				//NRF_POWER->TASKS_LOWPWR = 1UL;
				
//				#ifdef NRF52
//				NRF_POWER->RAM[0].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[1].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[2].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[3].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[4].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[5].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[6].POWER = RAM_RETENTION_OFF;
//				NRF_POWER->RAM[7].POWER = RAM_RETENTION_OFF;
//				#endif //NRF52

//				NRF_POWER->SYSTEMOFF = 0x1;
//				(void) NRF_POWER->SYSTEMOFF;
//				while (true);
				// ждем события
				
				__WFE();
				__SEV();
				__WFE();
			}

Also i did the same with nrf51 but it has DC/DC converter mode. In nrf51 case current consumtion is 1.5 - 2 uA, in nrf52 case 10 - 14 uA. Is it influence of LDO ?

[haakonsh]

Hey Roman,

The nRF52 series uses LDO in refresh mode in sleep/system OFF. I expect you to get 0.3µA in system off. How do you measure the current consumption? What else is on your board that can draw current? 

Håkon.

[Amigo]

Here is board schematics overhead.

My GPIO  setting and clock setting functions:

bool clocks_set(uint8_t source, bool state )
{
	NRF_CLOCK->CTIV = 16;
	if(source == XTAL_HF)
	{
		if(state == true)
		{
				#if defined (NRF51822)
						NRF_CLOCK->XTALFREQ = CLOCK_XTALFREQ_XTALFREQ_16MHz << CLOCK_XTALFREQ_XTALFREQ_Pos;
				#endif
				NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
				NRF_CLOCK->TASKS_HFCLKSTART = 1;
				while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
		}
		else if(state == false){
			// если генератор запущен
			NRF_CLOCK->TASKS_HFCLKSTOP = 1;
			__NOP;
		}
		return (bool)(NRF_CLOCK->HFCLKSTAT >> CLOCK_HFCLKSTAT_STATE_Pos);
	}
	else if(source == XTAL_LF)
	{
		if(state == true)
		{
			// если генератор не запущен
			NRF_CLOCK->LFCLKSRC = CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos;
			NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
			NRF_CLOCK->TASKS_LFCLKSTART = 1;
			while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0);
		}
		else if(state == false){
			NRF_CLOCK->TASKS_LFCLKSTOP = 1;
			__NOP;
		}
		return (bool)(NRF_CLOCK->LFCLKSTAT >> CLOCK_LFCLKSTAT_STATE_Pos);
	}
}
/*****************************************************************************************************/
void gpio_init( void )
{
	uint32_t err_code;
	//bsp_board_leds_init();
	NVIC_DisableIRQ(GPIOTE_IRQn);	
	NRF_GPIOTE->EVENTS_PORT = 0;
    #if defined (NRF51822)
	#elif defined (NRF52832)
		// Disable NFC pins
    NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
    NRF_UICR->NFCPINS = UICR_NFCPINS_PROTECT_Disabled << UICR_CUSTOMER_CUSTOMER_Pos;
    NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren<< NVMC_CONFIG_WEN_Pos;
	#endif
	// Светодиод - LED
	nrf_gpio_cfg_output(LED_0); 
	// Кнопка - Button
	nrf_gpio_cfg_sense_input(BUTTON, GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos, NRF_GPIO_PIN_SENSE_LOW); 
	// Геркон - Gerkon
	nrf_gpio_cfg_sense_input(GERKON, GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos, NRF_GPIO_PIN_SENSE_LOW); 
	NRF_GPIOTE->INTENSET = GPIOTE_INTENSET_PORT_Enabled << GPIOTE_INTENSET_PORT_Pos;   
}

There are no serious difference between nrf51822 and nrf52832 mcu code. But when i  use nrf51 current consuption is 1.5 - 2 ua against 10 uA with nrf52.

Also i noticed that in a low power mode ( __WFE(); instruction) HF generator stay active and sourced by RC gain. I thought it will inactive when LF (32768 crystal) using in LPM.

I cant use power off, becouse i need gpio (gerkon) interrupt on LOW and HIGH level both (switching between low and high).

I measure current consumption with my measuring tool with 0.1 uA resolution in LPM mode only. In RX & TX  modes it  consumes 14 - 20 mA as it is in datasheet.