Source code to achieve 1.5uA standby current

RE: Source code to achieve 1.5uA standby current

Simonr — Wed, 08 Jan 2020 13:35:04 GMT

I think the current consumption should go down if you do clear the RAM blocks in your main loop, I.E. setting #if 1 and not 0 in your main loop.

Best regards,

Simon

RE: Source code to achieve 1.5uA standby current

Sridhar Jonnavittula — Wed, 08 Jan 2020 10:32:12 GMT

#include "nrf.h"
#include "nrf_gpio.h"
#include "nrf_drv_rtc.h"
#include "nrf_drv_clock.h"
#include "boards.h"
#include "app_error.h"
#include "nrf_delay.h"
#include <stdint.h>
#include <stdbool.h>

#define COMPARE_COUNTERTIME  (3UL)                                        /**< Get Compare event COMPARE_TIME seconds after the counter starts from 0. */

#ifdef BSP_LED_0
    #define TICK_EVENT_OUTPUT     BSP_LED_0                                 /**< Pin number for indicating tick event. */
#endif
#ifndef TICK_EVENT_OUTPUT
    #error "Please indicate output pin"
#endif
#ifdef BSP_LED_1
    #define COMPARE_EVENT_OUTPUT   BSP_LED_1                                /**< Pin number for indicating compare event. */
#endif
#ifndef COMPARE_EVENT_OUTPUT
    #error "Please indicate output pin"
#endif

const nrf_drv_rtc_t rtc = NRF_DRV_RTC_INSTANCE(0); /**< Declaring an instance of nrf_drv_rtc for RTC0. */

/** @brief: Function for handling the RTC0 interrupts.
 * Triggered on TICK and COMPARE0 match.
 */
static void rtc_handler(nrf_drv_rtc_int_type_t int_type)
{
    if (int_type == NRF_DRV_RTC_INT_COMPARE0)
    {
       // nrf_gpio_pin_toggle(COMPARE_EVENT_OUTPUT);
    }
    else if (int_type == NRF_DRV_RTC_INT_TICK)
    {
        //nrf_gpio_pin_toggle(TICK_EVENT_OUTPUT);
    }
}

/** @brief Function configuring gpio for pin toggling.
 */
static void leds_config(void)
{
    bsp_board_init(BSP_INIT_LEDS);
}

/** @brief Function starting the internal LFCLK XTAL oscillator.
 */
static void lfclk_config(void)
{
    ret_code_t err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_clock_lfclk_request(NULL);
}

/** @brief Function initialization and configuration of RTC driver instance.
 */
static void rtc_config(void)
{
    uint32_t err_code;

    //Initialize RTC instance
    nrf_drv_rtc_config_t config = NRF_DRV_RTC_DEFAULT_CONFIG;
    config.prescaler = 4095;
    err_code = nrf_drv_rtc_init(&rtc, &config, rtc_handler);
    APP_ERROR_CHECK(err_code);

    //Enable tick event & interrupt
    //nrf_drv_rtc_tick_enable(&rtc,true);

    //Set compare channel to trigger interrupt after COMPARE_COUNTERTIME seconds
    //err_code = nrf_drv_rtc_cc_set(&rtc,0,COMPARE_COUNTERTIME * 8,true);
    //APP_ERROR_CHECK(err_code);

    //Power on RTC instance
    nrf_drv_rtc_enable(&rtc);
}

/**
 * @brief Function for application main entry.
 */
int main(void)
{
    leds_config();

    lfclk_config();

    rtc_config();

#if 0
//NRF_POWER->RAM[0].POWERCLR = 0xFFFF;
NRF_POWER->RAM[1].POWERCLR = 0xFFFF;
NRF_POWER->RAM[2].POWERCLR = 0xFFFF;
NRF_POWER->RAM[3].POWERCLR = 0xFFFF;
NRF_POWER->RAM[4].POWERCLR = 0xFFFF;
NRF_POWER->RAM[5].POWERCLR = 0xFFFF;
NRF_POWER->RAM[6].POWERCLR = 0xFFFF;
NRF_POWER->RAM[7].POWERCLR = 0xFFFF;
//NRF_POWER->RAM[8].POWERCLR = 0xFFFF;
#endif

    while (true)
    {
        __SEV();
        __WFE();
        __WFE();
    }
}


/**  @} */
#endif

I have modified RTC example as above. I get 54uA average for 1.5ms for every 20ms time. I did not change the LF clock source which is by default crystal.

May I know why it is consuming?

Thanks

RE: Source code to achieve 1.5uA standby current

Simonr — Wed, 04 Dec 2019 12:52:41 GMT

1. No, I also see ~3µA using the PPK. This is likely due to leakage currents on the DK, and if you measure this as an external board, using the nRF Only setting and the debugger of another DK you should be able to see ~1.5µA. You can see how to do this in the PPK user guide.

2. This seems somewhat unrelated to this ticket's topic, so please create a new ticket regarding this issue. We strive to keep each ticket to one topic, to keep it easier for future customers with similar issues to search for one specific topic.

Best regards,

Simon

RE: Source code to achieve 1.5uA standby current

Sridhar Jonnavittula — Wed, 04 Dec 2019 07:57:46 GMT

Actually we are using with other profiler. In PPK I see around 3uA.

1. Is 1.5uA is the value you have seen on your end?

2. Also I was trying to store some incremented value in NRF_POWER->GPREGRET in TICK event handler to store while in sleep. But it is not updating and I see same value every time in GPREGRET memory. Please tell the correct procedure.

RE: Source code to achieve 1.5uA standby current

Simonr — Wed, 04 Dec 2019 07:08:22 GMT

I tested your code and was not able to see a 60µA average current draw like you are. Please make sure you're looking at the avg. current and not the max. current in the Power Profiler app. It should not be necessary to include the POWERCLR block in order to see this either. I see the same current draw with and without this added to the main loop. You're using a development kit and a PPK for these measurements, right?

Best regards,

Simon

RE: Source code to achieve 1.5uA standby current

Sridhar Jonnavittula — Tue, 03 Dec 2019 13:00:42 GMT

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 */
/** @file
 * @defgroup rtc_example_main main.c
 * @{
 * @ingroup rtc_example
 * @brief Real Time Counter Example Application main file.
 *
 * This file contains the source code for a sample application using the Real Time Counter (RTC).
 *
 */

#include "nrf.h"
#include "nrf_gpio.h"
#include "nrf_drv_rtc.h"
#include "nrf_drv_clock.h"
#include "boards.h"
#include "app_error.h"
#include "nrf_delay.h"
#include <stdint.h>
#include <stdbool.h>

#define COMPARE_COUNTERTIME  (3UL)                                        /**< Get Compare event COMPARE_TIME seconds after the counter starts from 0. */

#ifdef BSP_LED_0
    #define TICK_EVENT_OUTPUT     BSP_LED_0                                 /**< Pin number for indicating tick event. */
#endif
#ifndef TICK_EVENT_OUTPUT
    #error "Please indicate output pin"
#endif
#ifdef BSP_LED_1
    #define COMPARE_EVENT_OUTPUT   BSP_LED_1                                /**< Pin number for indicating compare event. */
#endif
#ifndef COMPARE_EVENT_OUTPUT
    #error "Please indicate output pin"
#endif

const nrf_drv_rtc_t rtc = NRF_DRV_RTC_INSTANCE(0); /**< Declaring an instance of nrf_drv_rtc for RTC0. */

/** @brief: Function for handling the RTC0 interrupts.
 * Triggered on TICK and COMPARE0 match.
 */
static void rtc_handler(nrf_drv_rtc_int_type_t int_type)
{
    if (int_type == NRF_DRV_RTC_INT_COMPARE0)
    {
       // nrf_gpio_pin_toggle(COMPARE_EVENT_OUTPUT);
    }
    else if (int_type == NRF_DRV_RTC_INT_TICK)
    {
       // nrf_gpio_pin_toggle(TICK_EVENT_OUTPUT);
    }
}

/** @brief Function configuring gpio for pin toggling.
 */
static void leds_config(void)
{
    bsp_board_init(BSP_INIT_LEDS);
}

/** @brief Function starting the internal LFCLK XTAL oscillator.
 */
static void lfclk_config(void)
{
    ret_code_t err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_clock_lfclk_request(NULL);
}

/** @brief Function initialization and configuration of RTC driver instance.
 */
static void rtc_config(void)
{
    uint32_t err_code;

    //Initialize RTC instance
    nrf_drv_rtc_config_t config = NRF_DRV_RTC_DEFAULT_CONFIG;
    config.prescaler = 4095;
    err_code = nrf_drv_rtc_init(&rtc, &config, rtc_handler);
    APP_ERROR_CHECK(err_code);

    //Enable tick event & interrupt
    //nrf_drv_rtc_tick_enable(&rtc,true);

    //Set compare channel to trigger interrupt after COMPARE_COUNTERTIME seconds
    err_code = nrf_drv_rtc_cc_set(&rtc,0,COMPARE_COUNTERTIME * 8,true);
    APP_ERROR_CHECK(err_code);

    //Power on RTC instance
    nrf_drv_rtc_enable(&rtc);
}

/**
 * @brief Function for application main entry.
 */
int main(void)
{
    //leds_config();

    lfclk_config();

    rtc_config();

#if 1
//NRF_POWER->RAM[0].POWERCLR = 0xFFFF;
NRF_POWER->RAM[1].POWERCLR = 0xFFFF;
NRF_POWER->RAM[2].POWERCLR = 0xFFFF;
NRF_POWER->RAM[3].POWERCLR = 0xFFFF;
NRF_POWER->RAM[4].POWERCLR = 0xFFFF;
NRF_POWER->RAM[5].POWERCLR = 0xFFFF;
NRF_POWER->RAM[6].POWERCLR = 0xFFFF;
NRF_POWER->RAM[7].POWERCLR = 0xFFFF;
//NRF_POWER->RAM[8].POWERCLR = 0xFFFF;
#endif

    while (true)
    {
        __SEV();
        __WFE();
        __WFE();
    }
}


/**  @} */

I have modified the RTC example in SDK_16.0/examples/hardware_peripherals/rtc. In sdk_config.h kept LFCLK source as RC oscillator. I have commented RTC TICK events, LEDs. I have powered off all RAM banks except 0 and 8. I see 60uA current continuously other than COMPARE event.

Can you please suggest why I am seeing that much current? I have to see 1.5uA as in the first query.

Thanks

RE: Source code to achieve 1.5uA standby current

Simonr — Wed, 04 Sep 2019 11:55:47 GMT

1. The VIN 3-5 pin on P20 is not connected to VDDH, just the internal 5V regulator, so it will only power the nRF in VDD mode. I asked a developer for confirmation, and the only ways to run the nRF52840 in VDDH mode on the DK are USB (J3) and through the Li-Po battery connectors (J6 or P27).

2. Correct, the PPK is not intended to use to measure chips in VDDH mode, so you should rather use an oscilloscope or power analyzer.

Best regards,

Simon

RE: Source code to achieve 1.5uA standby current

Sridhar Jonnavittula — Wed, 04 Sep 2019 07:40:31 GMT

Ok. Please answer couple of questions:

1. I actually tried attaching 5V from external regulated power supply to VIN 3–5 pin on P20 (3.0–5.0 V)(This is the only source). In this condition when I read the MAINREGSTATUS register I see A=0 (Normal voltage VDD). Why is it so?

2. When I supply from Li-Po/ other than USB J2 port, I cant use Power profiler kit right? In this case do I need Oscilloscope?

Thanks

RE: Source code to achieve 1.5uA standby current

Simonr — Wed, 04 Sep 2019 07:08:16 GMT

Susheel is out of office, so I have been assigned your case. In order to achieve this current consumption on the Development Kit (DK), you have to power the board through VDDH. There are a few ways to do this on the DK. Check out Section 8.3 (Power Supply) in the DK user guide. The recommended option is using the Lithium polymer battery connectors J6 or P27 (2.5V-5.0V).

Best regards,

Simon

RE: Source code to achieve 1.5uA standby current

Sridhar Jonnavittula — Tue, 03 Sep 2019 07:51:39 GMT

If powered at J3 of PCA10056 DK(USB on long side labled nRF USB) and read MAINREGSTATUS, I observe A=1.

Actually I wanted to see this below attached current number and I am not able to find any other way other than powering at J3

Please suggest if there is any other way.

RE: Source code to achieve 1.5uA standby current

Susheel Nuguru — Mon, 02 Sep 2019 10:30:01 GMT

Not sure what you are trying to get with the MAINREGSTATUS. This is just a status register telling you which pins you have connected to. Which J3 connector are you referring to?

RE: Source code to achieve 1.5uA standby current

Sridhar Jonnavittula — Fri, 30 Aug 2019 09:55:46 GMT

Please tell me the different possible input supply hardware configurations on nRF52840 DK to achieve High voltage mode(as per below screenshot). Because I don't find any, other than J3 connector.

RE: Source code to achieve 1.5uA standby current

Susheel Nuguru — Tue, 27 Aug 2019 13:24:22 GMT

I get this when i try your code on Blinky example, About 1.3uA average current