wake up from system off

[Mikael]

Hello

I have found 2 strange behavoir when I want to wake up nrf from system off state:

1/ when I use pin 15, this does not work at all, but with pin 6 it does. Why?

2/ if i use gpiote to program the gpio pin for wake up this doesn't work. I have to program the pin with nrf_gpio_xxx interface. Why this does not work with GPIOTE ?

Thanks for your answer

Mikael

[Jared]

Hi,

Are you using the DK or a custom board? And how did you configure it to wake-up before you went to sleep? Could share your code?

regards

Jared

[Mikael]

Hi Jared,

I use a custom board. we use as well soft device.

I read on other post that "The only peripherals that are partially kept active in SYSTEM OFF are GPIO, LPCOMP and NFC"

So I deduced that GPIOTE is completely off.

Let me know if misunderstand something.

before I went to sleep I did

err_code = nrfx_gpiote_init();

    APP_ERROR_CHECK(err_code);

 

  nrfx_gpiote_in_config_t in_config = NRFX_GPIOTE_CONFIG_IN_SENSE_TOGGLE(true);

  in_config.pull = NRF_GPIO_PIN_PULLDOWN;

 

  // configure wakeup pin

  err_code = nrfx_gpiote_in_init( GPIO_WAKEUP_PIN, &in_config, wakeup_event_handler);

  APP_ERROR_CHECK(err_code);

 

  nrfx_gpiote_in_event_enable( GPIO_WAKEUP_PIN, true);

  // switch OFF both RAM banks when in System OFF mode

  NRF_POWER->RAMON |= (POWER_RAMON_OFFRAM0_RAM0Off << POWER_RAMON_OFFRAM0_Pos) |

                      (POWER_RAMON_OFFRAM1_RAM1Off << POWER_RAMON_OFFRAM1_Pos);

but does not work

Now I use

  // configure wakeup pin
  nrf_gpio_cfg_input( GPIO_WAKEUP_PIN, NRF_GPIO_PIN_PULLDOWN );
  nrf_gpio_cfg_sense_input( GPIO_WAKEUP_PIN, NRF_GPIO_PIN_PULLDOWN, NRF_GPIO_PIN_SENSE_HIGH );

  NRF_GPIOTE->INTENSET = GPIOTE_INTENSET_PORT_Msk;
  NVIC_EnableIRQ(GPIOTE_IRQn);

and its fine.

but something strange even. If the gpio goes from 0 to 1 and stay to 1 this does not work. the signal shall do 0-1-0 to work.

Regards

Mikael

[Jared]

 Hi,

You're assumption is correct.

You don't need to configure the pin as input before you call the nrf_gpio_cfg_input as it will do everything itself. 

Here is a quick sample that shows you how to configure it on the DK:

#include <stdbool.h>
#include <stdint.h>
#include "nrf_delay.h"
#include "boards.h"

#define PIN_GPIO_WAKEUP 3


/**
 * @brief Function for application main entry.
 */
int main(void)
{
    /* Configure board. */
    bsp_board_init(BSP_INIT_LEDS);


    for (int i = 0; i < LEDS_NUMBER; i++)
    {
        bsp_board_led_invert(i);
        nrf_delay_ms(500);
    }

    nrf_gpio_cfg_sense_input(PIN_GPIO_WAKEUP, NRF_GPIO_PIN_PULLDOWN, NRF_GPIO_PIN_SENSE_HIGH);
    bsp_board_leds_off();

    NRF_POWER->SYSTEMOFF = 0x1;
    (void) NRF_POWER->SYSTEMOFF;
    while (true);   
}

[Mikael]

Ok thank you for the answer.

have you got an idea of question 1?

1/ when I use pin 15, this does not work at all, but with pin 6 it does. Why?

thanks

[Jared]

Hi,

Are you using a custom board or a Development kit? If you're using the development kit and pin 15 then you have to observe that pin 15 is connected to Button 3. The pin is therefore connected to a button switch, that connects the pin to gnd when you press the button. You therefore have to do it like this:

#include <stdbool.h>
#include <stdint.h>
#include "nrf_delay.h"
#include "boards.h"

#define PIN_GPIO_WAKEUP 3


/**
 * @brief Function for application main entry.
 */
int main(void)
{
    /* Configure board. */
    bsp_board_init(BSP_INIT_LEDS);


    for (int i = 0; i < LEDS_NUMBER; i++)
    {
        bsp_board_led_invert(i);
        nrf_delay_ms(500);
    }
    
    //Note the difference in the PULLUP and the Sense requirment being changed to NRF_GPIO_PIN_SENSE_LOW 
    nrf_gpio_cfg_sense_input(BUTTON_3, NRF_GPIO_PIN_PULLUP,NRF_GPIO_PIN_SENSE_LOW);
    bsp_board_leds_off();

    NRF_POWER->SYSTEMOFF = 0x1;
    (void) NRF_POWER->SYSTEMOFF;
    while (true);   
}