Inability to sleep the nRF52832. Number of possible buttons in using the BSP module?

Question

Hi, 
 We have a custom device that has 15 buttons. Presently we use the following code to initialize and use the button interrupts. I am using a __WFE(); to wait for the next event (i.e. a button press) however when I press two specific buttons (by design) together it brings the device partially into sleep_mode. This method works sufficient for detecting the button presses, but in attempting to put the device into a lower power mode it seems that some sort of interrupt is triggering the device to come right out of the low power mode or not completely go into low power mode. The device does come out of the "low power (5mA)" mode but completes a reset in the process. The current draw drops from about 9 mA (with I2C device) down to 5 mA (likely, just without I2C device), but never drops to uA levels. My thought is that another interrupt triggers the device to come right out while keeping the I2C device off, but I'm not sure which one would do that. 
 
 /*
*
* The following contain the interrupt handlers for all button presses
*
*/
void in_pin_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
 buttons_pressed = true;
 chirp_led(BLUE_LED);

 ret_code_t err_code; 
 
 if(power_off_mode)
 {
 
 //Disable power-down button to prevent System-off wakeup
 
 for(int i = 0; i < NUM_BUTTONS; i++) {
 
 nrf_drv_gpiote_in_uninit(buttons[i]);
 nrf_drv_gpiote_in_event_disable(buttons[i]); 
 }

 //Configure wake-up button
 
 for(int i = 0; i < NUM_BUTTONS; i++) {
 nrf_drv_gpiote_in_config_t in_config = GPIOTE_CONFIG_IN_SENSE_LOTOHI(false); //Configure to generate interrupt and wakeup on pin signal high.
 in_config.pull = NRF_GPIO_PIN_PULLDOWN; //Configure pulldown for input pin to prevent it from floating.
 err_code = nrf_drv_gpiote_in_init(buttons[i], &in_config, in_pin_handler); //Initialize the wake-up pin
 APP_ERROR_CHECK(err_code); //Check error code returned
 nrf_drv_gpiote_in_event_enable(buttons[i], true); //Enable event and interrupt for the wakeup pin
 }
 
 //Enter System-off
 NRF_POWER->SYSTEMOFF = 1;
 }
}


//
//@brief Function for configuring: PIN_IN pin for input, PIN_OUT pin for output,
// and configures GPIOTE to give an interrupt on pin change.
//
static void gpio_init(void)
{
 ret_code_t err_code;

 nrf_gpio_cfg_output(BLUE_LED);
 nrf_gpio_cfg_output(RED_LED);
 
 if(nrf_drv_gpiote_is_init() == false)
 {
 err_code = nrf_drv_gpiote_init();
 APP_ERROR_CHECK(err_code); 
 }

 for(int i = 0; i < NUM_BUTTONS; i++) {
 nrf_drv_gpiote_in_config_t in_config = GPIOTE_CONFIG_IN_SENSE_LOTOHI(false);
 in_config.pull = NRF_GPIO_PIN_PULLDOWN;

 err_code = nrf_drv_gpiote_in_init(buttons[i], &in_config, in_pin_handler);
 APP_ERROR_CHECK(err_code);

 nrf_drv_gpiote_in_event_enable(buttons[i], true);
 }
} 
 Searching around I found a handful of explanations of using the BSP module along with a sleep_mode_enter() based on a button press. However, all of the documentation only shows 8 buttons available in the BSP module. Is there the ability to handle more buttons than that, 15 or more? If so what steps would need to be taken to modify the included files to allow for this? Do I need to modify the pca10040.h, bsp.h/c, boards.h/c, others? How so? 
 
 Thanks for the help!

BendaEng · Accepted Answer

Hi,

To answer your question, no I do not. However, basically what my equipment is telling me is the presence or absence of sleep (if 5 mA = ON, if 0mA = OFF, not taking into account any sort of accuracy).

On a different note, I have now been able to sleep my device. The following was the changes that I made to make the device sleep. Basically, I didn't let all of the 15 pins be a wakeup. Only two of them. I could never identify it, but I think one of those other pins (that are now not enabled for wakeup), was causing the wake-up. Maybe someone can shed light on this, but the pin cnf registers all seemed fine. Part of the issue could have been that my shutdown was contained in the input pin handler. Now it's in a separate function.

Anyway here's my changes.

OLD Non-Working

/*
*
* The following contain the interrupt handlers for all button presses
*
*/
void in_pin_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
   buttons_pressed = true;
   chirp_led(BLUE_LED);

   ret_code_t err_code; 
   
   if(power_off_mode)
      {
              
            //Disable power-down button to prevent System-off wakeup
                      
            for(int i = 0; i < NUM_BUTTONS; i++) {
                    
                    nrf_drv_gpiote_in_uninit(buttons[i]);
                    nrf_drv_gpiote_in_event_disable(buttons[i]);      
            }

            //Configure wake-up button
           
            for(int i = 0; i < NUM_BUTTONS; i++) {
                nrf_drv_gpiote_in_config_t in_config = GPIOTE_CONFIG_IN_SENSE_LOTOHI(false);    //Configure to generate interrupt and wakeup on pin signal high.
                in_config.pull = NRF_GPIO_PIN_PULLDOWN;                                         //Configure pulldown for input pin to prevent it from floating.
                err_code = nrf_drv_gpiote_in_init(buttons[i], &in_config, in_pin_handler);      //Initialize the wake-up pin
                APP_ERROR_CHECK(err_code);                                                      //Check error code returned
                nrf_drv_gpiote_in_event_enable(buttons[i], true);                               //Enable event and interrupt for the wakeup pin
            }
          
          //Enter System-off
          NRF_POWER->SYSTEMOFF = 1;
      }
}

NEW Working Code

void device_power_off(void)
{
  ret_code_t err_code = 0; 

 if(power_off_mode)
      {
              
            for(int i = 0; i < 5; i++)
            {
              chirp_led(RED_LED);
              nrf_delay_ms(100);
            }
            
            //Disable power-down button to prevent System-off wakeup
                      
            for(int i = 0; i < NUM_BUTTONS; i++) {
                    
                    nrf_drv_gpiote_in_uninit(buttons[i]);
                    nrf_drv_gpiote_in_event_disable(buttons[i]);      
            }

            //Configure wake-up button
           
           /*
            for(int i = 0; i < NUM_BUTTONS; i++) {
                nrf_drv_gpiote_in_config_t in_config = GPIOTE_CONFIG_IN_SENSE_LOTOHI(false);    //Configure to generate interrupt and wakeup on pin signal high.
                in_config.pull = NRF_GPIO_PIN_PULLDOWN;                                         //Configure pulldown for input pin to prevent it from floating.
                err_code = nrf_drv_gpiote_in_init(buttons[i], &in_config, in_pin_handler);      //Initialize the wake-up pin
                APP_ERROR_CHECK(err_code);                                                      //Check error code returned
                nrf_drv_gpiote_in_event_enable(buttons[i], true);                               //Enable event and interrupt for the wakeup pin
            }
            */

            nrf_drv_gpiote_in_config_t in_config = GPIOTE_CONFIG_IN_SENSE_LOTOHI(false);    //Configure to generate interrupt and wakeup on pin signal high.
            in_config.pull = NRF_GPIO_PIN_PULLDOWN;                                         //Configure pulldown for input pin to prevent it from floating.
            err_code = nrf_drv_gpiote_in_init(buttons[14], &in_config, in_pin_handler);      //Initialize the wake-up pin on FCN Button
            APP_ERROR_CHECK(err_code);                                                      //Check error code returned
            nrf_drv_gpiote_in_event_enable(buttons[14], true);                               //Enable event and interrupt for the FCN Button Wakeup Pin
            
            err_code = nrf_drv_gpiote_in_init(buttons[12], &in_config, in_pin_handler);      //Initialize the wake-up pin on BT Button
            APP_ERROR_CHECK(err_code);                                                      //Check error code returned
            nrf_drv_gpiote_in_event_enable(buttons[12], true);                               //Enable event and interrupt for the BT Button wakeup pin
          
          //Enter System-off
          power_off_mode = false;

          NRF_POWER -> SYSTEMOFF = 1; 

          //sd_power_system_off();     
      }


}

Thanks for the suggestions to get me here @Jared. Much appreciated!

Inability to sleep the nRF52832. Number of possible buttons in using the BSP module?

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