nrf_drv_gpiote input port event triggers handler only if RTT logging active

[Johannes]

Hi @ all. I have a strange behaviour that I can't get rid of. But first some specs:

• SD130 (2.0.0)
• nrf51822
• SDK 11
• custom board

I have an application where i use a lis3dh accelerometer to realize if the product is moving. The lis3dh toggles on nrf51 pin 13 on movement. I use the nrf_drv_gpiote module to configure pin 13 to trigger a function as soon as it senses a change. For test reasons, i use the handler to turn on an led on the board.

Here is the strange thing. I can turn on and off my leds just fine. but the one indicating that movement happened does not light up. Than is start the j-link rtt Viewer and zapp, the interrupt handler for pin 13 and the LED start working magically. Also - if I quit the RTT Viewer, the system keeps working as supposed. But if restarting - the handler again does not get called until i fire up the RTT-Viewer again.

Here some Code Snippets:

// config for pin 13 (movement)    
nrf_drv_gpiote_in_config_t movement_config = GPIOTE_CONFIG_IN_SENSE_TOGGLE(false);
    
// handler function (should get called if something happens on pin 13
    static void gpiote_event_handler (nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
    {  
// just show that function got called
        FL_LEDblink_switch_BTLE_R_LED(2);
    }
    // initialize gpiote and pins
    init(void){
    uint32_t err_code;
    		if(!nrf_drv_gpiote_is_init())
    		{
    				err_code = nrf_drv_gpiote_init();
    		}
    movement_config.pull = GPIO_PIN_CNF_PULL_Disabled; /*also tested pull_down, pull_up, ...*/
    	 nrf_drv_gpiote_in_init(13, &movement_config, gpiote_event_handler);
    	 nrf_drv_gpiote_in_event_enable(13, true);
    
    }

While doing some power profiling, i saw that as soon as i start the RTT Viewer, power consumption goes up - ans stays up even if i quit rtt viewer.

[Alex]

I think power consumption goes up because you enter debug mode when RTT Viewer started. In order to leave this mode you need to reset the chip. Sorry it is not answer on your question but may stop you thinking in wrong direction.

[Johannes]

Thanks for your response! Yes, right. That could be. But i'm not so focused on the power consumption but more on why the handler function is not called if not in debug mode. :/ Do you have any guess?

[Alex]

Are you sure your code running at all without RTT Viewer? What if you run without RTT but in debug mode from IDE?

[Johannes]

Yes, i'm sure.

• if running without RTT, it does its advertising and i can connect to it using a smartphone.
• timer triggered LED does still toggle on and of every 5 seconds
• if I use keil to debug, than everything works fine (like with RTT Viewer).

[Alex]

... and you can see on pin 13 signal from lis3dh without RTT? Just thinking if lis3dh is still programmed without RTT.