Variable Not Incrementing with nrf_delay_ms()

[Tanner Nelson]

I have the follow code in my application for a PCA10028 program from the nRF51 Development Kit (S110 v9.0):

int main(void)
{
    int i = 0;
    while(true)
    {
        SEGGER_RTT_printf(0, "%d\n", i);
        i++;

        nrf_delay_ms(1000);
    }
}

Output:

0
0
0
0

I want the variable "i" to increment 1,2,3... but it looks like during the nrf_delay_ms() the device is resetting my variable to 0 every time.

Is there any way to have this variable persisted without the use of "pstorage.h"?

[Tanner Nelson]

Thank you for the help, it turns out the culprit was not nrf_delay_ms() as I thought.

The full version of the code I was running included a call to advertising_start() in the while(true) loop.

That advertising_start() function looked like this:

/**@brief Function for starting advertising.
 */
static void advertising_start(void)
{
    uint32_t err_code;

    err_code = sd_ble_gap_adv_start(&m_adv_params);
    APP_ERROR_CHECK(err_code);

    err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
    APP_ERROR_CHECK(err_code);
}

Commenting out the first APP_ERROR_CHECK() call so that it looks like this

/**@brief Function for starting advertising.
 */
static void advertising_start(void)
{
    uint32_t err_code;

    err_code = sd_ble_gap_adv_start(&m_adv_params);
    //APP_ERROR_CHECK(err_code);

    err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
    APP_ERROR_CHECK(err_code);
}

fixed the issue. Commenting out the other APP_ERROR_CHECK() (or any other line in this method, or line in the main() method) has no effect. The only line that affects my variables being reinitialized is that line I commented out.

I have no idea why that would be happening, but my application works perfectly now since commenting that out.

I have both the int i = 0; in the main function and an external bool m_flip = false; that were getting reset by that APP_ERROR_CHECK() call in advertising_start(). I would be very interested to know how that function is affecting the memory for those variables.

[Hung Bui]

@Tanner Nelson: Instead of removing APP_ERROR_CHECK(err_code);, I think you should check and figure out why the sd_* API call return an error caused the assert handler to reset. You can add a break point and check what the error code is.

[Tanner Nelson]

@Hung Bui, after reading @Alex's comment I realized that APP_ERROR_CHECK() was throwing an error that restarted my program. I since removed the advertising_start() from the while(true) loop, so it's only called once. Now my program is functioning normally and no errors are being thrown.