watchdog does not reset when program get stuck in ' NRF_BREAKPOINT_COND; ' while in debug mode

[ziv123]

hello Nordic

i work with nrf52832, sdk 16, s132.

I set a watchdog but when i try to create a fault by adding breakpoints after ble starts scanning then i get stuck in the '   NRF_BREAKPOINT_COND; ' but the watchdog does not restart.

can something like that happen in real run when not in debug mode ?? and if so then how can i protect my program from getting stuck ??

is it related to interrupt priority or something like that ??

also, i read somewhere that the softdevice has a watchdog of its own, so is there really a point on implementing my own watchdog ??

best regards

Ziv

[Vidar Berg]

Hello Ziv,

Depending on the configuration, the WDT can be paused when your debugger halts on NRF_BREAKPOINT_COND. This can only happen in debug mode, please check out the register description here for more details: CONFIG

 The Softdevice does not implement a Watchdog.

Best regards,

Vidar

[ziv123]

hi Vidar

thanks for your reply

i know i can configure watch dog to run also when debugging with a breakpoints 

// <o> WDT_CONFIG_BEHAVIOUR  - WDT behavior in CPU SLEEP or HALT mode
 
// <1=> Run in SLEEP, Pause in HALT 
// <8=> Pause in SLEEP, Run in HALT 
// <9=> Run in SLEEP and HALT 
// <0=> Pause in SLEEP and HALT 

#ifndef WDT_CONFIG_BEHAVIOUR
#define WDT_CONFIG_BEHAVIOUR 9
#endif

in the sdk_config file i set the wdt to run at HALT and SLEEP (9), and i see that it does restart when i wait on a breakpoint when ble is not working but when i get to the ' NRF_BREAKPOINT_COND '  then it does not work, this is why i asked 

and i guess i am also asking if in real run, when system is NOT in debug mode, can the program ever get to that line ' NRF_BREAKPOINT_COND ' (with or without a watchdog) ??

best regards

Ziv

[Vidar Berg]

Hi Ziv,

I changed the default config to  "Run in SLEEP and HALT" in the WDT example in SDK 17.0.0 and added the NRF_BREAKPOINT_COND, but was not able to replicate the problem. Could you try the same?

Here's the code I used:

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/** @file
 * @defgroup nrf_dev_wdt_example_main main.c
 * @{
 * @ingroup nrf_dev_wdt_example
 * @brief WDT Example Application main file.
 *
 * This file contains the source code for a sample application using WDT.
 *
 */

#include <stdbool.h>
#include <stdint.h>

#include "nrf.h"
#include "bsp.h"
#include "app_timer.h"
#include "app_error.h"
#include "nrf_drv_wdt.h"
#include "nrf_drv_clock.h"
#include "nrf_delay.h"
#include "app_util_platform.h"

#define FEED_BUTTON_ID          0                           /**< Button for feeding the dog. */

nrf_drv_wdt_channel_id m_channel_id;

/**
 * @brief WDT events handler.
 */
void wdt_event_handler(void)
{
    bsp_board_leds_off();

    //NOTE: The max amount of time we can spend in WDT interrupt is two cycles of 32768[Hz] clock - after that, reset occurs
}

/**
 * @brief Assert callback.
 *
 * @param[in] id    Fault identifier. See @ref NRF_FAULT_IDS.
 * @param[in] pc    The program counter of the instruction that triggered the fault, or 0 if
 *                  unavailable.
 * @param[in] info  Optional additional information regarding the fault. Refer to each fault
 *                  identifier for details.
 */
void app_error_fault_handler(uint32_t id, uint32_t pc, uint32_t info)
{
    bsp_board_leds_off();
    NRF_BREAKPOINT_COND;
    while (1);
}

/**
 * @brief BSP events callback.
 */
void bsp_event_callback(bsp_event_t event)
{
    switch (event)
    {
        case BSP_EVENT_KEY_0:
            nrf_drv_wdt_channel_feed(m_channel_id);
            break;

        default :
            //Do nothing.
            break;
    }
}

/**
 * @brief Function for main application entry.
 */
int main(void)
{
    uint32_t err_code = NRF_SUCCESS;

    //BSP configuration for button support: button pushing will feed the dog.
    err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);
    nrf_drv_clock_lfclk_request(NULL);

    err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);

    err_code = bsp_init(BSP_INIT_BUTTONS, bsp_event_callback);
    APP_ERROR_CHECK(err_code);

    //Configure all LEDs on board.
    bsp_board_init(BSP_INIT_LEDS);

    //Configure WDT.
    nrf_drv_wdt_config_t config = NRF_DRV_WDT_DEAFULT_CONFIG;
    err_code = nrf_drv_wdt_init(&config, wdt_event_handler);
    APP_ERROR_CHECK(err_code);
    err_code = nrf_drv_wdt_channel_alloc(&m_channel_id);
    APP_ERROR_CHECK(err_code);
    nrf_drv_wdt_enable();

    //Indicate program start on LEDs.
    for (uint32_t i = 0; i < LEDS_NUMBER; i++)
    {   nrf_delay_ms(200);
        bsp_board_led_on(i);
    }
     err_code = bsp_buttons_enable();
     APP_ERROR_CHECK(1);

    while (1)
    {
        __SEV();
        __WFE();
        __WFE();
    }
}

/** @} */

Best regards,

Vidar

[ziv123]

hi Vidar 

this is exactly what i have done .. i set the WDT to run at SLEEP and HALT 

my observation is that  when i stop at a regular breakpoint then it gets stuck there and  after i press the continue it restarts but, with the NRF_BREAKPOINT_COND it just get stuck there (my assumption that it has something to do with interrupt priority but i am not sure )

so again the question is, could this kind of stuckness accrue while running not in debug mode ??

best regards

Ziv

[Vidar Berg]

Hi Ziv,

ziv123 said:

so again the question is, could this kind of stuckness accrue while running not in debug mode ??

No, this can only occur in debug interface mode.