FreeRTOS+WDT+SDK17 problem

[loquat]

I have added WDT to the blinky_freertos sample.

/** add **/
static nrf_drv_wdt_channel_id m_channel_id;

static void wdt_event_handler(void)
{
}
/**********/

int main(void)
{
    ret_code_t err_code;

    /* Initialize clock driver for better time accuracy in FREERTOS */
    err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);

    /* Configure LED-pins as outputs */
    bsp_board_init(BSP_INIT_LEDS);

    /* Create task for LED0 blinking with priority set to 2 */
    UNUSED_VARIABLE(xTaskCreate(led_toggle_task_function, "LED0", configMINIMAL_STACK_SIZE + 200, NULL, 2, &led_toggle_task_handle));

    /* Start timer for LED1 blinking */
    led_toggle_timer_handle = xTimerCreate( "LED1", TIMER_PERIOD, pdTRUE, NULL, led_toggle_timer_callback);
    UNUSED_VARIABLE(xTimerStart(led_toggle_timer_handle, 0));

    /* Activate deep sleep mode */
    SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;

/** add **/
    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();
/*********/

	/* Start FreeRTOS scheduler. */
    vTaskStartScheduler();

    while (true)
    {
        /* FreeRTOS should not be here... FreeRTOS goes back to the start of stack
         * in vTaskStartScheduler function. */
    }
}

And I am debugging with SEGGER ozone.

building with SDK17:

If you reset the software in the debugger and start it, the application freezes.
t stops in the following loop.
And RTC1 is not counting up.

*********************************************************************
port_cmsis_systick.c

     /* No SD -  we would just block interrupts globally.
      * BASEPRI cannot be used for that because it would prevent WFE from wake up.
     */
      do{
         __WFE();
      } while (0 == (NVIC->ISPR[0] | NVIC->ISPR[1]));

**********************************************************************
However, after WDT reset, blinky works normally.

I have built the same application with SDK15.
It was perfectly fine.

SDK17 seems to have a problem.

I found a difference with SDK15.

SDK17 nrf_drv_clock.c
*****************************************
nrf_drv_clock_init()
...
    if (nrf_wdt_started())
    {
        m_clock_cb.lfclk_on = true;
    }
*****************************************
If a software reset occurs after WDT is activated, WDT remains activated after the reset. However, LFCLK is stopped.
As a result, the above process does not start LFCLK, so even if RTC1 is started, it will not be counted up.

[Susheel Nuguru]

Syuji,

Sorry for late response, we started coming back from summer holidays. I will take a look at this problem today, will come back to you soon.

[Susheel Nuguru]

Where are you feeding the watchdog? (where is your application calling nrf_drv_wdt_channel_feed?)

For me it is working fine if i feed the wdt in the bsp_event_callback with a button press. the wdt reset happens if i do not press the button.

[loquat]

I add feeding the watchdog in led_toggle_task_function.

But the problem is not there.
The problem is that if a software reset occurs while WtchDog is running, FreeRTOS will not work properly.
And the cause is that LFCLK is not initialized properly.

[Susheel Nuguru]

loquat said:

The problem is that if a software reset occurs while WtchDog is running, FreeRTOS will not work properly.
And the cause is that LFCLK is not initialized properly.

i cannot see this behavior in my quick test on the desk. No software resets have happened in my test. Can you please attach your project so that i can test this. 

[loquat]

Target board is PCA10056(nRF52840).

/**
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 *
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 * are permitted provided that the following conditions are met:
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 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
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 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
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 *    engineered, decompiled, modified and/or disassembled.
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 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
/** @file
 * @defgroup blinky_example_main main.c
 * @{
 * @ingroup blinky_example_freertos
 *
 * @brief Blinky FreeRTOS Example Application main file.
 *
 * This file contains the source code for a sample application using FreeRTOS to blink LEDs.
 *
 */

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

#include "FreeRTOS.h"
#include "task.h"
#include "timers.h"
#include "bsp.h"
#include "nordic_common.h"
#include "nrf_drv_clock.h"
#include "sdk_errors.h"
#include "app_error.h"
#include "nrf_drv_wdt.h"

#define	WDT_ENABLE			1

#if LEDS_NUMBER <= 2
#error "Board is not equipped with enough amount of LEDs"
#endif

#define TASK_DELAY        200           /**< Task delay. Delays a LED0 task for 200 ms */
#define TIMER_PERIOD      1000          /**< Timer period. LED1 timer will expire after 1000 ms */

TaskHandle_t  led_toggle_task_handle;   /**< Reference to LED0 toggling FreeRTOS task. */
TimerHandle_t led_toggle_timer_handle;  /**< Reference to LED1 toggling FreeRTOS timer. */

/**@brief LED0 task entry function.
 *
 * @param[in] pvParameter   Pointer that will be used as the parameter for the task.
 */
static void led_toggle_task_function (void * pvParameter)
{
    UNUSED_PARAMETER(pvParameter);
    while (true)
    {
#if WDT_ENABLE
    	nrf_drv_wdt_feed();
#endif
        bsp_board_led_invert(BSP_BOARD_LED_0);

        /* Delay a task for a given number of ticks */
        vTaskDelay(TASK_DELAY);

        /* Tasks must be implemented to never return... */
    }
}

/**@brief The function to call when the LED1 FreeRTOS timer expires.
 *
 * @param[in] pvParameter   Pointer that will be used as the parameter for the timer.
 */
static void led_toggle_timer_callback (void * pvParameter)
{
    UNUSED_PARAMETER(pvParameter);
    bsp_board_led_invert(BSP_BOARD_LED_1);
}

#if WDT_ENABLE
static nrf_drv_wdt_channel_id m_channel_id;

static void wdt_event_handler(void)
{
}
#endif

static void bsp_evt_handler(bsp_event_t evt)
{
    switch (evt)
    {
        case BSP_EVENT_KEY_0:
    	NVIC_SystemReset(); /* Software Reset */
            break;
    	
    default:
    		break;
    }
}

int main(void)
{
    ret_code_t err_code;

    /* Initialize clock driver for better time accuracy in FREERTOS */
    err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);

    /* Configure LED-pins as outputs */
    err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, bsp_evt_handler);
    APP_ERROR_CHECK(err_code);

    /* Create task for LED0 blinking with priority set to 2 */
    UNUSED_VARIABLE(xTaskCreate(led_toggle_task_function, "LED0", configMINIMAL_STACK_SIZE + 200, NULL, 2, &led_toggle_task_handle));

    /* Start timer for LED1 blinking */
    led_toggle_timer_handle = xTimerCreate( "LED1", TIMER_PERIOD, pdTRUE, NULL, led_toggle_timer_callback);
    UNUSED_VARIABLE(xTimerStart(led_toggle_timer_handle, 0));

    /* Activate deep sleep mode */
    SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;

#if WDT_ENABLE
    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();
#endif
	/* Start FreeRTOS scheduler. */
    vTaskStartScheduler();

    while (true)
    {
        /* FreeRTOS should not be here... FreeRTOS goes back to the start of stack
         * in vTaskStartScheduler function. */
    }
}

/**
 *@}
 **/

And sdk_config.h modified
#define NRFX_WDT_CONFIG_RELOAD_VALUE 10000

If #define WDT_ENABLE 1.  (WDT enabled)
1. When PoweOnReset, LED is blinking.
2. When Button 1 pushed(execute SoftwareReset), LED blinking is stopped.
3. After 10 seconds, LED blinking is started.

If #define WDT_ENABLE 0. (WDT disabled)
1. When PoweOnReset, LED is blinking.
2. When Button 1 pushed(execute SoftwareReset), LED blinking is restarted quickly.