Assert in FreeRTOS task.c: configASSERT( ( xTickCount + xTicksToJump ) <= xNextTaskUnblockTime )

[Ray Ma]

Hello,

I am using configUSE_TICKLESS_IDLE with RTC2 setup for FreeRTOS tick, occasionally I am seeing the asserting in task.c at line configASSERT( ( xTickCount + xTicksToJump ) <= xNextTaskUnblockTime ). Looking at the tickless idle code, I am wondering it this is caused by the inaccuracy of RTC2. Have you seen any issue like this before? Is there any suggestion for how to debug this further?

Thanks,

-Ray

 

        /* Correct the system ticks */
        {
            TickType_t diff;
            TickType_t exitTime;

            nrf_rtc_event_clear(portNRF_RTC_REG, NRF_RTC_EVENT_TICK);
            nrf_rtc_int_enable (portNRF_RTC_REG, NRF_RTC_INT_TICK_MASK);

            exitTime = nrf_rtc_counter_get(portNRF_RTC_REG);
            diff =  (exitTime - enterTime) & portNRF_RTC_MAXTICKS;

            /* It is important that we clear pending here so that our corrections are latest and in sync with tick_interrupt handler */
            NVIC_ClearPendingIRQ(portNRF_RTC_IRQn);

            if ((configUSE_TICKLESS_IDLE_SIMPLE_DEBUG) && (diff > xExpectedIdleTime))
            {
                diff = xExpectedIdleTime;
            }

            if (diff > 0)
            {
                vTaskStepTick(diff);
            }
        }

[Simonr]

Hi Ray

What SDK version are you using for development? Can you try replacing the #ifdef statement (line 238-254) in port_cmsis_systick.c with the following snippet? I'm not sure if it's related but it's been the fix for surprisingly many FreeRTOS projects having issues with the tickless mode.

#if 0  // With FreeRTOS sd_app_evt_wait increases power consumption with FreeRTOS compared to _WFE (NRFFOSDK-11174)
#ifdef SOFTDEVICE_PRESENT
            if (nrf_sdh_is_enabled())
            {
                uint32_t err_code = sd_app_evt_wait();
                APP_ERROR_CHECK(err_code);
            }
            else
#endif
#endif // (NRFFOSDK-11174)
            {
                /* 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]));
            }
        }

Best regards,

SImon

[Ray Ma]

Hey Simon, I'll give that a try. What's the difference between sd_app_evt_wait() and WFE()? 

Thanks,

-Ray