stm32wb5mmg standby BUG?

[TH5]

Regarding the standby mode of the STM32WB5MMG, I have enabled only the RTC wake-up as trigger to wake up every second.
However, occasionally it freezes in standby mode, and after a watchdog reset, it doesn't even perform initialization processes.
Finally, it does not work until I manually turn the power off and on again.

Do you know any workaround for this freezing issue?

[Hl_st]

Hello,

can you also attach the code, where RTC is set and where MCU enters into standby mode?

[TH5]

Hl_st, thank you for your reply.
First, calls the following functions as initialization of RTC
・MX_RTC_Init
・Init_Rtc
・HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, RTC_WUT_TIME, (uint32_t)CFG_RTC_WUCKSEL_DIVIDER);
The code is given below.
===============================
static void MX_RTC_Init(void)
{
/** Initialize RTC Only
*/
hrtc.Instance = RTC;
hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
hrtc.Init.AsynchPrediv = CFG_RTC_ASYNCH_PRESCALER;
hrtc.Init.SynchPrediv = CFG_RTC_SYNCH_PRESCALER;
hrtc.Init.OutPut = RTC_OUTPUT_DISABLE;
hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
hrtc.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
hrtc.Init.OutPutRemap = RTC_OUTPUT_REMAP_NONE;
if (HAL_RTC_Init(&hrtc) != HAL_OK)
{
Error_Handler();
}
/** Enable the WakeUp
*/
if (HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, 0xFFFF, RTC_WAKEUPCLOCK_RTCCLK_DIV16) != HAL_OK)
{
Error_Handler();
}
}

static void Init_Rtc( void )
{
/* Disable RTC registers write protection */
LL_RTC_DisableWriteProtection(RTC);

LL_RTC_WAKEUP_SetClock(RTC, CFG_RTC_WUCKSEL_DIVIDER);

/* Enable RTC registers write protection */
LL_RTC_EnableWriteProtection(RTC);

return;
}

/* RTC_WUT_TIME is 16386U. CFG_RTC_WUCKSEL_DIVIDER is 3. */
HAL_RTCEx_SetWakeUpTimer_IT(&hrtc, RTC_WUT_TIME, (uint32_t)CFG_RTC_WUCKSEL_DIVIDER);
===============================

 

Here is the code just before entering standby:
===============================
LL_PWR_EnableBkUpAccess();

/* Reset Internal Wake up flag */
LL_RTC_ClearFlag_WUT(RTC);

/* Check that PWR Internal Wake-up is enabled */
if (LL_PWR_IsEnabledInternWU() == 0U)
{
/* Need to enable the Internal Wake-up line */
LL_PWR_EnableInternWU();
}

/* Set Standby mode */
LL_PWR_SetPowerMode(LL_PWR_MODE_STANDBY);

/* Set Standby mode of CPU2 */
/* Note: On STM32WB, both CPU1 and CPU2 must be in Standby mode to set the entire system in Standby mode */
LL_C2_PWR_SetPowerMode(LL_PWR_MODE_STANDBY);

/* Retain SRAM2a */
LL_PWR_EnableSRAM2Retention();

/* Set SLEEPDEEP bit of Cortex System Control Register */
LL_LPM_EnableDeepSleep();

/* Request Wait For Interrupt */
__WFI();
===============================

[Joe WILLIAMS]

Hi TH5

This post has been escalated to the ST Online Support Team for additional assistance.  We'll contact you directly.

Kind Regards

Joe WILLIAMS

STMicro Support