stm32l1xx_ll_rtc.h LL Header file v1.8.1(latest version) improper Read RTC function

[Vangelis Fortounas]

This function uint32_t LL_RTC_DATE_Get(RTC_TypeDef *RTCx) reads 4 times the DR(Date register) to take the date from RTC.

After the first read, the shadow registers are unlocked (in case don't bypass them). The next three readings from DR register made without locked Shadow Registers.

The workaround is not to use this function.

[Amel NASRI · Accepted solution]

Hello @Vangelis Fortounas​ ,

Thanks for highlighting this issue. It is reported internally.

Your comment is applicable also for LL_RTC_TIME_Get.

To fix these issues, you may use an implementation similar to the one of stm32f4xx_ll_rtc.h:

/***** LL_RTC_TIME_Get *****/
__STATIC_INLINE uint32_t LL_RTC_TIME_Get(RTC_TypeDef *RTCx)
{
  register uint32_t temp = 0U;
  
  temp = READ_BIT(RTCx->TR, (RTC_TR_HT | RTC_TR_HU | RTC_TR_MNT | RTC_TR_MNU | RTC_TR_ST | RTC_TR_SU));
  return (uint32_t)((((((temp & RTC_TR_HT) >> RTC_TR_HT_Pos) << 4U) | ((temp & RTC_TR_HU) >> RTC_TR_HU_Pos)) << RTC_OFFSET_HOUR) |  \
                    (((((temp & RTC_TR_MNT) >> RTC_TR_MNT_Pos) << 4U) | ((temp & RTC_TR_MNU) >> RTC_TR_MNU_Pos)) << RTC_OFFSET_MINUTE) | \
                    ((((temp & RTC_TR_ST) >> RTC_TR_ST_Pos) << 4U) | ((temp & RTC_TR_SU) >> RTC_TR_SU_Pos)));
}
 
/***** LL_RTC_DATE_Get *****/
__STATIC_INLINE uint32_t LL_RTC_DATE_Get(RTC_TypeDef *RTCx)
{
  register uint32_t temp = 0U;
  
  temp = READ_BIT(RTCx->DR, (RTC_DR_WDU | RTC_DR_MT | RTC_DR_MU | RTC_DR_DT | RTC_DR_DU | RTC_DR_YT | RTC_DR_YU));
  return (uint32_t)((((temp & RTC_DR_WDU) >> RTC_DR_WDU_Pos) << RTC_OFFSET_WEEKDAY) | \
                    (((((temp & RTC_DR_DT) >> RTC_DR_DT_Pos) << 4U) | ((temp & RTC_DR_DU) >> RTC_DR_DU_Pos)) << RTC_OFFSET_DAY) | \
                    (((((temp & RTC_DR_MT) >> RTC_DR_MT_Pos) << 4U) | ((temp & RTC_DR_MU) >> RTC_DR_MU_Pos)) << RTC_OFFSET_MONTH) | \
                    ((((temp & RTC_DR_YT) >> RTC_DR_YT_Pos) << 4U) | ((temp & RTC_DR_YU) >> RTC_DR_YU_Pos)));
}

-Amel