Posted on March 03, 2018 at 19:21
Hi, I think there is a bug in code generated by CubeMX for RTC. Problem is that if you enable wake-up timer interrupt in Cube, it is only enabled after you first power up MCU.
MX_RTC_Init
checks value of backup register to prevent RTC registers being reinitialised, but also prevents
HAL_RTC_Init
from being called.
/* RTC init function */
void MX_RTC_Init(void)
{
...
if (HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR0) != 0x32F2) {
...
if (HAL_RTC_Init(&hrtc) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
...
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR0, 0x32F2);
}
}�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?
HAL_RTC_Init
normally calls
HAL_RTC_MspInit
, which enables RTC clock and enables interrupts in NVIC.
void HAL_RTC_MspInit(RTC_HandleTypeDef* rtcHandle)
{
if(rtcHandle->Instance==RTC)
{
...
/* RTC clock enable */
__HAL_RCC_RTC_ENABLE();
/* RTC interrupt Init */
HAL_NVIC_SetPriority(RTC_WKUP_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(RTC_WKUP_IRQn);
...
}
}�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?
So, if you now reset MCU, interrupt for wake-up timer will NOT be enabled (clock for RTC will stay enabled, because it issaved in BDCR register, which is preserved after reset). I think this would occur every time device is reset without power being disconnected from Vbat.
Easy fix would be to still call
HAL_RTC_MspInit,
even if RTC registers do not need to be initialised:
/* RTC init function */
void MX_RTC_Init(void)
{
...
if (HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR0) != 0x32F2) {
...
if (HAL_RTC_Init(&hrtc) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
...
HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR0, 0x32F2);
}
else
{
HAL_RTC_MspInit(&hrtc);
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}�?�?�?�?�?�?�?�?�?�?�?�?�?�?
�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?
Of course we can enable interrupts at different place, but it probably would be better solution if this worked correctly.
Thanks
#wake-up #rtc
