我正在使用 stm32h753 和 stm32cubemx，并尝试在 VBAT 上运行 RTC 模块。为此，我已将电池连接到 MCU。RTC 连接到 LSE。接下来，我在代码中设置 RTC，然后断开 MCU 与电源的连接，然后重新连接。根据文档，这应该会自动将 RTC 电源从 VDD 切换到 VBAT。
我在启动时注释了MX_RTC_Init()，这样当MCU重启时RTC不会被重置。
下面是系统时钟配置、RTC Init 的代码，以及复位后读取 RTC 寄存器的代码。
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
/** Supply configuration update enable
*/
HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
/** Configure the main internal regulator output voltage
*/
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}
/** Configure LSE Drive Capability
*/
HAL_PWR_EnableBkUpAccess();
__HAL_RCC_LSEDRIVE_CONFIG(RCC_LSEDRIVE_LOW);
/** Macro to configure the PLL clock source
*/
__HAL_RCC_PLL_PLLSOURCE_CONFIG(RCC_PLLSOURCE_HSE);
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_LSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.LSEState = RCC_LSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 1;
RCC_OscInitStruct.PLL.PLLN = 84;
RCC_OscInitStruct.PLL.PLLP = 2;
RCC_OscInitStruct.PLL.PLLQ = 4;
RCC_OscInitStruct.PLL.PLLR = 2;
RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_3;
RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
RCC_OscInitStruct.PLL.PLLFRACN = 0;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2
|RCC_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;
RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV4;
RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_USART3
|RCC_PERIPHCLK_SPI1|RCC_PERIPHCLK_SDMMC
|RCC_PERIPHCLK_ADC;
PeriphClkInitStruct.PLL2.PLL2M = 1;
PeriphClkInitStruct.PLL2.PLL2N = 25;
PeriphClkInitStruct.PLL2.PLL2P = 4;
PeriphClkInitStruct.PLL2.PLL2Q = 2;
PeriphClkInitStruct.PLL2.PLL2R = 2;
PeriphClkInitStruct.PLL2.PLL2RGE = RCC_PLL2VCIRANGE_3;
PeriphClkInitStruct.PLL2.PLL2VCOSEL = RCC_PLL2VCOMEDIUM;
PeriphClkInitStruct.PLL2.PLL2FRACN = 0;
PeriphClkInitStruct.SdmmcClockSelection = RCC_SDMMCCLKSOURCE_PLL;
PeriphClkInitStruct.Spi123ClockSelection = RCC_SPI123CLKSOURCE_PLL;
PeriphClkInitStruct.Usart234578ClockSelection = RCC_USART234578CLKSOURCE_D2PCLK1;
PeriphClkInitStruct.AdcClockSelection = RCC_ADCCLKSOURCE_PLL2;
PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
}
这是 RTC 初始化代码
static void MX_RTC_Init(void)
{
/* USER CODE BEGIN RTC_Init 0 */
/* USER CODE END RTC_Init 0 */
RTC_TimeTypeDef sTime = {0};
RTC_DateTypeDef sDate = {0};
RTC_AlarmTypeDef sAlarm = {0};
/* USER CODE BEGIN RTC_Init 1 */
/* USER CODE END RTC_Init 1 */
/** Initialize RTC Only
*/
hrtc.Instance = RTC;
hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
hrtc.Init.AsynchPrediv = 127;
hrtc.Init.SynchPrediv = 255;
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();
}
/* USER CODE BEGIN Check_RTC_BKUP */
/* USER CODE END Check_RTC_BKUP */
/** Initialize RTC and set the Time and Date
*/
sTime.Hours = 0x0;
sTime.Minutes = 0x0;
sTime.Seconds = 0x0;
sTime.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
sTime.StoreOperation = RTC_STOREOPERATION_RESET;
if (HAL_RTC_SetTime(&hrtc, &sTime, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
sDate.WeekDay = RTC_WEEKDAY_MONDAY;
sDate.Month = RTC_MONTH_JANUARY;
sDate.Date = 0x1;
sDate.Year = 0x0;
if (HAL_RTC_SetDate(&hrtc, &sDate, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
/** Enable the Alarm A
*/
sAlarm.AlarmTime.Hours = 0x0;
sAlarm.AlarmTime.Minutes = 0x20;
sAlarm.AlarmTime.Seconds = 0x0;
sAlarm.AlarmTime.SubSeconds = 0x0;
sAlarm.AlarmTime.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
sAlarm.AlarmTime.StoreOperation = RTC_STOREOPERATION_RESET;
sAlarm.AlarmMask = RTC_ALARMMASK_DATEWEEKDAY|RTC_ALARMMASK_HOURS;
sAlarm.AlarmSubSecondMask = RTC_ALARMSUBSECONDMASK_ALL;
sAlarm.AlarmDateWeekDaySel = RTC_ALARMDATEWEEKDAYSEL_DATE;
sAlarm.AlarmDateWeekDay = 0x1;
sAlarm.Alarm = RTC_ALARM_A;
if (HAL_RTC_SetAlarm_IT(&hrtc, &sAlarm, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
/** Enable the Alarm B
*/
sAlarm.AlarmTime.Minutes = 0x40;
sAlarm.Alarm = RTC_ALARM_B;
if (HAL_RTC_SetAlarm_IT(&hrtc, &sAlarm, RTC_FORMAT_BCD) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN RTC_Init 2 */
/* USER CODE END RTC_Init 2 */
}
这是我在启动后用来读取 rtc 寄存器值的代码：
HAL_RTC_GetTime(&hrtc, &sTime, RTC_FORMAT_BIN);
HAL_RTC_GetDate(&hrtc, &sDate, RTC_FORMAT_BIN);
float subSecondsFloat = ( 255 - sTime.SubSeconds );
subSecondsFloat = (subSecondsFloat /255);
subSecondsFloat = (subSecondsFloat * 1000);
year = (uint32_t) (sDate.Year);
month = (uint32_t) (sDate.Month);
day = (uint32_t) (sDate.Date);
hours = (uint32_t) (sTime.Hours);
minutes = (uint32_t) (sTime.Minutes);
seconds = (uint32_t) (sTime.Seconds);
subseconds = (uint32_t) (subSecondsFloat);
sprintf(usartSendBuffer,"\n%lu,%lu,%lu,%lu,%lu,%lu,%lu\n", year,month,day,hours, minutes,seconds,subseconds);
printf(usartSendBuffer);
当我断开 MCU 与电源的连接，然后将其重新连接到电源时，上述代码在电源复位后给出以下结果（RTC 寄存器值）：
159,10,9,32,51,51,4294967295
所以 RTC 在 MCU 复位的某个地方被复位。考虑到我已经禁用了 MX_RTC_Init()，我不知道 RTC 在哪里被重置。
抱歉，如果问题是基本的，我对这个领域真的很陌生。
我非常感谢任何帮助，谢谢。
此致，
武里亚