RTC_TimeStamp Example Description

Configuration of the RTC HAL API to demonstrate the timestamp feature.

At the beginning of the main program the HAL_Init() function is called to reset all the peripherals, initialize the Flash interface and the systick.

Then the SystemClock_Config() function is used to configure the system clock (SYSCLK) to run at 48 MHz.

The RTC peripheral configuration is ensured by the HAL_RTC_Init() function. This later is calling the HAL_RTC_MspInit()function which core is implementing the configuration of the needed RTC resources according to the used hardware (CLOCK, PWR, RTC clock source and BackUp). You may update this function to change RTC configuration.

Note :

LSI oscillator clock is used as RTC clock source by default.
The user can use also LSE as RTC clock source.
- The user uncomment the adequate line on the main.c file.
  @code
    #define RTC_CLOCK_SOURCE_LSI  
    /* #define RTC_CLOCK_SOURCE_LSE */
  @endcode
- Open the ioc file with STM32CubeMX and select :
  LSE as "Crystal/Ceramic Resonator" in RCC configuration.
  LSE as RTC clock source in Clock configuration.
- Generate code
LSI oscillator clock is delivered by a 32 kHz RC.
LSE (when available on board) is delivered by a 32.768 kHz crystal.

HAL_RTCEx_SetTimeStamp_IT()function is then called to initialize the time stamp feature with interrupt mode. It configures the time stamp pin to be rising edge and enables the time stamp detection on time stamp pin. HAL_RTC_SetTime()and HAL_RTC_SetDate() functions are then called to initialize the time and the date.

The associated firmware performs the following:

  1. After startup the program configure the RTC (Time date) and enable the feature timeStamp.

  2. When applying a high level on the time stamp pin PC.13,(pin 23 connector CN7) a time stamp event is detected and the calendar is saved in the time stamp structures. Each time the connection realized. The current time and date are updated and displayed on the debugger in aShowTime and aShowDate variables.

Notes

  1. Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds) based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower) than the peripheral interrupt. Otherwise the caller ISR process will be blocked. To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.

  2. The application need to ensure that the SysTick time base is always set to 1 millisecond to have correct HAL operation.

Keywords

RTC, Timer, Timestamp, Counter, LSE, LSI, Current time, Real Time Clock

Directory contents

- RTC/RTC_TimeStamp/Inc/stm32c0xx_hal_conf.h    HAL configuration file
- RTC/RTC_TimeStamp/Inc/stm32c0xx_it.h          Interrupt handlers header file
- RTC/RTC_TimeStamp/Inc/main.h                  Header for main.c module  
- RTC/RTC_TimeStamp/Src/stm32c0xx_it.c          Interrupt handlers
- RTC/RTC_TimeStamp/Src/main.c                  Main program
- RTC/RTC_TimeStamp/Src/stm32c0xx_hal_msp.c     HAL MSP module
- RTC/RTC_TimeStamp/Src/system_stm32c0xx.c      STM32C0xx system source file

Hardware and Software environment

How to use it ?

In order to make the program work, you must do the following :