0904_APP/Hardware/rtc.c

#include "rtc.h"
#include "Uart.h"

void rtc_configuration(void)
{

     rcu_periph_clock_enable(RCU_BKPI);/* enable PMU and BKPI clocks */
     rcu_periph_clock_enable(RCU_PMU);

     pmu_backup_write_enable();/* allow access to BKP domain */

     bkp_deinit();/* reset backup domain */

     rcu_osci_on(RCU_LXTAL);/* enable LXTAL */
     rcu_osci_stab_wait(RCU_LXTAL);/* wait till LXTAL is ready */
     rcu_rtc_clock_config(RCU_RTCSRC_LXTAL);/* select RCU_LXTAL as RTC clock source */
     rcu_periph_clock_enable(RCU_RTC);/* enable RTC Clock */
     rtc_register_sync_wait();/* wait for RTC registers synchronization */
     rtc_lwoff_wait();/* wait until last write operation on RTC registers has finished */
     //rtc_interrupt_enable(RTC_INT_SECOND);/* enable the RTC second interrupt*/
     rtc_lwoff_wait();/* wait until last write operation on RTC registers has finished */
     rtc_prescaler_set(32767);/* set RTC prescaler: set RTC period to 1s */
     rtc_lwoff_wait();/* wait until last write operation on RTC registers has finished */
}
void set_time(uint32_t time)
{

    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();
    /* change the current time */
    rtc_counter_set(time);
    /* wait until last write operation on RTC registers has finished */
    rtc_lwoff_wait();

}
void rct_init(void)
{
    if (bkp_data_read(BKP_DATA_0) != 0xA5A5){

        printf("\r\nThis is a RTC demo!\r\n");
        printf("\r\n\n RTC not yet configured....");
        rtc_configuration();/* RTC configuration */
        printf("\r\n RTC configured....");

        /* adjust time by values entred by the user on the hyperterminal */
        set_time(1684302671);

        bkp_data_write(BKP_DATA_0, 0xA5A5);
    }else{

        if (rcu_flag_get(RCU_FLAG_PORRST) != RESET){/* check if the power on reset flag is set */
            printf("\r\n\n Power On Reset occurred....");
        }
        else if (rcu_flag_get(RCU_FLAG_SWRST) != RESET){
            printf("\r\n\n External Reset occurred....");/* check if the pin reset flag is set */
        }
        rcu_periph_clock_enable(RCU_PMU);/* allow access to BKP domain */
        pmu_backup_write_enable();
        printf("\r\n No need to configure RTC....");
        rtc_register_sync_wait();/* wait for RTC registers synchronization */
        rtc_lwoff_wait();/* wait until last write operation on RTC registers has finished */
    }

    //rcu_all_reset_flag_clear();/* clear reset flags */
}