STM32F103 habe ich die RTC richtig initialisiert?

#include "stm32f1xx.h"

void RTC_Handler(void)

{

    // Toggle LED at PA5

    GPIOA->ODR ^= GPIO_ODR_ODR5;

    // Clear interrupt flag

    CLEAR_BIT(RTC->CRL,RTC_CRL_SECF);

}

void initRtc()

{

    // Enable the backup domain

    SET_BIT(RCC->APB1ENR, RCC_APB1ENR_BKPEN + RCC_APB1ENR_PWREN);

    // Enable write access to the backup domain

    SET_BIT(PWR->CR, PWR_CR_DBP);

    // Enable LSE oscillator

    SET_BIT(RCC->BDCR, RCC_BDCR_LSEON);

    // Wait until LSE oscillator is ready

    while(!READ_BIT(RCC->BDCR, RCC_BDCR_LSERDY)) {}

    // Select LSE as clock source for the RTC

    MODIFY_REG(RCC->BDCR, RCC_BDCR_RTCSEL, RCC_BDCR_RTCSEL_LSE);

    // Enable the RTC

    SET_BIT(RCC->BDCR, RCC_BDCR_RTCEN);

    // Wait until RTC is synchronized

    while(!READ_BIT(RTC->CRL, RTC_CRL_RSF)) {}

    // Wait until last write operation is done

    while(!READ_BIT(RTC->CRL, RTC_CRL_RTOFF)) {}

    // Enable second interrupt

    SET_BIT(RTC->CRH,RTC_CRH_SECIE);

    // Wait until last write operation is done

    while(!READ_BIT(RTC->CRL, RTC_CRL_RTOFF)) {}

    // Enter configuration mode

    SET_BIT(RTC->CRL,RTC_CRL_CNF);

    // Divide oscillator frequency by 32767+1 to get seconds

    RTC->PRLL=32767;

    RTC->PRLH=0;

    // Leave configuration mode

    CLEAR_BIT(RTC->CRL,RTC_CRL_CNF);

    // Wait until last write operation is done

    while(!READ_BIT(RTC->CRL, RTC_CRL_RTOFF)) {}

    // Enable interrupt in NVIC

    NVIC_EnableIRQ(3);

    __enable_irq();

}

void initIo()

{

    // Enable Port A

    SET_BIT(RCC->APB2ENR, RCC_APB2ENR_IOPAEN);

    // PA5 = Output

    MODIFY_REG(GPIOA->CRL, GPIO_CRL_CNF5 + GPIO_CRL_MODE5, GPIO_CRL_MODE5_0);

}

int main(void)

{

    initIo();

    initRtc();

    while(1){};

}

  .word  PendSV_Handler

  .word  SysTick_Handler

  .word  0

  .word  0

  .word  0

  .word  RTC_Handler <----- Hier war eine 0

  .word  0

  .word  0