STM32F103 RTC Register problem

[Michael2023]

Hi. I have a problem with the RTC on STM32F103C6T6A. I wanted to add the ability to set the time. I would like to have a 24h clock. When CNTL overflows, CNTH does not increase making the clock reset close to 18h.

void RTC_IRQHandler(void){

while ((RTC->CRL, RTC_CRL_RTOFF) == 0 );

RTC -> CRL &= ~RTC_CRL_SECF;

licznik = RTC -> CNTH;

licznik <<= 16;

licznik = RTC -> CNTL;

godziny = licznik / 3600;

minuty = (licznik % 3600)/60;

sekundy = (licznik % 3600) % 60;}

void RTC_Config(void){

RCC -> APB1ENR |= RCC_APB1ENR_PWREN; //Power interface clock enable (aby kozystac z rejestru PWR)

RCC -> APB1ENR |= RCC_APB1ENR_BKPEN; //Backup interface clock enable (aby kozystac z rejestru BKP)

PWR -> CR |= PWR_CR_DBP; //Enable Acces to RTC registers (Disable backup domain write protection)

// RCC -> CSR |= RCC_CSR_LSION; //LSI 40kHz ON

// while(!(RCC -> CSR & RCC_CSR_LSIRDY)); //Wait for LSI Ready

RCC -> BDCR |= RCC_BDCR_LSEON; //LSE ON

while(!(RCC -> BDCR & RCC_BDCR_LSERDY)); //Wait for LSE Ready

// RCC -> BDCR |= RCC_BDCR_RTCSEL_1; //LSI source for RTC

RCC -> BDCR |= RCC_BDCR_RTCSEL_0; //LSE source for RTC

RCC -> BDCR |= RCC_BDCR_RTCEN; //RTC clock ENABLE

while(!(RTC->CRL & RTC_CRL_RSF)); //Registers synchronized flag

while(!(RTC->CRL & RTC_CRL_RTOFF)); //RTC status operation OFF

RTC -> CRL |= RTC_CRL_CNF; //Enter Configuration mode

RTC -> PRLL = 39999; //RTC prescaler

RTC -> CRH |= RTC_CRH_SECIE; //Global Interrupt form RTC ENABLE

while(!(RTC->CRL & RTC_CRL_RTOFF)); //RTC status operation OFF

RTC -> CRL &=~ RTC_CRL_CNF; //Exit Configuration mode

while(!(RTC->CRL & RTC_CRL_RTOFF)); //RTC status operation OFF

}

[JTP1]

Hello

Put or | like this

licznik = RTC -> CNTH;

licznik <<= 16;

licznik| = RTC -> CNTL;

And make sure licznik is 32 bit

Br.J.T

[Michael2023]

Hi. Still nothing. 
when I exceed the value of 18h (CNTL overflow) RTC resets leaving "garbage" as minutes. (18h->RESET->0:48h).

CNTH still 0.

[Michael2023]

the main problem is CNT registers. When CNTL is overload CNTH isn't increment automatic.

[waclawek.jan]

Do you use some of the low-power modes?

> while ((RTC->CRL, RTC_CRL_RTOFF) == 0 );

Did you want to use the comma expression here?

JW

[Michael2023]

The only thing I use is a Vbat power supply to back up the RTC when it shuts down