STM32F107VC/Using the RTC Real Time Clock
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Preparing for programming the STM32F107VC Real Time Clock.
//Define where in the memory the RTC start address peripheral is located
#define RTC_BASE 0x40002800 // See reference manual page 52
//Define the RTC register map. See reference manual section 18.4.7 page 474
unsigned short int volatile * const rtc_crh = (unsigned short int *) RTC_BASE + 0x0;
unsigned short int volatile * const rtc_crl = (unsigned short int *) RTC_BASE + 0x4;
unsigned short int volatile * const rtc_prlh = (unsigned short int *) RTC_BASE + 0x8;
//Initialize the RTC peripheral. See reference manual section 18 page 463
void rtc_init(void) {
// Your code here
}
Initializing the RTC
- Goals
- Enabling the RTC
- One seconds TICK
- No interrupts enable
- Initializing second counter to present time (Epoch 1/1-1970 00:00:00)
- Using external XTAL
- Write protect against accidental writes
Enabling the RTC
- To enable the RTC it is necessary to enable the Power interface in the RCC->APB1ENR register by setting the PWREN bit to 1. (Reference manual section 8.3.8 page 144)
- To disable write protection to the Backup domain control register - enabling configuration of the RTC in the PWR->CR register setting the DBP bit to 1. (Reference manual section 5.4.1 page 75)