STM32F401RE RTC driver public API. More...

#include <stdint.h>
#include "err.h"

Include dependency graph for stm32f401re_rtc.h:

This graph shows which files directly or indirectly include this file:

Classes
struct	TIME_ts
	Holds a time-of-day value (hours, minutes, seconds). More...
struct	CALENDAR_ts
	Holds a calendar date (year, month, day, weekday). More...

Enumerations
enum	WEEK_DAYS_te { WEEK_DAYS_MONDAY , WEEK_DAYS_TUESDAY , WEEK_DAYS_WEDNESDAY , WEEK_DAYS_THURSDAY , WEEK_DAYS_FRIDAY , WEEK_DAYS_SATURDAY , WEEK_DAYS_SUNDAY }
	Day of the week. More...
enum	MONTHS_te { MONTHS_JANUARY , MONTHS_FEBRUARY , MONTHS_MARCH , MONTHS_APRIL , MONTHS_MAY , MONTHS_JUNE , MONTHS_JULE , MONTHS_AUGUST , MONTHS_SEPTEMBER , MONTHS_OCTOBER , MONTHS_NOVEMBER , MONTHS_DECEMBER }
	Month of the year. More...

Functions
ERR_te	rtc_init (void)
	Initializes the RTC peripheral.
void	rtc_set_calendar (CALENDAR_ts const *date)
	Sets the RTC calendar (date and weekday).
void	rtc_set_time (TIME_ts const *time)
	Sets the RTC time (hours, minutes, seconds).
void	rtc_get_time (TIME_ts *time)
	Reads the current time from the RTC.

Detailed Description

STM32F401RE RTC driver public API.

Author: github.com/Baksi675

This module provides a driver for the STM32F401RE Real-Time Clock (RTC) peripheral, supporting calendar and time configuration and readback.

The RTC is clocked by the LSE (Low-Speed External, 32.768 kHz) oscillator and is configured with the standard 24-hour format. Prescalers are set to produce a 1 Hz tick (PREDIV_A = 127, PREDIV_S = 255).

A backup register pattern (0xABCD in BKP0R) is used as an initialization sentinel. If the pattern is present on startup, the RTC is assumed to already be configured and rtc_init returns ERR_MODULE_ALREADY_INITIALIZED without overwriting the current time. To force re-initialization, call rcc_reset_bkpd first.

Typical usage:

Call rtc_init once at startup (via init_rtc)
Call rtc_set_calendar and rtc_set_time to set the initial values
Call rtc_get_time anywhere in application code to read the current time

Version: 0.1

Date: 2026-01-23

Definition in file stm32f401re_rtc.h.

Classes

Enumerations

Functions

Detailed Description