1 /* mbed Microcontroller Library
2 *******************************************************************************
3 * Copyright (c) 2014, STMicroelectronics
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
9 * 1. Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 * 3. Neither the name of STMicroelectronics nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
25 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *******************************************************************************
32 static int rtc_inited = 0;
35 RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE); // Enable PWR clock
37 PWR_BackupAccessCmd(ENABLE); // Enable access to RTC
39 // Be sure to start correctly
40 RCC_BackupResetCmd(ENABLE);
41 RCC_BackupResetCmd(DISABLE);
43 // Note: the LSI is used as RTC source clock
44 // The RTC Clock may vary due to LSI frequency dispersion.
45 RCC_LSICmd(ENABLE); // Enable LSI
47 while (RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) {} // Wait until ready
49 RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI); // Select LSI as RTC Clock Source
51 RCC_RTCCLKCmd(ENABLE); // Enable RTC Clock
53 RTC_WaitForSynchro(); // Wait for RTC registers synchronization
55 uint32_t lsi_freq = 40000; // [TODO] To be measured precisely using a timer input capture
57 RTC_InitTypeDef RTC_InitStructure;
58 RTC_InitStructure.RTC_AsynchPrediv = 127;
59 RTC_InitStructure.RTC_SynchPrediv = (lsi_freq / 128) - 1;
60 RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;
61 RTC_Init(&RTC_InitStructure);
67 RCC_DeInit(); // Resets the RCC clock configuration to the default reset state
71 int rtc_isenabled(void) {
77 RTC_WeekDay 1=monday, 2=tuesday, ..., 7=sunday
78 RTC_Month 1=january, 2=february, ..., 12=december
79 RTC_Date day of the month 1-31
82 tm_sec seconds after the minute 0-61
83 tm_min minutes after the hour 0-59
84 tm_hour hours since midnight 0-23
85 tm_mday day of the month 1-31
86 tm_mon months since January 0-11
87 tm_year years since 1900
88 tm_wday days since Sunday 0-6
89 tm_yday days since January 1 0-365
90 tm_isdst Daylight Saving Time flag
92 time_t rtc_read(void) {
93 RTC_DateTypeDef dateStruct;
94 RTC_TimeTypeDef timeStruct;
97 // Read actual date and time
98 RTC_GetTime(RTC_Format_BIN, &timeStruct);
99 RTC_GetDate(RTC_Format_BIN, &dateStruct);
101 // Setup a tm structure based on the RTC
102 timeinfo.tm_wday = dateStruct.RTC_WeekDay;
103 timeinfo.tm_mon = dateStruct.RTC_Month - 1;
104 timeinfo.tm_mday = dateStruct.RTC_Date;
105 timeinfo.tm_year = dateStruct.RTC_Year + 100;
106 timeinfo.tm_hour = timeStruct.RTC_Hours;
107 timeinfo.tm_min = timeStruct.RTC_Minutes;
108 timeinfo.tm_sec = timeStruct.RTC_Seconds;
110 // Convert to timestamp
111 time_t t = mktime(&timeinfo);
116 void rtc_write(time_t t) {
117 RTC_DateTypeDef dateStruct;
118 RTC_TimeTypeDef timeStruct;
120 // Convert the time into a tm
121 struct tm *timeinfo = localtime(&t);
123 // Fill RTC structures
124 dateStruct.RTC_WeekDay = timeinfo->tm_wday;
125 dateStruct.RTC_Month = timeinfo->tm_mon + 1;
126 dateStruct.RTC_Date = timeinfo->tm_mday;
127 dateStruct.RTC_Year = timeinfo->tm_year - 100;
128 timeStruct.RTC_Hours = timeinfo->tm_hour;
129 timeStruct.RTC_Minutes = timeinfo->tm_min;
130 timeStruct.RTC_Seconds = timeinfo->tm_sec;
131 timeStruct.RTC_H12 = RTC_HourFormat_24;
133 // Change the RTC current date/time
134 PWR_BackupAccessCmd(ENABLE); // Enable access to RTC
135 RTC_SetDate(RTC_Format_BIN, &dateStruct);
136 RTC_SetTime(RTC_Format_BIN, &timeStruct);
137 PWR_BackupAccessCmd(DISABLE); // Disable access to RTC