rtc_time.h

00001 /** Implementation of the C time.h functions
00002  *
00003  * Provides mechanisms to set and read the current time, based
00004  * on the microcontroller Real-Time Clock (RTC), plus some 
00005  * standard C manipulation and formating functions. 
00006  *
00007  * Example:
00008  * @code
00009  * #include "mbed.h"
00010  *
00011  * int main() {
00012  *     set_time(1256729737);  // Set RTC time to Wed, 28 Oct 2009 11:35:37
00013  *      
00014  *     while(1) {    
00015  *         time_t seconds = time(NULL);
00016  *         
00017  *         printf("Time as seconds since January 1, 1970 = %d\n", seconds);
00018  *  
00019  *         printf("Time as a basic string = %s", ctime(&seconds));
00020  *
00021  *         char buffer[32];
00022  *         strftime(buffer, 32, "%I:%M %p\n", localtime(&seconds));
00023  *         printf("Time as a custom formatted string = %s", buffer);
00024  *    
00025  *         wait(1);
00026  *     }
00027  * }
00028  * @endcode
00029  */
00030  
00031 /* mbed Microcontroller Library - rtc_time
00032  * Copyright (c) 2009 ARM Limited. All rights reserved.
00033  */
00034 
00035 #include <time.h>
00036 
00037 #ifdef __cplusplus
00038 extern "C" {
00039 #endif
00040 
00041 #if 0 // for documentation only
00042 /** Get the current time
00043  *
00044  *  Returns the current timestamp as the number of seconds since January 1, 1970
00045  *  (the UNIX timestamp). The value is based on the current value of the 
00046  *  microcontroller Real-Time Clock (RTC), which can be set using <set_time>.
00047  *
00048  * @param t Pointer to a time_t to be set, or NULL if not used
00049  *
00050  * @returns
00051  *   Number of seconds since January 1, 1970 (the UNIX timestamp)
00052  *
00053  * Example:
00054  * @code
00055  * #include "mbed.h"
00056  * 
00057  * int main() {
00058  *     time_t seconds = time(NULL);
00059  *     printf("It is %d seconds since January 1, 1970\n", seconds);
00060  * }
00061  * @endcode
00062  */
00063 time_t time(time_t *t);
00064 #endif
00065 
00066 /** Set the current time
00067  *
00068  * Initialises and sets the time of the microcontroller Real-Time Clock (RTC)
00069  * to the time represented by the number of seconds since January 1, 1970 
00070  * (the UNIX timestamp). 
00071  * 
00072  * @param t Number of seconds since January 1, 1970 (the UNIX timestamp) 
00073  *
00074  * Example:
00075  * @code
00076  * #include "mbed.h"
00077  *
00078  * int main() {
00079  *     set_time(1256729737); // Set time to Wed, 28 Oct 2009 11:35:37
00080  * }
00081  * @endcode
00082  */ 
00083 void set_time(time_t t);
00084 
00085 #if 0 // for documentation only
00086 /** Converts the tm structure in to a timestamp in seconds since January 1, 1970
00087  *  (the UNIX timestamp). The values of tm_wday and tm_yday of the tm structure 
00088  *  are also updated to their appropriate values.
00089  *
00090  * @param t The tm structure to convert
00091  *
00092  * @returns
00093  *   The converted timestamp
00094  *
00095  * Example:
00096  * @code
00097  * #include "mbed.h"
00098  *
00099  * int main() {
00100  *     // setup time structure for Wed, 28 Oct 2009 11:35:37
00101  *     struct tm t;
00102  *     t.tm_sec = 37;    // 0-59
00103  *     t.tm_min = 35;    // 0-59
00104  *     t.tm_hour = 11;   // 0-23
00105  *     t.tm_mday = 28;   // 1-31
00106  *     t.tm_mon = 9;     // 0-11
00107  *     t.tm_year = 109;  // year since 1900
00108  * 
00109  *     // convert to timestamp and display (1256729737)
00110  *     time_t seconds = mktime(&t);
00111  *     printf("Time as seconds since January 1, 1970 = %d\n", seconds);
00112  * }
00113  * @endcode
00114  */
00115 time_t mktime(struct tm *t);
00116 #endif
00117 
00118 #if 0 // for documentation only
00119 /** Converts the timestamp pointed to by t to a (statically allocated) 
00120  *  tm structure. 
00121  * 
00122  * @param t Pointer to the timestamp
00123  *
00124  * @returns
00125  *   Pointer to the (statically allocated) tm structure
00126  *
00127  * Example:
00128  * @code
00129  * #include "mbed.h"
00130  *
00131  * int main() {
00132  *     time_t seconds = 1256729737;
00133  *     struct tm *t = localtime(&seconds);
00134  * }
00135  * @endcode
00136  */
00137 struct tm *localtime(const time_t *t);
00138 #endif
00139 
00140 #if 0 // for documentation only
00141 /** Converts a timestamp to a human-readable string
00142  *  
00143  * Converts a time_t timestamp in seconds since January 1, 1970 (the UNIX
00144  * timestamp) to a human readable string format. The result is of the 
00145  * format: "Wed Oct 28 11:35:37 2009\n"
00146  *
00147  * Example:
00148  * @code
00149  * #include "mbed.h"
00150  *
00151  * int main() {
00152  *     time_t seconds = time(NULL);
00153  *     printf("Time as a string = %s", ctime(&seconds));
00154  * }
00155  * @endcode
00156  * 
00157  * @param t The timestamp to convert
00158  *
00159  * @returns Pointer to a (statically allocated) string containing the
00160  *            human readable representation, including a '\n' character
00161  */
00162 char *ctime(const time_t *t);
00163 #endif
00164  
00165 #if 0 // for documentation only
00166 /** Converts a tm structure to a custom format human-readable string
00167  *  
00168  * Creates a formated string from a tm structure, based on a string format 
00169  * specifier provided.
00170  *
00171  * Format Specifiers: 
00172  * - %S - Second (00-59)
00173  * - %M - Minute (00-59)
00174  * - %H - Hour (00-23)
00175  * - %d - Day (01-31)
00176  * - %m - Month (01-12)
00177  * - %Y/%y - Year (2009/09)
00178  * - %A/%a - Weekday Name (Monday/Mon)
00179  * - %B/%b - Month Name (January/Jan)
00180  * - %I - 12 Hour Format (01-12)
00181  * - %p - "AM" or "PM"
00182  * - %X - Time (14:55:02)
00183  * - %x - Date (08/23/01)
00184  *
00185  * @param buffer String buffer to store the result
00186  * @param max Maximum number of characters to store in the buffer
00187  * @param format Format specifier string
00188  * @param t Pointer to the tm structure to convert
00189  *
00190  * @returns
00191  *   Number of characters copied
00192  * 
00193  * Example:
00194  * @code
00195  * #include "mbed.h"
00196  * 
00197  * int main() {
00198  *     time_t seconds = time(NULL);
00199  *  
00200  *     char buffer[32];
00201  *     strftime(buffer, 32, "%I:%M %p\n", localtime(&seconds));
00202  *     printf("Time as a formatted string = %s", buffer);
00203  * }   
00204  * @endcode
00205  */
00206 size_t strftime(char *buffer, size_t max, const char *format, const struct tm *t);
00207 #endif
00208 
00209 #ifdef __cplusplus
00210 }
00211 #endif