rtc_time.h

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