rtc_time functions

Data Structures
struct	timeval

Functions
void	set_time (time_t t)
	Implementation of the C time.h functions. More...
void	attach_rtc (time_t(*read_rtc)(void), void(*write_rtc)(time_t), void(*init_rtc)(void), int(*isenabled_rtc)(void))
	Attach an external RTC to be used for the C time functions. More...
int	gettimeofday (struct timeval *tv, void *tz)
	Standard lib retarget, get time since Epoch. More...
int	settimeofday (const struct timeval *tv, const struct timezone *tz)
	Standard lib retarget, set time since Epoch. More...

Detailed Description

Function Documentation

set_time()

void set_time

(

time_t

t

)

Implementation of the C time.h functions.

Provides mechanisms to set and read the current time, based on the microcontroller Real-Time Clock (RTC), plus some standard C manipulation and formatting functions.

Example:

#include "mbed.h"
 
int main() {
    set_time(1256729737);  // Set RTC time to Wed, 28 Oct 2009 11:35:37
 
    while (true) {
        time_t seconds = time(NULL);
 
        printf("Time as seconds since January 1, 1970 = %u\n", (unsigned int)seconds);
 
        printf("Time as a basic string = %s", ctime(&seconds));
 
        char buffer[32];
        strftime(buffer, 32, "%I:%M %p\n", localtime(&seconds));
        printf("Time as a custom formatted string = %s", buffer);
 
        ThisThread::sleep_for(1000);
    }
}

Set the current time

Initializes and sets the time of the microcontroller Real-Time Clock (RTC) to the time represented by the number of seconds since January 1, 1970 (the UNIX timestamp).

Parameters

t	Number of seconds since January 1, 1970 (the UNIX timestamp)

Note

Synchronization level: Thread safe

Example:

#include "mbed.h"
 
int main() {
    set_time(1256729737); // Set time to Wed, 28 Oct 2009 11:35:37
}

attach_rtc()

void attach_rtc	(	time_t(*)(void)	read_rtc,
		void(*)(time_t)	write_rtc,
		void(*)(void)	init_rtc,
		int(*)(void)	isenabled_rtc
	)

Attach an external RTC to be used for the C time functions.

Note

Synchronization level: Thread safe

Parameters

read_rtc	pointer to function which returns current UNIX timestamp
write_rtc	pointer to function which sets current UNIX timestamp, can be NULL
init_rtc	pointer to function which initializes RTC, can be NULL
isenabled_rtc	pointer to function which returns if the RTC is enabled, can be NULL

gettimeofday()

int gettimeofday	(	struct timeval *	tv,
		void *	tz
	)

Standard lib retarget, get time since Epoch.

Parameters

tv	Structure containing time_t seconds and useconds_t microseconds. Due to separate target specific RTC implementations only the seconds component is used.
tz	DEPRECATED IN THE STANDARD: This parameter is left in for legacy code. It is not used.

Returns

0 on success, -1 on a failure.

Note

Synchronization level: Thread safe

settimeofday()

int settimeofday	(	const struct timeval *	tv,
		const struct timezone *	tz
	)

Standard lib retarget, set time since Epoch.

Parameters

tv	Structure containing time_t seconds and useconds_t microseconds. Due to separate target specific RTC implementations only the seconds component is used.
tz	DEPRECATED IN THE STANDARD: This parameter is left in for legacy code. It is not used.

Returns

Time in seconds on success, -1 on a failure.

Note

Synchronization level: Thread safe