wiring_time.c File Reference

Time functions: millis(), micros(), delay(), delayMicroseconds() and _gettimeofday(). More...

#include "Arduino.h"

Functions
unsigned long	millis (void)
	Get the number of milliseconds since the board started.
unsigned long	micros (void)
	Get the number of microseconds since the board started.
void	delay (unsigned long ms)
	Pause the program for the given number of milliseconds.
void	delayMicroseconds (unsigned int us)
	Pause the program for the amount of time (in microseconds) specified as parameter.
int	_gettimeofday (struct timeval *tv, void *tz)
	Gives the number of seconds and microseconds since the Epoch.

Detailed Description

Time functions: millis(), micros(), delay(), delayMicroseconds() and _gettimeofday().

Function Documentation

_gettimeofday()

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

Gives the number of seconds and microseconds since the Epoch.

Based on milliseconds since last power on.

Note

The function is declared as weak to be overwritten in case of other implementations in user file (using RTC values for example).

Parameters

tv	Argument is a struct timeval.
tz	Argument is a struct timezone (unused).

Returns

0, always.

delay()

void delay

(

unsigned long

ms

)

Pause the program for the given number of milliseconds.

Calls yield() while waiting, so cooperative threads can run.

Parameters

ms	Number of milliseconds to pause.

delayMicroseconds()

void delayMicroseconds

(

unsigned int

us

)

Pause the program for the amount of time (in microseconds) specified as parameter.

Parameters

us	Number of microseconds to pause.

micros()

unsigned long micros

(

void

)

Get the number of microseconds since the board started.

Interrupt-compatible version.

Returns

Microseconds since startup. Overflows after about 70 minutes.

millis()

unsigned long millis

(

void

)

Get the number of milliseconds since the board started.

Note

Interrupts are not disabled while the counter is read, see the ToDo in the implementation.

Returns

Milliseconds since startup. Overflows after about 49 days.