Interval Timer

Functions
int	IntervalOSSem (OS_SEM *p_toSem, int num_per_sec, int timer=FIRST_UNUSED_TIMER)
	Posts to a semaphore at the requested interval.
int	IntervalOSFlag (OS_FLAGS *p_toFlag, uint32_t flag_value, int num_per_sec, int timer=FIRST_UNUSED_TIMER)
	Sets a flag at requested interval.
int	IntervalInterruptCallback (void(*p_toCallbackFunc)(), int num_per_sec, int timer=FIRST_UNUSED_TIMER)
	Calls a function at requested interval. Note that the callback function is called from within the timer's interrupt handler so you should treat your callback function as an interrupt.
void	IntervalStop (int timer_number)
	Stops an existing Interval Timer and frees the resource.

Detailed Description

#include< IntervalTimer.h >

The Interval Timer is used to create a periodic interrupt (IRQ) that can trigger the following:

• Call an Interrupt Service Routine (ISR). An example of this is located in \nburn\examples
• Post an OS semaphore
• Post an OS flag

Example: Create an interval timer that posts 20 times per second

OS_SEM timerSem;
timerSem.Init();
 
int timerNumer = IntervalOSSem(&timerSem, 20);
if(timerNumer < 0)
{
 iprintf("Error %d\r\n", timerNumer);
 break;
}

When you have no further use for the interval timer, call IntervalStop() so that the hardware timer is released.

See also

High Resolution Delay Timer

Stopwatch Timer

OSTimeDly()

Function Documentation

IntervalInterruptCallback()

int IntervalInterruptCallback	(	void(*)()	p_toCallbackFunc,
		int	num_per_sec,
		int	timer = FIRST_UNUSED_TIMER )

#include <IntervalTimer.h>

Calls a function at requested interval. Note that the callback function is called from within the timer's interrupt handler so you should treat your callback function as an interrupt.

Parameters

p_toCallbackFunc	Pointer to the callback function
num_per_sec	Number of posts per second, minimum is 20 posts per second.
timer	Optional parameter, timer number of -1 for first unused timer

Returns

The timer number, -1 if no timer is available, or -2 if num_per_sec is invalid.

IntervalOSFlag()

int IntervalOSFlag	(	OS_FLAGS *	p_toFlag,
		uint32_t	flag_value,
		int	num_per_sec,
		int	timer = FIRST_UNUSED_TIMER )

#include <IntervalTimer.h>

Sets a flag at requested interval.

Parameters

p_toFlag	Pointer to the semaphore
flag_value	OS Flag value to set
num_per_sec	Number of posts per second, minimum is 20 posts per second.
timer	Optional parameter, timer number of -1 for first unused timer

Returns

The timer number, -1 if no timer is available, or -2 if num_per_sec is invalid.

IntervalOSSem()

int IntervalOSSem	(	OS_SEM *	p_toSem,
		int	num_per_sec,
		int	timer = FIRST_UNUSED_TIMER )

#include <IntervalTimer.h>

Posts to a semaphore at the requested interval.

Parameters

p_toSem	Pointer to the semaphore
num_per_sec	Number of posts per second, minimum is 20 posts per second
timer	Optional parameter, timer number of -1 for first unused timer

Returns

The timer number, -1 if no timer is available, or -2 if num_per_sec is invalid.

IntervalStop()

void IntervalStop

(

int

timer_number

)

#include <IntervalTimer.h>

Stops an existing Interval Timer and frees the resource.

Parameters

timer_number

Number of the timer to stop.