OS_SetAlarm

Syntax

#include <nitro/os.h>

void OS_SetAlarm(
             OSAlarm*       alarm,
             OSTick         tick,
             OSAlarmHandler handler,
             void*          arg );

Arguments

`alarm`	Pointer to an alarm structure that is initialized for this alarm.
`tick`	Tick count until the alarm goes off (the handler is called).
`handler`	Alarm handler.
`arg`	Argument when the handler is called.

Return Values

None.

Description

Sets up a one-time alarm.

A handler is called after the tick count that is specified by tick. The V-Count alarm handler handler is an OSVAlarmHandler function defined by the following.

typedef void (*OSAlarmHandler)( void* );

When the handler is called, it takes arg as an argument. The handler argument is passed from the OS timer interrupt handler. Therefore, interrupts are prohibited.

One tick count unit is 1/64 of the hardware system clock.

If alarm is specified for the pointer to the OSAlarm structure in which the alarm has been set, it stops with OS_Panic.

In the following example, by setting an alarm, the handler function is called 0.5 seconds later, and "handler called. arg=0x12345678" is displayed.

Example:

#define COUNT 　OS_MilliSecondsToTicks( 500 )
#define ARG　0x12345678
OSAlarm 　alarm;

main()
{
		：
	OS_InitTick();
	OS_InitAlarm();
		：
	OS_CreateAlarm( &alarm );
	OS_SetAlarm( &alarm, COUNT, handler, (void*)ARG );
		:
}

void handler( void* arg )
{
	OS_Printf( "handler called. arg=0x%x\n", arg );
}

Revision History

2005/03/08 Standardized the use of the term "interrupt" in Japanese.
2004/12/22 Added a statement about the alarm handler's being called from the timer interrupt handler.
2004/08/30 Added a statement about not being able to use the set alarm structure.
2004/02/25 Changed systemClock to tick.
2004/02/04 Initial version.