OS_SetPeriodicVAlarm

Syntax

#include <nitro/os.h>
void OS_SetPeriodicVAlarm(
                OSVAlarm*           alarm ,
                s16                 count ,
                s16              delay ,
                OSVAlarmHandler     handler ,
                void*            arg );

Arguments

alarm Pointer to the V-Count alarm structure for setting V-Count alarm
count The V-Count at which the V-Count alarm will be actuated (handler will be called) in each frame.
delay The maximum permissible number of V-Counts for delay.
handler The V-Count alarm handler
arg The argument used when the V-Count alarm handler is called

Return Values

None.

Description

Sets a periodic V-Count alarm.

In each frame, handler is called when the V-Count reaches count. The V-Count alarm handler handler is an OSVAlarmHandler function defined by the following:

typedef void (*OSVAlarmHandler)( void* );

handler is called from the OS V-Count interrupt handler. Therefore, interrupts are prohibited. When the handler is called, it takes arg as an argument.

It is possible to specify the amount of permissible delay when the hander cannot be called at the exact number of specified V-Count because of another V-Count alarm or interrupt. For example, at count=100 and delay=5, V-Count is called if it is possible to call it by count 105, even if it was not possible to call it by count 100. When you specify 0, the alarm is called only at the specified V-Count. If OS_VALARM_DELAY_MAX, it is always called when a call is possible for the specified V-Count and subsequent V-Counts. For details, see the description in VAlarm Overview.

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

OS_CancelVAlarm() or OS_CancelVAlarms() is used to stop the V-Count alarm.

See Also

OS_InitVAlarm, OS_CreateVAlarm, OS_SetVAlarm,
OS_CancelVAlarm, OS_CancelVAlarms

Revision History

2005/03/08 Standardized the use of the term 'interrupt' in Japanese.
2004/08/30 Added statement about not being able to use the set V alarm structure.
2004/07/06 Added statement about delay.
2004/02/24 Initial version

CONFIDENTIAL