SND_SetupAlarm

Syntax

#include <nitro/snd.h>
typedef void (*SNDAlarmHandler)( void* arg );
void SND_SetupAlarm(
        int alarmNo,
        u32 tick,
        u32 period,
        SNDAlarmHandler handler,
        void* arg );

Arguments

alarmNo The alarm number. Takes a value between 0 and 7.
tick The tick count until the first sound of the alarm.
period The periodic spacing for sounding the alarm.
handler The alarm handler called when alarm is invoked. This callback is called from within the interrupt handler.
arg The value passed to the alarm handler's argument.

Return Values

None.

Description

This function sets up the sound alarm.

Use the Sound alarm to conduct processes accurately synchronized with channel sounds and captures. Start alarms with the SND_StartTimer function.

The alarm will sound tick tick-counts after the alarm has been started. It will sound with a periodicity specified by period. If 0 is specified for period, the alarm will sound once and then stop automatically.

When the alarm sounds, the alarm handler handler gets called and arg gets passed to the alarm handler's argument. arg is passed to the alarm handler argument.

The values for the tick-count tick and the alarm period period are expressed in units of 1/32 of the sound timer clock SND_TIMER_CLOCK. Thus, if a channel has the channel timer value timer and you want to completely synchronize with that channel, you would set timer/32. For this, timer must be divided by 32.

Note

This function is an ARM7 reserved function. After this function is called, its processing will occur only after the command is issued with the SND_FlushCommand function.

If program execution must be synchronized with process completion, first use the SND_GetCurrentCommandTag function to obtain the command tag immediately after calling this function. Then, after the command is issued, use the command tag and call either the SND_IsFinishedCommandTag or SND_WaitForCommandProc function to confirm that processing has finished or to wait for it to complete.

See Also

SND_StartTimer, SND_FlushCommand, SND_GetCurrentCommandTag, SND_IsFinishedCommandTag, SND_WaitForCommandProc

Revision History

2005/06/01 Added statement about callbacks being called from the interrupt handler.
2005/02/17 Added cautions for ARM7 command processing.
2004/10/21 Standardized terminology so handler argument is referred to as alarm handler.
2004/07/20 Initial version

CONFIDENTIAL