這是一個很簡音的Linux下揚聲器發聲的小程序，以下為源程序。
#include
#include
void play(unsigned int* freq, unsigned int* delay);
main()
{
int i;
unsigned int freq[]={ 330 , 392 , 330 , 294 , 330 , 392 ,
330 , 394 , 330 , 330 , 392 , 330 ,
294 , 262 , 294 , 330 , 392 , 294 ,
262 , 262 , 220 , 196 , 196 , 220 ,
262 , 294 , 330 , 262 , 0 } ;
unsigned int time[]={ 50 , 50 , 50 , 25 , 25 , 50 ,
25 , 25 , 100, 50 , 50 , 25 ,
25 , 50 , 50 , 25 , 25 , 100,
50 , 25 , 25 , 50 , 25 , 25 ,
50 , 25 , 25 , 100 };
unsigned int freq2[]={
196,262,262,262,330,294,262,294,330,294,262,
330,394,440,440,394,330,330,262,294,262,294,
330,294,262,230,230,196,262,440,394,330,330,
262,294,262,294,440,394,330,330,394,440,523,
394,330,330,262,294,262,294,330,294,262,230,
230,196,262,440,394,330,330,262,294,262,294,
440,394,330,330,394,440,523,394,330,330,262,
294,262,294,330,294,262,230,230,196,262,0
};
unsigned int time2[]={
25,38,12,25,25,38,12,25,12,12,56,25,25,50,25,
38,12,12,12,38,12,25,12,12,38,12,25,25,100,25,
38,12,12,12,38,12,25,25,38,12,25,25,100,25,38,
12,12,12,38,12,25,12,12,38,12,25,25,100,25,38,
12,12,12,38,12,25,25,38,12,25,25,100,25,38,12,
12,12,38,12,25,12,12,38,12,25,25,100
};
unsigned int freq_alert[]={
2000, 2400, 0
};
unsigned int time_alert[]={
50, 60
};
for(i = 0; i < 5; i++)
{
play(freq_alert, time_alert);
}
play(freq2, time2);
}
void play(unsigned int* freq, unsigned int* time)
{
int i;
for(i=0;freq[i]!=0;i++)
{
speaker(freq[i], time[i]);
}
}
int speaker(unsigned int freq,unsigned int delay)
{ static int flag=0,bit;
if(flag==0)
{
flag=1;
iopl(3);
}
outb(0xb6,0x43);
outb((freq & 0xff),0x42);
outb((freq >> 8),0x42);
bit=inb(0x61);
outb(3 | bit,0x61);
usleep(10000*delay);
outb(0xfc | bit,0x61);
}
