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我最近写一个PWM测试程序,刚开始在mini2440板子上可以启动蜂鸣器。可后来却不行了。一切运行都正常,就是蜂鸣器不响。有哪位朋友可以帮助解决?
源代码如下:
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
int freq[40]={0};
int main()
{
int fd,i,reset;
/*open*/
fd=open("/dev/pwm",0);
if(fd<0)
printf("Open pwm is failed!\n");
else
printf("Open pwm is successful!\n");
for(i=0;i<40;i++)
{
freq=100+10*i;
}
for(i=0;i<40;i++)
{
reset=ioctl(fd,PWM_IOCTL_SET_FREQ,freq);
if(reset<0)
printf("set the pwm is failed!\n");
else
printf("set the pwm is successful!\n");
}
sleep(10);
reset=ioctl(fd,PWM_IOCTL_STOP);
if(reset<0)
printf("stop the pwm is failed!\n");
else
printf("stop the pwm is successful!\n");
close(fd);
return 0;
}
运行结果都是successful!就是蜂鸣器不响???
[ 本帖最后由 PreNewDream 于 2009-8-14 21:22 编辑 ] |
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