用89S51单机P1^0出1KHZ和500HZ的音频信号要求1KHZ信号响100ms,500HZ信号响200ms 替换进行P1^7接一开关进行操控当开关闭合响警报信号当开关断开时警报中止编写程序如下
#include
#define uchar unsigned char
sbit K =P1^7;
sbit out =P1^0;
void main ( )
{while ( 1)
{if (K ==0)
uchar i ;
for (i =200;i >0;i –)
{m _500HZ ( );
}
for (i =200;i >0;i –)
{m _1KHZ ( );
}
}
}
}
void m _500HZ ( )
{out =~out
delay (2);
}
void m _1KHZ ( )
{out =~out
delay (1)
}
void delay (uchar z )
{uchar x ;
uchar y ;
for (x =z;x >0;x –)
{for (y =55;y >0;y –)
}
}