利用单片机实现555的应用

/*************** writer:shopping.w ******************/ #include <reg52.h> #define uint unsigned int #define uchar unsigned char sbit Signal = P1^0; sbit BEEP = P3^7; void Delay(uint x) { uchar i; while(x--) { for(i=0;i<120;i++); } } void main() { while(1) { if(Signal) { BEEP=~BEEP; Delay(3); } } }