基于51单片机的电子门铃 c语言程序

#include<reg52.h> #define uchar unsigned char #define uint unsigned int sbit speaker=P1^7; uchar cnt750hz,cnt500hz; uint cnt; bit flag; void main() { TMOD=0x02; TH0 =0x06; TL0 =0x06; EA =1; ET0=1; TR0=0; EX0=1; IT0=1; while(1) {} } void t0() interrupt 1 { cnt++; if(cnt==2000) { cnt=0; if(flag==0) flag=~flag; else TR0=0; } if(flag==0) { cnt750hz++; if(cnt750hz==3) { cnt750hz=0; speaker=~speaker; } } if(flag==1) { cnt500hz++; if(cnt500hz==4) { cnt500hz=0; speaker=~speaker; } } } void int0() interrupt 0 { TR0=1; }