02-继电器蜂鸣器

 #include "reg52.h"
 
 sbit HC138_A = P2^5;
 sbit HC138_B = P2^6;
 sbit HC138_C = P2^7;
 
 void delay(unsigned int t)
 {
     while(t--);
     while(t--);
 }
 
 void YN(unsigned char n)
 {
     switch(n)
     {
         case 4:
         HC138_C = 1;
         HC138_B = 0;
         HC138_A = 0;
     break;
     case 5:
         HC138_C = 1;
         HC138_B = 0;
         HC138_A = 1;
     break;
     case 6:
         HC138_C = 1;
         HC138_B = 1;
         HC138_A = 0;
     break;
     case 7:
         HC138_C = 1;
         HC138_B = 1;
         HC138_A = 1;
     break;
     }   
 }
 
 void outputP0(unsigned char channel,unsigned char dat)
 {
     YN(channel);
     P0 = dat;
 }
 
 void LEDrunning()
 {
     unsigned char i;
     
     for(i = 0;i<3;i++)
     {
         outputP0(4,0x00);
         delay(60000);
         delay(60000);
         outputP0(4,0xff);
         delay(60000);
         delay(60000);
     }
     for(i = 1;i<=8;i++)
     {
         outputP0(4,(0xff << i));
         delay(60000);
         delay(60000);
     }
     outputP0(5,0x10);
     delay(60000);
     outputP0(5,0x00);
     
     for(i = 1;i<=8;i++)
     {
         outputP0(4,~(0xff << i));
         delay(60000);
         delay(60000);
     }
     
     outputP0(5,0x40);
     delay(60000);
     outputP0(5,0x00);
 }
 
 void InitSysyem()
 {
     outputP0(5,0x00);
 }
 
 void main()
 {
     InitSysyem();
     while(1)
     {
         LEDrunning();
     }
 }