51/avr单片机频率计小程序

利用BANK 3部分电路设计一个频率计，用来检测该部分555脉冲发生器产生的脉冲的频率，将测量结果显示在数码管上。
#include <reg52.h>
sbit P1_2=P1^2;
sbit P1_3=P1^3;
code ledyang[10]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; //0~9
code scan[8]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};
unsigned char cnt[8];
unsigned char i=0,j=0,c;  
void delay(unsigned char m)
    {
     unsigned char a,b;
     for(a=0;a<m;a++)
     for(b=0;b<5;b++);
     }
void display_number()
   {
     P0=ledyang[cnt[i]];
     P1_3=1;   
     P1_3=0; 
     delay(10);
     P0=scan[i];
     P1_2=1;
     delay(5);
     P1_2=0;
     delay(10);
     i++;
     if(i==8) i=0;
     P0 = 0x00;//消影 
     P1_2=1;   
     P1_2=0;