不理解锁存器的含义及作用，求解释（网上的也看不太懂）
#include <REGX52.H>
#define uchar unsigned char
uchar j,k,i,a,A1,A2,second;
sbit dula=P2^6; //锁存器控制端定义
sbit wela=P2^7;
uchar code table[]=
{ //数字编码
0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71
};
void delay(uchar i)//延时函数
{
for(j = i;j>0;j--)
for(k=125;k>0;k--);
}
void desplay(uchar sh_c,uchar g_c)//段选
{
dula = 0;
P0 = table[sh_c];//显示十位
dula =1;
dula = 0;
wela = 0;
P0 = 0xfe;
wela = 1;
wela = 0;
delay(5);//亮5ms
P0 = 0xfd;
wela = 1;
wela = 0;
delay(5);//亮5ms
}
void main()
{
while(1)
{
if(second==60)//判断是否到60
second = 0;//如果到了则清零
A1 = second/10;//分离出10位和个位
A2 = second%10;
for(a = 50;a>0;a--)//显示部分，至于时间大概时多少
{ //请用户用软件仿真看时间约等于1s
display(A1,A2);//便可，如果需要精准确定时请用定时器
}
}
}
