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我網(wǎng)上找了一個關(guān)于單片機LED數(shù)字倒計時的程序但是看不太懂
有沒有大神幫我注釋一下意思 再弄個protues 仿真電路圖
# include <reg51.h>
sbit kh=P1^1;
sbit km=P1^1;
sbit ks=P1^2;
sbit st=P1^3;
sbit b=P3^7;
unsigned char
table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88, 0x83,0xc6,0xa1,0x86,0x8e};
unsigned char i=0,hour=0,minute=0,second=0;
void delayms(unsigned int x)
{ unsigned char a=160;
while(x--) { while(a--); a=160; } }
main() { TH0=(65536-50000)/256;
TL0=(65536-50000)%256;
TMOD=1;
TR0=0;
ET0=1;
EA=1;
while(1) {
P0=table[hour/10];
P2=0x20;
delayms(1);
P2=0xff;
P0=table[hour%10];
P2=0x10;
delayms(1);
P2=0xff;
P0=table[minute/10];
P2=0x08;
delayms(1);
P2=0xff;
P0=table[minute%10];
P2=0x04;
delayms(1);
P2=0xff;
P0=table[second/10];
P2=0x02;
delayms(1);
P2=0xff;
P0=table[second%10];
P2=0x01;
delayms(1);
P2=0xff;
if(!kh)
{ delayms(200);
hour++;
if(hour>23)
hour=23; }
else if(!km)
{ delayms(200);
minute++;
if(minute>59)
minute=59; }
else if(!ks)
{ delayms(200);
second++;
if(second>59)
second=59; }
if(!st)
{ delayms(200);
TR0=1; }
if(TR0==1&&hour==0&&minute==0&&second<3) b=!b; delayms(1); } }
void t0() interrupt 1 { TH0=(65536-50000)/256; TL0=(65536-50000)%256;
i++;
if(i>=20)
{ i=0; second--;
if(second>59)
{ second=59;
minute--;
if(minute>59)
{ minute=59;
hour--;
if(hour>23)
{hour=0; minute=0; second=0; TR0=0; } } } } }
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