在KEIL环境下的51编程LED两位数倒计时答:include<AT89X51.H> unsigned char flag1=0;unsigned char counter=0;unsigned char first=0;unsigned char second=0;unsigned char code dptable[]= {0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};//段码表 main(){ TMOD=0x10;//定时器T1,方式1 TH1=0xfa;//晶振为3....