C51单片机及应用系统设计 -99秒表

#include"at89x51.h" unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; unsigned char second; unsigned char keycnt; unsigned int tcnt; void main(void) { TMOD=0x02; ET0=1; EA=1; second=0; P0=dispcode[second/10]; P2=dispcode[second%10]; while(1) { if(P3_5==0) { keycnt++; switch(keycnt) { case 1: TH0=0X06; TH0=0X06; TR0=1; break; case 2: TR0=0; break; case 3: keycnt=0; second=0; P0=dispcode[second/10]; P2=dispcode[second%10]; break; } while(P3_5==0) ; } } } // } void t0(void) interrupt 1 using 0 { tcnt++; if(tcnt==1000) { tcnt=0; second++; if(second==1000) { second=0; } P0=dispcode[second/10]; P2=dispcode[second%10]; if(P0==dispcode[0x6f]&&P2==dispcode[0x6f]) { TR0=0; } } }