AT89C51与8255A的按键C程序设计.doc

AT89C51与8255A实现数码管显示按键数值的C程序#include#define PA8255 XBYTE4000 /8255的A口地址#define PB8255 XBYTE4001 /8255的B口地址#define PC8255 XBYTE4002 /8255的C口地址#define PD8255 XBYTE4003 /8255的控制口地址 #define uchar unsigned char#define uint unsigned intuchar code table=0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e,0x00;uchar li zhi ting( void );void li(uchar xms )uchar i,j;for(i = xms; i0; i-)for(j = 110; j0;j- );void main()uchar key;PD8255 = 0X81;while(1)PA8255 = 0;li(100);key = 16;key = li zhi ting();PB8255 = tablekey;uchar li zhi ting(void)uchar temp,key;PC8255 = 0xef;if(P3 != 0Xef)delayms(10);temp = PC8255;if( temp != 0xef)switch(temp)case 0xe0: key = 3;break;case 0xeb: key = 7;break;case 0xed: key = 11;break;case 0xee: key = 15;break;default: key = 16;while(PC8255&0x0f!=0x0f);PC8255 = 0xdf;if(P3 != 0Xdf)delayms(10);temp = PC8255;if( temp != 0xdf)switch(temp)case 0xd7: key = 2;break;case 0xdb: key = 6;break;case 0xdd: key = 10;break;case 0xdf: key = 14;break;default: key = 16;while(PC8255&0x0f!=0x0f);PC8255 = 0xbf;if(P3 != 0Xbf)delayms(10);temp = PC8255;if( temp != 0xbf)switch(temp)case 0xba: key = 1;break;case 0xbb: key = 5;break;case 0xbd: key = 9;break;case 0xbe: key = 11;break;default: key = 16;while(PC8255&0x0f!=0x0f); li(100);PC8255 = 0x7f;if(P3 != 0X7f)delayms(10);temp = PC8255;if( temp != 0x7f)switch(temp)case 0x77: key = 0;break;case 0x7b: key = 4;break;case 0x7d: key = 8;break;case