數(shù)碼管顯示矩陣鍵盤掃描值

?/*矩陣鍵盤掃描出鍵值，在數(shù)碼管上顯示出來
?????? P0口接數(shù)碼管的段選碼，P2口通過反相器接數(shù)
?????? 管的位選碼*/
?????
?????? #include??? //所用的器件是AT89S52
?????? #define uchar unsigned char
?????
?????? void delayms(uchar j);??? //聲明延時(shí)函數(shù)?
?????? uchar getkey(void);???? //聲明掃描函數(shù)
?????? void keydisp(uchar k); //聲明顯示函數(shù)
?????? void disp(uchar l);???? //聲明顯示子程序
?????
?????? uchar code table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,
?????????????????????????? 0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,
?????????????????????????? 0x86,0x8e};
???????????????????????????? //共陽數(shù)碼管0-F顯示代碼
?????
?????? void main(void)??????? //主程序
?????? {
?????????? uchar key;
?????????? while(1)
?????????? {
??????????? key=getkey();
??????????? delayms(20);
??????????? keydisp(key);
?????????? }
?????? }
?????
?????? void delayms(uchar j)??? //延時(shí)子程序
?????? {
??????? uchar n,m;
??????? for(n=0;n ??????? {
???????? for(m=0;m<120;m++)?? //延時(shí)時(shí)間為1ms
???????? {;}
??????? }
?????? }
?????
?????? uchar getkey(void)????? //掃描取鍵值程序
?????? {
??????? uchar rcode,ccode;
??????? P1=0xf0;
??????? if((P1&0xf0)!=0xf0)
??????? {
???????? delayms(20);?? //為消除抖動(dòng)，延時(shí)20ms
???????? if((P1&0xf0)!=0xf0)
???????? {
????????? rcode=0xfe;?? //開始發(fā)行掃描信號(hào)
????????? while((rcode&0x10)!=0)
????????? {
???????? P1=rcode;
?????????? if((P1&0xf0)!=0xf0)
?????????? {
??????????? ccode=(P1&0xf0)|0x0f;
??????????? do{;}while((P1&0xf0)!=0xf0); //當(dāng)松鍵后顯示
??????????? return((~rcode)+(~ccode));??? //返回掃描代碼
?????????? }
?????????? else rcode=(rcode<<1)|0x01; //此行無鍵按下，變化行掃描信號(hào)
????????? }
???????? }
??????? }
??????? return 0;?? //無鍵按下，返回0
?????? }
?????
?????? void keydisp(uchar k)??? //顯示程序
?????? {
??????? switch(k)
??????? {
???????? case 0x11:disp(0);break;
???????? case 0x21:disp(1);break;
???????? case 0x41:disp(2);break;
???????? case 0x81:disp(3);break;
???????? case 0x12:disp(4);break;
???????? case 0x22:disp(5);break;
???????? case 0x42:disp(6);break;
???????? case 0x82:disp(7);break;
???????? case 0x14:disp(8);break;
???????? case 0x24:disp(9);break;
???????? case 0x44:disp(10);break;
???????? case 0x84:disp(11);break;
???????? case 0x18:disp(12);break;
???????? case 0x28:disp(13);break;
???????? case 0x48:disp(14);break;
???????? case 0x88:disp(15);break;
??? default:break;
??????? }
????? }
????
????? void disp(uchar l) //顯示子程序
????? {
?????? P0=table[l];
?????? delayms(20);
?????? P2=0x7f;?? //共陽極數(shù)碼管的位選碼
????? }

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