51单片机 矩阵

unsigned char key()

{

unsigned char keyNum;

P1=0xFF;

P1_7=0;

if(P1_3==0){Delay(20);while(P1_3==0);Delay(20);keyNum=1;}

if(P1_2==0){Delay(20);while(P1_2==0);Delay(20);keyNum=2;}

if(P1_1==0){Delay(20);while(P1_1==0);Delay(20);keyNum=3;}

if(P1_0==0){Delay(20);while(P1_0==0);Delay(20);keyNum=4;}

P1_6=0;

if(P1_3==0){Delay(20);while(P1_3==0);Delay(20);keyNum=5;}

if(P1_2==0){Delay(20);while(P1_2==0);Delay(20);keyNum=6;}

if(P1_1==0){Delay(20);while(P1_1==0);Delay(20);keyNum=7;}

if(P1_0==0){Delay(20);while(P1_0==0);Delay(20);keyNum=8;}

P1_5=0;

if(P1_3==0){Delay(20);while(P1_3==0);Delay(20);keyNum=9;}

if(P1_2==0){Delay(20);while(P1_2==0);Delay(20);keyNum=10;}

if(P1_1==0){Delay(20);while(P1_1==0);Delay(20);keyNum=11;}

if(P1_0==0){Delay(20);while(P1_0==0);Delay(20);keyNum=12;}

P1_4=0;

if(P1_3==0){Delay(20);while(P1_3==0);Delay(20);keyNum=13;}

if(P1_2==0){Delay(20);while(P1_2==0);Delay(20);keyNum=14;}

if(P1_1==0){Delay(20);while(P1_1==0);Delay(20);keyNum=15;}

if(P1_0==0){Delay(20);while(P1_0==0);Delay(20);keyNum=16;}

return keyNum;

}