给初学单片机的40个实验-2(7)

MOVC A,@A+DPTR MOV P0,A

DK4A: MOV A,P3 ANL A,#0FH XRL A,#0FH JNZ DK4A NOKEY4: LJMP WAIT DELY10MS: MOV R6,#10

D1: MOV R7,#248 DJNZ R7,$ DJNZ R6,D1 RET

TABLE: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H DB 7FH,6FH,77H,7CH,39H,5EH,79H,71H END

7． C语言源程序

#include <AT89X51.H>

unsigned char code table[]={0x3f,0x06,0x5b,0x4f, 0x66,0x6d,0x7d,0x07, 0x7f,0x6f,0x77,0x7c, 0x39,0x5e,0x79,0x71}; unsigned char temp; unsigned char key; unsigned char i,j;

void main(void) {

while(1) {

P3=0xff; P3_4=0; temp=P3;

temp=temp & 0x0f; if (temp!=0x0f) {

for(i=50;i>0;i--) for(j=200;j>0;j--); temp=P3;

temp=temp & 0x0f; if (temp!=0x0f)