Hello...

Am interfacing the matrix keypad 4 * 4 to 8052, i have to taken three ports two ports for row n col and last one to display in seven segment but am not getting any thing on seven segment and i checked the signal at the Last port ( i.e one which has given to seven seg ) but there is no signal coming..i don't know wats wrong in my code..plz see my code and tel me wat r my mistakes..

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This is my code :
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# include <reg51.h>
# include <stdio.h>

# define ROW P1
# define COL P2
# define SEVEN_SEG P3

char keypad [4][4] = { 0, 1, 2, 3,
4, 5, 6, 7,
8, 9, 10, 11,
12, 13, 14, 15 };

char seven_seg [ ] = { 0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x69, 0x6f, 0x79, 0x63, 0xc7, 0x77, 0x63 };


void main ( ) {
char temp, row, col, count;
ROW = 0x0F;
COL = 0x00;
SEVEN_SEG = 0x00;

while ( 1 ) {
COL = 0x0F;
ROW = 0x00;
while ( !( ROW & 0x0F ) );
for ( temp = 0x01, count = 0; temp <= 0x08; temp <<= 1, count++ )
if ( temp & ROW ) {
row = count ;
break;
}
/*for ( temp = 0x01, count = 0; count < 4; temp <<=1, count++ )
if ( temp & COL ) {
col = count;
break;
} */

for ( COL = 0x01, temp = 0x01, col = count = 0; temp <= 0x08; COL = (temp <<= 1), count++ )
if ( row & ROW ) {
col = count;
break;
}

temp = keypad [row][col];
SEVEN_SEG = seven_seg [temp];
}
}