Neeed Coding and schematic fort a 4 x 4 keypad interfacing with PIC microcontroller

[bskumar7080]

Hi all,

Need a schematic and coding for 4 x 4 keypad interfacing with PIC18F452 microcontroller


thanks and regards

 

[ansarmytheen]

Dear friend,

look mikroc help key pad interface.

 

[lockman_akim]

i think will this will help even it use 16f77A..
what u need to know is how to connect the keypad to pic rite?

 

[cool.man]

you can call this function from the main routine to scan keypad.
No need for pull up resistors in this scheme.

int readkeypad (void)
{
 output_bit (r1, 0);
 output_bit (r2, 0);
 output_bit (r3, 0);
 output_bit (r4, 0);
 output_bit (r1, 1);//activate 1st row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 10;
 IF (input (c2)) RETURN 0;
 IF (input (c3)) RETURN 11;
 //IF (input (c4)) RETURN 12;
 output_bit (r1, 0);//Deactivate 1st row
 output_bit (r2, 1);//activate 2nd row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 7;
 IF (input (c2)) RETURN 8;
 IF (input (c3)) RETURN 9;
 //IF (input (c4)) RETURN 13;
 output_bit (r2, 0);//Deactivate 2nd row
 output_bit (r3, 1);//activate 3rd row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 4;
 IF (input (c2)) RETURN 5;
 IF (input (c3)) RETURN 6;
 IF (input (c4)) RETURN 14;
 output_bit (r3, 0);//Deactivate 3rd row
 output_bit (r4, 1);//activate 4th row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 1;
 IF (input (c2)) RETURN 2;
 IF (input (c3)) RETURN 3;
 IF (input (c4)) RETURN 15;
 output_bit (r4, 0);//Deactivate 4th row
 RETURN 255;
}

 

[akoangsimula]

hi..
how to use 4x3 keypad interfacing in zilog...thanks

 

[Th3r4p1sT]

here is. i wrote a second ago.
https://www.edaboard.com/threads/191625/