Keypad Interfacing with Seven Segment Display Through 8051 Microcontroller-7 Segment Display Code in C Programming

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Keypad Interfacing with seven segment display through 8051 microcontroller

INTRODUCTION:

  • This project corporates the simple interfacing between the popular 4 x 4 keypad matrix with a single seven segment display in order to manually input numbers or ASCII characters on the seven segment display.
  • Here the idea is to display any letter on the 7 segment display according to the keypad pressed.
  • In this way we can manually display string of characters or numbers.

Which is the idea after all.

KEYPAD MATRIX:

  • The keypad matrix is used for interfacing with the seven segment .
  • It is 3 x 3 matrix keypad with each key having a specific value as designed by the programmer.
  • Alternatively a keypad predefined with symbols can also be interfaced with the seven segment display through 8051 microcontroller board.

SOURCE CODE:

#include<reg51.h>

sbit R0= P1^0;

sbit R1= P1^1;

sbit R2= P1^2;

sbit R3= P1^3;

sbit C0= P1^4;

sbit C1= P1^5;

sbit C2= P1^6;

void seg(unsigned int);

void main()

{

R0=R1=R2=R3=1;

R0=0;

if (C0==0)

seg(0xF9);

R0=R1=R2=R3=1;

R1 =0;

if (C1 ==0)

 seg(0xA4);

R0=R1=R2=R3=1;

R2=0;

if(C2 == 0)

 seg (0xB0);

R0=R1=R2=R3=1;

R1=0;

if(C0== 0 )

seg (0x99);

R0=R1=R2=R3=0;

R1 = 0;

if (C1==0)

seg(0X92);

R0=R1=R2=R3=0;

R1 = 0;

if (C2==0)

seg(0X82);

R0=R1=R2=R3=0;

R2 = 0;

if (C0==0)

seg(0XF8);

R0=R1=R2=R3=0;

R2 = 0;

if (C1==0)

seg(0X80);

R0=R1=R2=R3=0;

R2 = 0;

if (C2==0)

seg(0X90);

R0=R1=R2=R3=0;

R3 = 0;

if (C1==0)

seg(0XC0);

}

void seg (unsigned int ch)

{

P2=0x00;

P2 = ch;

}

Proteus simulation program:

Explanation:

  • Here there are  three seven segment displays interfaced with the hex keypad through 8051.
  • By using proteus simulation diagram we can pre predict whether the circuit is working or not.
  • When different keypads are switched the corresponding number is displayed(0- 9 range).

CONNECTION DIAGRAM:

WORKING:

  • Initially the microchip is placed onto the ACP slot after dumping the code in it.
  • A 9V  power supply is used to power up the circuit on desire.
  • Then the 9th pin  of the microcontroller is connected to the 5V supply before powerup of the circuit.
  • After powering on the circuit the reset pin is connected to ground.
  • Whereas the four rows (R0 – R3) are connected to corresponding pins of Port 1 of ATS9852 microcontroller chip as well as the three columns (C0 – C2).
  • Secondly the channel port, in this case is the Port 2 of the microcontroller.
  • The port 2 is interfaced with the 8 segments(a-g and h for decimal) of single seven segment display component.
  • Finally the common pins of the seven segment can be either shorted and given a separate 5v connection or just one common pin can be connected to ground if reset pin is given to 5V pin on the board.

CONNECTION VIDEO:

Click here to see the video.