Interfacing of seven segment display with pic16F877A microcontroller

4 digit up counter using seven segment display on PIC16f877A

Introduction

Write a program forInterfacing of seven segment display with pic16F877A microcontroller using mikroC Pro. In this tutorial, I will guide you how to create a first project on mikroC Pro software for designing a counter using PIC16F877A microcontroller. First mikroC Pro code simulations will be shown. For checking the result PROTEUS simulations will also be shown. Finally I will show the results on PIC development board.

Basic components of the circuit involved

In this tutorial deign of 4 digit UP counter will be explained. The major components involved are mentioned below

  1. 4-digit seven segment display
  2. PIC16F877a Microcontroller
  3. Crystal Oscillator
  4. Bread Boar
  5. Supply Voltages.
  6. PICKit 3 debugger

If you are using a PIC development board, then you can easily write and test your program.

Description of Components

PICkit3 Programmer

In order to import the HEX file we need a programmer or burner that will actually transfer code to the ROM of microcontroller.

 

PICkit 3 programmer
PICkit 3 programmer

Here is the description of PinOut of PicKit 3

PicKit3 Pin Out
PicKit3 Pin Out

Pins connections of PICkit3 with PIC Microcontroller

Pins connections of PICkit3
Pins connections of PICkit3

There are three LEDs and a button on its front face. These LEDs have specific meaning and are named as

  • Power LED: It lights up when PICkit 3 receives power.
  • Active LED: If PICkit 3 establishes a connection with PC properly then it will light up the active LED.
  • Status LED: It lights up yellow when PICkit3 is busy in writing program to the controller.

Seven Segment Display

Since the task is to design a 4 digit UP counter, that’s why there is a need of 4 digit seven segment display.  Before learning how to use it let us first learn about the seven segment display.

What is the seven segment display?

A seven segment display is used for displaying the decimal numbers/digits form 0 to 9. There are 8 LED, 7 of which are used for displaying the digit/number while the eight one is used for displaying the dot in case of a decimal number.

seven segment
seven segment

So with this arrangements of LED, any number ranging from 0 to 9 can be displayed.

There are two types of seven segments.

  • Common Anode
  • Common Cathode

Common Anode Seven Segments displays

In these seven segments displays all the anodes of LEDs are tied together just like shown below and we need to apply separate signals at the cathode terminals for turning ON/OFF the particular LED. As we know that we can turn ON an LED if anode to cathode potential is High (+5V). Here anode is connected to +5V or Vcc and cathode is tied to 0v if we want to turn ON any particular LED.

common anode 7 segment display
common anode 7 segment display

 

Common Cathode Seven Segments displays

In this type all the cathodes are tied together and hence we need to apply 0V or GND to this common terminal while any pin (a,b,c,d,e,f,g) will be connected to high logic level (+5V) in order to turn it ON.

common cathode seven segment display
common cathode seven segment display

Lets see how these arrangements help to display a number

seven segment numbers
seven segment numbers

Code for 4 digit counter in C language

This code can be run either on MPLAB or MikroC Pro. For the time being I am using MikroC Pro as it is eay to configure. In this Project PORTB is used for connecting pins of seven segment display while PORTD last 4 pins (4,5,6,7) are used for selecting the segments. (S1,S2,S3,S4). As I have used common anode seven segment display thats why I have used the following sequence of Hex values for displaying the numbers. The Table Shows the exact values.

Numbers Hex values
0 0xFC
1 0x60,
2 0xDA
3 0xf2
4 0x66
5 0xb6
6 0xbe
7 0xe0,
8 0xfe
9 0xf6

 

#define segone   0x10 //for selecting D4

#define segtwo   0x20 //for selecting D5

#define segthree 0x40//for selecting D6

#define segfour  0x80 //for selecting D7

 

void delay_ms(unsigned int ms_count)

{

unsigned int i,j;

for(i=0;i<ms_Count;i++)

{

for(j=0;j<1000;j++);

}

}

int main() {

char seg_code[]={0xFC,0x60,0xDA,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6,0x77,0x7C,0x39,0x5E,0x79,0x71};

int cnt, num, temp,i;

/* Configure the ports as output */

TRISB = 0x00; // Data lines

TRISD = 0x00; // Control signal PORTD0-PORTD3

while (1)

{

for (cnt = 0x00; cnt <= 9999; cnt++) // loop to display 0-9999

{

for (i = 0; i < 100; i++)

{

num = cnt;

temp = num / 1000;

num = num % 1000;

PORTD = segfour;

PORTB = seg_code[temp];

delay_ms(1);

 

temp = num / 100;

num = num % 100;

PORTD = segthree;

PORTB = seg_code[temp];

delay_ms(1);

temp = num / 10;

PORTD = segtwo;

PORTB = seg_code[temp];

delay_ms(1);

temp = num % 10;

PORTD = degone;

PORTB = seg_code[temp];

delay_ms(1);

}

}

}

}

 

Proteus Simulations for the seven segment UP counter

Also read here

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