Interfacing 7-Segment to Arduino

 

Aim:

The main aim of this project is how to interface 7-segment and display 0 to 99 values on 7-segments.

Description:

Introduction

Till now you have learn what is an embedded system, basic memory architecture of a microcontroller, how to implement assembly language and use of some softwares like pinnacle 52, keil-C and flash magic; we also have come across how to interface LEDs from a microcontroller and how to generate different pattern through it. now its time to move forward and learn one more step ahead towards the completion of our 6-weak training. so here today we will learn about 7-Segment display; How to interface and program it; and some of the applications of it.

 7-Segment Display

A 7-Segment display is a useful electronic component use to produce numeric, alphabetic and some non-alphabetic symbols using a specific arrangement of LEDs as shown in figure here.

A 7-Segment display has 10-Pins representing each a, b, c, b, e, f, gand h LEDs respectively along with two extra pins for GND andVSS. following shown an original 7-Segment display device along with its pin diagram. LED h is also denoted by symbol dp.

As we have studied in LED interfacing a 7-segment display is also interfaced in same way as it is also made of LEDs. So we can interface LEDs in three ways bu here difference is that 7-Segment displays comes in two types by manufacturers i.e. “Common Anode” and “Common Cathode“; the logics are shown in figure below.

and thus which logic is o implement is on the bases of these specifications provided by manufacturer.

Digit Drive Pattern:

To display the digits on 7 segment, we need to glow different logic combinations of segments. For example if you want to display the digit 3 on seven segment then you need to glow the segments a, b, c, d and g. 

Block Diagram

Schematic

Code

// ******************************************************
// Project: 0 to 99 display in 7-segments using Arduino
// Author: Hack Projects India
// Module description: Operate two 7-segments
// ******************************************************
int num_array[10][7] = {  { 1,1,1,1,1,1,0 },    // 0
                          { 0,1,1,0,0,0,0 },    // 1
                          { 1,1,0,1,1,0,1 },    // 2
                          { 1,1,1,1,0,0,1 },    // 3
                          { 0,1,1,0,0,1,1 },    // 4
                          { 1,0,1,1,0,1,1 },    // 5
                          { 1,0,1,1,1,1,1 },    // 6
                          { 1,1,1,0,0,0,0 },    // 7
                          { 1,1,1,1,1,1,1 },    // 8
                          { 1,1,1,0,0,1,1 }};   // 9
                                       
//function header
void Num_Write(int);

void setup() 
{ 
  // set pin modes
  pinMode(2, OUTPUT);   
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  
 
}

void loop() 
{
  
  //counter loop
  
  for (int counter1 = 0; counter1 < 10; counter1++) 
  {
    for (int counter2 = 0; counter2 < 10; counter2++) 
    {
     delay(20);
     digitalWrite(10,LOW);
     digitalWrite(11,HIGH);
     Num_Write(counter1); 
     delay(50);
     digitalWrite(11,LOW);
     digitalWrite(10,HIGH);
     Num_Write(counter2); 
    }
  }
  delay(3000);
}

// this functions writes values to the sev seg pins  
void Num_Write(int number) 
{
  int pin= 2;
  for (int j=0; j < 7; j++) {
   digitalWrite(pin, num_array[number][j]);
   pin++;
  }
}

Downloads:

The code was compiled in Keil uvision4 and simulation was made in Proteus v7.7.
To download code and proteus simulation click here.

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