How to interface keypad with 8051 microcontroller (AT89C51)

[nikhil]

In the project-how to interface keypad with 8051(AT89C51) there is a code given for displaying 1-9,0,# & *…………..so if i want to display more nos. lyk 1- 99 wat modifications i hav to do in the code?……………..also i need help  to interface seven segment display and keypad with AT89C51 to display 1-99 nos…….i need it..

[Qaisar]

 

interfacing 2 dig seven segment display with 89C51

 

Compiler:  Keil

Simulator: Proteus

 

C Code:

 

 

#include <AT89X51.H>

unsigned char unit1 = 0;
unsigned char tens1 = 0;

char e = 0;

unsigned char font[10] = 0;

void delay(void)
{
 int i = 0;

 for(i = 0; i < 300; i++)
 {
 
 }
}

void mux(void)
{
int i = 0;

 for(i = 0; i < 100; i++)
 {

 P2 = unit1;
 P1_0 = 0;
 delay();
 P1_0 = 1;

 P2 = tens1;
 P1_1 = 0;
 delay();
 P1_1 = 1;

 

}
}

void decode(void)
{
 unit1 = e % 10;
 tens1 = (e % 100) / 10;

 unit1 = font[unit1];
 tens1 = font[tens1];

}

 

void main(void)
{

// 7 seg (CC) equivalent codes
font[0] = 0x3f;
font[1] = 0x06;
font[2] = 0x5b;
font[3] = 0x4f;
font[4] = 0x66;
font[5] = 0x6d;
font[6] = 0x7d;
font[7] = 0x07;
font[8] = 0x7f;
font[9] = 0x6f;

 while(1)
 {

  e++;
  if(e == 100)
  {
  e = 0; 
  }
  decode(); 
  mux();

  
 }
}

[Qaisar]

wysiwyg_imageupload:2500:

[Qaisar]

 

 

interfacing keypad and seven segment with 89C51

 

C Code:

//////////////////////////////////////////////////////////////////////////

 

#include <AT89X51.H>
#include <my.h>   //delay built in function

#define led P1_0

char unit, tens,e = 0;

char scan (void);

 

#define row1 P3_0
#define row2 P3_1
#define row3 P3_2
#define row4 P3_3

 

#define col1 P3_4
#define col2 P3_5
#define col3 P3_6
#define col4 P3_7 

 

unsigned char ch = 0;
unsigned int ar[1] = 0;
unsigned int font[10];
unsigned char counter = 0;

 

void decode(void)
{
 unit = e % 10;
 tens = (e % 100) / 10;

 unit = font[unit];
 tens = font[tens];
 

}
 void display(void)
{
 int i = 0;

 for(i = 0; i < 100; i++)
 {

 P0 = unit;
 P2_1 = 0;
 delay(1);
 P2_1 = 1;

 P0 = tens;
 P2_0 = 0;
 delay(1);
 P2_0 = 1;

 

}}

 

void main (void)
{               // 7 seg equivalent code

    font[0] = 0x3f;
    font[1] = 0x06;
    font[2] = 0x5b;
    font[3] = 0x4f;
    font[4] = 0x66;
    font[5] = 0x6d;
    font[6] = 0x7d;
    font[7] = 0x07;
    font[8] = 0x7f;
    font[9] = 0x6f;

while(1)
{
decode();
display();

 ch = scan();
 
 if(ch != 100)
 {
  if(ch == 13)  // % symbol in keypad causes reset
  {
   e = 0;
   counter= 0;
   
  }
  if(ch < 10)
  {
   e = ch;
   
   if(counter < 2)
   {
    ar[counter] = ch;
    counter++;

    if(counter == 2)
    {
     e = ar[0] * 10;
     e = e + ar[1];

     decode();
     display();
     counter = 0;
}}

}}}  }
 

 

 

char scan (void)

{
row1 = 0;
row2 = 1;
row3 = 1;
row4 = 1;

col1 = 1;
col2 = 1;
col2 = 1;
col4 = 1;

 
if (col1 == 0)
{
led = 1;
delay(100);
led = 0;
return 1;
}

if (col2 == 0)
{
led = 1;
delay(100);
led = 0;

return 2;
}

if (col3 == 0)
{
led = 1;
delay(100);
led = 0;

return 3;
}

if (col4 == 0)
{
led = 1;
delay(100);
led = 0;

return 13;
}

 

row1 = 1;
row2 = 0;

if (col1 == 0)
{
led = 1;
delay(100);
led = 0;

return 4;
}

if (col2 == 0)
{
led = 1;
delay(100);
led= 0;

return 5;
}

if (col3 == 0)
{
led = 1;
delay(100);
led = 0;

return 6;
}

if (col4 == 0)
{
led = 1;
delay(100);
led = 0;

return 14;
}

 

row2 = 1;
row3 =0;

if (col1 == 0)
{
led = 1;
delay(100);
led = 0;

return 7;
}

if (col2 == 0)
{
led = 1;
delay(100);
led = 0;

return 8;
}

if (col3 == 0)
{
led = 1;
delay(100);
led = 0;

return 9;
}

if (col4 == 0)
{
led = 1;
delay(100);
led = 0;

return 15;
}

 

row3 = 1;
row4 = 0;

if (col1 == 0)
{
led = 1;
delay(100);
led = 0;

return 11;
}

if (col2 == 0)
{
led = 1;
delay(100);
led = 0;

return 0;
}

if (col3 == 0)
{
led = 1;
delay(100);
led = 0;

return 12;
}

if (col4 == 0)
{
led = 1;
delay(100);
led = 0;

return 16;
}

row4 = 1;

return 100;
}

 

wysiwyg_imageupload:2503:

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