Keypad Interfacing with 8051 Program

#include<reg51.h>

void lcd_cmd(char);
void lcd_init();
void lcd_data(char);
void delay(int);

sbit rs=P2^0;
sbit oe=P2^1;

void column1();
void column2();
void column3();
char getkey();

sbit c1=P1^0;
sbit c2=P1^1;
sbit c3=P2^2;
sbit r1=P2^3;
sbit r2=P2^4;
sbit r3=P2^5;
sbit r4=P2^6;

int x,y;
char num[4][3]={{'1','2','3'},
                {'4','5','6'},
       {'7','8','9'},
       {'*','0','#'}};
void main()
{
char c;

Token System Program for 8051

#include<reg51.h>

void lcd_cmd(char);
void lcd_init();
void lcd_data(char[]);
void delay(int);
void lcd_dataint(int);

void counter1();  //to print the count value at counter1 location
void counter2();                                     //(on lcd)
void counter3();

sbit rs=P2^4;
sbit oe=P2^0;
sbit but1=P2^1;   //counter1 button 
sbit but2=P2^2;   //counter2 button
sbit but3=P2^3;   //counter3 button

int token_no=0;   //overall count 

void main()
{
   rs=0;
   oe=0;
   but1=1;but2=1;but3=1;
   TMOD=0x01;
   lcd_init();
   lcd_data("C1    C2    C3  ");

Simple ELEVATOR program for 8051

#include<reg51.h>
#include"lcd_display.h"

sbit ON = P1^0;
sbit floor1 = P1^1;
sbit floor2 = P1^2;
sbit floor3 = P1^3;
sbit dooropen = P1^4;

sbit motorF = P2^0;
sbit motorR = P2^1;
sbit motor_en = P2^3;
sbit led_doorOpen = P2^2;
sbit ON_led = P2^4;

void delay_sec(int);

short int PresentLevel = 0, RequestLevel;


void main()
{
motorF = motorR = led_doorOpen = motor_en = ON_led = rs = en = 0;
ON = floor1 = floor2 = floor3 = dooropen = 1;



TMOD = 0x01;
P3=0x00;
lcd_init();
motor_en=0;

Wired ROBO car Program for 8051

/* wired robo car program for 8051 microcontroller

 design description:;: contains two motors one on left(ml) and one on right(mr)::contains headlights and backlights::moreover this is wired robo car (not wireless) */

#include<reg51.h>

sbit mr_p = P2^0;      //motor_right_positive
sbit mr_n = P2^1;      //motor_right_negetive
sbit ml_p = P2^2;      //motor_left_positive 
sbit ml_n = P2^3;      //motor_left_negetive
sbit leds_front = P2^4;
sbit en_mr = P2^6;     //motor_right_enable
sbit en_ml = P2^7;     //motor_left_enable
sbit led_backL = P3^0;
sbit led_backR = P3^1;

sbit head_lights = P1^6;    //inputs
sbit key = P1^5;
sbit fw = P1^0;
sbit re = P1^1;
sbit left = P1^2;
sbit right = P1^3;
sbit stop = P1^4;

void main()
{
  int i;  

  fw = re = left = right = stop = head_lights = key = 1;
  mr_p = mr_n = ml_p = ml_n = leds_front = en_mr = en_ml = 0;
  led_backL = led_backR = 0;
  

Electronic Voting Machine

#include<reg51.h>


void nominee(char[],int);

void lcd_cmd(char);
void lcd_init();
void lcd_data(char[]);
void delay(int);
void lcd_dataint(int);
void results();

sbit start=P1^0;
sbit n1=P1^1;
sbit n2=P1^2;
sbit n3=P1^3;
sbit rs=P2^0;
sbit oe=P2^1;
sbit again=P1^4;
sbit result=P1^5;

int nom[3]={0,0,0};
int overallC=0,permission=0;

     
  void main()
   {
     n1=n2=n3=start=1;
     oe=rs=0;
     P3=0x00;
     TMOD=0x01;

understanding getch(), getche() and getchar() in C

/* program to understand the getch(), getche() and getchar() differences */

//note that these three functions are for getting character from the cosole only but they differ the way they take

#include<stdio.h>
#include<conio.h>
void main()
{
char ch[2],op;
int i=0;
clrscr();
while((i++)<=2)      //just i am rotating this for 3 times
{
printf("\na.getch() \nb. getche() \nc.getchar()\n\t");
puts("enter your option");
ch=getche();

switch(op)
{
case 'a': puts("\nenter char");
ch[0]=getch();      //here character entered is stored but not displayed on console
break;                                             
case 'b':puts("\nenter char");      
ch[1]=getche();   //here char entered is taken(no need to press enter) and displayed on console
break;                                          
case 'c': puts("\nenter char");
ch[2]=getchar();           //here character entered is displayed on console and
break;                           //entered char is stored only after pressing 'enter key'

}
}
printf("\nstored values are %s",ch);
getch();
}

C program for Decoding an Encoded file

/*program to decode an encoded file and storing decoded data into an another file */

#include<stdio.h>
void main()
{
int d,i;
char c;
FILE *fp1,*fp2;
clrscr();
fp1=fopen("resume_e.txt","r");           //open same encoded file in previous post
fp2=fopen("dec_resume.txt","w");

while((c=fgetc(fp1))!=EOF)      
{
d=c;
d=d-30;                     //here you should use the same value ie., in the previous
c=d;                            //post I used d=d+30 so here i should use d=d-30;
fputc(c,fp2);
puts("processing...");              
}
clrscr();
fclose(fp1);
fclose(fp2);
puts("decoding is over");
getch();
}