dc motor speed control

delay.c

#include<reg51.h>
void delay_us(unsigned int us_count)
 {  
    while((us_count*4)!=0)
      {
         us_count--;
       }
   }

delay.h

#ifndef delay_H
#define delay_H
void delay_us(unsigned int us_count);
#endif

main.c

/*
Four quad motor speed controller

8051 and L293D , need LCD as well

Clock Wise
Anti clock wise
forward brake
reverse brake
Speed Control,Speed control is done using PWM

LCD is connected to port 2
Register select pin connected to P2.0
Read Write pin connected to P2.1
Enable pin connected to P2.2
Hiher 4 bits of P2 to the Higher 4 bits of LCD (P2.4 to D4 ...)

Switches - port 1
p1.0 - clock wise
p1.1 - Anti clokc wise
P1.2 - Break Clockwise
P1.3 - Break anti clokc wise
P1.4- Speed increase
P1.5- Speed decrease

L293D

in1 - p0.7
in2 - p0.6
enable -p0.5

TMOD - Timer mode
Gate -0,
mode 1, (M0-0,M1-1)

TCON- timer control
TR0, timer 0 run control bit, set 1 to start the timer,0 to stop the timer
TL0,TH0,TL1,TH1
*/
#include <reg51.h>
#include "lcd.h"
#include "delay.h"

sbit c=P1^0;
sbit ac=P1^1;
sbit bc=P1^2;
sbit bac=P1^3;
sbit si=P1^4;
sbit sd=P1^5;

sbit m1_p=P0^7 ; //motor 1 positive
sbit m1_n=P0^6 ;//motor 1 negative
sbit m1_c=P0^5; //motor 1 control (enable)
float speed=100; //(0 to 100)
float cnst=6000;
int break_delay=1000;


//motor control functions
void m1_stop(){
	m1_p=0;
	m1_n=0;
}
void m1_clock(){
   m1_p=1;
   m1_n=0;
}
void m1_antiClock(){
  m1_p=0;
  m1_n=1;
}

void m1_break_clock(){
	int i=0;
	m1_antiClock();
	for(i=0;i<break_delay;i++);
    m1_stop();
}
void m1_break_antiClock(){
	int i=0;
	m1_clock();
	for(i=0;i<break_delay;i++);
    m1_stop();
}

void checkKeyBoard(){//by default all keys are high
	if(!c){
		m1_clock();
        LCD_Clrscr();
	    LCD_DisplayString("Dir: Clock");
	    LCD_Gotoxy(0,1);
	    LCD_DisplayString("Speed: ");
	    LCD_DisplayNumber(speed);
	}
	else if(!ac){
	   m1_antiClock();
        LCD_Clrscr();
	    LCD_DisplayString("Dir: AntiClock");
	    LCD_Gotoxy(0,1);
	    LCD_DisplayString("Speed: ");
	    LCD_DisplayNumber(speed);	
	}
	else if(!bc){
	    m1_break_clock();
        LCD_Clrscr();
	    LCD_DisplayString("Dir: fwd break");
	    LCD_Gotoxy(0,1);
	    LCD_DisplayString("Speed: ");
	    LCD_DisplayNumber(speed);		
	}
	else if(!bac){
		m1_break_antiClock();
        LCD_Clrscr();
	    LCD_DisplayString("Dir: Rvr Break");
	    LCD_Gotoxy(0,1);
	    LCD_DisplayString("Speed: ");
	    LCD_DisplayNumber(speed);	
	}
	else if(!si){
		speed++;
		if(speed>100){
			speed=100;
		}
    	LCD_Gotoxy(0,1);
	    LCD_DisplayString("Speed: ");
	    LCD_DisplayNumber(speed);		
	}
	else if(!sd){
		if(speed>0){
		  speed--;
	    }
	    LCD_Gotoxy(0,1);
	    LCD_DisplayString("Speed: ");
	    LCD_DisplayNumber(speed);		   
	}

}



int main(){
int pwm_1,pwm_0;
  //switch of the motor
  m1_c=0;
	m1_stop();
	LCD_Init();
	LCD_Clrscr();
	LCD_DisplayString("--welcome--");

	while(1){
		//LCD_Gotoxy(0,1);
		//LCD_Clrscr();
     pwm_1= (int)(cnst*(speed/100.0));
     pwm_0= (int)(cnst*((100-speed)/100.0));
     m1_c=1;
	 //LCD_DisplayNumber(pwm_1);
	 //LCD_DisplayString(",");
	 delay_us(pwm_1);
     m1_c=0;
	 //LCD_DisplayNumber(pwm_0);
	 delay_us(pwm_0);
     checkKeyBoard();	
}}