Servo motor control using AT89S52

Today we would like to control TowerPro MG996R servo motor using AT89S52,
Actually AT89S52 is not supported hardware PWM, so we needs use two timer to
simulation PWM.

 This's use breadboard

Here we use three buttons to control the Servo rotation, left button is let motor to rotate to 0 degree. middle button is let motor to rotate to 90 degree, and right button is let motor to rotate to 180 degree.

Here have three buttons according to control Servo to rotation

Schematic

Above video is show you the project I have press buttons each other, then the Servo motor will rotation according to the button.

#include <regx52.h>
#include <intrins.h>
#include <stdio.h>

//700us = 0 degree
//1.5ms = 90 degree
//2.5ms = 180 degree

void delay(unsigned int ms){
 unsigned long int us = ms*1000;
 while(us--){
  _nop_();
 }
}

void delay_us(unsigned int us){
 int i = 0;
 for(i=0; i<us;i++);
}

void delay_motor(unsigned int us){
 while(us--){
  _nop_();
 }
}

void time0() interrupt 1{
 // Using Time0 to delay 20ms
 TL0 = (65535 - 20000) & 0xFF;
 TH0 = ((65535 - 20000) & 0xFF00) >> 8;

  // Rotate to 0 degree
 if(P1_1){

   /*
  As normally 65535-500 is 0.5ms, it's should be rotate to 0 dgress.
  But I don't know why not roate to 0 degree,
  TL1 = (65535 - 700) & 0XFF;
  TH1 = ((65535 - 700) & 0xFF00) >> 8;
  */

   TL1 = (65535 - 700) & 0XFF;
  TH1 = ((65535 - 700) & 0xFF00) >> 8;
 }
 // Rotate to 90 degree
 if(P1_2){
  TL1 = (65535 - 1500) & 0XFF;
  TH1 = ((65535 - 1500) & 0xFF00) >> 8;
 }
 // Rotate to 180 degree
 if(P1_3){
  TL1 = (65535 - 2500) & 0XFF;
  TH1 = ((65535 - 2500) & 0xFF00) >> 8;
 }

  // Turn OFF the motor pin
 P1_0 = 1;

  // Turn ON Timer
 TR1 = 1;
}

void timer1() interrupt 3{
 //Turn ON the motor pin
 P1_0 = 0;
 TR1 = 0;
}


void main(){
 IE = 0x8A;
 TMOD = 0x11;

  TR0 = 1;
 TF0 = 1;

  P1_0 = 1;
 P1_1 = 1;
 P1_2 = 1;
 P1_3 = 1;

    while(1){

   if(P1_1){
   P0_1 = 0; //ON LED
   delay_us(922*5);
   P0_1 = 1;
   delay_us(922*5);
  }

   if(P1_2){
   P0_2 = 0; //ON LED
   delay_us(922*5);
   P0_2 = 1;
   delay_us(922*5);
  }
  
  if(P1_3){
   P0_3 = 0; //ON LED
   delay_us(922*5);
   P0_3 = 1;
   delay_us(922*5);
  }

    }
}