C51 program for simulating RS232 serial communication with microcontroller IO port

#include "reg52.h"
#include "intrins.h"  
#include "math.h"     
#include "stdio.h"
sbit BT_SND =P1^5;
sbit BT_REC =P1^6;
sbit LED =P1^7;
bit LED_flage=1;
//MCU IO port simulates 232 serial port communication program
//C program using two methods to occupy timer 0
#define MODE_QUICK
#define F_TM F0
#define TIMER0_ENABLE TL0=TH0; TR0=1;
#define TIMER0_DISABLE TR0=0;
sbit ACC0= ACC^0;
sbit ACC1= ACC^1;
sbit ACC2= ACC^2;
sbit ACC3= ACC^3;
sbit ACC4= ACC^4;
sbit ACC5= ACC^5;
sbit ACC6= ACC^6;
sbit ACC7= ACC^7;

void IntTimer0() interrupt 1
{
  F_TM=1;
}
//Send a character
void PSendChar(unsigned char inch)
{
 #ifdef MODE_QUICK
    ACC=inch;
    F_TM=0;
    BT_SND=0; //start bit
    TIMER0_ENABLE; //Start
    while (!F_TM);
    BT_SND=ACC0; //Send the low bit first
    F_TM=0;
    while(!F_TM);
    BT_SND=ACC1;
    F_TM=0;
    while(!F_TM);
    BT_SND=ACC2;
    F_TM=0;
    while(!F_TM) );
    BT_SND=ACC3;
    F_TM=0;
    while(!F_TM);
    BT_SND=ACC4;
    F_TM=0;
    while(!F_TM);
    BT_SND=ACC5;
    F_TM=0;
    while(!F_TM);
    BT_SND=ACC6;
    F_TM= 0;
    while(!F_TM);
    BT_SND=ACC7;
    F_TM=0;
    while(!F_TM);
    BT_SND=1;
    F_TM=0;
    while(!F_TM);
    TIMER0_DISABLE; //Stop timer
    #else
    unsigned char ii;
     ii=0;
     F_TM=0;
     BT_SND= 0; //start bit
     TIMER0_ENABLE; //Start
     while(!F_TM);
     while(ii<8)
 {
   if(inch&1)
  {
   BT_SND=1;
  }
  else
  {
   BT_SND=0;
  }
   F_TM=0;
 while(!F_TM) ;
   ii++;
  inch>>=1;
    }
  BT_SND=1;
  F_TM=0;
  while(!F_TM);
    #endif
    TIMER0_DISABLE; //Stop timer
 }
//Receive a character
unsigned char PGetChar()
{
 #ifdef MODE_QUICK
 TIMER0_ENABLE;
 F_TM =0;
 while(!F_TM); //Wait until the start bit
 ACC0=BT_REC;
 TL0=TH0;
 F_TM=0;
 while(!F_TM);
 ACC1=BT_REC;
 F_TM=0;
 while(!F_TM);
 ACC2=BT_REC;
 F_TM =0;
 while(!F_TM);
 ACC3=BT_REC;
 F_TM=0;
 while(!F_TM);
 ACC4=BT_REC;
 F_TM=0;
 while(!F_TM);
 ACC5=BT_REC; 
 F_TM=0;
 while(!F_TM) ;
 ACC6=BT_REC; 
 F_TM=0;
 while(!F_TM);
 ACC7=BT_REC;
 F_TM=0;
 while(!F_TM)
    {
  if(BT_REC)
  {
    break;
  }
    }
 TIMER0_DISABLE; //Stop timer
 return ACC;
 #else
 unsigned char rch,ii;
 TIMER0_ENABLE;
 F_TM=0;
 ii=0;
 rch=0;
 while(!F_TM); //Wait for the start
 bitwhile(ii<8)
    {
     rch>>=1;
  if(BT_REC)
  {
  rch|=0x80;
  }     
  ii++;
  F_TM=0;
  while(!F_TM); 
    }
 F_TM=0;
  while(!F_TM)
    {
  if(BT_REC)
  {
     break;
  }
    }
 TIMER0_DISABLE; //Stop timer
 return rch;
 #endif
}
//Check if there is a start
bit StartBitOn()
{
  return (BT_REC==0);
}
//Timer 1 initialization
void Time1_Init(void)
{
   TMOD=0x22; //Timer 1 is working mode 2 (8-bit automatic reload), 0 is mode 2 (8-bit automatic reload) 
   PCON=00;
   TR0=0; //Start using it when sending or receiving
   TF0=0;
   TH0=(256-96); //9600bps means the timer is executed in 1000000/9600=104.167 microseconds//104.167*11.0592/12= 96
   TL0=TH0;
   ET0=1;
   EA=1;
}
//Send string
void Send_Char(char *byte)
{
   int i=0;
   for(i=0;*(byte+i)!='';i++)
   {
      PSendChar(*(byte+i));
   }
}
//void delay(int x)
//{
// int a,b;
// for(a=x;a>0;a--)
// for(b=10;b>0;b--); 
//}
//void main()
//{
// unsigned char gch;
// Time1_Init();
// LED=0;
// // Send_Char("S00.0C00.0%E00.0C00.0%L00000lx");
// while(1)
// {   
//      
// PSendChar('1');
// delay(1000);
//// if(StartBitOn())
//// {
//// gch=PGetChar();
//// if(gch=='1')
//// {
//// LED=LED_flage;  
//// delay(1000);
//// LED_flage=~LED_flage;
//// } 
////  
//// } 
//    
// }    
//
//}