các pro giúp minh ý nghĩa mấy dòng code này với ^^

[rikilo1234]

pro nào giúp mình biết ý nghĩa của mấy dòng code này với.
Mình đọc mà hiểu ko hết, cái này mình chỉ mới học còn gà lắm, phiền các pro giúp mình chi tiết 1 chút nhé!!
thanks nhìu

#include <AT89x52.h>
#include <Delay.h>
#include "intrins.h"

#define	dataso		P1_0  
#define	clockso 	P1_1    	
#define latchso		P1_2   


#define SDA			P0_0             
#define SCL			P0_1

#define  On    		1             
#define  Off   		0

// DS1307
#define	psec		0x00    
#define	pmin 		0x01
#define	phour    	0x02
#define	pday    	0x03
#define	pdate		0x04
#define	pmonth		0x05
#define	pyear		0x06
#define	pcontrol   	0x07

#define stbangso	10
#define soled 	10		

unsigned char idata buffht[soled];
	
unsigned char tam1=0,tam2=0,tam3=0,tam4=0,tam5=0,tam6=0;
unsigned char i,adr_so,chiso,dem;
unsigned char gio,phut,giay,ngay,thang,nam,ngay1,ngay2,bienngay1,bienngay2,bienngay3;
unsigned int num,bienngay;
bit nhapnhay = 0;
//============= RTC DS1307 ==================
//Dien giai tu day

void start(void)
{
	SCL=0;                     
	SDA=1;                     
	_nop_();_nop_();_nop_();   
	SCL=1;                      
	_nop_();_nop_();_nop_();   
	_nop_();_nop_();_nop_();   
	_nop_();_nop_();_nop_();   
	SCL=1;                     
  	SDA=0;                     
	_nop_();_nop_();_nop_();   
	SCL=0;                        
}
void stop(void)
{
	SCL=0;
	SDA=0;
	_nop_();_nop_();_nop_();
	SCL=1;
	_nop_();_nop_();_nop_();
	_nop_();_nop_();_nop_();
	_nop_();_nop_();_nop_();
	SCL=1;
  	SDA=1;
	_nop_();_nop_();_nop_();
	SCL=0;
}
bit write_data(unsigned char chr)
{ 
unsigned char temp,ack;
  	for(temp=0;temp<8;temp++)
    { 
		SDA = (chr & 0x80);//
      	SCL=1;             
      	SCL=0;             
      	chr=chr<<1;        
    }
  	SDA=1;
	SCL=1;
	ack=SDA;
  	SCL=0;  
  	return(ack);
}
unsigned char convertBCD(unsigned char _data)
{                                            
unsigned char temp;
  	temp=(_data/10<<4)|(_data%10&0x0F);
  	return temp;
}
unsigned char read_data(void) 
{                             
unsigned char temp1,temp2=0;
  	for(temp1=0;temp1<8;temp1++)
    { 
		SCL=1;
      	temp2=temp2<<1;
      	temp2=temp2|((unsigned char)(SDA));//temp2 =0x01, 
      	SCL=0;
    }		 // ra duoc 1 byte
  	return(temp2);
}
void write_RTC(unsigned char address, unsigned char _data)
{ 
bit status;
  	start();
  	write_data(0xD0);
  	write_data(address);
  	write_data(_data);
  	stop();
  	start();
  	status=write_data(0xD0);
  	while(status)
    { 
		start();
        status=write_data(0xd0);
     }                          
}                               
unsigned char read_RTC(unsigned char address)
{ 
unsigned char k;
  	start();
  	write_data(0xD0);
  	write_data(address);
  	start();
  	write_data(0xD1);
  	k=read_data();
  	stop();
  	return ((k>>4)*10+(k&0x0F));
}
unsigned char read_RTC_chuan(unsigned char address)
{ 
unsigned char k;
  	start();     
  	write_data(0xD0);
  	write_data(address);
  	start();  
  	write_data(0xD1); 
  	k=read_data();
  	stop();   
  	return k; 
}

//Ket thuc o day
//////End DS1307//////////
////////////////////////////////////////////
void  main (void) 
{                              
	P0=0xff;
	P1=0x00;
	P2=0x00;
	P3=0x00;
	
}  // of main