eeprom与串口通信不懂 高手指点

#include <reg52.h>
#include <intrins.h>
#define uchar unsigned char
#define uint unsigned int
//  共阳极数码管字模 0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e
sbit sclk=P2^0;
sbit sda=P2^1;
uchar flag,tem1,tem2,num;
void delay();
void init_uart();
void init_I2C();
void I2C_start();
void I2C_end();
void send_byte(uchar temp);
uchar read_byte();
void respond ();
void eeprom_write (uchar address,uchar dat);
uchar eeprom_read (uchar address );

void delay1(uint z)
{
  uint x,y;
  for(x=z;x>0;x--)
  for(y=123;y>0;y--);
}

void main()
{
  P1=0;
  init_I2C();
  init_uart();
  while(1)
  {
    if(flag==1)
    {
      eeprom_write (23,num);
      delay1(100);
      
      P1=eeprom_read (23);
      flag=0;
      REN=1; 
    }
  }
}

void delay()
{
  _nop_();
  _nop_();
  _nop_();
  _nop_();
  _nop_(); 
}

void init_uart()
{
  TMOD=0x20;
  TH1=0xf3;
  TL1=0xf3;
  REN=1;
  TR1=1;
  EA=1;
  ES=1;
}

void init_I2C()
{
  sclk=1;
  sda=1;
}

void I2C_start()
{
  sclk=1;
  delay();
  sda=1;
  delay();
  sda=0;
  delay();
  sclk=0;
}

void I2C_end()
{
  sclk=0;
  delay();
  sda=0;
  delay();
  sclk=1;
  delay();
  sda=1;
}

void send_byte(uchar date)
{
  uchar temp,i;
  temp=date;
  for(i=0;i<8;i++)
  {
    temp=temp<<1;
    sclk=0;
    delay();
    sda=CY;
    delay();
    sclk=1;
    delay(); 
  }
  sclk=0;
  delay();
  sda=1;
  delay();    
}

uchar read_byte()
{
  uchar temp,i;
  temp=0x00;
  for(i=0;i<8;i++)
  {
    sclk=0;
    delay();
    if(sda)
    temp=temp|0x01;
    temp<<=1;
  }
  return temp;
}

void respond ()
{
  uchar i;
  sclk=1;
  delay();
  while((sda==1)&&(i<250))i++;
  sclk=0;
  delay();
}

void eeprom_write (uchar address,uchar dat)
{
  I2C_start();
  send_byte(0xa0);
  respond();
  send_byte(address);
  respond();
  send_byte(dat);
  respond();
  I2C_end();
}

uchar eeprom_read (uchar address)
{
  uchar num;
  I2C_start();
  send_byte(0xa0);
  respond();
  send_byte(address);
  respond();
  I2C_start();
  send_byte(0xa1);
  respond();
  num=read_byte();
  I2C_end();
   return num;
}

void ser() interrupt 4
{
  RI=0;
  num=SBUF;
  REN=0;
  flag=1;
}