IIC memory microcontroller power-on times

IIC has a memory function. Actually, I didn't understand why it can remember before, because the program I wrote was to make the light flash, so I didn't understand the so-called memory principle. Today, I let it remember the number of times the microcontroller was turned on through the digital tube. Finally, I learned its true principle tomorrow. In fact, when the microcontroller controls it, the program keeps running, and the data obtained by the program is constantly written into the IIC register. The register will not lose data after power failure, so when we turn off the program, that is, the data is saved after power failure. The next time you turn it on, the program starts from the beginning, but the address starts from the address stored in our register last time, so the memory function is achieved. This application is very large in data storage and protection, such as traffic lights memorizing illegal vehicles, account storage, data accumulation, etc. can be stored by it.

The following is the program for IIC to memorize the number of times the microcontroller is powered on:

The program is as follows:
//Copyright: Single Chip Computer Network http://www.51hei.com 
#include
#include
#define uchar unsigned char//macro definition
#define uint unsigned int
sbit scl=P2^0; //These two bits are defined to control the pins of IIC      
sbit sda=P2^1;
uchar number[10]={ //Digital tube array definition
0x3f,
0x06,
0x5b,
0x4f,
0x66,
0x6d,
0x7d,
0x07,
0x7f,
0x6f
};
void delayt(void)//Delay of digital tube
{
 uint x,y;
 for(x=0;x<5;x++)
 for(y=0;y<120;y++);
}
void delay(void)//Adaptive delay of IIC
{
 _nop_();_nop_();_nop_();_nop_();
 _nop_();_nop_();_nop_();_nop_();
}
void start()//Start
{
 sda=1;
 delay();
 scl=1;
 delay();
 sda=0;
 delay(); 
}
void stop()//Stop
{
 sda=0;
 delay();
 scl=1 ;
 delay();
 sda=1;
 delay();
}
void init()//Initialization settings
{
 sda=1;
 scl=1;
}
void answer()//Response
{
 uchar i;
 scl=1;
 while((sda==1)&&(i<250))i++;
 scl=0;
 delay();
}
void noanser()//Non-response
{
 scl=1;
 delay();
 sda=1;
 delay( );
 scl=0; 
 delay();
}
void writebyte(uchar dat)//Write byte
{
 uchar i;
 scl=0;
 delay();
 for(i=0;i<8;i++)
 {
  if(dat&0x80)
  {
  sda=1;
  }
  else
  {
  sda=0;
  }
  dat=dat<<1;
  delay();
  scl=1;
  delay();
  scl=0;
  delay();
 }
 sda=1;
 
}

uchar readbyte()//Read byte
{
 uchar i,dat;
 scl=0;
 delay();
 sda=1;
 delay();
 for(i=0;i<8;i++)
 {
 scl=1;
 delay( );
 dat=dat<<1;
 if(sda)
 {
 dat++;
 }
 scl=0;
 delay();
 }
 return dat;
}

void write_byte(uchar add,uchar dat)//Write byte encapsulation
{
 init();
 start();
 writebyte(0xae);
 answer();
 writebyte(add);
 answer();
 writebyte(dat);
 answer( );
 stop();
}
uchar read_byte(uchar add)//Read byte encapsulation
{
 uchar value;
 init();
 start();
 writebyte(0xae);
 answer();
 writebyte(add);
 answer();
 start();
 writebyte(0xaf);
 answer();
 value=readbyte();
 noanser();
 stop();
 return value;
}
void main()
{
 
 
 uchar temp,k,j;

 temp=read_byte(0x10);//digital tube units and tens operation
 k=temp/10;
 j=temp%10;
 temp++;
  write_byte(0x10,temp);
 delay();
 while(1) //digital tube display
 {
 P1=number[k];
 P0=0;
 delayt();
 P1=number[j];
 P0=1;
 delayt();
 }
}