problem with DS3231 and pic16F876A

Hello,
I'm new to this forum, I try to display the time and date from the component RTC S3231S, the result is displayed on an LCD display, I used this program:
// LCD
sbit LCD_RS at RB4_bit;
sbit LCD_EN at RB5_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
// Configuration PIN LCD
sbit LCD_RS_Direction at TRISB4_bit;
sbit LCD_EN_Direction at TRISB5_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
void main()
{
// Declaration

unsigned int secondes,sec1,op1,Tr1;
unsigned int minutes;
unsigned int hours;
unsigned int day;
unsigned int mounth;
unsigned int year;
unsigned int temp;
char*DATE;
char buffer1[8], buffer2[8], buffer3[8];
// Initialisation LCD
LCD_Init();
LCD_Cmd(_LCD_CLEAR);
LCD_Cmd(_LCD_CURSOR_OFF);
while(1)
{
// Communication I²C
I2C1_Init(10000); // initialisation I²C

I2C1_Start(); // Start I²C
I2C1_rd(0xD0); // Adress Ds3231
sec1=I2C1_rd(0x00); // read secondes
Tr1=BCD2DEC(sec1);
IntToStr(Tr1,buffer1);
Lcd_Out(1,1,buffer1);
I2C1_Stop(); // Stop signal I²C
Delay_100ms();
}
}
the problem is when i execute my program in simulation (Proteus), the circuit work, but on a reality, the LCD is stuck on the value 149
Note:
in the program, several variables are declared but not used, my priority is to read and display the seconds
I don't know where is a mistake in my program,....please, who can help me ... Thanks