AVR Freaks

Hi all, I am making a program in which I am interfacing LM75A (temperature IC) with Atmega8 using I2C and then getting the value of temperature serially to my laptop. I have written the code but I think there is some problem in it and that's why I am not getting exact output. please help.

Here is the code:

< 

#ifndef F_CPU
#define F_CPU 8000000UL 
#endif

#include <avr/io.h>
#include<util/delay.h>
#include <stdio.h>

//Serial tansmit
void serial_avr(char *str)
{
    UCSRB=(1<<TXEN);
    UCSRC=(1<<UCSZ1)|(1<<UCSZ0)|(1<<URSEL);
    UBRRL=51;
    
    for (unsigned int i=0;str[i]!=0;i++)
    {
        UDR=str[i];
        //UDR = 0;
        while(!(UCSRA&(1<<UDRE)));
    }

    _delay_ms(500);
}

void i2c_init(void)
{
     TWSR=0x00;            
     TWBR=0x47;            
    TWCR=0x04;        
}

void i2c_start(void)
{
        TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
        while ((TWCR & (1 << TWINT)) == 0);
}

void i2c_write(unsigned char data)
{
        TWDR = data ;
        TWCR = (1<< TWINT)|(1<<TWEN);
        while ((TWCR & (1 <<TWINT)) == 0);
}

unsigned char i2c_read(unsigned char isLast)
{
        if (isLast == 0)
        TWCR = (1<< TWINT)|(1<<TWEN)|(1<<TWEA);
        else
        TWCR = (1<< TWINT)|(1<<TWEN);
        while ((TWCR & (1 <<TWINT)) == 0);
        return TWDR  ; 
    
}

void i2c_stop()
{
            TWCR = (1<< TWINT)|(1<<TWEN)|(1<<TWSTO);
}

void main(void)
{
        
         char temp; 
                        
        i2c_init();
        i2c_start();
        i2c_write(0b10010001); //slave address for LM75A
        i2c_write(0x00); //temperature register address
        temp = i2c_read(1);
        i2c_stop();
            
        while(1)
        {
            serial_avr(temp);
            _delay_ms(2000);
               
        }

}

>

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