AVR Freaks

Are you sure that is the correct part number?  Details are important.

Jim

void dataRead( unsigned int )
{
    unsigned int j = SPDR0;
    j<<8;
    j|=SPDR0;
}

Umm I don't think so for many reasons.

Presumably this was supposed to look something like:

uint8_t SPI_transfer(uint8_t byte) {
    SPDR = byte;
    while(!(SPSR0 & (1 << SPIF)));
    return SPDR;
}

uint16_t dataRead(void)
{
    uint16_t j;
    j = SPI_transfer(0xFF) << 8;
    j |= SPI_transfer(0xFF);
}

Of course, for this to be useful you then have to call it somewhere. At present all you have is:

    lcd_print("%d, j");

which appears to be printing some variable called 'j' and yet I don't see where that is either defined or assigned? (it will have nothing to do with the local 'j' in your uncalled dataRead( ) function.

BTW in the above I have introduced an SPI_transfer() function  - this recognizes the fact that every time you use SPI you both send and receive a byte. Sometimes the value of the byte you send does not matter but, as master, you still have to send it to make the SPI system "clock". In the example code I am sending a dummy 0xFF value each time simply to persuade the device to actually return the high and low bytes I'm interested in. (does it really return high then low rather than low then high??).

Just this small bit of your code I have looked at suggests to me that you don't yet have a grasp of even the fundamentals of C programming (like returning values from functions) so I would spend a few weeks just learning C basics before trying to apply that to an actual AVR application.

PS even this:

void lcd_print( char *str )
{
    unsigned char i = 0;
    while (str[ i] !=0)
    {
        lcdData (str[ i] ) ;
        i++ ;
    }
}

could be better - there's no need for 'i' in this:

void lcd_print( char *str )
{
    while (*str)
    {
        lcdData (*str++) ;
    }
}

EDIT: actually I just noticed another thing. Your program structure is essentially:

int main()
{
    lcd_init();

    lcd_print("%d, j");

    while(1);
}

Surely you don't want it to just make one reading at power on then stop? Surely you want a structure more like:

int main()
{
    uint16_t j;

    lcd_init();

    while(1) {
        j = dataRead();
        lcd_print("%d, j");
    }
}

so that it attempts to read and print over and over again.

(obviously I left out a whole bunch of other init stuff - you need that back as well).

Oh hold on. I just realised you used:

        lcd_print("%d, j");

My eyesight must be failing - even THAT is wrong. If this lcd_print() function is something like printf() with variadic parameters then I imagine you mean:

        lcd_print("%d", j);

but if it isn't then you need to convert the value into a string first using a function such as sprintf():

char buf[30];
...
        sprintf(buf, "%d", j);
        lcd_print(buf);

As I say there are just so many fundamental C errors in the code that I think you need to take a step back and learn C first before trying to do anything with it like reading thermocouples.

After work very hard to fix my code to get my project done, I did some improvement to my code,

The description you provide is very lacking...does the display work AT ALL?  Can you get it to say "hello" ...why do you overlook stating what is working?

We can not tell what is happening...you could even have bad wiring.  Getting the display functioning is step one, before trying to show other items that themselves need to be up & running.

Ok, that is good to know (you should state this earlier!)--so now we can concentrate on whether the readings are simply not coming in, or whether reading are being rcvd, but not being formatted properly such that they will show on the display