Hi Ragu,

I am working with same microconverter and with same problematic in my work. I try to explain you basic methods to solve your problem.

1. At the first. You must read about ADC on ADuC848 as was mentioned in previous messages. Especially this area:
ADCMODE - here you cane select continuous or single conversion, zero, full system calibration
ADC0ON1, ADC0CON2 - input range and so on
SF - set to 5 Hz (disable CHOP - default) 5 Hz is enough to measuring temperature
You can use second ADC (ADC1CON) as internal temp sensor, and this can be usefull to read environment temperature to substract this value from thermocouple's temperature. But this can be done only when the ADuC848 will be at surrounding environment (not direct in measuring environment).
in thermocouples you dont need to use ICON (I sources)
NOTE: I think you can set unipolar mode to better calculation.

2. try to specify type of your thermocouple (J,K ...) and make correct input range settings in ADC0CONx

3. make simply mathematic to calculate from ADC value to correct voltage, best way to do that is to take generator and store some values (may be only 2 points) in the device memory
HINT: to store values (X - ADC value, Y - voltage) in multipoints table, you can effective use code memory via ULOAD mode. By do this you can easy and better access table from other program code.

4. the next point to achieve finish :) is to take correct voltage value from previous table and get correct value of temperature. You can use formula with correct type of thermocouple OR you can use another table with X - voltage, Y - temperature and set table's value as shown in table within your thermocouple.

5. substract surrounding temperature from previous table's value to get FINAL temperature VALUE :)

6. this final value you can then show on display or send via serial link or other way...

I hope it will be helpfull for you. If you have any other questions write :) Good luck.