Hi Alfredo,

Does your I2C code work on a different part, for example a SEEPROM? Is the device address correct? Are there other I2C devices on the I2C bus? (some parts don't coexist well). Do you have an oscilloscope to view the I2C bus to verifiy SDA/SCL correctness? Do you have an emulator to see what is happening inside your 89C52 to verify that the device is responding to your I2C code device address? Are you sending byte data msb first or lsb first? Is your I2C code written for 100KHz or 400KHz? What speed does your LM92 require?

Just a few things to check...start at the beginning, the very base level of your code, and verify that it's correct, go up to the next level and repeat the process until it's all working.

Good luck!

Dennis