Abstract: On the basis of introduction of the structure,principle and mode of data trassmission of I²C bus,the paper summarizes the advantages of I²C bus.As for the microcontroller without I²C bus interface,it can use the microcontroller's I/O interface to simulate I²C bus,which provides a simple way to realize serial extension.According to the application of I²C bus to the temperature controlling system,the design of hardware and the software program in assemble language are introduced in detail.

Key words: I²C bus, microcontroller, DS1624