This is a software emulation of the I2C-bus by using two general purpose timers of a microcontroller from the C166 family. The I2C-bus is used in many applications mainly to communicate between devices connected to the bus. 1 Introduction to I2C-bus 3 2 I2C-bus Specifications 3 2.1 Data Transfer Formats 3 2.2 Timing Diagram 6 2.3 Hardware Connection 8 3 Software Description 9 3.1 Software Concept 9 3.2 Description of Module Subroutines 10 3.3 Software Compilation 15