In today's digital (electronics) world, people's desire for electronic goods that ease their life at work, and leisure is increasing the complexity of the products of the embedded systems industry. For example, MP3 players for listening to music and cell phones for communicating with people.The gap between the hardware and software parts of embedded systems is being reduced by the use of System Level Design Languages (SLDL) that can model both hardware and software simultaneously. One such SLDL is SpecC.In this thesis, a SpecC model of a Real Time Operating System (RTOS) is constructed. It is shown how RTOS features can be incorporated into a SpecC model. The model is used to develop an application involving a robot avoiding obstacles to reach its destination. The RTOS model operates similar to the actual RTOS in the robot.The application includes a testbench model for the robot, including features such as interrupts, sonar sensors and wheel pulses, so that its operation closely resembles the actual robot. The sensor model is programmed to generate the values from the four sensor receivers, similar to the behaviour of the sensors on the actual robot. Also the pulses from the wheels and associated interrupts are programmed in the model so that it resembles the interrupts and wheel pulses present on actual robot.