In automotive field, the ECU’s tests are mainly executed employing HIL (Hardware-In-The-Loop) simulators. These are, essentially, computers capable to provide and acquire analogue and digital signals which represents the ones exchanged among ECUs, sensors and actuators in real vehicles, and simulates in Real-Time the controlled plant properly modelled. Moreover, in a real vehicle there are many ECUs which communicates each other by means of communication protocols and HIL simulators are also able to use these protocols. The aim of this final thesis held in Kineton, a company based in Turin, is the design and development of the prototype of an expansion board for an HIL simulator, in particular an electronic board able to expand the simulator’s digital output channels by the acquisition of a CAN message containing as information the frequencies and duties, given by the simulator itself or another device able to communicate through this protocol, and provide a digital signal as output in 3 different working modalities.