In this study, a processor-in-the-loop (PIL) simulation of the four-channel interleaved buck converter is presented. According to the rapid prototype concept, the power model of the system was created by Simscape blocks, which includes power electronics components, in the MATLAB/Simulink environment. The load voltage is regulated with the conventional PI controller. The transfer function and controller parameters of the system are obtained by using the PID Tuner App of MATLAB and then obtained parameters are applied to the PI controller. A sub-model that contains the phase-shifted PWM signal generation for the four-channel interleaved buck converter and the PI controller is prepared and run with TMDSCNCD28388D. The required model-code conversion to run the sub-model in the TMDSCNCD28388D platform is performed using Simulink Embedded Coder. The obtained PIL results are compared to the MATLAB/Simulink simulation results to verify the proposed PIL design.