Demand for customized wireless microcontroller unit (MCU) has been expanding due to the requirement of end-to-end IoT solution, product requirement, and potential IP. As such, the development for design complexity growth poses by the evolution of the SoC technology, causing the issue of time spent in the area of validation has increasing for the newly complex design developed. Thus, this research was highlighted on the RTL Platform Validation methodology by utilizing the existing method for newly developed MCU to overcome the time spent on the validation. As the goal of this research to find the fastest method that can be customized to the current MCU design, hence this RTL validation were divided into two levels which were module level and system level. For module level, the verification was focused on the IP’s source code. Thus, in this module level, the simulation-based method, which is code coverage technique was utilized and being implemented in white box environment as to verified the quality of the codes and to obtain the maximum reasonable coverage to be covered. For this MCU system, the reasonable coverage that needs to be obtained at the module level was more than 80%. The advantage of the code coverage technique was the bugs and errors of the design can be detected at the early stage. As if the IP only achieves the targeted coverage than will move to the next level of verification, which is system level. Otherwise, the IP design was declared as unsuccessful and resulting to redesign as specified. Meanwhile, for system level, the verification was based on the implementation of test bench as to verify the system with a set of test vector. The detailed on the techniques used and the results of this research were presented in the thesis.