Post Silicon Validation is critical step in order to deliver quality microcontroller chips to customers but is increasingly becoming complex and time consuming process as the design size is increasing. Due to increased number & diversity of design intellectual property, microcontroller post silicon validation has moved towards customized validation concept and hardware setup for individual design block. Two major challenges faced by validation team are to generate sufficient number of system level test-cases that can cover wide range of configuration and second to ensure quality & stability of these test-cases throughout validation cycle. This paper describes challenges in test-case generation and factors that impact post silicon test content stability. This paper presents a method to auto generate system level test-cases and to improve test content stability. The proposed technique was deployed in validating advanced driver assistance systems in next generation of automotive microcontroller.