The continuing demand for more performance, complexity and cost reduction require the semiconductor industry to develop Microcontrollers with both high density design technology and higher clock frequencies. This has intrinsically increased the noise emission and noise sensitivity. Application developers therefore, must now apply EMC “hardening” techniques in the design of firmware, PCB layout and at system level. This note aims to explain ST Microcontroller EMC features and compliance standards to help application designers reach the optimum level of EMC performance.