Microcontroller devices and applications based upon ARM’s Cortex-M processor family are becoming the de facto choice for modern embedded systems. The complexity and functionality of these modern designs is increasing at an incredible rate, with an expanding portfolio of Cortex-M based microcontrollers that are rapidly making the traditional 8/16/32-bit processor classification obsolete. This paper will highlight design considerations. It will focus on how carefully researching and selecting key technology components, at the design start, will enable the development team to achieve its goals, and enable organization to provide a platform for future designs and developments.