This application note describes how to design a printed circuit board (PCB) with optimum performance and compatibility between ST92E196 or ST92T196 (SDIP56 package) and ST92186 (SDIP32 and SDIP42 packages) microcontrollers. It also describes the external filters and components needed for the ST92186 family of microcontrollers (MCU), and provides advice on how to develop applications for ST92186 microcontrollers in SDIP32 or SDIP42 packages using ST92E196 / ST92T196 devices.