ST’s STM32 microcontrollers are a very successful implementation of ARM’s Cortex-M family of 32-bit cores. In my opinion, a big part of that success is their ease of use : ST provides low-cost modules and development kits that beat the living crap out of Arduinos, and the software development tools to match. This section covers all sorts of information on how to use them, both in terms of hardware and software. The topic is vast.