STM32 gotchas
193. My STM32 board does not work. Are all these pins properly connected?

When bringing up a new hardware design, sometimes it happens that a connection gets overlooked, or on a prototype, a bad solder joint or a short prevents some pin being physically connected to where it belongs. This may result in a situation where "nothing is working", i.e. the STM32 does not respond to a known-good programmer or debugger.

Here is a list of pins, which should be connected in some particular way for basic functionality of an STM32 design:

For each STM32 family/subfamily, ST does provide an appnote named Getting started with STM32xxxx MCU hardware development or similarly. These do contain most the above information and more, so it's essential to check them out before starting to make a new hardware design. Another good source of inspiration for hardware design are be the Nucleo/Disco/EVAL boards, for which ST provides schematics and BOM on their respective product pages.