STM32 Baremetal Examples
The STM32 line of ARM Cortex-M microcontrollers are a fun way to get started with embedded programming. The nice thing about these chips is that they don’t require much setup, so you can start to learn about them bit by bit, starting with almost no code. And they are much more capable than the 8-bit processors used in many ‘Arduino’-type boards – some can run at over 400MHz, and they can have advanced peripherals up to and including simple graphics accelerators.
But in this tutorial, we will just learn the absolute minimum required to get a program running on one of the simpler STM32 chips. We’ll cover how to support multiple chips in a later post, but this example will use the STM32F031K6 as an example. ST makes an affordable ‘Nucleo’ development board with this chip, which costs just over $10 from somewhere like Digikey, Mouser, etc.
This guide will assume some familiarity with C programming and the popular GCC compiler + GDB debugger, but I will try to explain all of the parts specific to coding for microcontrollers. I’d also like to make these posts more accessible, and would welcome feedback if anything is unclear or could be better explained.
On the bright side, the very low-level starting code demonstrated in these first few examples are things that you won’t have to worry about once it is set up. If you want to skip these examples, there are tools such as ST’s CubeMX which can generate these sorts of empty starting projects. But it’s nice to have some idea of what goes on inside of the chip, so let’s get started! You can view the entire minimal example project described in this post in this Github repository.