Open-source capacitive linear encoder / DIY DRO scale: KiCad PCBs, STM32 firmware, and test data. Same principle as digital calipers.
STM32 core support for Arduino
Mongoose OS - an IoT Firmware Development Framework. Supported microcontrollers: ESP32, ESP8266, CC3220, CC3200, STM32F4, STM32L4, STM32F7. Amazon AWS IoT, Microsoft Azure, Google IoT Core integrated. Code in C or JavaScript.
Customizable Bootloader for STM32 microcontrollers. This example demonstrates how to perform in-application-programming of a firmware located on an external SD card with FAT32 file system.