An OCaml generic virtual machine for microcontrollers

Other

OMicroB

A secure embedded operating system for microcontrollers

tock

Go compiler for small places. Microcontrollers, WebAssembly (WASM/WASI), and command-line tools. Based on LLVM.

tinygo

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.

mongoose-os

MicroPython - a lean and efficient Python implementation for microcontrollers and constrained systems

micropython

Given an Arduino compatible microcontroller or Raspberry PI (experimental), JTAGenum scans pins[] for basic JTAG functionality and can be used to enumerate the Instruction Register for undocumented instructions. Props to JTAG scanner and Arduinull which came before JTAGenum and forwhich much of the code and logic is based on.  Feel free to branch and modify religiously (readme, credits, whatever)

JTAGenum