There are 2 repositories under cortex-m3 topic.
Frosted: Free POSIX OS for tiny embedded devices
Programming internal SRAM over ARM Cortex M3 SWD
A bare metal (register level) STM32F103C8T6/STM32F103 MCU program written in pure Rust without any IDE, SDK, HAL or library, and no assembly code, the only tool required is the Rust compiler.
DEPRECATED: Use instread https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm Cortex M3/M4 with LLVM toolkit
Bare metal STM32F1 examples for various modules
A collection of code examples for the STM32F103C8Tx microcontroller
Tutorials centred around Gowin FPGA parts for the /r/GowinFPGA subreddit
Easier way to program on ARM Cortex™-M3 STM32F103 in C++
A minimum preemptive OS on Cortex-M3 (specially on blue-pill board) written in Rust.
high performance AES implementations optimized for cortex-m microcontrollers
Open source firmware for MIDIPLUS SmartPAD MIDI controller
STM32F103C8T6: Projects done with "Blue Pill" board for learning purposes.
The firmware for STM32F103 microcontrollers that emulates CH340 IC (USB to UART interface)
GPS-based local relative navigation system for group of up to 6 members
ARM Cortex-M3 Real-Time Operating System for educational purpose.
Experimental subroutine threaded and optimized version of CoreForth
Laboratories of the Computer Architectures course of the master degree in Embedded System (Electronic Engineering) of Politecnico di Torino, academic year 2019/2020
Nano OS - Open source preemptive real time multitasking scheduler targeting 8 to 32 bits microcontrollers
USART protocol implementation in STM32 using various methods and frameworks
Badminton Robot for Robocon 2015
Simple C projects for lpc1769 microcontroller from NXP. Code developed with MCUXpresso.
ARM assembly code to blink LEDs on STM32F4 discovery board
A free, fast and accurate ARM Cortex-M3 floating-point library
A little Cortex-M3 OS from scratch
Examples for Gowin Tang Nano 4k FPGA-board.
Bootloader with TFTP Server