sOS - simple Operating System

This repository contains a highly portable simple Operating System (sOS) to run tasks on a MCU.

Features

• Task creation and deletion
• Round robin scheduling
• lightweight timers

sOS API

• tasks
• timers

MCUs

• AVR

Builds

This repo keeps build tooling inside the build/ directory:

• build/win32 contains the Visual Studio solution/project for the Win32 example app.
• build/avr contains the CMake project and helper scripts for the AVR build.

Win32 (Visual Studio)

Tools required:

• Visual Studio 2022 with the Desktop development with C++ workload.

Open the solution:

• build/win32/sOS.sln

Build:

• Select Debug or Release, then Build.

Output:

• build/win32/bin/sOS.exe

Notes:

• The Win32 build is only for the example app and host-side testing.

AVR (CMake + avr-gcc)

Tools required:

• CMake 3.20+
• Ninja (recommended for fast builds)
• AVR GCC toolchain (Microchip/Atmel)
  • Default toolchain path used by CMake: C:\Program Files (x86)\Atmel\Studio\7.0\toolchain\avr8\avr8-gnu-toolchain\bin
  • Fallback: C:\Program Files\Microchip\xc8\v2.36\avr\bin

Build (from a terminal in build/avr):

build.bat

Clean (removes all AVR build artifacts):

clean.bat

Output:

• build/avr/bin/sOS_atmega1284p.hex
• build/avr/bin/sOS_atmega1284p.lst

Configure MCU and clock:

• Edit build/avr/CMakeLists.txt:
  • SOS_MCU (default: atmega1284p)
  • SOS_F_CPU (default: 16000000UL)

Notes:

• AVR build products and intermediate files live under build/avr.
• The CMake build tree is under build/avr/obj.