[Back] [Impressum, Datenschutz]

rupsched

rupsched is a small operating system for 8-bit AVR microrontrollers. It uses the Linux kernel build system and Kconfig, and the rest is also very Linux-like. It features a scheduler, timers and rolls its own interrupt support. All components are optional, even the scheduler.

Directory structure, names of header files, functions and macros, as well as coding style are oriented on the Linux kernel, whoever is used to hack the Linux kernel will feel at home in rupsched.

History

I managed the configuration of first my AVR projects with the Linux kernel's menuconfig, but for a very long time I only used a binary of menuconfig. I managed my projects in a single SVN repository and so it slowly grew infrastructure which supports the programming model used in the Linux kernel.

One of the first things I implemented was the scheduler and that's where the name comes from.

Features

• FUSE configuration in Kconfig
• Centralized IRQ handling (saves space for IRQ prologues/epilogues)
• Scheduler (with mutexes and completions)
• Timers (using Timer0)
• character devices
  • USART driver
  • Morse output
• printk

  During the build, all format strings are examined and only the used flags will be implemented in vdevprintf, leading to a very small footprint most of the time.

• BUG(), BUG_ON(), panic
• tests and example applications
• Linux-style GPIOS: (The naming is not yet matching precisely) gpio_set_output(GPIO_D5); gpio_out(GPIO_D5, 0); gpio_toggle(GPIO_D5);

rupsched contains a parser for atpack files, theoretically supporting all ATMega devices, but currently only a few models are used at the moment. To add your own device, change the DEVICES variable in arch/avr/scripts/decode_packs, and remove arch/avr/devs to force a rebuild.

Planned features

I have started working on these, but they are not yet ready for release

• 1-Wire support
• SLIP protocol on serial port
• compression support for data segment
• boot loader
• lcd display support
• file system in flash
• tcp/ip networking

Extended wishlist features (not yet started to work on it)

I have not yet started working on these features. I will start working on that when the above list is implemented.

• kernel modules
• user-space processes
• sd-card driver

Requirements

To build rupsched, a Linux environment is required, with the following packages installed:

• avr-gcc
• bash
• bison
• flex
• gcc
• make
• md5sum
• ncurses-devel
• php-cli
• php-dom
• unzip
• wget

It should also be possible to compile using Cygwin on Windows, however I never tested that.

License

Most of this work is licensed GPL v2, however some files have a different but compatible license.

Download

To get the latest version of rupsched, clone the git repository:

git clone https://www.rupert-eibauer.de/rupsched.git rupsched

Releases

• rupsched-0.6.0.tar.gz

  Lots of new features, most notable are:

  • GPIO support
  • Fixed the scheduler. No more lock-ups when tasks are woken up from an interrupt. The only remaining problem is that priority inheritance is not complete and may miss to boost a task which is waiting on an unrelated mutex.
  • Stack checking and stack size reporting. Is useful to estimate stack size needed.
  • Stack checking and stack size reporting
  • __irqentry only saves call-used registers
  • Registers can be reserved in Kconfig
  • Timers and threads now have a pointer argument.
  • Dynamic memory allocation (kmalloc/kfree)
  • Kernel threads can now have variable/inidivdual stack size
  • System can be compiled with -mtiny-stack, saving quite some code. This requires task_struct to be allocated by kmalloc to make sure the stack doesn't cross a 256-byte boundary.
• rupsched-0.5.1.tar.gz

  Added support for calculating, reading and burning fuses.

  Direct and common interrupt handling can now be mixed.

  LTO optimization can now be used.

• rupsched-0.5.0.tar.gz