LiteBSD is variant of 4.4BSD operating system for microcontrollers

github.com

60 points·coderjames··13 comments

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There are many reasons why you don't want a general purpose OS for a microcontroller:

- Embedded systems are very price sensitive. if you're making it general purpose, you're wasting money.

- Embedded systems generally have some form of real-time requirements. General Purpose OSes are not suitable here.

- Time-Efficiency; don't waste cycles.

- Space-efficiency; don't waste memory.

- power-efficiency; be asleep as much as possible.

Simple schedulers such as FreeRTOS/RTX/ChibiOS/etc/etc/etc are much more suitable, but better just to implement a nice simple super-loop. Primitive but efficient.

Not really for "microcontrollers" in general, more for top end chips.

I often wonder if there is a nice super portable OS for your more "average" microcontroller, something in the ballpark of 16bit, 32k program space, and 2k of RAM. Also an alternative to C for something in that ballpark would be fantastic.

Maybe NuttX? http://www.nuttx.org

FreeRTOS?

This doesn't provide any hardware abstraction, you rely on vendor libraries for portability.

"TinyOS". It's on Github.

There are alternatives to C, people just need to search for them.

http://www.mikroe.com/mikropascal/pic/

http://www.mikroe.com/mikrobasic/pic/

With support for all really tiny CPUs out there. The language runtime does the OS role.

Just one possible example, there are other vendors.

or ChibiOS? http://www.chibios.org/

A general-purpose operating system really seems inappropriate for 2kB of RAM. In that space I think it's all custom applications doing very specific things.

2k? and alternative to C? Use forth or stick with assembly.

Contiki ?

RIOT?

https://www.riot-os.org/

There's also retrobsd - http://retrobsd.org/wiki/doku.php

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