How to code a RTOS for a 8 bit microcontroller?

[sakthimanju]

can anyone plz give some idea on how to code a RTOS for a 8 bit microcontroller like what the initialization shud contain etc..and which programming language will be convenient to write the code

 

[lambtron]

steps to write an rtos for 8 bit microcontroller

You should write the kernel in assembly. This is necessary not only for performance reasons, but also because the kernel must directly access and modify the processor's stack pointer and other registers.

Regarding initialization, this depends on your rtos architecture. At a minimum you will have to set aside storage for and initialize entities such as task control blocks and semaphores.

 

[prabhak]

steps to write an rtos

I suggest you to read some book on this.

you need a minimal scheduler, and few tasks to do the work.

you could use a simulator to start with and then proceed with real hardware.

In most cases, scheduler will come in library, you need to link your project to it and later the compiler image can be directly flashed to board.

 

[atcm]

user manual rtos

Please refer to the open source RTOS for PIC18 family, the PICos18 at www.picos18.com. You can refer to the source codes of PICos18 for writting your own RTOS.

 

[magesh]

minimal rtos

Can anyone suggest me a good SIMULATOR for any RTOS,so as to get a good hands-on for basic rtos related topics?

 

[aandavan]

rtos 8 bit microcontroller

HI magesh,
As a beginner you can go for UCOS II. Its freely available. So try for this...

 

[LBdgWgt]

open source rtos for 8 bit microcontrollers

HI magesh,
As a beginner you can go for UCOS II. Its freely available. So try for this...

I think it is not to useful to use uC/OS-II on 8 bit microcontroller.
It is a little bit too bog for 8 bit microcontrollers which usually have less than 1-2 KB RAM and several KBs of Flash memory. I ported it to 16 bit uC HCS12 of Freescale, and it needed 3KB Flash and 1 KB RAM just for the minimum RTOS without any feature.

Anyway he asked to write RTOS right?
read the 2nd chapter of this book for basic concepts:


Why do u need RTOS? if it is not compulsory (such as homeworks from the school), just use a common super loop method. The microcontroller is quite fast after all. I worked with 8 bit uCs for several projects until now, no RTOS, and it seemed quite "real time" for me tough

 

[yousafzai]

Re: RTOS

There is a good user manual for UC/OS-II at edaboard . Search through the topics and u will find it. It gives all the details of a RTOS.

 

[flyatwind]

Re: RTOS

Hallo, never tried SALVO OS for 8 bit micros? I heard about it this year, in a seminar.

Peace to this poor world.

 

[rickleicn]

RTOS

try to write in yourself,the task scheduler is vital to the success.you should know the low level details of the uc and assembly.

 

[Beeblebrox]

Re: RTOS

I have personally positive experience with PicOS18. I've been talking to people who successfully implemented uC/OS II and FreeRTOS.
Anyway a deep knowledge of software/hardware is mandatory to be able to implement RTOS. There are many resources on the net, e.g. see Microchip Application Notes AN777, etc.