uCOS-II

Only for personal use.

There's a fee for commercial use, but it isn't particularly large.

tim

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If this ever became a commercial product the fee wouldn't be a problem as it would just be passed to the customer. How do you 'register' to get the nocomm copy? or do i just need to go buy the book? I guess 40 bucks isnt much to waste if i don't like his code...

The licensing terms for the uc/OS kernel distributed with the first edition of the book make its use free even for commercial applications as long as you do supply the kernel only in object form. May be you can find a copy of the 1st ed and use that version. On the other hand, that may have been an x86 only version.

ziggy scrobe on the papyrus:

Have a look here:

Salvo is free, but it seems to work on just about everything except the Rabbit.

--
John B

After posting that, I remembered that Intel put their old real time kernels for 8080s and 8051s (different products, not one product ported to both architectures) in the public domain.

While looking for them (did not find them yet) I found this:

For the 8051, I found a copy of DCX51 here:

(there are other goodies worth checking in that page.)

It seems I was mistaken in my believe that the 8080 real time kernel was also in the public domain. The IRMX product line was sold to Tenasys (

). They still sell descendants of IRMX-86, but I couldn't find any reference to a free download version of RMX-80.

Roberto Waltman

[ Please reply to the group, return address is invalid ]

Cool, thanks..

Going to check out that salvo link from another guy that responded.

You Buy the Book You Get a Personal Copy. You Pay the Fee You get the Latest Version. The Book Version Works fine. There are ports available on the net and at the micrium (I hope that is spelled right) web site. There is 1 CPU specific file. BTW uCOS-II is a little heavy for the

8052. It works, but there is not much left for very many tasks.

And this

with several RTOS's.

Actually Salvo is a commercial product. You can try a limited version for free, but once you produce a product the license fees kick in.

If you like the cooperative task switching approach Salvo uses and don't need all the bells and whistles, take a look at csRtos

Cooperative task switching means you are responsible for task latency, but you don't need seperate stack space for each task. That's helpful on a micro with very little RAM.

csRtos is freeware. There are currently versions available for Atmel AVRs and Microchip PICs. If you're interested in porting it to the

8051, and your C compiler supports setjmp and longjmp I have a version that should be pretty simple to convert.

Mark

I haven't checked back to the mucos site recentley but last time I did it was an honesty system, just like it is with any source code supplied OS that sells via "license per product".

Once you have the source, there's nothing to stop you using the code for.a product that isn't the originally registered one.

But (genrally) a corporate isn't going to do this, the amount of money is too small in relation to the total development spend to take the risk of being caught. Note that you often don't have to pay until you are some way into the development, so it is possible (and legal) to use OS on a trial basis at no cost (other than the engineer's learning curve that is) until you have a product you are sure you want to ship

tim

Greetings,

FreeRTOS.org can provide you with a very small OS. I have managed to boil it down to less than 3K5 using GCC 4.1.1 and an ARM7 uC.

/RaceMouse

ziggy wrote:

I do not think I really need a RTOS. a full blown OS will just wast your time to get familiar with it.

what we need is a job dispatcher and an inter task synchronous mechanism. It is easy to build one from scratch.

usually the engineering manager do not understand the low level programming and want to find a commercial RTOS.

ziggy wrote:

But this is essentially what uC/OS II does. It's a very tiny system, with only a couple source files as I remember, and then the customer supplies a few processor specific routines (context switching and interrupt control).

So you could pay the tiny license fee and spend the engineer's time porting it to your system, or you could write your own from scratch. It's not a hard job, but it will definately take longer than to port uC/OS. Unless you've already got your own OS from a prior product.

-- Darin Johnson

I treat the ucos as a example to learn RTOS. I would like to build one from scratch. no matter how easy to port a existing os to a new platform, we have to hire a low level person, right? while let him/her idle?just keep him/her busy.

Dar> > what we need is a job dispatcher and an inter task synchronous

If the op just needs update rates in the fraction of a second range for simple application, then an rtos is most likely overkill, unless you are looking for an excuse and have the project time to get familiar with someone elses code base. It's much quicker and fairly trivial to write a simple round robin scheduler entirely in C. Each function or task is called every n clock ticks to set priority and always runs to completion. Message based comms with handshake using a single castable U32 are used to move data between tasks. Message queues are optional. Each task then typically becomes a simple state machine, where if there is no message, the function exits, though tasks don't have to use messaging. The advantage is almost zero overhead, small footprint, no need to work out stack space for each task and a simple framework to get results fast. Such an approach may not have all the bells and whistles of an rtos, nor be quite so glamorous, but it gets the job done and can be inherently deterministic. Total code for the scheduler should not be more than 2 or 3 pages of C using such an approach...

Chris

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