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RE: Recommend me an evaluation board, please

Posted by Warren Buckles on January 27, 2012
Hello Angel:

I have successfully ported FreeRTOS to a number of Ti/Stellaris parts, notably the LM3S811 (about $50 US)

https://estore.ti.com/EKC-LM3S811-EKC-LM3S811-Evaluation-Kit-with-CodeSourcery-Tools-P1878.aspx


and the LM3S6965 ($80 US)

https://estore.ti.com/EKT-LM3S6965-EKT-LM3S6965-Ethernet-Evaluation-Kit-with-Code-Red-Technologies-Tools-P1897.aspx

The LM3S6965 is a very nice part albeit a bit long in the tooth these days.

Each of these eval kits is available with a different set of tools in a 30 day evaluation version. I'm VERY partial to Code Red's tools but they are expensive to own - ~$1,000 US for a license - but you get what you pay for.

Code Sourcery has a free 'lite' version of their tool set that is really just a gnu compiler and associated stuff. You can make it work but it's a bit tedious.

A nifty gizmo built with the Stellaris LM3S9B92, a newer spin of the Cortex part, is the Evalbot ($150)

https://estore.ti.com/EKT-EVALBOT-EKT-EVALBOT-Evaluation-Kit-with-Code-Red-Technology-Tools-P2390.aspx


They are using the Evalbot to push Micrium’s μC/OS-III, a commercial RTOS with much to recommend it - you can get an Evalbot and a book on Micrium’s μC/OS-III for $200 US.

This is, of course, my two bits worth - there are many, many other evaluation boards out there that will run FreeRTOS quite nicely. The LM3S6965 is near and dear to me as it kicked off may career in doing Free RTOS projects several years ago.

Have many fun,

ss/wb

RE: Recommend me an evaluation board, please

Posted by Angel Galindo on January 28, 2012
Thanks a lot! LM3S6965 seems very nice, and I see FreeRTOS appears as third part tools. But the cost of the license of the tools can really be aproblem. I want to buy a bunch of them and buying licenses could make it all too much expensive. Is there any evaluation board that has or free tools or at least free tools with a not-so-limited functionality?

Mmmm, usb sticks are also very nice, but at least the ones from T.I. store are not FreeRTOS capable.

Thanks in advance?

RE: Recommend me an evaluation board, please

Posted by Warren Buckles on January 29, 2012
Hello Zoquero/Angel Galindo:

I think you might be confusing the hardware which you can buy and sell like a piece of steel or string and development software which you use but do not transfer to the end user. Development software is usually licensed to an individual developer or a company they control or work for. So you don't have to buy a $1kUS toolset for each part you program - you buy one $1k toolset and program many, many parts with it (luck and the Gods of Marketing being with you, of course).

If you use a toolchain to develop software for a device such as the LM3S6965 AND all the software you develop is based on your own work then there is no connection between the toolchain licensed to you and the software in the device, which you have developed and, I assume, hold copyright to and will, in turn, license to you client.

Think of a hammer and a piece of steel - if you use a hammer to pound a piece of steel into a different shape, the manufacturer of the hammer has no claim on the steel you have pounded or the shape you have pounded it into. Nor has the steel maker have any claim on the piece of steel (assuming you bought if from them in a legal transaction) or the shape you have pounded it into. The steel is yours and the shape is yours. You can sell it to someone else without any strings attached (unless string is part of your device...). You can bang on all the steel you want and sell it all, too, without any claim by the hammer manufacturer or the steel vendor.

Software is a bit more complicated. Say you use a toolset (a hammer) to program a chip (the steel) but you use your own code as well as code covered by other licenseholders. That's as if you etched a photograph taken by someone else into the steel - the photograph is covered by copyright as determined by the person who made the photograph. That copyright may be very restrictive, requiring you to pay the copyright holder for each example of their image you use, or it may be very liberal, for example, only requiring you to acknowledge the other person's ownership of the image. (for example, my SourceForge Avatar is available for use in strictly foolish ways but you have to acknowledge that I made it and own the copyright.)

This situation has lead to the development of a class of public licenses, of which the GNU General Public License is an example. See http://www.gnu.org/copyleft/gpl.html

In general, toolchains make no claim on work done by licencees using their products provided you don't include things they, in turn, have licensed to you and you only.

If you buy a demo board you usually can use it in whatever application you like w/o further payment UNLESS it includes software that has a non-transferable license. If you pull in pieces of the Stellaris/TI Library (nearly unavoidable unless you like reinventing wheels, filesystem interfaces, integer number output routines, PWM interfaces or all the myriad pieces of a modern application), then their license terms apply to that piece and you have generated what license terms call a combined work.

However, the Stellaris library home page, found here:

http://www.ti.com/tool/sw-lm3s

includes the following text:

Free license and royalty-free use (for use with Stellaris MCUs).

You would have to read the Stellaris license carefully (and it has been a few years since I read one end-to-end) to make sure the sentence above is correct for your situation, but it implies that you can use the Sellaris library on a Stellaris MCU w/o any further payment.

Other pieces of projects can use different licenses and it can be very confusing to get it all straight. The GPL requires you to apply its terms to certain projects developed using GPL-licensed tools, a situation that some companies and individuals cannot work with (for example, TI/Stellaris).

When it comes to FreeRTOS, it is licensed under a modified version of the GPL and the license terms are outlined here:

http://www.freertos.org/index.html?http://www.freertos.org/a00114.html

By the way, I have never figured out how the Ti/Stellaris license terms and the FreeRTOS terms work together - if they do at all.

I hope I have thrown some light on this and not done as some to whom Mark Twain once referred:

"The researches of many commentators have already thrown much darkness on this subject, and it is probable that if they continue we shall soon know nothing at all about it."

And yes, USB sticks are very nice but, as someone once said, now that you have taught the dog to talk, what does it have to say?

Have many fun,
ss/wb


RE: Recommend me an evaluation board, please

Posted by Angel Galindo on January 29, 2012
Hi:

I know about licenses. This is why I do use GNU/Linux instead o Microsoft Windows. And this is why I do develop software with free software utilities and I do link my software with GNU static libraries.

Maybe my short reply has led to a misunderstanding. My interest is just to teach my students about developing embedded systems and then realizing how a real-time OS like FreeRTOS or eCos simplifies your process. I would do accept to have to pay to SELL a piece of hardware that contains pieces developed by others if so I choosed but I want to give to my students the oportunity to learn about embedded systems using a piece of hardware that they could even buy and use in their home to learn more if they would without having to pay more than the steel.

I know there are some integrated development tools like WinAVR which work for Atmel AVR microcontrollers that also include libraries that at least can be used for education without limitations. Others like Code Composer for Texas Instruments devices at least let you work on a "not-more-than-xxx-KiloBytes" mode. I don't know about Code Red products. I don't know if there's an equivalent for the devices which FreeRTOS supports that fulfill my requirements.

So, does any body know if there's a development board which:
* has well known behaviour with FreeRTOS (ported and tested)
* is non-expensive (under $100, for example)
* has a microcontroller so that there are tools and libraries so that:
** you can develop small projects without having to pay licenses
** you can run the hardware for academical purposes without having to pay licenses
* can be debugged (or includes the interfaces or they are clear and non-expensive, like the MSP-FET430UIF for TI, for example)
* has at least some devices:
** input = really a simple button is enough (more are welcome)
** output = really a simple led is enough (more are welcome)
** If there were some boards with a little more hardware option (GPIO, I2C, UART, Ethernet, VGA, ...) without been really more expensive then it would be really great. I mean : maybe there's a hardware platform that has in the same family low devices on a low development board and also higher-end devices bundled in higher-end development boards. This could let students learn using a really cheap device in class and then been able to buy a bigger board with more devices on home ... or even spinning off and using it in their works.

Any help would be really welcome.
Best regards,

/ Angel Galindo Muñoz


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