HopeRF RFM24W

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1054

Hi Mark,

This is a very hard part to use. Lots of features = lots of details to observe. We have found that many times one action creates problems with another. The data sheet(s) are huge, and a new version of the Si4460 just came out, along with new docs and new tools. The tools also do not manage all issues, nor all options/features. So some of the things we had to do was to start with the WDS output, then translate that to a usable form in BASCOM, but *then* you have to figure out what to manually change.

For example, Dave did most of all of the start up work. He got the thing to work in a minimal way, so we could move forward. We had to create a translator program for the WDS so we (he) was not spending so much time manually translating the WDS C code to BASCOM. That got a transmitter, and receiver working, and working well. Great range, low power, excellent low power sleep (meets the data sheet). And some of the functions like sleep, wake, power setting, getting RSSI, battery level etc, were relatively easy. Relatively.

What I found was that going from a transmitter or receiver to a pair or transceivers is NOT easy! I spent 3 solid 7 day weeks at least 10 hours each day to get this to work. To be fair, I am not the most talented, but also not the worst either. Ultimately it took lots of trial and error. Lots of google research and lots of research on the Si website/user group. BTW, my project is still not done. I took a week off of it for Thanksgiving and to get a new perspective on the issues in my project that remain.

Having said all that, I had serious second thoughts on going from the RFM12b to this new part, which actually is not using the latest Si chip. However after spending all of that time and effort and frustration, when it finally *started* to work, then worked reasonably well, I thought that maybe it was worth the effort.

Things to look out for include the *version* of the microcode within the Si4460 chip! The microcode is upgradeable, although I have not tried it and probably wont for a long time, you must be aware of this since it is critical when using the WDS. If the current generation of microcode is set in the WDS, a completely different output (C code) is provided from the WDS which will NOT work!

Likely the current microcode version is better, and hopefully more completely matches the documentation - that is another issue altogether that I have found - but at this point I am working with the hardware I have and do not want to get into upgrading the micro code.

Finally, I am sure this does not answer your question, but likely raises even more. It is not an easy part by any measure. But also not impossible.
Tim

mmarlette · Joined: 30 Nov 2007 Posts: 311 Location: Delano, MN

Tim,

Thank you for the reply and status update.

Sounds like you have been busy but still not to any data points yet on performance.

Seems understandable if the part is that difficult to incorporate into a design. Seems odd as the trend seems to be in the other direction on most embedded solutions.

Appreciate the feedback, will have to llok further in to this as my design project is coming closer to the for front of projects.

Cost of development and time to market are big factors to consider.

Wish you the best of luck and please provide status at your milestones, good read(s)! Smile

Regards,

Mark

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1054

It is touted as easy. But is not.
You have to use the Silicon Labs documentation. Start there first.

BTW, what data points exactly were you looking for? Maybe I can fill in that blank.

Tim

mmarlette · Joined: 30 Nov 2007 Posts: 311 Location: Delano, MN

Tim,

I am looking for some data points on range / terrain / data throughput.

At 1/2 mile range it appeared that you had 56kbs but not sure ATM if this was on an older module or this new one.

The range is good but in my field testing for my app it will be 1/4 mile, but terrain is not flat, 250 ft change in elevation in 1/4 mile(steep). This means I might have to design repeaters??

Data packets are over 1MBytes, can reduce but gauging for worst case in the design requirements ATM.

I suppose they say it is easy as long as you are on their C platform and tools.

Move off of that and it is where you are and me wishing I was where you are... Smile

No problem, it is mostly about research, then dive!

Any feedback appreciated.

Regards,

Mark

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1054

You may need repeaters, and sending more than 128 bytes is going to be harder. The txd and rxd buffers are each 64 bytes. They can be combined but still sending large packets is going to take some work. Look at AN633. That will give you an idea of what you are up against.

But even using C, the output from the WDS is still incomplete and needs editing by hand. So porting from C is not the real difficult part. BTW, we did not port the C code from HopeRF nor silicon labs. We ported the WDS output which is much like a C header file.

Tim

Dave · Joined: 05 Feb 2005 Posts: 314 Location: OR

Mark
I don't have any good data points but my sense after working with the rfm24/26w, rfm12b and rfm22 is that the rfm24/26w have much better range then rfm12b and slightly better then rfm22.

For you app try the higher power rfm26w or something with even more power.

You can have packets of any length but at some point your throughput is going to get smaller not bigger. For example if on average you get one bad bit every 10M bits your chances of getting 1Mbyte packets through are small. But if you break your 1M byte up into smaller 64 byte packets you will only have to resend one 64 byte packet per 1M byte on average. I'm just talking rough numbers here to make my point.

Also with the rfm24w or rfm26w small packets, <=64 bytes, are handled by the rfm. Bigger packets must be handled in your code making your code much more time critical and so harder to write.

One last thought, here in the USA you can have more power output without a FCC license in the 915MHz band then in the 440MHz band. I don't remember the numbers but it's something to look into if you haven't already.

Cheers,
Dave

mmarlette · Joined: 30 Nov 2007 Posts: 311 Location: Delano, MN

Dave,

Thanks for the tips. I will do some more reading.

As far as packet size, I should have said, typical file transfer will 500K-1.5M bytes. Packet size will be what works best and error checking can resend the corrupt packet for optimal performance.

Will look in to different frequency spectrum. Want to have a working prototype by late summer 2015 if projects go as planned. Then do they ever? Smile

Thanks again!!!! Good luck with your app!

Mark

protoncek · Joined: 16 May 2011 Posts: 52 Location: Slovenia

Mark, check out Hope's HM-TRP module, it has 100 mW power and it has very long range. It's somewhat expensive, but it's very nice to work with - it has serial communication and only a couple of commands. I have 868MHz module (i'm in Europe) and after i did some testing results are very good - 5km distance is easily acchieved, even more with appropriate antenna.
Modules are preprogrammed to certain frequency, although you can change it to 433 MHz, 916MHz in software .... range is then somewhat shorter, as output filter is calculated to factory freyuency. Also you can change output power in 6 or 7 steps.

Only - i don't know how fast is the module, since i sent only a couple of bytes at a time, so you should check out if it's OK for you, since you need bigger transfer rate.

MadAl · Joined: 26 Jul 2010 Posts: 48

Dear Tim,

I recently designed and built a project with loads of sensors and the Silabs Si4463 transceiver. Little did I know this chip is a bit daunting to use (understatement). I searched high and low on the i-net to get some info and my quest ended in this forum.
I am a user of Bascom so my expectations were high. The RFM26W hardware is basically what I have on my PCB, hooked up to an ATxMega. So my question is, can the RFM26W (or Si4463 for that matter) be kicked to life with Bascom? Did you manage to get some data transmissions? I am looking for a smple low bit rate way of getting some telemetry data across (GPS NMEA sentences and altitude).
Thanks, Allard

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1054

Hello MadAl,

Dave did most all of the front end work with the RFM24W, I think he got a RFM26 and has worked with that too, but he would need to confirm. I agree with you 100% on the challenges these parts encompass - along with the documentation. They just released a firmware update (Silcon Labs) for the 4460 and maybe the 446x but I have not installed or tried it. I do know that the output from the WDS is MUCH different when you change the 4460 from version B2 to C1. There also is much that is not included in the WDS output as well. I spent hours (more like days and days) trying to find answers. I did to many questions but only after searching the forums and then finding potential solutions from posts that had nothing to do with my search but at lesat provided some indication of why some things are not in the WDS - which helped dramatically.

To answer your question directly, yes it does work. It is complex, and nothing appears very straightforward - especially error handling.

Tim

MadAl · Joined: 26 Jul 2010 Posts: 48

Would it be possible to share some BasCom source code to get me going? I can then compare with the C code generated by the development suite.
If not, I understand and have to dig further. Thanks!

Dave · Joined: 05 Feb 2005 Posts: 314 Location: OR

MadAi.
If you contact me at "email address deleted" I may be able to help.
Dave

TSEYFARTH · Joined: 01 Jul 2006 Posts: 1054

Hi MadAl

I am sorry, I did not get a email with regard to your last post.
Send me a pm if you need material that Dave has not provided. We shared much together months ago, and we both have converters. But he did work specifically with the RFM26. I did all mine with RFM24W on both 900 and 433 mHz bands.

Tim

MadAl · Joined: 26 Jul 2010 Posts: 48

Thanks guys, very much appreciated. I sent Dave a PM.
For some reason I have troubles changing my email address. The page doesn't accept my userID/password.
I registered some years ago under an old email.
Pls. contact me under ******
thanks!

MadAl · Joined: 26 Jul 2010 Posts: 48

Dave, you email address bounces. Something wrong with your server?