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Re: [Gumstix-users] How to read in PWM on Robostix
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From: Marq R. <mar...@ya...> - 2007-12-28 21:24:00
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Dave, Thanks a ton for your help. I have been researching and have came across the same stuff. I have downloaded the SmartPropo program and tried it with my remote. I tried to configure the remote to the flight simulator but it cant seem to make sense of the data the remote is giving it. After playing with it for a while I could not get it to work and decided to go a different direction. Also looking into their web page some more I think they only support the older JR pcm coding. I have found an older style receiver the uses the ppm setup and changed my remote to work with it. Reading your code you say that you want to give the clock signal from the receiver to robositx. How can you tell what the remote it doing from a clock signal? Reading the third document that you reference on the wiki and in the RCInput.h file figure 29 signal A is only a clock and does not correspond to the input data. I was under the assumption that I would want to read in signal E as in figure 30 in the same paper or signal D0 from a scope reading I collected for this receiver: http://i98.photobucket.com/albums/l249/TurboFiero/pin_8.jpg I am also trying to understand the code in the RCInput.c file and am having a hard time seeing what is going on. Is there somewhere I can read about some of the variables/functions you are using. I would have a hard time writing code like this, but need to learn how.... any suggestion on where to start? I have got the RC-Test code up and working with 2 channels and am working on getting it reading all 6. I have changed the Num_Channels to 6 and a couple of the conditional statements from 2 to 6 but it is still only reading 2 channels. Do I need to change the Num_Avg_Samples to a different value? I am not using a LCD and change all of the LCD print statements to regular ones and am using serial_log to view the data. Thanks -Marq Dave Hylands wrote: > > Hi Marq, > >> > I hooked each PWM channel up to an oscilloscope and probed around the >> chip >> > until I found something that looked like data. Here are a few screen >> shots >> > of the scope: >> > channels D1-D7 are the PWM signals that would normally go to the servo >> > D0 is the data coming into the chip >> > http://i98.photobucket.com/albums/l249/TurboFiero/test_4.jpg >> > http://i98.photobucket.com/albums/l249/TurboFiero/test_3.jpg >> > http://i98.photobucket.com/albums/l249/TurboFiero/test_2.jpg >> > >> > I also probed around the receiver and found what I think to be the >> shift >> > register and also a place that I can easily solder to. My problem now >> is >> > that I need to decode the information. Any ideas on where I can look to >> try >> > and figure this out? > > It may be that your receiver uses PCM encoding. This page has a tiny > amount of information: > <http://raph.people.8d.com/arm-linux-notes.html> > > And going back to your original post, I see that you're using an SPCM > receiver. > This page has some more details: > <http://www.aerodesign.de/peter/2000/PCM/PCM_PPM_eng.html#Anker144351> > > After a bit more research, I discovered a package called SmartPropo. > An older version, which includes source code (for Windows) is > available here: > <n.ethz.ch/student/mmoeller/fms/alpha/smartpropoplus.zip> > > Apparently, it's been converted into a sourceforge project, although > this doesn't seem to have any source. > <https://sourceforge.net/projects/smartpropoplus> > > This seems to be the home page: > <http://www.geocities.com/shaul_ei/SmartPropoPlus.html> > and it has links to the latest sources (Dec 2007) > > Some other random links which seem to relevant: > <http://www.runryder.com/helicopter/t229035p1/> > > -- > Dave Hylands > Vancouver, BC, Canada > http://www.DaveHylands.com/ > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2005. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > -- View this message in context: http://www.nabble.com/How-to-read-in-PWM-on-Robostix-tp14460836p14531633.html Sent from the Gumstix mailing list archive at Nabble.com. |
