RC5 questions

[jlcstrat]

I've Googled my brains out for days, and can't seem to find out an answer.  With RC5 remote controls, is there a modulated carrier that the pulses are on?  I know the highs are pulsed around 36Khz, but is this signal modulated again with a steady 36khz wave?  I need to write the c-code for a pic, and it would be much easier if there was no "second" modulation.

[jahonen]

I'm not sure what you mean by second modulation, but with Philips RC5 code, Logic 0 is sent as 889 µs burst of 36 kHz carrier and then 889 µs of "silence". Logic 1 is respectively other way around. I think this page shows it quite clearly.

Regards,
Janne

[jlcstrat]

Thanks, that's what I thought.  I read a couple things that suggested that that pulsed waveform was then modulated again with a 36Khz sine wave.  That was where I was having a hard time coming up with any sort of code.

[Thermal Runaway]

Hi, what are you up to with RC5? I designed and built an RC5 decoder earlier in the year, just for fun, and so now I know the RC5 protocol backwards.  I can probably help you with any questions about the protocol, or how to use it in a project.

Check it out in prototype form:



And in a first build form:





I have started writing an explanation of RC5 which will build into a tutorial on how to design a project that uses it.  But it's not finished yet.

Brian

[jlcstrat]

Brian, I saw your pics on another forum.  I might be changing protocols.  This is just a project for school, and I don't have any remotes laying around that use RC5.  I think I'll just take the most convenient device and base it around that.  I'll definitely find you if I get stuck.

[Thermal Runaway]

I used a Philips Universal Remote to generate RC5 codes.  It's good because you can select from TV, VCR, SAT1, SAT2 modes - this gives you the option of sending commands with different addresses.

Yeah sure - give me a shout if you need any help. 

Brian