Decoding Syma 107 RC signal (IR coaxial) with PIC18

[Triode]

I'd like to make a PIC18F1320, or any PIC 18, receive the signal from a syma remote. Someone on an RC forum decoded the transmission method as this:

carrier frequency: 38.17kHz (26µs period)

(all timings in µs)
constant length, package-to-package 328000
header: 474 pulse, 314 space, 1669 pulse, 293 space
zero: 440 pulse, 300 space
one: 890 pulse, 300 space
end: 440 pulse, 303000 space
length of data: 28 bits, 4 groups à 7 bit
no checksum, rotational trim is transmitted as extra value, forward/backward trim buttons are transmitted as single bits

I am not familiar with this encoding type, so I'm not sure where to start. I can read pulse widths since I have learned to capture PWM signals, but I figure this may be a job for the USART module, or some other existing peripheral or method. I have gathered that it is probably IR coaxial encoding and that UART may be able to read it.

 

[Pommie]

If you receive the signal with a standard IR receiver and feed the resulting signal to the capture/compare pin, you will be able to use the CCP module to get the timings (as you already know). The decoding can be done in an interrupt. I would attempt to detect the start pattern first and see if you get the right number per second. Then go on to detect the individual bits. If you have a junebug then you already have the required hardware. I have somewhere posted a thread about reading IR remotes on here but can't find it.

Have fun,

Mike.

 

[Triode]

Thanks, that's the approach I was thinking of. I just wanted to make sure there wasn't a better way that I hadn't heard of. I'll post about how it goes.