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For a strange project I need to measure the PWM of the Airplane Remote Control Receiver Servo 5 outputs and each one will through a PIC control a digital pot.
My question is if the outputs of a RC receiver are in sync between them. I mean, if all say 10 outputs of the receiver are set to high at the same time every 20ms and then each pulse will stay high for the corresponding channel control signal.
Ioannis
Hi, Ioannis
Halas, the Rx outputs do not work like that ... and there are many solutions ...
1) classical output ... the signals come from a shift register, so, the second channel begins ~ 10 NANOseconds after channel 1 signal falls ...and so on. ( see 4017 Datasheet ...)
2) µPoutput, here, channels can be outputted 2 per 2 or 3 per 3 ... sequence is i.e. ch1 + 5,ch 2+6, ch3+7, ch4+8 ... leading edge synchronized.
3) and, for some others ( generally old PCM systems ...) Ch, 1,2,3,4,5,6 ...Ch 1,2,3,4,5,7 ...Ch 1,2,3,4,5,8 ...
So, no universal output capture device possible ... you must know wich rx you will "sample" ...
There's a thread about these days on RC Groups :
http://www.rcgroups.com/forums/showthread.php?t=752440
The guy is from china ... "Shanghai fool" ...
Alain
Thanks a lot Alain.
This project was strange for me at the beggining. I did not thought that other people might do similar things!
Ioannis