PPM output waveform
I am working on an engineering senior project to make a UAV. My job is to get the plane flying, while two teammembers work on the payload.
The design criteria for the project required the use of a TI microcontroller somewhere in the project. I am trying to replicate some of the functionality of the PPM encoder on an MSP430. I already have it measuring all 8 channels out of my Flysky radio (probably quite inefficiently), and can send that data out of a serial port. However, I have not successfully made a PPM signal that ardupilotmega can interpret. I might have a poor conceptualization of the signal, or I might just be going about it the wrong way. Could someone send me a picture of the whole PPM waveform? Preferably an 8ch one, but any would do.
Replies to This Discussion
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Permalink Reply by Ross Kerley on -
the attached picture is the closest approximation to the PPM waveform that I have made. It has 8 pulses of 1.5ms each, separated by approximately 0.250us. The pulse sets are delimited by a single 3.75ms pulse.
Should that timing be read by the APM firmware?
I have it going into pin PL0 on the atmega2560. There is a solder jumper that could connect it also to PL1, should that be shorted?
- Attachments:
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tek00003.png, 32 KB
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Permalink Reply by Ross Kerley on
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Neither the GUI or CLI report receiving any signals from the radio.
What am I missing in the waveform?
I haven't attached sensors yet, do they need to be present for it to analyze the PPM stream?
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