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Bare minimum 8ch TX to XJT module?

Posted: Tue May 28, 2019 9:25 am
by TimShoo
Hello everyone. I made my own TX a while back using a ps4 controller, usb host shield, arduino leonardo, and maple mini. The only reason for the maple mini(could have been any arduino board I had but this one was on top of the box) was because the ps4 controller sketch used 96% of my program space. The leo just sends the values through serial to the maple, then the maple spits out ppm to the trainer port on my Q-X7. The main problem is that now I have to lug around a ps4 controller, the arduino/maple stack and the Q-X7 if I want to use the mod. I don't need a screen or model selection or anything fancy, I just need something to talk to the XJT module that I just bought.

I've been searching all week, found a cppm to pxx library that didn't work(or even seem to put out the correct wave form according to my headphones), some outdated pxx documentation and random bits(and arguments) about pxx protocol. The XJT manual says that it accepts ppm and pxx and will automatically decide witch one to use but I can't get the XJT to do anything with my setup or ppm for the external module selection on the Q-X7. Works fine in XJT D8 and D16 on the Q-X7.

So my question...
What do I need to get rid of, and from what firmware, to simply send my stick values successfully to my XJT. Or do I need to do something else with the ppm stream that nobody else is talking about.

Re: Bare minimum 8ch TX to XJT module?

Posted: Tue May 28, 2019 1:21 pm
by Kilrah
PPM straight to the XJT should work. It might need a firmware older than latest.
Don't forget to set the DIP switches correctly for your receiver type.

Re: Bare minimum 8ch TX to XJT module?

Posted: Wed May 29, 2019 2:42 am
by TimShoo
Does the signal need to be present at startup or should there be a delay? Also does the xjt send anything back? I see an s port plug and a serial port on the back but it would be nice to get s port through the module instead of running more wires around to the other side.

Re: Bare minimum 8ch TX to XJT module?

Posted: Wed May 29, 2019 12:59 pm
by MikeB
No need for a delay. Telemetry data is sent on the bottom pin of the module connector, the same data as on the SPort connector on the back.

Mike