JR X-Bus Mode B

[rickp]

Spurred on by Marty and Phil, I poked at a new JR X-Bus receiver, in Mode B. The hope was that we could understand enough of it so that Marty and I could use that RX direct into the Pixhawk in lieu of PPM. Turns out that its pretty simple - looks like the SXRL Multiplex protocol, running at 115200 baud, 8n1:

Default:
0xA1 0x0800 0x07FF 0x0800 0x01B7 0x01B7 0x0123 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0xDEAC

Aileron high:
0xA1 0x0CB7 0x0800 0x0800 0x01B7 0x01B7 0x0123 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0xCD2B

Elevator high:
0xA1 0x0800 0x0348 0x0800 0x01B7 0x01B7 0x0123 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0xC5F7

Rudder:
0xA1 0x0800 0x07FF 0x0E48 0x01B7 0x01B7 0x0123 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x324C

Throttle:
0xA1 0x07FF 0x07FF 0x0800 0x01B7 0x0E48 0x0123 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x4929

Ch 5:
0xA1 0x07FF 0x07FF 0x0800 0x01B7 0x01B7 0x0EDC 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x01B7 0x4CF7

Simple enough to decode - I';ll be looking at making this work with the Pixhawk when mine arrives...

[Marty McFly]

Thank you so much Rick,now I can use my beloved XG8 with the Pixy,I am one seriosly happy bunny and you are a super star,Marty, :scotland:

[rickp]

Yup, this is great news for those of us using JR and who want to use pixhawk with its lack of PWM converter. Does mean a new RX, but at least its not a new TX...
I';ll poke the pixhawk code once mine arrives, but it looks to be quite straightforward looking at whats there now...