How to use CRSF on one Serial with proto 23 (RCIN) for RC input in the same time as CRSF on another serial with proto 29 (Crossfire VTX) for VTX

ArduCopter Copter 4.1
1

Hi, I’m trying to use two different serials for CRSF RC (TBS nano RX) and CRSF VTX (TBS Unify Pro 32). My problem is that when I activate Proto 29 on the second serial, the first one RCIN stop working and my RX in not more seen by Arducopter. Is it a known problem or just not possible ?
Thanks

2

Protocol 29 is not designed to be used with protocol 23. Instead only connect your RX to the flight controller and use protocol 23, then connect your VTX to ch out3/4 on your RX and make sure this is configured to use CRSF. The RX will forward VTX packets between the flight controller and VTX

3

Thanks, that’s clear. Will try this wiring configuration.

4

Well, I did the wiring and now I can control the VTX from my CRSF TX (directly from LCD screen of TX or through my TX16s RC) which is cool but I can’t control it from Arducopter VTX functions. RX and VTX are both configured with CRSF protocol and RC is well recognized by Arducopter. I use only one Serial for the RC which is configured with proto 23. It seems that VTX commands from FC are not seen, or propagated, by RX to the VTX.

5

You need to set the VTX control function on the TX to “RX”, if you have it set to TX then nothing will work.

Let me know if this works for you - I have a change pending to improve this but am having all sorts of problems with different CRSF firmware versions which I am investigating with Trappy.

Also please post you firmware versions on RX/TX and AP version

6

Hi, Thanks for your reply. VTX control on my TX was already set to “RX”. Seems it’s the default value. Here are some informations about my setup:
TX/RX firmware: 6.13
VTX firmware: 1.15
AP version: V4.1.2 (03bf772a)

7

6.13 has a known bug with VTX control. On my Chimera I was using 6.10 with good effect, although now I wonder whether it was only entering and exiting pitmode that was working properly.