Solved No OSD on Gremlin Guardian V2 w/ DJI O4 - TX/RX reversed!

[InsatiableAmos]

Hi Folks! I realized the DJI O4 Air Unit ("lite") would bolt right up to the Guardian and gave it a shot. Everything's working except arming and the OSD.

I *think* the arming issue is because Betaflight is unhappy I have uncalibrated accelerometers, which I will fix as soon as I actually mount everything.

The OSD issue is more confusing... I've wired it all up per the wiring diagram and configured UART1 for VTX MSP+Displayport duty. The O4 unit is clearly getting power since it links to the goggles and shows the basic Goggles OSD, however the OSD I've configured in Betaflight doesn't show up.

Any ideas? Any good ways to test my TX/RX connections?

BTW, I am not using the DJI remote for control, sticking with the R81 and that's working great.

 

[LitterBug]

I use walksnail not DJI but the serial connection should work the same. Give us a screenshot of the serial ports tab and the OSD config screens.

I have had issues with some serial ports, especially if they are configured for a receiver. they may have an inverter on them which messes with the signaling. Can you try a different serial port?
If you are using the standard Guardian FC, that should not be the issue. What version of BetaFlight?

 

[InsatiableAmos]

Running Betaflight 4.5.1 (updated to latest since the FC didn't come preconfigured)

Here are screenshots of the ports, OSD, and CLI settings that I know about...

Only other details I can think of are that I omitted the sbus and control ground when soldering the O4 unit, but that's generally what folks seem to advise when you're not planning on using DJI controllers...

 

[InsatiableAmos]

Solved! Someone on the FPV subreddit asked about how I'd connected the TX/RX leads, and it turns out I'd reversed them. Didn't know TX>RX and vice-versa.

A quick resolder and all is well!

 

[LitterBug]

Nice. That was going to be my next guess.