Matek f405 Smart Port telemetry

Is there anyone who has gotten smart port to work on a matek f405 wing? I have the yaapu script running on my X9D and it says no telemetry. I also do not get the telemetry by discovering sensors. I’m using uart 6 with a yaapu wire connecting to the sport on an x8r. In ardupilot I’m using serial protocol 10 and serial option 7. If anyone has this working I would love to know how you have it wired and what ardupilot parameters you are using.

Thanks in advance!

The docs at specify a “non-inverted (hacked) S.Port signal”. This is probably the key.

Normal s.port is an inverted protocol (high voltage means logical zero, which is opposite to what the flight controller expects), and the F405 chip can’t invert arbitrary ports the way the F7/H7 processors can.

You’ll need to use an sbus inverter (like or you can make one with a transistor and two resistors). Alternately, you’ll need a receiver with a non-inverted s.port pin/pad as discussed at Uninverted SBUS and Smart Port on Frsky Receivers - Oscar Liang