Need help with rfd900x

So I am generating a SBUS signal with 100000 baudrate, 8 bits,even, 2 stop bits, and want to transmit this signal wirelessly to reach my flight controller. To do that I am using the rfd900x, more specifically the pin 15 that can be configured to a SBUS pin.

The local unit is correctly configured as input SBUS and the remote as the output, as shown below:

S16=0 GPI1.1 RC-IN S16=0 GPI1.1 RC-IN
S17=0 GPI1.1 RC-OUT S17=0 GPI1.1 RC-OUT
S18=1 GPI1.1 S.BUS-IN S18=0 GPI1.1 S.BUS-IN
S19=0 GPI1.1 S.BUS-OUT S19=1 GPI1.1 S.BUS-OUT

I don’t think it’s the signal because I already tested physically connecting the source of the signal and my flight controller and it shows the SBUS’ channels. Do I need to do further configuration on the pair? Like changing their baudrate to match the signal or something? The signal is already inverted when it passes to the input unit.

I don’t know if this influences anything but the type of SBUS I am using encodes encodes 16 RC channels and 2 digital channels and each frame is transmitted every 15ms and Failsafe state is transfered via single is flags byte.

The data baud rate is independent of the RC Control signals, so long as the NetID and a few things are matched.

Are you using two RFD900X radios with the ground radio getting an external input?
Or are you using the TXMOD in a JR bay and an RFD900X in the air?
What RC transmitter do you have?

Any particular reason for parity and 2 stop bits??
You don’t necessarily need RTS/CTS and you definitely dont need ECC unless there is a security requirement.
What are all the rest of your settings in the radios?

What are your Ardupilot parameters for the serial port in use?

For higher than standard data rates with RFD900 radios you can use:
Baud 115
Air Speed 200
Max Window (ms) 80

Hello, thank you for answering,
So, I am using two units of rfd900x, with the ground radio’s pin 15 getting the sbus signal input and configured the pin to deal with sbus protocol;

I am generating the sbus signal from a microcontroller;

The SBUS protocol requires the parity and 2 stops bits;

Is there a specific setting you want to know?

I didn’t do any configuration in Ardupilot because I am not using a serial port, I am trying to use the RC IN;

You will need to take control with conventional RC at some point

Yes you would definitely use the RCin for the SBUS RC signal. You should also set up a serial port and use the telemetry data feature of the RFD radios - otherwise you are doing this all for nothing and you should have just bought a long range RC transmitter and receiver.

I’m not sure of the overall aim, but I would strongly recommend using normal RC control with a conventional transmitter like a Taranis or whichever you prefer. You can still use an RFD radio in the air and a TXMOD on the transmitter to handle the RC signals AND the telemetry. - or use a conventional transmitter and receiver, depends on budget and other requirements.
Use the telemetry of the RFD radios for your microcontroller or ground station and Guided mode when you want computer control. This is what the radios and guided mode is made for.

I dont see the value in generating the SBUS signal from a microcontroller and transmitting that over RFD radios and NOT using the telemetry features.

Obligatory car analogy, please take in jest:

  1. It’s like buying a Ferrari just to drive to the shops - overkill
  2. Use a horse to pull the Ferrari to save fuel, or just see if it can be done