Hi Guys,

running speedybeef 3.5.7 on my speedybee, flashed fport firmware on my r-sxr reciever, connected the s.port wire of the reciever, set FBUS in settings tab, however:


only on uart 2 (default reciever/sbus port) i get stick output on in the transmitter tab of betaflight but no telemetry on the radio.

I know I shouldnt use the uart 2/sbus for flying but instead use a different uart. however i never get the stick output shown nor telemetry on my taranis q x7.

tried uart 3 and 4 with half serialrx_duplex on/off, and serialrx_inverted on/off but no telemetry nor stick reaction on the transmitter tab.

anyone any idea how to fix? thanks in advance!

Even with F.Port firmware, the S.Port pin on the R-XSR still outputs an inverted signal that your F4 flight controller can't handle. Your FC will need an uninverted signal. So if you want to use F.Port with your F4 board you have two options:-

1. Solder a wire from the minuscule "P" pad on the R-XSR to a the TX pad of a spare UART on your flight controller.
   
2. Do a mod to your R-XSR by cutting the S.Port pin and soldering a wire from the minuscule "P" pad to the S.Port pin so that pin is re-purposed as an uninverted S.Port pin. There is a how-to on doing that HERE courtesy of Scott_M. Take note of Voodoo's comment in post #5 of that thread suggesting that you re-purpose the SBUS IN pin instead.
   

Then run the following commands in the CLI. This assumes you will be using the TX pad on UART 3...


If you use the TX pad on UART4 then replace the "2" directly after the "serial" command above with a "3" (that number is the UART number - 1)

It sounds like you are using the SBUS pad on the FC, which is a UART RX. You need to solder to UART TX. On Speedybee, I would used T1 or T3. You need the "P" as indicated by Snow or hack I suggested in the link.

Thanks for your swift reply!
I was under the impression that ANY F4 flightcontroler was able to use the FBUS with the r-sxr's S.port pin without doing the mod or using the solder pin.

Your mini howto makes perfect sense so thanks very much!

I will work on option 1 tonight and keep you posted

(21-Mar-2019, 05:28 PM)Guarana Wrote: I was under the impression that ANY F4 flightcontroler was able to use the FBUS with the r-sxr's S.port pin without doing the mod or using the solder pin.

Sadly not. There is also nothing wrong with the original proven 2-wire SBUS & S.Port setup so you still have the option of using that if you want to. You can do that without any uninversion hacks because the SBUS pin just goes to the SBUS pad on your FC which can handle an inverted signal, and the S.Port pin goes to the TX pad of a spare UART on your FC. Then you just configure and enable SoftSerial for that UART which will uninvert the S.Port signal.

The three main advantages of using F.Port is less wires, you only tie up one UART, and RSSI is sent directly from the receiver to the flight controller without having to send it back from the transmitter over a spare channel.

Although the F.Port protocol is non-inverted protocol, currently it is still using S.Port pin to push out the signal which is inverted. And S.Port on Frsky receiver are all hardware inverted. As long as Frsky uses S.Port for F.Port it will still be inverted. In the future, I can see them releasing an F.Port only receiver. For example, the R9MM has an pin called "inverted S.Port", but they could have easily just called it an F.Port pin.

Here is a good read to what I am saying.

https://www.propwashed.com/frsky-fport/

Fixed used the pad and uart 4.
Downside... one of the antennas ‘clicked’ off..
Cleaned it and snapped it back on.
Now have to wait 24hrs for the E6000 glue to dry... no flying tomorrow

(22-Mar-2019, 12:29 AM)Guarana Wrote: Fixed used the pad and uart 4.
Downside... one of the antennas ‘clicked’ off..
Cleaned it and snapped it back on.
Now have to wait 24hrs for the E6000 glue to dry... no flying tomorrow

I am a big fan of the UV cure glue like Bondic or something similar.

UART 4 is meant for ESC telemetry. But you can use it.

I’m not using esc telemetry for now so that’s no problem thnx for the UV glue tip. Have to check if it’s available in the Netherlands