This tutorial explains how to setup the R9M TX module and R9 Mini receiver in Betaflight. The R9M is a long range module that operates on 900MHz band. It’s compatible with most Frsky’s radios including the Taranis X9D-Plus, QX7 and Horus X10.
You can get the FrSky R9M from these vendors (some are R9 Mini bundles):
R9 Mini Receiver – Beware!
The original R9 mini receiver has the SBUS_IN for redundancy feature. But I guess that’s not being used much so they have decided to replace it with “Inverted S.Port” in the new version – R9 MM.
In the new version, you now have two SmartPort outputs, one inverted, and one uninverted. It’s really confusing I know, but basically, you’d want to use the “Inverted S.Port” as shown in the manual for F4 boards, the FC can read it directly without extra inverters or using Soft Serial. This pin is also used for FPort so it’s even more important!
If you are using F4 boards, and getting new receivers, make sure it’s the new version – the “R9 MM”. For F3 and F7 boards it doesn’t really matter as they can understand both uninverted and inverted S.Port signal just fine.
This post explains what “inverted SBUS and SmartPort signals” are.
Buy the R9 MM here:
Update OpenTX on your Taranis to the latest firmware, at least 2.2.2 or newer. For instructions: Tutorial: Flash OpenTX (2.2) firmware to Taranis
And also update the R9 Mini receiver to the latest firmware for bug fixes and improvement. It’s a popular option to flash it to support FPort, you can download the firmware here:
Note: Don’t flash the FPort firmware if you want to use SBUS!
- On your Taranis, go to Model Setup page
- Turn OFF “Internal RF Mode”
- Under External RF, Mode, Choose R9M
- Set Failsafe to your desired option, I prefer “No Pulse” as explained in this post
You can also change the power level here: 10mW, 100mW, 500mW, 1W. The lower the power, the longer battery life you will get. Remember, the range should double as power is increased 4 times, theoretically. (Maybe only 2 to 3 times in real life)
The wiring depends on what receiver protocol you plan to use. If you have the “R9 MM” receiver with the “Inverted S.Port” output, then you might want to use FPort.
If you have the original “R9 Mini” that comes with the “SBUS_IN” pin, it’s going to be tricky to set up FPort with F4 flight controllers. I see some people use Soft Serial as a work around, and it’s okay for things like SmartPort Telemetry. But I wouldn’t recommend doing it for RC links because the update rate might not be fast enough (not confirmed though). So if you are in this situation, maybe just go with the old method, use SBUS with SmartPort.
For FPort, the connection is only 3 wires: 5V to 5V, GND to GND, TX pin of a spare UART on the FC to the S.Port pin on the Receiver.
For SBUS and SmartPort, here is the connection:
Follow this tutorial to setup SBUS and SmartPort, it should get the job done and you can skip the rest of this post 🙂
If you want to setup FPort, please continue with this post 🙂
Here is how to setup FPort in Betaflight, to summarize:
- Fire up Betaflight Configurator
- In the Ports tab, find the UART you’ve connected to the receiver, and enable “Serial RX”
- In the Configuration tab, Select “FPort” in Receiver Protocol
Now check in Receiver tab if the channels are working (if they move with the sticks), and if you are getting telemetry data.
If the RC link is not working, try changing this setting on and off in CLI:
set serialrx_inverted = ON
If telemetry isn’t working, try setting this on and off:
set serialrx_halfduplex = ON
Also try select “Rediscover Sensor” in your Taranis’s Telemetry Menu.
Still not working? We can help you on IntoFPV forum.