The manual for the Crossfire system can be found on Team Blacksheep’s website here. Note that this manual is for all Crossfire parts, not just the micro bundle that I purchased. The documentation for the micro kind of sucks, which is the reason I am writing this guide.

How to Install the Crossfire Receiver in a Quadcopter

The TBS manual is a little lacking when it comes to explaining how the Crossfire Micro RX should be wired to a miniquad. I’ll try to ameliorate this problem in this section.

The first thing to understand about Crossfire receivers is that almost all of the pins can be mapped in software. What we will be doing in this guide is configuring the Crossfire Micro RX to have a pin configuration that looks like this:

tbs crossfire

This should simplify wiring a bit. Remove the pins for channels 3 and 4 as we will not be using them. Wire everything else to the flight controller as normal: GND to GND, 5V to a 5V pin, CRSF TX to a UART RX pin and CRSF RX to a UART TX pin. Unlike Smartport telemetry, you must connect both CRSF TX and CRSF RX to the same numbered UART.

Note that CRSF is not an inverted protocol. You cannot wire it inverted pins on F4 flight controllers, which are often labeled “SBUS” or “SPORT”.

Mounting the Crossfire Antenna

The TBS Crossfire RX antenna is fairly unique in how large it is. As a result, mounting it on your quadcopter can be quite challenging. In order to maximize your range, you should attempt to mount it on your quadcopter in such a way that the end of the “T” on the antenna floats out in free air with both ends of the antenna pointing away from each other. It does not appear that TBS stocks spare antennas for their micro receiver. As a result, the most important factor in your mounting decision should be to keep the antenna away from the props. Here is how I mounted the antenna on my quadcopter:

tbs crossfire mounting

Note on this install, the antenna is fully 4 inches below the props. It is stabilized via a T-formation of 3 zip ties which are glued to the FPV antenna in such a way that the antenna is kept very far below the prop arc. In this configuration, the antenna is high up in clear air when the quadcopter is flying at speed. Some interference will occur between the VTX antenna and the CRSF antenna but I deemed it acceptable.

Searching Google images for “crossfire antenna mount” will result in plenty of example images (some of which are quite poor) which you can use for your own placement ideas. There are also several 3D-printable antenna holders available on Thingiverse.

Crossfire TX Firmware Update

Before you do anything, you should make sure you have the latest version of the Crossfire firmware on your TX module. Start by installing the TBS Agent software found here.

Once you launch the TBS Agent software, plug your Crossfire module into your computer and you should see something like this:

tbs crossfire agent

Click “Update” to update the firmware.

Taranis X9D Set-up

One of the coolest features of the Crossfire system (to me) is its integration with the FrSky Taranis. Unlike most other radio modules, the Crossfire module utilizes the scripting functionality available in the Taranis’ OpenTX operating system to allow you to do all your programming and set-up from the front controls. It is about as close as possible to transforming your Taranis into a real Crossfire radio.

Unfortunately the price for this convenience is a rather complicated (and not well-documented) set-up process. I’ll go over that process in the following steps.

Upgrade your Taranis to OpenTX 2.2.0

The first thing you’ll need to do is make sure that your Taranis is running the latest version of OpenTX, version 2.2.0. This release was made in May of 2017, so most of our readers will likely need to perform this upgrade if they have not already.

We recently put together a guide on updating the Taranis firmware – check it out if you haven’t done this!

Get TX Module Working

Once you’ve upgraded to OpenTX 2.2.0 (or later), you should have everything you need to get your radio to talk to the Crossfire TX module.

Start by plugging the module into the Taranis, if you haven’t already. The pins in the transmitter port are long and can bend – make sure they are actually going into the Crossfire TX module’s sockets. Mine were not, instead jamming themselves into the Crossfire TX module’s plastic case. This caused the module to be almost impossible to remove, and it obviously didn’t work. A little bit of pin bending fixed the problem.

With the module properly plugged in, turn on your Taranis and create a new model for your quadcopter that will be using Crossfire. If you already have a model for that quadcopter (converting to Crossfire), you can just use that existing model.

In the Model Setup page on the Taranis, set the Internal RF mode to “off”. This must be done first. Next, set “External RF” to “CRSF” with a channel range of CH1-16.

taranis setup tbs crossfire

Once you exit this menu, your Crossfire TX module should power up.

How to Pair Crossfire RX to Crossfire TX Module

The initial pairing process between the TX Module and the RX is both easy and a bit frustrating. That’s because the Crossfire TX Module was clearly designed with its bigger brother in mind, which has a status display which the user can use to view messages and warnings. With the Micro TX Module, you only have a light.

Here are the steps for your first pairing between a TX module and a micro RX:

  1. Turn on your Taranis.
  2. Short press the button on the back of the TX module.
  3. The light on the TX should blink green.
  4. With the light blinking green, power on the RX.
  5. The light on the TX should blink blue. If it does not, short press the bind button on the RX.
  6. A blinking blue light indicates the TX module telling you that it cannot pair with the RX because the RX is running a different firmware version than the TX module. Luckily, the Crossfire can do an over-the-air update:
  7. Press the TX module center button again to start the OTA update.
  8. The light on the TX should turn solid blue. The light on the RX should turn solid green.
  9. After approximately 2 minutes, the TX light will breath green and the RX light will rapidly flash green. The RX is updating its firmware.
  10. After the update is complete, both the RX and TX will stay green.
  11. Pairing is complete.

Here are the steps for subsequent pairings between a TX module and an RX:

  1. Turn on your Taranis.
  2. Short press the button on the back of the TX module.
  3. The light on the TX should blink green.
  4. With the light blinking green, power on the RX.
  5. The RX and TX should flash their lights a few times and end up on a solid green light.
  6. Pairing is complete.
Configuring your Crossfire micro RX to work with Betaflight

Once your TX module and RX are paired, you can configure your RX from your Taranis. Long press Menu from the home screen to enter the Radio Setup page. Press “page” once to enter the SD Card menu. Select the “CROSSFIRE” folder and long press “crossfire.lua”. Select “execute”. You can now configure both the Crossfire TX and RX. You can tinker with these settings however you like, but you must configure the RX output mapping to get the receiver to talk to Betaflight. To do this, press into “XF Micro RX” and “Output Map”.

“Output Map” is where we tell the receiver to talk via the CRSF protocol on its first two pins. Configure your RX as pictured:

tbs crossfire crsf taranis

While in this menu, you may also want to configure a RC channel to output RSSI so Betaflight can pick up the signal strength of your radio control system and display it on your OSD. Do this by scrolling down to the “Channel Map” section and changing one of the channels (6+) to RSSI. I chose 8 here:

taranis rssi config

How to Configure Betaflight For Crossfire RX

With your Crossfire system installed in your quadcopter and your radio system fully set-up, it is time to finally tell your flight controller how to talk to your new radio control system. This part of the set-up process is very easy.

First, go to your “Ports” tab and configure the UART you connected CRSF to as a “Serial RX”:

betaflight ports

Next, go to the “Configuration” tab, and make the changes in the red boxes found below:

betaflight config

Finally, go to your “Receiver” tab and make the changes in the red box:

betaflight receiver setup

After hitting “Save” in the Receiver tab, you should power on your Transmitter and quadcopter and wiggle your sticks to make sure that you see some response in this page. If not, go through this guide again to make sure you did everything right. Pay special attention to wiring, binding and RX set-up. You can also see our RX troubleshooting page.

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