The XM+ radio receiver is a tiny SBUS diversity RX from Frsky. It’s insanely light weight making it a great alternative to X4R-SB and XSR RX for micro quad builds. In this post we will show you the features of XM+ and how to use it.
Get your Frsky XM+ receiver from http://bit.ly/2nx0pe6
For more information about RX, check out our list of Frsky radio receivers for mini quads.
What are the advantages of XM+ receiver?
- Much smaller size and lighter weight than X4R-SB and XSR
- It’s a full range receiver, similar range to X4R-SB and XSR
- Using same antenna/connector as the X4R-SB, replacement is very easy
- It’s possible to direct solder RX to FC with header pins without wires (if FC supports it)
- Only 3 pins: Vcc, GND and Signal – there is no confusion
- XM+ is even smaller than the LR1000 by FuriousFPV, great RX option for their micro quads (such as the Moskito70)
Only downside of XM+ RX is the lack of S.Port full telemetry (Smart Port), there is only RSSI telemetry. RSSI has a dedicated solder pad and it’s also available on the 16th channel.
More info on XM+ RSSI Output
For those who would like to display RSSI in OSD.
RSSI pin outputs PWM signal (0-3.3V). Please be aware that this signal should not be connected to MinimOSD directly, as it will give you 0% or 100% only. You will need a digital to analogue converter (low pass filter) to convert PWM to analogue voltage level.
However the XM+ can output RSSI through Channel 16, so in Betaflight/Cleanflight should be set to use CH16 for telemetry signal and limit aux channels to 12.
Binding and Failsafe
Binding and Failsafe Setup process is exactly the same as other X series Frsky Receivers:
Red LED on RX means it’s not bound or not detecting TX. To bind, enter Bind mode on TX, hold down F/S button on RX and power on. After a few seconds, Green LED will light up indicates binding has completed.
To setup up failsafe, power on both TX and RX. Set your TX channels to desire positions, and press the F/S button on the RX. The green LED should flashes and indicates F/S has been setup. Please confirm if F/S is now working as expected by turning off TX. To remove F/S, simply rebind the RX.
Differences Between XM and XM+ (plus) versions
Both are SBUS receivers, but there is some differences between the 2 RX.
- Size and Weight are different
- XM – 15.0×10.0x3.5mm – 1.0g
- XM+ (plus) – 21.5x12x3.5mm – 1.6g
- The XM+ has Diversity Antennas (2 antennas), XM only has 1 antenna. Diversity antennas gives better range
- Slightly different input voltage:
- XM – 3.5V-10V
- XM+ (plus) – 3.7V-10V
RX is bound, but not getting signal in FC
One common problem getting SBUS to work: RX is bound to TX (solid LED on RX) but not getting signal to FC (no activity in receiver tab).
- Make sure TX is in D16 mode
- Some FC has built-in SBUS inversion, some don’t. Try setting SBUS inversion on or off, it normally fix it
sbus_inversionSERIALRX_INVERTED = on
Common mistake after typing in set SERIALRX _INVERTED=on
You have to type “save” afterwards or it won’t take affect the next time you boot up.
Someone will say “duh”! But if this is your first stab at CLI commands you may not know that.
I can’t bind xm+ to frsky q x7 access? I wondering if these two are compatible, any ideas?
You might need to flash to fcc firmware on the xm+. Check the internet for how to flash it. Its not easy.
Hi, I got a issue with the last firmware update of my FC
Everything was working fine but with the update the my xm+ is not detected anymore from the FC. It is connected with the SBUS pad, I also tried to solder again all, but nothing. The bind it’s ok because I have fixed green light on and red when I turn off the radio, but nothing change on my FC. I am using a Racerstar starf4s, I don’t have idea what is going on with this last firmware flash
Please help me
please could you post your question on IntoFPV.com? we will help you go through some troubleshooting steps.
Hi, how to show signal strength of XM+ on TX?
RSSI is on channel 16, so select channel 16 in RSSI channel in Receiver tab.
H ello Oscar
I have a problem with the XM +! as soon as I am close to my drone (20 cm) with my radio Qx7 it starts in failsafe. And as soon as I go away it reconnects and I can fly far enough without problem!
Thank for you answer !
You are running into a phenomenon known as “swamping”. It’s pretty normal and 20cm isn’t bad at all.
See electronics.stackexchange.com/questions/455233/what-does-it-mean-to-swamp-a-radio-signal for details.
I have the XM+ Micro. It always failsafe eventhough I am very near like 5 meters distance horizontally and about 5 meters vertically. Though I am under a tree and a tall concrete chimney.
Can I get RSSI value in screen of Taranis QX7 radio with XM rx?
Yea, use this trick.
I binded xm receiver with taranis x9d+. while binding ,everything looks great, all lights like must be . but tx does not show signal status. when I plug into battery ,ESC’s are beeping but it is not rx matched beeping. it is like there is no rx. I want to use it with pixhawk . can you help me ?
Hi I’m using the XM+ as a slave reciever to a G-RX6. and am trying to get the RSSI from the XM+ connected to the AIN2 on the G-RX6. I’ve connected the RSSI pad on the XM+ (the one on the back near the S pin) but It on gives 0 or 3.3v is this a firmware issue or is the pad out not a linear voltage output. Thanks
I was from spektrum. I now have x-lite with xm+ dropouts at 10metres range. Worse than spektrum Oem rx i have used in the past.
What the heck is wrong?
Hi Trying to get RSSI output from ch16 only getting fixed 50% output it does not change ever any ideas what I’m doing wrong. I’ve gone through all the setup videos I’m on BetaFlight 3.2.5 so having to use Aux 12 channel but still no joy. RSSI output always says 50% I’m using QX7 with non-eu external module for global receivers
Update your your firmware will fix this issue
The xm/xm+ don’t come with the rssi ch8 or ch16 firmware from the factory. You need to update the firmware with an fdti or a taranis to make use of rssi via osd. There’s videos on how to do it on YouTube.
Flash the xm+ with the rssi firmware.
I have just received the Bfight 210 with the XM+ already installed. However I have tried for hours to bind this to my taranis qx7 and nothing is working. any suggestions?
Maybe RX and TX have different types of firmware on them.
Check what firmware you have on the TX (if you don’t know already), and flash your RX to make sure:
Hi my has that issue it binding fine both no switch inputs are showing active on the quad or in betaflight. Tried switching inversion in cli no diffrence also is in D16 on tx. Please shed some light.
I do not understand if it is necessary to have DAC or not in order to have RSSI with XM+. It seems that channel 16 of betaflight can handle the input signal as it comes directly from the rssi pad of the xm+, I m confused.
“You will need a digital to analogue converter (low pass filter) to convert PWM to analogue voltage level.
However the XM+ can output RSSI through Channel 16, so in Betaflight/Cleanflight should be set to use CH16 for telemetry signal and limit aux channels to 12.”
Just wanted to say I really appreciate all your reviews you’ve done since the beginning! They’ve all been really informative. I do have a question related to caps.
To install caps on mini-drone is it just cap negative to negative (esc or pdb) and cap positive to positive (esc or pdb)? Maybe it’s just a silly question
Yes that’s correct.
Hi Oscar, I recently ran into this problem when setting up a new AIO FC with blheli 32 esc on betaflight 3.2. I set it up as usual with my frsky XM+ using sbus but it wouldn’t arm the quad and I notice upon powering up the FC the LED indicator would flash non stop which normally indicates if there is no signal from the rx. But as soon as the FC is usb connected into Betaflight GUI the led flash stop and i could see in the GUI rx tab that all the channels would work normally. I disconnected from GUI and power cycle the quad and again the same thing happened. I did what you said doing the sbus inversion on/off in CLI but still it wouldn’t work. I replaced another new XM+ with the same disappointing results. I did all the firmware updates on the XM+ but still it does not work and all this time the XM+ was bound to my taranis with a solid green light. Than with the last try, I had an old Frsky XSR rx and i plugged it into the FC and tried, immediately it worked like magic. Power up the quad with the usual motor sounding and the FC led blinking afew flashes and stop indicating is ready to arm. And it did arm, this quad built was like any other quad that i have built ready to be flown. This is the 1st time i have encountered that a FC would only take a XSR but not XM+. Any thoughts on this?
I unfortunately have the exact same problem.
I have updated the firmware on the XM+ with XM+LBT170313-RSSI8.frk as my XJT module is in LBT mode.
The 2 are bound fine (solid green light) but I have no signal in base flight. The FC is an afromini rev 3.
Just like you it does work fine with an XSR.
Did you manage to solve the problem?
I know that this is an old thread but I have just discovered that if you connect the RSSI pad to the FC (in my case a Kakute F7 AIO) and also use channel 16 for signal monitoring at the same time then I kept having trouble keeping the connection with the controller (Taranis Q X7). Cut the RSSI wire between the receiver and the FC (or don’t bother connecting it in the first place) and the problem is solved. I can still get RSSI on my OSD anyway.
In case anyone else has these symptoms with the XM+ Frsky receiver then try the above fix:
Receiver only connects reliably when USB powered.
Sometimes need to repeatedly disconnect and reconnect the battery to obtain a connection with the receiver.
Kept getting fail-safe during flights.
Flickering green light on receiver when connected.
i accidently tried to flash the wrong firmware.
Now i it is just impossible to flash any firmware on my xm+. Allways get failure message.
Any advice on this?
You can adjust PIDs via OSD though.
Oscar, when using RSSI on ch 16, is it necessary to do any calibration? It would seem that any PWM value 2000 reads 100%. Everything else is in between but there must be a need to calibrate this?
no the RSSI on ch16 is a PWM signal not an analog signal, so your FC is probably not seeing the signal correctly.
You might need a ADC to convert the signal to anaolog signal first before feeding it to your FC.
Or you can do this hack
Is their anyway to get RSSI on thru OSD while using a Kiss FC?
Oscar, I have done a lot of range testing with my x4r-sb and these XM+ antennas, and I’m happy to say that I actually get much better range with the XM+! I thought it was a fluke, but after putting 5 xm+ receivers on my quads they all perform the same. I have a test field that I fly, and 1,500 feet out my x4r-sb is getting in the low 70s for RSSI, while the XM+ is still in the mid/low 90s. I don’t really understand how these are getting a good amount better range, but it’s great. Just thought I would share with you and others that read this website!
I’ve flashed 2 xmplus with latest firmware both 16 and 8 channel for non LGBT.
And I am getting the worst signal ever.
Only about 10meters and the quad drops from the sky.
I’ve tried my x4r and that completely works a treat no drop outs.
So confirmed it is not the radio.
Could someone help shed some light on this please?
Hi, I have the same problem as you
I lose the signal on 10 to 20 meters with my XM.
While the scope is meant to be> 600.
@Fl0ppsy how are yoy adjusting PIDs, etc over S. Port?
We have a tutorial coming next week.
It is possible to use XM plus as the X4R-SB with the Lua script (with smartport) ?
no XM+ doesn’t have Smart port.
Is it possible to set the rx for PPM? if so, how can I do that ?
I would also like to know if PPM is possible or un-inverting the sbus for CC3D
I get a green light after binding but wont arm. was working before on old receiver. Fc is kombini and using a passado osd. do you have any thought on what to check?
this is one of those common problem, try to Google it first. But here are a few things you can check:
– check receiver tab activity
– check if you have the correct configuration setup for RX
There is new released firmware that let you put RSSI to channel 8.
thanks :) thats good to know!
hi oscar, after update can using rssi out (ch8) into betaflight and forwarded into hubosd?
I am not using HUBOSD, but I don’t they support RSSI display at all..
Being able to adjust PIDs, Rates and VTX settings over the S.Port link makes not having that feature a big fail for these receivers.
like I said in the title, it’s great for micro builds, where space and weight are constraints. Anyway it’s great too on bigger builds if S.Port is not needed.
great for plane too :)