New FrSkyX protocol

Fernandez wrote: Did some more test to check latest nightly and range FRSKY X protocol, and the culprit seem to be the Irange XSR receivers not deviation, I got two of them and the range is very poor. (it is even less than an X4R range in range check mode, so this Rx is unflyable for me....) Possibly there is an issue with PA/LNA chip or antenna coupling, the range is as about same with 100uW or 150mW, even an cc2500 only would do better........

The range of Frsky X4R is fine, no issue and when switching from 100uW to 150mW range increased.
I need to dig a bit more into the issue, maybe there are others with experience.

Fernandez I have a iRangex xsr and will test the range hopefully this weekend and tell you

Just Re-flash the last nightly on my DEVO10 and made a simple range test.
Even if the XSR is not a long range receiver, i think there is a problem.
I'll make another video in same conditions but with my favourite old nightly

@Sfersystem, I have similar, I see you are also using XSR. The irange XSR is a copy or clone of the original RX, I even got the original Frsky Firmware installed on it.
www.frsky-rc.com/download/view.php?sort=...56&file=Firmware-XSR
(there is also a newer Beta which I did not use)

Next to that the RX may have been bad or broken, so I used another bran new irange XSR out of box (with stock firmware as it came, also it has the range issue with deviation.) Same issue.

The X4R Frsky receiver, I seem not to have an issue, or at least range is better.
I tested the Tx output, and can confirm that RF output seem normal, and yes when changing deviation output power it changes also RF output. So rf module is ok.

On youtube, I find a movie, showing that full range with this RX should be possible.


One thing what surprise me is that there seem to be a lot of fast fluctuation in the RSSI, even when not moving or changing any orientation, far from stable.
need some more testing......... what surprise me 100uW or 100mW, I get dropout at about same range.......

I'm using a guenine FRSKY XSR

I just made a test in the dark, 3x more range and still about 90d (from 109d) with the '' deviation-devo10-v5.0.0-1d8c208 ''

Tomorrow i'll make another video and you'll that the range is really better.

Thanks would really help something weird is going on.....?
Anybody who has a report flying the latest nightly with X protocol at full range?

@Sfer, but don't look at the RSSI nrs, as scale has been changed, please look at range to failsave and compare that, between old and new release?

As you can see, the range with old nightly (drop from 109 to 87) at 72 meters compare with the new nightly (from 90 to 45) at 23 meters.
Same setup, same conditions, different firmware.
i'm sorry but there is something different.


Thank you for help / advice.

What's different is the scaling of the RSSI value. It was fixed to accurately represent the value represented by the received data.

Refer to this graph to convert from old values to new values. For example, find where the blue line has a value of 109. From there drop to the red line, and the value is about 87.

Do you still have control of the quad at 72 meters with the latest nightly?

Thank you for reply Hexfet.

I've understand the RSSI value update, that's why i've done the update to the new nightly
I'll take the time to test the real range between the to updates.

If i look the graph, at 72m with the new RSSI value, i should have about 45, so it will mean that i can set the warning at 20 for example ?
It mean that the range is not increased between the old and the new nightly ?

On Taranis, when the signal go below 45 it's the limit.

Just a question before flashing the last nightly again, why do i have sometimes message from missing modules, with the old nightly i've never.
thx

The range should be the same as previous versions. Nothing changed in the radio setup or protocol.

I haven't done a full range test yet so don't know what a good RSSI alarm value would be. Anyway it depends on the radio installation and antenna setup so won't be the same for everyone.

Not sure about the missing modules message. What is your radio setup (individual, multi-module, etc)?

Thanks, i'll make a range test tomorrow with the last nightly.

I'm using multi-module board 1.2 with only a cc2500 +pa+lna and a 2.4 3dbi antenna

I think victzh has already commented on possible issue with multi-module and spi_switch but can't find the post. Wanted to learn the git for this and created a test build that should be the latest nightly without the spi_switch commits (nor the target_defs simplification that I couldn't figure out how to merge).

Please give the test build a try and see if there's any difference in the frequency of missing module warnings. If it works I wouldn't fly anything with it without some testing as my git-fu may be weak.

Great work all, i have just flashed the devo7e with the latest nightly (today 9-2-17) and got a bind to the xm+ rx.
thanks for all the hard work thats been put in.

i have one small question regarding the frsky x protocol options. could some one explain the pros and cons of the Hold, No pulse, and RX failsafe options.

i am assuming the RX option is a programmable FS set to a given stick/switch positions.

Updated manuals are here , though still need to add the EU info. From the FrskyX section:

Failsafe: The Frsky failsafe options are fully supported. If the channel failsafe (in mixer channel config) is set this
value is sent to the receiver every 9 seconds. The receiver will use these values in failsafe mode unless the protocol
option is set to RX.
For channels with failsafe set to off, the default Failsafe protocol option "Hold" commands the receiver to hold the
last received channel values when the receiver enters failsafe mode. The "NoPulse" setting causes the receiver to not
send any signal on PPM outputs (Testing on X8R showed SBUS values went to minimum, but SBUS behavior is not
specified by the protocol). The "RX" setting prevents Deviation from sending failsafe settings so the receiver will
use whatever failsafe values have been stored in the receiver.

A question on this protocol...

Is the fine frequency related to the module or the receiver?

I use -45 for an X4R receiver all the time, so is it safe to assume that -45 should work with other receivers as well?

I've bound just fine to an X4R in the past, but I can't for the life of me bind to this XM+. The light is always flashing red, and never turns green.

sfersystem wrote:

Omino wrote: I also get RSSI on channel 16, which is then displayed in my OSD (Betaflight 3.1 compatible).

How do you get the RSSI on the channel 16, have we to setup something in the DEVO ?
I would like to setup the rssi on my micro minimosd too.

I have already the vbat and rssi on my DEVO10 screen.

thank you

You get it with the XM+ receiver. It outputs RSSI on channel 16. See this video for the details.

raketemensch wrote: A question on this protocol...

Is the fine frequency related to the module or the receiver?

I use -45 for an X4R receiver all the time, so is it safe to assume that -45 should work with other receivers as well?

I've bound just fine to an X4R in the past, but I can't for the life of me bind to this XM+. The light is always flashing red, and never turns green.

This is what I did to pair my FrSky XM+

1. TX off and RX off
2. Power on the TX and go to Model Setup menu > Bind
3. Make sure FrSkyX is selected, then click on FrSkyX and set the frequency to -60.
4. Click on Bind
5. Switch on power to RX while pressing the bind button
6. Green RX light flashes once
7. Bind complete
8. Power off RX and TX

When you power on the TX and RX, the RX red light flashes until the green light turns solid.

I had to fine tune the frequency to less than 0 to make the XM+ bind. It can bind till -127. I picked -60 as it's in between the min and the max. You can't use telemetry to choose the best LQI value as the XM+ does not have telemetry.

I have not had any issue with the XM+ and 4in1 module so far.

After some tests today with a dry sunny day, i can confirm that with DEVO10 and xsr i can reach 400m without any problem.

I don't know why with last nightly's, i have sometimes missing modules messages at start.

I've just uploaded Devo10 nightly from 22nd Feb, I am getting the Missing Modules message too.
Devo 10 with BG CC2500 module
Only want to bind XSR but can't get that far, would be happy to bind without telemetry as I was just going to wire the RSSI into my OSD anyway. Might try some other nightlys.

If you just have the cc2500, sometimes you have to raise the number in your .ini file up 1 or down 1, I forget which off the top of my head.

Try setting your enable-cc2500 = A13 or A15.