FrSky X4R and X4R-SB with CPPM Firmware

[quadfather]

FrSky have released a beta firmware for the X4R and X4R-SB which enables CPPM output.

This upgrade turns output 1 into 8-channel CPPM, with the rest of the outputs becoming additional PWM channels.  On the X4R-SB CPPM and SBUS are both available without the need of reflashing or jumpering any signal pins.

[attachimg=1]

Flash the firmware with your preferred method, e.g. via FUC-3 or through Taranis.  Put a jumper on signal pins 2 & 3 when you bind the RX, that enables CPPM on output 1.  Once bound you remove the jumper and you can use the additional PWM channels.

Firmware is attached to this post and contains both EU and non-EU versions.  This is a beta firmware, use it at your own risk.

Official FrSky forum thread.

Edit:  Firmware is now out of beta.  See my post below for the official links and instructions.

[quadfather]

Just to add, I have done the upgrade with my X4R-SB using the FUC-3 cable and can confirm it';s working (tested with a Flip32+ and Cleanflight).  I had the full eight channels available and did not notice any unusual side effects.  This was a bench test only, not flown anything with it yet.  I don';t have a X4R to test, but I';d expect the same results.

[kilby]

That';s good to know, they also promised a price drop for the X4.

People where asking for all sorts of additions to the firmware (I did ask for visual confirmation of zero output failsafe having been set)

[Hands0n]

Hey Tim, thats an awesome update  Makes the X4R-SB incredibly versatile.

So, the binding with pins 2 & 3 shorted simply enables CPPM on pin 1 plus S.Bus on pin 4 otherwise it is PWM on all four channels? Is that right?? 

[quadfather]

Hey Tim, thats an awesome update  Makes the X4R-SB incredibly versatile.

So, the binding with pins 2 & 3 shorted simply enables CPPM on pin 1 plus S.Bus on pin 4 otherwise it is PWM on all four channels? Is that right??

Almost. 

X4R
Binding without the jumper retains the original behaviour, i.e. PWM channels 1-4.
Binding with jumper turns output 1 into CPPM channels 1-8, the rest become PWM channels 9-11.

X4R-SB
Binding without the jumper retains the original behaviour, i.e. PWM channels 1-3 and SBUS on output 4.
Binding with jumper turns output 1 into CPPM channels 1-8, outputs 2 & 3 become PWM channels 9 & 10, and output 4 is still SBUS.

Essentially this firmware turns the X4R into an 8+3-channel RX, and the X4R-SB into a 8+2/16-channel RX.

[quadfather]

These firmwares are now out of beta and officially released.

EU Version:
http://www.frsky-rc.com/download/view.php?sort=Firmware&down=209&file=X4R-X4RSB-CPPM-EU%20Version

Non-EU Version:
http://www.frsky-rc.com/download/view.php?sort=Firmware&down=210&file=X4R-X4RSB-CPPM-%20Non-EU%20Version

If you';re running OpenTX 2.1 here';s an easy way to upgrade them:
http://www.multi-rotor.co.uk/index.php?topic=14805.0

[kilby]

Funny enough I was looking to see if the official had rolled out earlier today.

I';m considering making a change to the X series receiver for my next machine

[realpastaman]

I have both X4R and X4RSB I have flashed both for EU CPPM output. I want to use them with NAZA systems.

The X4RSB I got working with SBUS on the NAZA OK and the additional PWM outputs I';ve tested with a servo OK. The NAZA doesn';t seem to like the CPPM signal  on pin 1 and I cant get it to calibrate.

The X4R - NAZA doesn';t seem to like the CPPM signal though on pin 1 either and I cant get it to calibrate.

Now I have tested this on a scope I have seen some problems

This is the same for two X4R and one X4RSB I have tested. I have uploaded a video to youtube

https://www.youtube.com/watch?v=-7InuKb798E

Looking at the video there are some large unexplained spikes and instability when the transmitter is turned on. Later in the video the transmitter is turned off.

Anyone else has this working? any comments on what is causing this?

I';m using the EU version of the firmware.

[realpastaman]

I have both X4R and X4RSB I have flashed both for EU CPPM output. I want to use them with NAZA systems.

The X4RSB I got working with SBUS on the NAZA OK and the additional PWM outputs I';ve tested with a servo OK. The NAZA doesn';t seem to like the CPPM signal  on pin 1 and I cant get it to calibrate.

The X4R - NAZA doesn';t seem to like the CPPM signal though on pin 1 either and I cant get it to calibrate.

Now I have tested this on a scope I have seen some problems

This is the same for two X4R and one X4RSB I have tested. I have uploaded a video to youtube

https://www.youtube.com/watch?v=-7InuKb798E

Looking at the video there are some large unexplained spikes and instability when the transmitter is turned on. Later in the video the transmitter is turned off.

Anyone else has this working? any comments on what is causing this?

I';m using the EU version of the firmware.

Still trying to find an answer on this   Has anyone got CPPM to work with these?

[quadfather]

Yes, I have it working with a X4R-SB, but I don';t have a Naza or oscilloscope.  What';s the reason for using PPM when you can use the superior SBUS?  Gimbal control?

[teslahed]

If you wanted to use it with a naze32 then ppm would just work whereas SBUS would need an inverter or a hack.

[realpastaman]

If you wanted to use it with a naze32 then ppm would just work whereas SBUS would need an inverter or a hack.

I';m using them on NAZA flight controllers but the CPPM firmware doesnt work as they say. The NAZA does work OK on SBUS on the X4RSB without and inverter but the point of the firmware update is to have usable CPPM and this dosen;t work as the CPPM has really bad glitches and spikes as you can can from the video.

https://www.youtube.com/watch?v=-7InuKb798E

[realpastaman]

Yes, I have it working with a X4R-SB, but I don';t have a Naza or oscilloscope.  What';s the reason for using PPM when you can use the superior SBUS?  Gimbal control?

Thanks quadfather -  yes the updated X4RSB  does work on the NAZA on SBUS and that leaves me some outputs for gimbal  control.

I also have two udated X4R that I need to work with NAZA';s so these need to work with PPM and use the PWM outputs for gimbal etc as they do not have SBUS

Despite FrSky having this update neither the the X4R or X4RSB produce a usable PPM outputs so that is why I looked on a scope to see what its wrong with the PPM outputs.  I';m  very doubtful that this update works as it should. The PPM output is full of SPIKES on the PPM channel and jitters all over the place. This can';t be right.
You can see the spikes on the attached picture. What do you think? Tried contacting FrSky but they cant understand the problem!

 

[teslahed]

Have you rebound the receiver since updating it? I hear not doing that can cause problems.

[wobblybob]

I managed to mod my X4R to Sbus simple job.
If you want to convert a X4R-X4R-SB it';s only the position of this link between the two models it seems .
Move R34 (0 ohm link)

to R35


Links to PWM/SBUS stuff for the X4R

http://boltrc.com/blog/x4r-sbus-mod-how-to/
http://www.boltrc.com/documents/manual/txrx/Frsky/How%20to%20change%20the%204th%20chanel%20to%20SBUS%28X4R%29.pdf

[realpastaman]

Have you rebound the receiver since updating it? I hear not doing that can cause problems.

Thanks teslahed I have done that with signal pins 2 and 3 joined together as they said - I think SBUS and PWM work fine but not PPM and PWM - I have yet to find anyone using PPM and PWM after the mod! Most people seem to use SBUS and PWM.

Have to say that FrSky dont seem to be that helpful.

I bought two X4R on the assumption this mod works      

[quadfather]

I meant to ask, did you flash the beta version from the forum or the official release from the website?

[realpastaman]

I managed to mod my X4R to Sbus simple job.
If you want to convert a X4R-X4R-SB it';s only the position of this link between the two models it seems .
Move R34 (0 ohm link)

to R35


Links to PWM/SBUS stuff for the X4R

http://boltrc.com/blog/x4r-sbus-mod-how-to/
http://www.boltrc.com/documents/manual/txrx/Frsky/How%20to%20change%20the%204th%20chanel%20to%20SBUS%28X4R%29.pdf

Thanks wobblybob my soldering skills are pretty good so this may be my only option. Can I ask you what was your technique to remove the surface mount resistor?

[realpastaman]

I meant to ask, did you flash the beta version from the forum or the official release from the website?

Official release - Do you think it makes any difference what version I';m running on the tx? It did bind ok and my tx is eu 2015 and the firmware was the eu version.

[wobblybob]

Thanks wobblybob my soldering skills are pretty good so this may be my only option. Can I ask you what was your technique to remove the surface mount resistor?

I just heated one side then lifted it a little , then pushe it free from the other soldered side . My iron is a bit on the ropey side but the PCB is good quality so the pads arn';t going to lift with out lots of abuse .
I nearly lost the link but seeing as it';s 0 ohm a blob of solder will do the job .

[quadfather]

Official release - Do you think it makes any difference what version I';m running on the tx? It did bind ok and my tx is eu 2015 and the firmware was the eu version.

No, I was thinking that it may have been an artefact of the beta version, but seeing that you have the release. 

Perhaps, you could flash the beta version from the forum and run the scope over it?  Maybe the glitches were introduced after the beta?

[realpastaman]

No, I was thinking that it may have been an artefact of the beta version, but seeing that you have the release. 

Perhaps, you could flash the beta version from the forum and run the scope over it?  Maybe the glitches were introduced after the beta?

Great idea - I can also check the MD5 checksum of the files to see any differences! - Kind of a dumb question but where do I find the beta files on this forum?

[quadfather]

Great idea - I can also check the MD5 checksum of the files to see any differences! - Kind of a dumb question but where do I find the beta files on this forum?

It was attached to my original post, but I removed it after the official release.

You can still get it from FrSky';s forum here http://www.frsky-rc.com/BBS/viewtopic.php?f=4&t=6793&sid=dedd9e51d19e5c11ca8482264a52e040&start=30#p12452

[realpastaman]

It was attached to my original post, but I removed it after the official release.

You can still get it from FrSky';s forum here http://www.frsky-rc.com/BBS/viewtopic.php?f=4&t=6793&sid=dedd9e51d19e5c11ca8482264a52e040&start=30#p12452

I ran an MD5 checksum and the two files (beta and final) are identical

[realpastaman]

I managed to mod my X4R to Sbus simple job.
If you want to convert a X4R-X4R-SB it';s only the position of this link between the two models it seems .
Move R34 (0 ohm link)

to R35


Links to PWM/SBUS stuff for the X4R

http://boltrc.com/blog/x4r-sbus-mod-how-to/
http://www.boltrc.com/documents/manual/txrx/Frsky/How%20to%20change%20the%204th%20chanel%20to%20SBUS%28X4R%29.pdf

Goodbye CPPM / PWM hello SBUS and PWM :)
After all my problems and thanks to everyone on this thread I converted my two X4R to give SBUS by removing the link r34 and soldering it to r35 which I also now agree was pretty easy! Thanks wobblybob - The SBUS works fine with the NAZA and I have two PWM outputs at the same time for gimbal + other. Thanks again everyone! I still say however there is a problem with this firmware update if you need CPPM and PWM :)

[anarchy83]

sorted

[Spy]

Hoping to get some help on the X4RSB.

I have set the X4RSB in Sbus/PWM mode and connected it OP on a CC3D FC.
It is set up as D16 wth SBUS on CH 1-8.

Configured SBUS and it is all working fine with the FC. Channels 1-5 are asigned for sticks and flight modes.

I now want to assign one of the Taranis switches to control the LEDs via PWM. I have set it all up on the Taranis with Channel 11 assigned to the switch and I have plugged the LED lights in Pin 3 on the X4RSB but it doesn';t seem to work. I have tried a few different configurations but nothing which is making me wonder if my understanding of channel number on Taranis to Pin number on X4RSB is correct.

My assumption is that on the X4RSB in SBUS/PWM mode and bound as D16 (Ch1-8) that :
- Pin 4 is SBUS controlling channels 1-8
- Pins 1-3 are PWM controlling channels 9-11

Is this correct ?

[quadfather]

My assumption is that on the X4RSB in SBUS/PWM mode and bound as D16 (Ch1-8) that :
- Pin 4 is SBUS controlling channels 1-8
- Pins 1-3 are PWM controlling channels 9-11

Is this correct ?

No.  The PWM outputs are channels 1-3 as well.

I have never tried this, but in theory you should be able to set up the channel outputs on the Mixer page in your Taranis.  Make channels 1-3 the PWM outputs (or however many you want to set up), then follow up with the control sticks.  When you do the transmitter calibration in OpenPilot it should pick up the correct channels.

Something like this:
CH1 PWM for LEDs
CH2 Ail
CH3 Ele
CH4 Thr
CH5 Rud
CH6 Aux for flight modes
CH7 and following whatever else

The alternative is to use the CPPM firmware on your X4R.  When you enable CPPM mode then output 1 is CPPM (channels 1-8), outputs 2 & 3 are channels 9 & 10 respectively and output 4 is still SBUS as usual.

[Spy]

Thanks Quadfather.

I have moved my quad controls onto channels 4-8 on the Taranis and also matched these assignments on the CC3D. Tested the stick movements and flight mode switch on the OP PC software and it is picking them up on the new channels.

In theory, I assume this means that any PWM signal on X4R pins 1-3 should be coming through on channels 1-3 from the Taranis.
Plugged the LEDs into Pin 3 (assuming channel 3) but still not working.

What is the best way to check that there is a PWM signal coming through on that Pin ?

[Spy]

OK, got it working, it was a stupid mistake but initially fixing the channel overlap between PWM and SBUS enabled me to track down the next and final issue !

There is an On/Off switch for the LEDs on the PDB (Eachine Racer 250) and it has to be Off (WTF !) for the LEDs to be controlled from the receiver.

It now works fine with channels 1-3 on PWM pins 1-3 and Sbus on channels 4+ on Pin 4.

Thanks for your help.