accelerometer stops working when Taranis and x4r are connected

[horstrainer]

Hallo to the rc explorer world!

I have the mini Tri with the F3FC and the stock electronics.
After some tinkering with the dx6i I switched to the taranis plus and a X4R.
I got everything running and followed the instructions, but had some problems with arming and getting the first flights right.
After some troubleshooting I realized, that everytime the tx and rx are connected the accelerometer stops working.
I checked this while the mini Tri is connected via USB to to Cleanflight.

I checked the X8R which came with the Taranis and finally it worked!

next step was to flash the X4R. – No improvement.

And on the next day I wanted to go flying with the X8R, even that refused to let the IMU work.
Checking in cleanflight showed the same behavior like the X4R.

any suggestions what i can check or try to find the mistake?

could it be something with the board itself?
I am tempted to order a new one and try to reproduce the mistake.

[JRach]

I would try reflashing the F3FC (make sure you flash in DFU mode (hold down boot button while plugging into pc). SBus should be connected to UART 1 yellow/white to the RX pin. Smartport should be on UART 2 TX pin.
In the PORTS tab in cleanflight. UART 1 should have serial RX enabled. UART 2 should have telemetry enabled and Smartport selected (not FRSKY). In the configuration tab RX_SERIAL should be selected. Also under Serial Receiver provider you should have selected Subs. Lastly, scroll to the bottom and select Telemetry output. Hope this helps. Happy flying!
– Jacob Rachwal

[horstrainer]

Thank you very much for the input!
I will try this tomorrow.
Isn’t it even better to try it without telemtry? Or is telemtry needed?

From what I remember, everything should be like you mentioned, but i will check and doublecheck that and will go through this process again.
Maybe I can try it in the morning before work.
Thanks.

[norwenkel]

do you use the x4r or the x4r sb? Which x4r firmware is in use? Cppm/sbus or original sbus? when connecting s.port telemetry you only need to connect the (green) s.port to the unused UART TX.

[horstrainer]

Hello norwenkel,
I am using the X4R sb.
Firmware is the one with lbt. More precise info is coming tomorrow. This one has sbus afaik (not cppm).
In the receiver tab of cleanflight everything is working as it should. That should show that its not the wrong firmware in terms of cppm or sbus…
Thanks for the input.

[GAntonjo]

Both X4R and X4R-SB can provide CPPM if bound to the Taranis according to this instruction: https://quadmeup.com/ppm-output-on-frsky-x4r-and-x4r-sb-receivers/.

Only pre-requisite needed is that the receivers are produced with the latest firmware, or you flash the latest firmware as explained in the link. If you try to bind with signal 2 and 3 shorted and CPPM is NOT output on channel 1, you have to flash new firmware.

I have 2 X4R-SB that output CPPM on CH1, PWM on CH2 and CH3 and SBUS on CH4 😉 My one X4R I have not tested yet, as I have it stored in case I’ll by me an in-door fixed wing to play with during winter;-) Or, I will bind it in CPPM mode if needed for my tris/quads;-)

[horstrainer]

Hello GAntonjo,
Do I understand you correct? You suggest to use cppm?
After reading a bit on oscar’s site
I thought its better to use sbus.

https://oscarliang.com/ppm-sbus-d4r-ii-x4r-sb/

But I can try cppm. If it works i would be happy.

[GAntonjo]

You may use SBUS or CPPM as you prefer. CPPM will free up one UART but is a “liitle slower”. It all depends on how you fly and whether the millisecond difference will be crucial for your way of flying;-) I just saw you mentioned that you have the X4R-SB and doubting that it could do CPPM, so that’s why I added the information on how to bind it in CPPM+SBUS mode 😉 Actually, for the X4R-SB there is nothing that stops you from leaving it with CPPM enabled, as SBUS still is sent on CH4 while it is only the PWM output on CH1 that is replaced with CPPM output.

[Terje]

Back to basics: What do you have connected to the different UARTs?

[horstrainer]

@ GAntonjo: Thanks for the clarification. I just thought the hint on “no CPPM” could identify which firmware i used, but I will try both ways- maybe that helps.
To the Question of “my way of flying”? Right now i don’t have a way of flying because i am just learning. I had 2-3 Lipos of LOS flying when evrerything coincidently worked- FPV is the next step.

@ Terje: black (brown), red and yellow cables connect the CH4 with UART1 (GND, +, RX)like the picture of the F3FC board shows. Telemetry was tried, but for Troubleshooting I de-activated it and deconnected the s-port cable (don’t know the colour because I don’t have it in front of me right now) on the TX pin of UART2.

Right now i don’t care about other ports that i need for OSD or Blackbox or whatever. I just want to fly FPV and get it running. So I will test everything again- hopefully tonight.

Thanks for the help so far! It’s a great community! I am very happy to have asked here in the forum.

[norwenkel]

@horstrainer you are using triflight 0.5? i would reflash the board with full full chip erase and manual baud rate set to 256000 and start all over again. Bye the way did you get some i2C (2 to 4 seems to normal) or packet errors. Also check the sensors in the sensor tabs (with and without the x4r connected) if you noticed some unusual graph.

[horstrainer]

@Norwenkel Yes I use triflight 0.5.
I will start from zero with:
-board(with manual baud rate)
-TX (EU-OpenTX)
-RX (EU- LBT- will try cppm and S-bus).
-I will check (again 😉 all cables and the whole setup
-with and without telemetry

If that doesn’t help i could try the non EU version for rx and tx, but i doubt, that this makes a big diffenrence.
I will report the outcome.

Where do i get/see the i2C or packet errors? (didn’t find much helpfull with a (very) short google research)

[norwenkel]

You will find the messages or number of errors at the bottom line in CF

[horstrainer]

Now i got back at the bench.
what i did so far:

_____________
taranis

companion 2.0.20
opentx _x9DP-mode2_EU (2.1.6 variant217)
factory reset (eeprom erase)

_____________
internal XJT
flash internal module
XJT_eu_150413

_____________
X4R
flash external module
X4R-X4RSB-CPPM-EU Version 150624 (on frsky-rc.com it is listed as Version 150729)

bind with taranis while CH2+3 are jumpered (in D16 with channels 1-16)

_____________
Cleanflight
Configurator 1.2.3
firmware: triflight_0_5_ALPHA2_servo_release_RCE
full chip erase
baud manual to 256000
-> usb device successfully closed (after flashing)

now in cleanflight- connected it shows 0 packet errors and I2C errors: 3

connecting via sbus
make all adjustments like JRach (scroll up in this thread) and David (his video how to set up electronics)
– setting up ports
– configuration like JRach wrote down
– leaving PID alone
– adjusting the taranis on the correct microsettings
– mapping the channels in the right order (forgot that on first try- copter wont arm because throttle isnt at zero ;))
– setting up all modes and switches
– calibrating servo
– calibrating accelerometer
– calibrating escs

and now: TADAAA!!! it works!
JIPIEH!!!

I will try it out rommorow- hopefully the weather is nice to me.
Thanks to you all giving me hints and tips!

What does the I2C error:3 mean?

[norwenkel]

Glad that you made it @horstrainer. 3 i2c errors seems to normal. Do not worry.
Just a hind: because you have bind the x4r with the jumper on 2 and 3 you should have (c)ppm on ch 1. Meaning you could use one UART more for serial devices. I´m using now on UART 3 OSD (with a switch Blackbox), UART 2 s.port and UART 1 GPS (+ magnetometer on i2c).
Happy flying
Norbert

[Author]

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