openrcforums

Hi all,

I'm after some guidance as I've been reading page after page of information on telemetry, but to be honest I've just confused the hell out of myself.

My current setup is,

9xr (non pro) running ER9x-r813, out of date but it does what I want it too, if I need to update this it is no big drama.
Frsky XJT module running 16 channels on 2x 8XR receivers, currently set to mode 2 & 3 (non telemetry)

I'm planning to add a new model soon which is a boat running a LiPo. Currently I run model trucks on the NiMh batteries so I have no call for telemetry or LiPo monitoring.

My planning is to add a FrSky FLVSS LiPo Voltage Sensor so I can monitor the lipo voltage when out on the lake.
After reading quite a bit of information I'm confused if I need to do the 9xr Frsky DJT mod or whether the XJT is plug and play so to speak ?
Or is there a different mod for the XJT ?
I know I will need to set the receivers up in Pxx telemetry mode, then add Cvlt and Ctot to the telemetry section.

Sorry if this is a real dumb post but any guidance will be most appreciated.

Cheers

Steve

The XJT doesn't need any modification, but the 9XR will need the telemetry mod done to it (the one that moves the AIL and THR switches to other pins on the processor) to enable telemetry data in to the processor.

Mike.

Thanks Mike,

That is what I was fearing. I'm not the best with a soldering iron on small items so a bit of thought is required...... at the moment I may give this a miss!

The good news is the 9XR has the processor pins tracked to another chip that has pins on a wider spacing. Given a bit of time I can locate the specific info for the connections if you want to go ahead with the mods.

Mike.

Thanks again Mike.

I'll take the back off tomorrow and have a look with the magnifying glass.
Just to be clear, 220ohms on pin 41 & 42 and then a 500ohm to the Rf board?

Cheers

Steve

Unlike to original 9X, the 9XR has an extra chip (U6 an MC14051B). The processor pins 41 and 42 are connected to this, and you will most likely find it easier to solder to this chip then the processor.
Processor pin 41 is connected to U6 pin 11.
Processor pin 42 is connected to U6 pin 10.

Mike.

Mike, does the XJT put out 3.3V logic on the s.port pin or is it RS232?

Thanks

João

It's inverted serial at 3.3V, so the mod will need an inverter between pin 5 and the processor connection.

Mike.

MikeB wrote:Unlike to original 9X, the 9XR has an extra chip (U6 an MC14051B). The processor pins 41 and 42 are connected to this, and you will most likely find it easier to solder to this chip then the processor.
Processor pin 41 is connected to U6 pin 11.
Processor pin 42 is connected to U6 pin 10.

Mike.

Thanks again Mike.

One more question, will I still need to put in the 500ohm resistor to the RF board?

Cheers

Steve

Yes.

Mike.

Right, had a little go this evening and it hasn't gone to well.

I've soldered in the 2 wires from 41 & 42. This is direct to the chip. The other ends are too the 200ohm resistors on the pcb and then I've cut the 2 tracks.
I've put in the 500ohm rf wire too.

Each step was checked with a multi-meter with no shorts to each other and showing 200ohms on the other side of resistor.

When turning on the TX the THR & AIR are showing as on and can not be switched off.
I've rechecked all the wiring and checked it again.
In the end I took the 3 new wires back out and bridged the 2 cuts on the PCB. TX normal operation is then ok.
Now I did one wire, 41 to the resistor, no shorts , TX on and AIR is on and won't switch off. THR is ok.
Removed that wire and the did just 42, same THR on and won't switch off. AIR is ok.

So any ideas what I've done wrong or missed?

Cheers

Steve

What you have missed is you need to either flash the telemetry specific version of er9x, or set the option to indicate you have done this mod. Which depends on which processor you have. If you have a '128 processor, then you just need to set the option.
The option for the '128 is called "FrSky Mod. Done". It's in the radio setup (I think it is in r813), probably in "General", unless r813 has a "Hardware" menu.

Mike.

Sorry for the late reply but all the switches are now working as the should.

Mike was right I needed to set the option in the hardware menu. Out of the guides I read before doing this mod not one said about setting the option, just to flash with the correct software. Not to worry I'm there I think just need to test it when frsky lipo sensor turns up.
Also is there a way i can monitor the RX voltage of my 8XR ?

Thanks again for all your help.

Cheers Steve

This appears as the A1 value. Go to the telemetry menu and set the range of A1 to 13.2. A1 should then show the receiver voltage. You may need to adjust the 13.2 if the displayed voltage is not quite the same as the measure receiver voltage.

Mike.

Is there a way to tell what firmware level the XJT and X8R are on as I can't get this working.

The date stamp on the XJT is 2013 but I have read the earlier firmware were buggy and telemetry didnt work correcly in D16 mode. I also only have one X8R set to telemetry mode and the other is switched off.

Or is there another way to confirm that the mod I carried out is good?

Any ideas??

Cheers

Steve

What exactly is not working?
I'll specify some things you should have set/done.
1. Set the protocol to PXX, and the type to D16.
2. Power on the receiver in bind mode (hold the small button pressed while it is powered on)
3. On the protocol menu, go down to BIND and press menu.
The receiver should bind (red LED starts flashing).
4. Power the receiver off, then back on.
5. Press EXIT to leave BIND mode on the Tx.
6. The receiver should now be working. Navigate to a telemetry display (DOWN LONG from the main screen) and look for the RSSI value. This should read something between 80 and 110.

Mike.

Thanks Mike for the quick response.

Sorry I should be clearer, i got both the 8XR to bind ok so step 5 on your list above.
I can't get any telemetry so no A1 or Rssi , they just read zero

There are a couple of posts above mentioning the need for inverting the signal from the bottom pin of the module connector before it connects to the pad leading to the processor pin.
Have you done this?

Mike.

Yes it has with a 500 ohm resistor.

The 8XR have been set to mode 5 and mode 3 which I believe is correct.
Would get I Tssi info even if the 8XR was set wrong?

Cheers Steve

With the XJT you no longer get TSSI, it is SWR instead and is likely to be 0.
What inverter have you used?

Mike.

Thanks again Mike for your reply,

I have followed a number of guides to do this mod, the first one being, http://forum.turnigy9xr.com/converting- ... e65474ebca
This is for DJT module so I did up to pin5 of the RF board to the 2nd Pin of the ATmega with a 500 ohm resistor. No mod was carried out to the XJT.

I couldn't get this work so with the above mention of a inverter and following these posts.

http://openrcforums.com/wiki/index.php/ ... y_Lite.jpg

viewtopic.php?f=95&t=6038

http://openrcforums.com/wiki/index.php/ ... _telemetry

I have used a inverter from here,
http://www.t9hobbysport.com/frsky-recei ... -lite-ful1

I haven't connected anything to pin 2 of the RF board, just pin 5. but the only difference I have is that I've just noticed I've used a 500 ohm resistor instead of the 470ohm. I'll get this changed.

One thing I am confused about is the "Cut free on both sides" statement on this diagram on pin 5 ?? what does this mean?



I do have a 2nd inverter as I brought a 2nd to do my 9x as well so I might swap them over just in case it is faulty.

Cheers

Steve

It means you have to isolate that pin on both sides of the backboard.. Top and Bottom as it is connected to ground on both sides.
You DO NOT need to isolate pin 5. it only goes to the big pad that before connected to the 35Mhz antenna, and it is only connected to pin 5. This pad is easier to solder to than pin5. I don't know why someone once suggested that pin 5 should also be isolated

João

The reference to cutting free pin 5 is for the 9X. Since you are using a 9XR, this is not needed. On the 9XR the pin 2 is connected to ground, so would need isolating if you needed to use it. You don't need it for an XJT.
470 or 500 ohms is fine, no need to change the 500 out for a 470.

Worth double checking you do have the wire from the R1out of the inverter going to pin 2 of the processor.
Also possibly double check the track cuts to disconnect the THR and AIL switches are really cut.
You may, of course, have already done these checks.
I've not done this mod to a 9XR myself, I've only done a 9X (several!), but it should work.
One other settings check, on the model setup, telemetry menu, check the Usr Proto. is set to FrHub (or FrSky) and not WSHHI.

Mike.

YES!!!!!

Finally we are there and have Telemetry.



I need to add the LiPo voltage sensor yet and fine tune the A1 but least I now have some readings.

Thanks all for all your help, specially Mike.. you are a diamond.

I've take photos of how I've done this so I may knock up a how to post as there is a lot of conflicting information out there. Also I may look at a small conversion board that plugs into the com ports as most of the wiring is there, just need to run one to Pin 5 of the RF board

Oh and the problem was............. A faulty inverter.... would you believe it!!

Thanks all

Cheers

Steve

Hi Steve did you knock up some photos of this as I am interested in doing this?

(maybe my post/question is a better place here)
Hi Mike!
Hi all!
I have normal T9X (not XR) radio with ER9X mod. I have an XJT frsky module.. If I do the frsky mode with Rs232 level converter:
1. I only need to connect Atmega 2. pin MOSI to the XJT smart port (which is the 5pin on t9x module bay) through the rs232 to TTL converter? So MISO connection and use the 2pin of XJT (which is hartbeat signal) and t9x module bay is NOT necessary and also can damage XJT if i connect MISO pin from processor to XJT through level converter?
2. Do I need cut traces at pin 5 at module bay to isolate it from gnd?
3. Do i need to cut traces around pin 2 at module bay on the radio, if I need to connec hera MISO pin?
4. RSSI is working now on the latest 820 ER9x frsky version with XJT and Xsr receiver, or which version need I use to see RSSI? Or if I can see the SWR it can show similar signal strenght to prepare a failsafe situation in time?

If i understood welll the tutorials only on wire needed between atmega MOSI>> TTL to RS232>> 470ohm resistor>> XJT 5. pin (smart port) beside the reroute the pin 41 and 42 mode?

I not want to use DJT module only the XJT.
Thanks for your help

1. Correct, a connection to pin 2 of the module connector is only needed for the DJT. If you do connect the converter output to pin 2 of the module connector, no damage will occur to the XJT.
2. No, it only connects to the (old) antenna connector.
3. Yes.
4. The telemetry from the XJT has been supported for a long time and is in r820.

Mike.

Thanks for quick support!
Now i can start my second mod on my t9x.
Cool

Hi!
I have one more question.
Can I use this method also on T9X with ER9X or ER9X frsky version to send rssi data back to the receiver and get that value in osd also?

described in the first part of the blog in case for taranis
https://oscarliang.com/rssi-ppm-channel-taranis/

So can I get rssi value through the cppm or sbus channel by using t9x and ER9x. This is a configuration need to see rssi in cleanflight and on minimosd.

Yes, the mechanism works, the only difference is setting the source of a mix to be RSSI. On er9x you need to do the following:
1. Configure a Scaler (SC1) (select ModelEdit|Globals, then scroll down past the GVARs).
Source RSSI
Offset = -1024
Multiplier 205
Divisor 10
Set Offset at LAST
2. Configure a mix with SC1 as the source.

Mike.