Hi, Thanks for your reply.
I did not test them in XConfig after setting to 57600, because were working fine before, on 38400 (but not with APM2) and I just change the frequency. About resistors you did mention, all work OK on 34800, I believe my resistor is 10kohm
I did reset also the button on APM, but not yet luck.
When your are connection on APM2, you just select the proper port (as from device manager) and press Connect (top-right) button on Mission Planner, correct?
I do the same, is trying to connect, but at the end there is a message from APM that beat heart are missing.
When I am connecting one XRF to APM and the next one to PC on HappyKilmore GCS, I can see the data comming from APM2, but the data is not on the compatible format (strange characters), but at least I see data coming. When I put to APM2, I can not connect. Is any other setup I need to do on APM2? Thanks, Chris

Strange characters - sounds to me like a baud rate issue. Check that you can talk to each one at 57600. You may have forgotten to issue a ATWR to save the config in which case they will still be at 38400 when re-powered.

Don't forget that you can start up the XRFs in default mode by shorting pins 19 and 20. You should then be able to talk to the XRF at 9600.

I am able to make my XRF communicating at 38400 both or TX at 38400 and RX at 115200.
When I try to make both to communicate at 57600 (minimum for Arduino), they are not able to "decode" characters, so I can see data coming, but still "strange characters". Also not able to communicate with TX at 57600 and RX at 115200.
When I change in XCM Config manager, I do change only the Baud Rate (ATBD) from drop down list. Should I change other values?
Usually, after Upload Config, I do ATAC and ATWR and then I download again to be sure the save is correctly.
Also please let me know if the port on device manager need to be changed also? I tried different values, and default 9600, but still only "strange values". Those "strange values" are different when looking into the XCM Serial Monitor, depending of the Baud rate selected.
I can attache some print screen with those strange values if you believe it can help.
So, in conclusion, 38400 on both is fine, also TX=38400, RX=115200.
But 57600 or greater on both does not work:(

Thanks again

Hi Rob,

Which is the APM Planner version you are able to make the XRF-APM2 communication? And which mavlink protocol are you using? 0.9 or 1?
I did try APM Planner v1.1.92 and v.1.2.2, but still not able to make the communication.
My both XRF can well communicate each other on 34800 only, with HKGCS, but not able to make them on APM on 57600 or higher.

Thanks,
Chris

I've attahed the settings for the gerneral and advanced tab. Both xrf units are set the same.

I've used both mavlink 0.9 and 1.0 and MP 1.2.7. All have connected. Dont worry about strange characters in the MP console window. Thats just mavlink doing it thing.

I've changed the com8 port to 57600 too but if yours works at a higher and lower rate then you dont need to do that.

Are you using a laptop? I've notice it sometimes wont connect when the laptop psu is plugged in.

I've attahed the settings for the gerneral and advanced tab. Both xrf units are set the same.

I've used both mavlink 0.9 and 1.0 and MP 1.2.7. All have connected. Dont worry about strange characters in the MP console window. Thats just mavlink doing it thing.

I've changed the com8 port to 57600 too but if yours works at a higher and lower rate then you dont need to do that.

Are you using a laptop? I've notice it sometimes wont connect when the laptop psu is plugged in.

ooops double post due to a 500 server error.

Thanks Bob again for your reply.

When I did compare your XFRConfig with mine, I did notice on Advance tab, the packet size on your setup is bigger than mine, see attachment. Yours is 140 chars, mine is 12 chars. Those 12 chars were the default, I did not change anything here.
Did you change those values yourself?
I will try to see if using your value will work, but a reply from you would be good before modifying mine.
Also my XRF version is 0.48B (higher), comparing to yours.

I think so. Cant be sure to be honest

Still not working...
So, I did put both XRF to 57600 with 140 chars, connect one XRF to laptop with FTDI cable (no psu plug) and the other XRF to APM2. When try to connect at 57600, it is trying and at the end it saying not heart bat ...
The XRF from APM2 is sending data since both LED are blinking and also I can monitor on XCM the values or see on Terminal also (see attachment).

I did notice on web someone say APM2 need to be "setup to accept wireless connections", something in APM_config, but not sure what to check. Is any parameter I need to setup to allow APM2 to communicate wireless?
Also I am wondering if voltage on APM2 could not be good? I have 3 x 1.2V battery.
As I mentioned, when connected XRF to 34800 and using one with a Mediatek GPS (not APM2) and the other to lapton, with HK GCS, I can see data very well.
But when try using the APM2 (with it's GPS) data are send, but nothing recognize. APM2 works fine on the plane with missions, but I can hot have telemetry with radio.

This still looks like a baud rate mismatch to me. Are you sure that the APM2 is sending data at 57600?

You can check out the XRFs by disconnecting the APM2 and connecting Rx to Tx at the remote end - that way anything you send will be echoed back. If you then swap XRFs and check again this will demonstrate that both XRFs are communicating at 57600. After that then you need someone to help you with the APM2 (we do not have one).

Another test would be to remove both XRFs and to link the FTDI Rx directly to the APM2 Tx and the FTDI Tx directly to the APM2 Rx (also link the grounds) and see if you can get that to work at 57600 - that would establish whether the APM2 is in fact communicating at 57600.

I think i changed the telemetry rate to 3,,3,1,3,3 for the planner settings.

I've always used a 11.1v lipo via a BEC to power the APM2

Not heard for a couple of weeks, assuming all is OK now.

Indeed, it WAS OK for a while, I was able to make XRF communicate each others on Ardupilot on 57600.

But today the communication does not more work. I did check each XRF on XRFConfig and one of them is not more responding.
I did notice when I plug it into USB port with a FTDI cable, the one I suspect is problem do have both LEDs light, very dim and not blinking. The good one does respond to XRFConfig and LED is blinking.
I am sure the one with both LEDs dimmed and not blinking has a failure.
Is any way to reset it? It this module under some warranty?

Thanks, Chris