PPM encoder - failsafe with turnigy 9x v2 receiver

i purchased APM 2.6, then i updated to last FW revision each time you issued a new revision.
if i well remember, my apm was able (in the past ) to recognize when the radio was powered off.
actually with last FW revision i find that apm stays on last known signal frequency on all radio channels.
Then i connected my receiver turnigy 9x8cv2 to a esc+motor and i verified that after few seconds that i power off the radio, the PWM output goes to NO SIGNAL and the motor stops rotation.

then i read that it could be a problem on the PPM encoder and i found this link:
copter.ardupilot.com/wiki/common … tmega32u2/

My questions are 2:
1)am i correct telling that this problem was not present in the previous versions of FW?
2)am i correct that i need to update my PPM ENCODER on the APM board?
3)i can not follow the procedure cause i can’t put the APM in DFU MODE.someone wrote that in this case it means that there is no bootloader… I’m a little bit confused.

i better analyzed the problem:

  • connecting APM channels 1 to 5 to the turnigy receiver the APM doesn’t recognize the shutdown of the radio.

  • after few tries i found that my turnigy receiver channel 1 continues to supply the PWM output, even when the radio is off.

-disconnecting the channel 1 of my receiver from the APM, the APM started to correclty set the throttle to 900 as soon as i power off my radio control.

  • I also tried connecting the channel 1 to another APM input but the result is the same.

I think that this could be a problem in the APM firmware and not on the PPM encoder.

I think that if at least the throttle stops to arrive to apm, you should activate the failsafe.

on my previous post i wrote an error but i’m not able to edit it.
the problem is not channel 1 of the receiver but channel 4 (i made a typing error).

I found the problem origin:

On this video is well explained that turnigy receiver channel 4 and 5 does not stop the PWM in case of radio connection lost: youtube.com/watch?v=I6lVYA7z9NE

this means that i have to use the other channels.
in my setup this caused me a lot of pain.

now the questions are the following:

  1. did you changed something in firmware updates? i can’t remember this problem before, but it is also possible that i changed the connections

  2. don’t you think that the firmware can be stronger if you activate the failsafe if you find at least 2 channels dead for at least 1 second?
    why you expect all the channels to be dead simultaneously?


following the procedure linked on my first post, in order to flash the PPM encoder, i was experiencing an error on the atmel tool named FLIP.
the error is "AtLibUsbDfu.dll not found"
this error can have different meanings.
One reason for that error could be that the bootloader is not present on the atmel chip.
In my case i was using Windows 64 bit while there is a know bug of FLIP with Windows 64 bit.
Then i found a Windows xp 32 bit computer and i tried again the procedure with success.
I followed the procedure linked on my first post and i successfully flashed the PPM encoder.

Now the problem is solved and the APM can detect the failsafe with my turnigy 9x v2 transmitter and receiver.

Isn’t it possible to automatically flash the PPM encoder AND the APM when you choose a firmware on the mission planner?

I just lost 12 hours around this problem. I hope that someone else will find this thread usefull, and save at least 8 hours of work.