Warning, value overflow

The original alternative firmware. Suitable for all 9x based radio control transmitters.
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Warning, value overflow

Post by Volhout » Fri Mar 14, 2014 12:43 pm


This warning applies to TH9X software in combination with a V2 RF modules (FlySky) on a Turnigy 9x

I have been a great fan of TH9X software. Have been using it since R56.
I use a Turnigy 9X V2 (internal RF module).
Last couple of years I have used R184. I fly motor airplanes.

Last sunday at the field I discovered a flaw in TH9X code. And I was glad I found it while the plane was still on the ground.

I was increasing the throws for elevator from 100 to 120%, with limits for the servo set to 120%.
What I did not realize that this particular servo had an offset of 25% (from trimming).
The combined control for the servo caused a "variable overrun" (I hope I this translation is good, English is not my native language).

While driving the stick through it's extremes I noticed:
- at the most extreme stick position, the servo would return back to mid position
- at the most extreme stick position, servo's for aileron and rudder would be affected (change position).

I tried 3 different receivers (3CH, 6CH and 8CH), and all 3 give the same result.
I tried 3 different TH9X software versions (R184, R235 and R285) an all shows the problem.
So either the problem resides in the TH9X code, or it resides in the V2 RF modules that gets out of control due to the pulse width applied to it.

I have programmed the transmitter with openTX now (R2940) and have loaded the same EEPROM file.
openTX recognizes the EEPROM format from TH9X R184, and does not show the problem.

I am not sure however where the actual problem is caused. It is possible that openTX processes the settings inside the EEPROM different (maybe it has an internal limiter) and that the actual culprit is the V2 RF module).

But fact is... this bug is gone.


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Re: Warning, value overflow

Post by jhsa » Fri Mar 14, 2014 1:04 pm

You were using an ancient firmware on your radio.. it's something like the Cave Men of the 9x firmwares :D

er9x and opentx are based on the TH9x firmware but are already miles ahead.. Of course there were bugs then ;).. There are still some once in a while :D
My er9x/Ersky9x/eepskye Video Tutorials

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Re: Warning, value overflow

Post by Volhout » Fri Mar 14, 2014 1:10 pm

Agreed !!

Once you are happy with something, you tend to stick to it.... :P
I just wanted to point out that even the most recent TH9X code (R285) has this problem.
The problem may not exist for non-V2 RF modules, but I cannot verify that.

Reason I was stuck on TH9X originally was that it is so much simpler (fewer menu's, fewer options).


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