328P FC freaks out when using FlySky RX on throttle input

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n8lbv
Posts: 62
Joined: Fri Aug 15, 2014 3:29 pm

328P FC freaks out when using FlySky RX on throttle input

Post by n8lbv »

I've been using 8ch FlySky RX units and FLysky TX modules on TUrnighy 9X and 9XR now for quite some time.
This one --> http://www.xheli.com/79p-r8b-receiver.html
Although inexpensive these TX-RX have proven to be very well performing, long range and reliable!
I've been using them on 450 and 500 size CP helicopters.

Thought I'd try one on my second quad build because it has 8CH and gives me some extras to play around with.
I'm just now finding out that this is part of a problem that has been bugging me for over a week.
I have another thread open on this and have just came to this conclusion recently at the end of this thread:
Please see viewtopic.php?f=18&t=5605
I'm breaking off topic a bit and will monitor both very closely and share any information between them before closing the original.
I absolutely HAT abandoned threads even if the OP gives up.

Also I have a youtube video detailing the issue as it occurs.
Please see http://youtu.be/MsaABFhlrkM

What is happening is that even though I am sending minimum throttle when the FC is first initialized it shows "1500" being received on the FC throttle input port.
The FC throttle value being received does not change or update until I actually bump the stick up some and bring it back down.
Then the FC starts showing live data.
It's as if the FC does not like something about the minimum throttle value or level that the FLysky RX is sending to it when at low throttle stick!

Also when bumped up and brought back down quickly the throttle value being received in the FC *STICKS*!! like at 1200 or 1400 or 1245 etc...
Is very sporatic but seems that it stops reading the RX whenever the stick is quickly brought up and back down.
The video details this.

It's very weird, I've confirmed that when the RX is connected to a servo or directly to one of the 4 esc channels for the quad that it works very nicely properly and does not stick anywhere at all.
Any ideas what may be causing this?? and why it only happens on the FlySky RX?
If I trade out the RX for a 6CH OrangeRX spektrum clone the sticking problem goes away completely.
Yet the FLySky RX when tested standalone works perfectly.. My power and grounds are excellent no problems there..
Just the FC is freaking out a bit and throttle input values are sticking and not coming back down to minimum even though the flysky rx is sending it's minimum signal to the FC when the
stick is brought down.
The throttle value sticking issue is happening 100% of the time if you move the stick up & down very quickly.
Doesn't matter if motors are armed or not or if anything is actually hooked to the motor output channels on the FC.
It realiably sticks and fails and the problem can easily be reproduced.
Switching to a different RX fixes everything I get actual throttle read (low stick) when board initializes and the value never sticks by moving the throttle stick quickly.
Crazy!

n8lbv
Posts: 62
Joined: Fri Aug 15, 2014 3:29 pm

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by n8lbv »

Exact frequency; Does it matter?
Everything 'looks' good on both RX looking at a scope on the RX throttle output channel on startup and during changes.
Looks great.
However on the OrangeRX (spektrum compatible) Pulse frequency is: 45.4Hz
Coming out of the FLySky RX I get: 51.2Hz
Should we care?
Other than that I can't tell what is different from the OrangeRX to the FlySky and why one is working and the other is acting up!

n8lbv
Posts: 62
Joined: Fri Aug 15, 2014 3:29 pm

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by n8lbv »

Scopeshot pulserange & all look fine to me.
Difference in freq. is not that much I don't think that matters either.
Attachments
CH1 Throttle from Flysky RX.
CH1 Throttle from Flysky RX.

n8lbv
Posts: 62
Joined: Fri Aug 15, 2014 3:29 pm

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by n8lbv »

Really stinking stumped:
I figured out if I set the FLysky radio not to go below 1000 on the throttle command there is no sticking or problems.
When it goes below 1000 the FC freaks out and "sticks" at various values from 1100 to 1600 when you move the sticks quickly.
trimming/setting the tx not to go below 1000 seems to be a fix and work-around.
Frustratingly if I set the Spektrum TX to go below 1000 and down to 910 there are still no problems and no value sticking.
I really want to know wtf is causing this!

Setting the FLysky TX to 1000 at min also stops the startup at 1500 until stick is moved up and then down problem.
This makes no sense!!
All looked good (below 1000) on the scope and a direct connected ESC or digital server work perfectly from 1000 down to 900.
WTF gives here!?

waltr
Posts: 733
Joined: Wed Jan 22, 2014 3:21 pm
Location: Near Philadelphia, Pennsyvania, USA

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by waltr »

This is a good one for mind blowing.
I do recall some info about not setting minimum pulse width from the radio less than 1000 and recommended to set minimum at about 1050.
I don't remember where I read this and the person writing said something about having trouble some years ago (earlier version of MW) and still does it out of habit.

Maybe this is the solution to use and understanding why is not going to happen. Hope you do figure this out.

n8lbv
Posts: 62
Joined: Fri Aug 15, 2014 3:29 pm

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by n8lbv »

Yeah it's a stumper.
Guess I'd also expect there'd be more folks out there trying to use the flysky radios on multiwii as well.
A bit shocked I'm the only one.
There's a lot of these radios out there. It's stick with a Turnigy 9X.

waltr
Posts: 733
Joined: Wed Jan 22, 2014 3:21 pm
Location: Near Philadelphia, Pennsyvania, USA

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by waltr »

Well I do use a FlySky CT-6 radio with MW. My issue with it was that at the maximum stick gain (in the TX setup) I could not get the full 1000 to 2000 values but only 1120 to 1890. This required changing the MINCHECK and MAXCHECK defines in config.h so the stick commands would work.
Another Issue I have is each RX I have bought (have four now) the stick center and end point values are different using the same TX. Therefore each Quad's config.h has a different MIDRC defined value so that the TX's trim tabs are the same for all quads.
At least once I understand the issues MW had a good way to account for these differences.
So just do the setup that actually works then go fly.

n8lbv
Posts: 62
Joined: Fri Aug 15, 2014 3:29 pm

Re: 328P FC freaks out when using FlySky RX on throttle inpu

Post by n8lbv »

Thanks, good to know at least someone else is also using flysky.
I don;t think you'd have time to test for the sticking throttle issue wouldya?
Also MY rx is a totally different model the ones I have are 9X8Cv2
Mine are going down to about 910 ish on the low side and anything below I get the throttle sticking.
I programmed my spektrum radio to make it go down to about 920 and there's no sticking whatsover.
If I program the flysky to no send below 1000 there's no sticking (*which means I'll be able to fly it*)..
But I'm still going nuts trying to figure out why I get the sticking (and startup stuck at 1500) with the flysky radio but not the spektrum when Sending values below 1000

If you or anyone else with flysky want to see if you can replicate the problem that'd be fun but I don;t expect anyone to go through the hassle.
I don;t have any other flysky RXs except my 8CH mentioned above. to test with.

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