WLToys Q303

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26 Nov 2016 14:32 - 14 Dec 2016 16:31 #56299 by ajtank
Replied by ajtank on topic WLToys Q303
@goebish
On the separate module, CE is always tied to Vcc. However, if I measure correctly, CE on the 4-in-1 is not tied to Vcc. How is CE controlled in your code?
It was discovered later that the CE on the module was tied to Vcc via a 4k7 resistor.
Last edit: 14 Dec 2016 16:31 by ajtank.

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26 Nov 2016 14:35 #56300 by goebish
Replied by goebish on topic WLToys Q303
We do not control CE for this kind of modules, it should always be tied to Vcc, or it wouldn't work, whatever the protocol is.

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26 Nov 2016 15:57 #56302 by goebish
Replied by goebish on topic WLToys Q303
.. could also be an inaccurate crystal or associated trim caps.

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28 Nov 2016 13:45 - 29 Nov 2016 04:35 #56342 by ajtank
Replied by ajtank on topic WLToys Q303
The crystal on the 4-in-1 is very tiny and I don't have an immediate replacement part.
I have written a sketch to put the NRF24L01+ in continuous carrier mode. I can confirm that the chip on the 4-in-1 is not genuine but is actually a disguised Si24R1. The genuine chip neglects bit 0 of register RF_SETUP whilst Si24R1 responds to bit 0. In other words the genuine chip has only 4 different transmit power settings and hence 4 consumption current readings. Si24R1 has 8 settings and hence 8 current readings. I compared the current against the typical values on the datasheet and they matched.
A summary so far:
a) genuine or fake chip on 4-in-1 module will not bind Q303 but can bind my other quads
b) genuine chip on separate module will bind any quads
c) fake chip on separate module will not bind Q303 but can bind my other quads
My next step will be looking at the clock frequency and attempting to remove the carrier board off the 4-in-1 to make it a separate module. Any other comments are appreciated.
This is in one way frustrating and in another way interesting. I wrote my first program and soldered a QFN by hand. Great job for a 50-yr old newbie :)
Last edit: 29 Nov 2016 04:35 by ajtank.

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28 Nov 2016 13:54 #56343 by goebish
Replied by goebish on topic WLToys Q303
Thanks for those experiments, the results are interesting, and welcome to the hobby ;)

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04 Dec 2016 13:24 #56508 by ajtank
Replied by ajtank on topic WLToys Q303
Here are the SPI capture for the recevier using two stock transmitters.

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04 Dec 2016 13:33 #56510 by goebish
Replied by goebish on topic WLToys Q303
Thanks, but those captures won't help, I'd need to see the RF channels expected by the RX given some crafted TX IDs.
I was only asking if it is possible to connect the analyzer to the RX, looks like the answer is yes ;)

Now I'd need a RX myself because that would be tiresome to do it remotely.

Do you know if this Q303 flight controller (that's all I need) can be bought separately for cheap, or can you send one to me ?
I'll ship it back once I don't need it anymore.
(PM if you need my shipping address)

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04 Dec 2016 13:54 #56511 by ajtank
Replied by ajtank on topic WLToys Q303
Just sent you a PM. I have spare receiver boards.

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04 Dec 2016 13:58 #56512 by goebish
Replied by goebish on topic WLToys Q303
Ok, replied :)

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07 Dec 2016 16:54 #56622 by ajtank
Replied by ajtank on topic WLToys Q303
@Goebish
You mentioned before that the transmitter frequency was higher than 2472Mhz. Will it be higher than 2485Mhz?

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07 Dec 2016 17:03 #56623 by goebish
Replied by goebish on topic WLToys Q303
The higher frequency I've seen in your dump is 2478, but that doesn't mean that another tx with a different tx id couldn't use higher frequencies.

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10 Dec 2016 07:02 - 14 Dec 2016 01:08 #56734 by ajtank
Replied by ajtank on topic WLToys Q303
I grabbed a RF explorer and measured the carrier frequency using an Arduino setup. Offset for standalone module is 10-20ppm whilst the 4-in-1 is 40-50ppm. The datasheet of XN297L specifies 20ppm maximum for 250kbps mode. After changing the 2 loading capacitors of the crystal to 15pF, the offset is improved to within 10ppm. I can now bind Q303 and the result is consistent on two Devo 10 transmitters. This fix works on both nRF24L01+ and the clone chip Si24R1. The genuine nRF24L01+ datasheet asks for 60ppm crystal but it seems XN297L is more sensitive to the crystal accuracy.

A brief summary:
a) The 4-in-1 carries a clone chip Si24R1 which is out of the module seller's intention. Seller has started recalling the modules from Banggood and replacing with genuine chips.
b) The clone works fine with XN297L 250kbps mode after changing the loading capacitors to 15pF (size 0402). Module seller has also purchased a Q303 and verified more than 10 modified modules.
c) The clone will affect YD717 protocol causing a lagged response, see here. A workaround is to disable auto-acknowlegment as verified by user NathanBarguss. Hopefully deviation developers can review the possibility to change the protocol.
d) Some Eachine E010 users reported the difficulty to bind at high transmit power. Both the module seller and I have verified a bunch of Eachine E010 but we could not reproduce the problem using 4-in-1 modules with clone chips. So this is still a mystery.

Observation using Arduino:
a) I have to modify my Arduino Uno SPI from 5V to 3V otherwise the 4-in-1 module will not work. The SPI bus of the standalone module is 5V tolerant though.
b) If I control the CE pin of standalone module via Arduino, module works fine up to ch125. If I tie CE to Vcc as the 4-in-1 module, I cannot set it to beyond ch80. Same issue happens on the 4-in-1 using Arduino.
c) If I unplug the USB cable off the Arduino or add a 47uF capacitor across the standalone module, the above problem will vanish.
Since this is my first time writing a program, I cannot guarantee the correctness of my observation.
Last edit: 14 Dec 2016 01:08 by ajtank.

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10 Dec 2016 14:05 - 10 Dec 2016 14:08 #56735 by goebish
Replied by goebish on topic WLToys Q303
Cool, so the theory of a bad crystal and/or caps is confirmed :)

a) that would be nice, at least use a "better" clone than the Si24R1
b) yes, that's the culprit, now let's hope 15pF will always be fine for those crystals
c) there's already a protocol option to disable AA with the YD717 protocol in the nightly
d) seems most x-in-1 modules are working with the E010, but some don't, or only at lower power level. Perhaps replacing the crystal caps would fix the issue as well ...

a) take care, some chips on the bus are not 5V tolerant (eg A7105), 5V might damage them.
b-c) I'm not an expert but maybe higher frequencies require cleaner power supply.
Last edit: 10 Dec 2016 14:08 by goebish.

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10 Dec 2016 15:12 - 10 Dec 2016 15:46 #56736 by ajtank
Replied by ajtank on topic WLToys Q303
Indeed thanks a lot for your continuous support and advice for this model. It is also great to have a nightly build getting rid of the YD717 AA issue (I only saw the build posted by NathanBarguss). The 4-in-1 seller has also purchased a quadcopter usiing YD717 protocol and will use it to test the chips for future procurement.
Last edit: 10 Dec 2016 15:46 by ajtank.

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13 Dec 2016 14:50 #56779 by brylant
Replied by brylant on topic WLToys Q303
> a) The 4-in-1 carries a clone chip Si24R1 which is out of the module seller's intention. Seller has started recalling the modules from Banggood and replace with genuine chips.

Any idea if he's going to replace/refund existing owners..?

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13 Dec 2016 14:52 - 13 Dec 2016 14:53 #56780 by goebish
Replied by goebish on topic WLToys Q303
The Si24R1 is not a problem, the only issue is that auto acknowledge has to be disabled for the protocols that use it, not a big deal ...
Last edit: 13 Dec 2016 14:53 by goebish.

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13 Dec 2016 15:04 #56781 by justyn07
Replied by justyn07 on topic WLToys Q303
i have a banggood 4 in 1 module in my devo 19 do i get to send it back for an updated one.

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13 Dec 2016 15:05 - 13 Dec 2016 15:07 #56783 by goebish
Replied by goebish on topic WLToys Q303
I doubt there will be any replacement ... If you want an "updated" one, just wait (they don't exist yet) then buy another one.
Anyway, this question can't be answered here, just ask banggood or the seller you got your board from.
Last edit: 13 Dec 2016 15:07 by goebish.

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13 Dec 2016 15:11 #56785 by brylant
Replied by brylant on topic WLToys Q303
> (...) then buy another one.

well... it was advertised as NRF24L01 and not Si24R1. And it wasn't particularly cheap either so I guess I'll talk to BG and see what can be done on "buy another one" front ;))
anyway - thanks for reply and all your work!

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14 Dec 2016 05:40 - 14 Dec 2016 05:42 #56807 by ajtank
Replied by ajtank on topic WLToys Q303
The clone has the same marking as the genuine chip. So the seller himself is also a victim. As stated by Goebish, the current module with clone chip is still good for most models. There is also a fix for the problematic YD717 protocol.
Regarding aftersales policy, it is better to consult Banggood. I have no affiliation with the seller but it just happens that I can communicate with him in Chinese. I reworked my own 4-in-1 modules by replacing the chip and capacitors. And now I have purchased tools and equipment more than an average hobbyist should :)
Last edit: 14 Dec 2016 05:42 by ajtank.

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