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.

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

Here are the SPI capture for the recevier using two stock transmitters.

Just sent you a PM. I have spare receiver boards.

@Goebish
You mentioned before that the transmitter frequency was higher than 2472Mhz. Will it be higher than 2485Mhz?

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.

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.

> 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..?

i have a banggood 4 in 1 module in my devo 19 do i get to send it back for an updated one.

> (...) 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!

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