JD 395 cx-10

The new green Board on the Cheerson cx-10 uses the same protocol as the JD 395.

Is there a way to use that protocol with a devo 7e?



Thank you for your help,

kamueone wrote: The new green Board on the Cheerson cx-10 uses the same protocol as the JD 395.

Is there a way to use that protocol with a devo 7e?



Thank you for your help,

Actually, none of the Gurus here (PB, Victzh, Hexfet, etc...) have such models. I have the JXD 395, but to collect the SPI it's very hard coz the RF chip is directly soldered on the TX board. I will try to see if associated SPI pins are derivated somewhere else on the TX MCU for example.

Maybe if you can tell us exactly where to put the logic analyzer probes...

someone with the skill to solder can grab a log.

Daryoon wrote: Maybe if you can tell us exactly where to put the logic analyzer probes...

someone with the skill to solder can grab a log.

It will be almost impossinle to solder on these pins (without specific material). You need 5 probes : GND, MOSI, MISO, TCK and CSN.

You can find these pins on the nRF24L01+ datasheet.
The best think to try first is to check if these pins are not linked with pins of the main MCU of the TX. On this one, soldering job will be easier

I don't think it's impossible. Looks easy to me.

Why do you think it's nRF24L01+ ? It looks like it, but the letters 345 are in the wrong direction.

Could you clean it with alcohol and make another photo?

In theory, the pins with fan-out (bottom side) are the ones, but the rightmost pin is not visible enough and it's unclear how to connect to it. The photo of the back would help.

victzh wrote: Why do you think it's nRF24L01+ ? It looks like it, but the letters 345 are in the wrong direction.

Could you clean it with alcohol and make another photo?

In theory, the pins with fan-out (bottom side) are the ones, but the rightmost pin is not visible enough and it's unclear how to connect to it. The photo of the back would help.

Because, on the quad (on the JXD 395 at lease), there is a Beken 2423 ...
So I guess it's nRF24L01 compatible chip

victzh wrote: Why do you think it's nRF24L01+ ? It looks like it, but the letters 345 are in the wrong direction.

Could you clean it with alcohol and make another photo?

In theory, the pins with fan-out (bottom side) are the ones, but the rightmost pin is not visible enough and it's unclear how to connect to it. The photo of the back would help.

I take what I said back... taking a macro shot now.

Ok Looked again for the JXD 395, it's a XN297 which is compatible nRF24L01 ....

EDIT ... Below XN297, the second number is : 345 ....

So it"s confirmed should be this chip also for the CX-10.

Here's the chinese document with the pin out.



From the website:
"1 Product description
XN297 is a short distance transceiver chip, using GFSK modulation. Chip integrated RF transceiver channels, GFSK modem and digital
data link. Users only need to send / receive channels for simple setup, you can communicate. In Auto Transceive mode, the chip can root
automatically determine the data according to the response information delivery / reception was successful, so retransmission, packet loss, continue to send and wait for the other operations, with simplified
user program.
2 Recommended Operating Conditions
 Power supply voltage: 3.3V
Ø Working temperature: -40 ℃ ~ 85 ℃"

This chips must be even cheaper than the BK2423 ...
The Moontop M9911 have the same chip too ...
(see Moontop M9911 thread )

Another document with the pinout (identical to the nRF24L01)

Could someone post an image of the entire PCB where the MCU is visible ?
I'm usually attaching my probes to the MCU, not the RF chip itself.
You can see traces running from RF chip to the lower part of the PCB on the backside, so these are the ones we're interested in. The contacts through the board at the lower part looks like standard pitch, easy to solder / attach SMD probes.

One can also try to solder to these "trough-board" contact rings.

Full resolution:

Here's a full resolution shot with the front and back overlayed on top of each other.

The back has been flipped horizontally so the traces lines up with the component in the front of the board.



I also have the Photoshop layered file you can change the opacity on if you have Photoshop and want a copy of the PSD.

Daryoon - I must admit, that's just genius! Funny thing they didn't bother to connect MISO. Strictly speaking, you can get away without it at the cost of some reliability.

So, the answer for SPI traces - 4 wires going from the top to the bottom of the board and connected (my guess) to the bottom right 4 pins of MCU.

I hook up the Logic Analyzer on the bottom 4 legs of the MCU.

Left to Right on the MCU corresponds to:
CH1, CH2, CH3, CH4 on the Logic Analyzer

Hope you can make sense of it. LOL

hacksmods.com/files/cx10_green_capture1.zip

After the LA has been hooked up.

I powered up the quad and TX.

Then moved the stick up and down to complete binding or arming of the quad.

Then I gave throttle and moved the cyclic stick around. Then moved the rudder stick around.

Then I pressed the left stick in to activate the three rate mode. I pressed the right stick in to activate flip mode. However, I didn't complete the flip.


Let me know if there's a better procedure I should be following.

Thanks.

-Daryoon