P3S - how flash gimbal circuit board?

[quaddamage]

The wiki here was mostly prepared for P3X/P3S, but most of it also applies to P3C. Read that:

Firmware m0100

Tools for handling firmwares of DJI products, with focus on quadcopters. - o-gs/dji-firmware-tools

github.com

First simple thing to check is whether you can make the Ambarella generate log on the SD-card. Read the above wiki for details.

If that won't do anything, 2nd thing is to check all service pads with power voltages, using multimeter. Ie. 1V8 means there should be 1.8V on that pad to power the chip correctly.

If all voltages are present, you can start working on UART link. That requires 3 wires to work: RX, TX and GND.
You connect the wires to USB-to-TTL dongle. Buy one which allows to select between 3.3V and 5V by a jumper. Avoid any which claim to be "automatic" or "intelligent".

You will find details on the UART connection here; in the docs I'm connecting to different boards, but everything else you can use for your scenario:

GitHub - quaddama9e/dji-technical-stuff: Technical details and howtos about DJI drones

Technical details and howtos about DJI drones. Contribute to quaddama9e/dji-technical-stuff development by creating an account on GitHub.

github.com

An example output on UART of a working Ambarella is available on the "Firmware-m0100" wiki I linked earlier.

the remote seems it is linked ok.

I don't think what I wrote got to you. There are two radio links. Separate links, on different protocols and frequencies. You can't tell if both are ok without relinking. Unless you can somehow tell that the Wifi connection is established?

 

[Cuboide]

I relinked the remote to drone following the standard procedure, I guess it links both frequency? otherwise not sure how to check if are both linked.

 

[quaddamage]

I relinked the remote to drone following the standard procedure, I guess it links both frequency?

Yes, if you did the re-link this can be considered checked.

Actually, if I was implementing the linking, I would make sure the procedure fails if video channel linking fails. Would have to be verified whether DJI engineers really did it that way, but if that's correct, then the linking ending with success also confirms that Atheros chip works correctly.

 

[Cuboide]

Great, one less thing to worry about
I tried the first step, I created a text file and renominated changing also the extension. Put the SD cad back in the drone powered it + control and waited 5 minutes, powered off and pulled the SD back and could not find any log new log. The card is displayed just what there was before ie the DJI file and the card set volume info folder.
time for the tricky step 2...

 

[Cuboide]

 

[Cuboide]

I opened the camera case and pulled the top board. Photos attached of both boards.
I see the top board with 1v8. so to power the board I need to connect a positive 1.8v source there and the negative to any ground pad right? what can I use to generate 1.8v?

 

[quaddamage]

I see the top board with 1v8. so to power the board I need to connect a positive 1.8v source there and the negative to any ground pad right?

It is highly unlikely that the whole board is powered at 1.8V.

You see the colis there, 2.2uH? Such coils are a part of DC-DC converters. Input voltage is most likely the highest one, here 5V.

 

[Cuboide]

got it! I should use those 2 to power the board, ok?

 

[quaddamage]

got it! I should use those 2 to power the board, ok?

The board normally gets power from the connected FFC cable. Check with multimeter if these are shorted to one of the connector pins, and you'll be sure.

This way you can also start preparing pinout description of said connector.

 

[Cuboide]

so basically with the multimeter I touch the 5v pad and each of the ribbon cable pin to check a short correct?

 

[Cuboide]

ok, I did not try any short and connected directly to 5v. the board powered up as you can see in the photo.
I checked all volts with the multimeter and all are correct.
we can move to the next phase, probably next weekend once I have received the USB-to-TTL dongle

 

[Cuboide]

also I powered the drone with the board on an without case

cover to see if the green light was on just to be sure it is not ribbon not bringing energy

 

[Cuboide]

@quaddamage
When I receive the USB-to-TTL dongle I will connect the circuit board with 3 wires to work: RX, TX and GND. Do I have to connect also the 5v service pad?
0nce all is connected, how do I read the chip? is there a string I have to load on CMD in wind 10 or I need a software like putty? tx!

 

[quaddamage]

Do I have to connect also the 5v service pad?

Not sure what exactly you're asking. All electronic devices need to have power to run. You can't communicate to the chip if it's not turned on. To provide power you have to connect two wires, in order to allow flow of current. In this case power is connected through 5V and GND.

The board has probably relatively high current requirements, like 1.5 - 2 Amps. Your voltage source need to be able to provide such current.

 

[Cuboide]

ok thanks for clarifying, I thought the board could have been powered by the TTL/USB

 

[Cuboide]

I received the TTL-USB dongle. installed the driver, downloaded putty and also Termius. I made the soldering connections to the board. Despite trying all settings Boud / COM matching etc I cannot type or see any code in the terminal/s. Not sure what I am doing wrong. Also tried the dongle disconnect from the board. Any idea how to get this working?

 

[Cuboide]

 

[captainmilehigh]

I must admit, I admire your perseverance and tenacity in trying to fix this issue. I am not that patient.

Me ?............I would have just replaced the gimbal assembly including the camera from a donor drone......or from a reputable repair shop like Drone Nerds here in Florida. They do all my work that I can't figure out on my own.

** I don't mean any disrespect to you or your efforts in fixing your drone yourself in recommending other alternatives, but you have WAY MORE patience than I do. Best of luck ....

 

[Cuboide]

thanks Captain, let see how it goes, itis mostly for fun, to learn this stuff

 

[captainmilehigh]

thanks Captain, let see how it goes, itis mostly for fun, to learn this stuff

For 'fun' huh..? I'd be using foul language, ripping out my hair, and throwing loose objects by now. My brain and small electronics don't play well together. Again,....good luck.