Hello!

I am trying to get a M300 drone run some sample codes from OSDK 4.0 on a Raspberry Pi 3B but kept getting the error message

"ERRORLOG/1 @ getDroneVersion, L1676: Drone version not obtained! Please do not proceed."

I tried other resources online but the problem remains.

My setup is: Raspberrt Pi USB <---> TTL converter <--->OSDK expansion module <--->OSDK port on the drone.
Configurations I did:

1. I've configured the pi to dial out by using the command "sudo usermod -a -G dialout $USER".
2. The USB port was found by using the command "ls /dev/tty*" before and after the TTL converter is plugged in
3. I tried swapping the TX/RX pins but it didn't help
4. API control enabled in DJI Assistant 2
5. Baud rate in /build/bin/UserConfig.txt is the same as the baud rate in DJI Assistant 2's setting. All listed baud rates in Assistant 2 were tried out.
6. I also tried connecting the UART pins on the Pi directly to the expansion module, didn't work either
7. The command I used to run the code was "./djiosdk-mission-sample UserConfig.txt /dev/ttyUSB0" or "./djiosdk-mission-sample UserConfig.txt"
8. The UserConfig.txt file can be seen below, I couldn't find any ACM port from my tty devices so I deleted the "acm_port : /dev/ttyACMx" line. However, I also tried putting "acm_port : /dev/ttyACM0" on even though the port doesn't exist. The code complained about "Failed to initialize ACM Linker channel!" and proceeded to throw the "Drone version not obtained" error.
9. Smart controller was ON during the debug process.

Observations:
1. TTL board has only TX LED lit up, maybe there's no signal coming from the drone's side? (TTL board tested to work)
2. There is 3.3V on TX and RX in both the TTL board and the expansion module when they're not connected to each other
3. A screenshot of the error messages I got can be found attached
4. Photos of my setup can be found attached, USB connection to PC is taken out for better clarity but it does present while debugging.


I'm suspecting this to be a problem of the ACM port (inspired by this post ) but since I couldn't find it from "ls", I'm not sure how to fix this.

Any help would be great! Thanks in advance!

PS.
Since I'm at it, I might as well summarise some of the potentially useful threads related to this problem for future reference by other people.
OSDK and OSDK-ros activation failure with solution and checklist
Github Issue
Similar issue solved by swapping TX and RX pin
Custom made OSDK expansion board

Hi, sorry this isn’t a
Response on your post but I believe you have done some work with external positioning and OSDK before? We have a project requiring this for M300, can you let me know if you could help?