Hello,

I hope you are doing well today.

I am attempting to connect an UP board companion computer to the M300 thru the OSDK port. The UP board computer uses Ubilinux 4.0 as the OS, which is based on debian stretch.
UP Board Computer by UP:
https://up-shop.org/up-board-series.html


Ubilinux 4.0 by Emutex:
https://emutex.com/products/ubilinux


I am able to compile and install all the necessary libraries for the Onboard SDK to work. Furthermore, I am able to connect to the M300 using the OSDK through the OSDK Port serial pins ( Tx(A8) / Rx(A5) pins). I have run the telemetry samples and the flight control samples. I have also built a simple autonomous flight program that sends velocity commands and logs the states.

My next task requires that I try to incorporate some of the advanced-sensing streams so we can analyze the 3D stereo-image data. According to the documentation (and some forum posts), we are required to connect the serial connections ( Tx(A8) / Rx(A5) ) and the USB ( D+(A6) / D-(A7) ) connections to the companion computer so we are able to receive the aforementioned data.

To create the plug for the OSDK port, I have followed the guidelines provided by the dji documentation and the following forum post:  https://forum.dji.com/thread-219723-1-1.html

Sanity Checks:
1) I have verified the connections on the M300 make sense by reading the voltages across the pins ( (D+) -> (D-) = ~2.3V;  (D+) -> (GND) = ~2.3V; (D-) -> (GND) = 0V   ). Note that the voltages across the D+/D- pins on the computer side read 0V (Not sure if this makes much sense?)

2) I run the 'dmesg' command and see that the USB is registered, and is even set to the port 'ttyACM0'. However, it quickly unmounts itself (see output of 'dmesg' at end of this email).

I have not been able to figure out a good solution to this issue, so if you have any advice or ideas, that would be extremely helpful!

Thanks,
-Zack

Output of 'dmesg' after M300 is powered on and connected to companion computer via USB:

[  294.415467] usb 1-4: new high-speed USB device number 12 using xhci_hcd
[  294.556923] usb 1-4: New USB device found, idVendor=2ca3, idProduct=001f
[  294.556931] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  294.556936] usb 1-4: Product: e1e
[  294.556940] usb 1-4: Manufacturer: DJI
[  294.556943] usb 1-4: SerialNumber: 123456789ABCDEF
[  294.748693] cdc_acm 1-4:1.4: ttyACM0: USB ACM device
[  294.751070] usbcore: registered new interface driver cdc_ether
[  294.753329] usbcore: registered new interface driver cdc_acm
[  294.753332] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
[  294.758610] rndis_host 1-4:1.0 usb0: register 'rndis_host' at usb-0000:00:15.0-4, RNDIS device, 3e:ce:ed:16:41:da
[  294.758663] usbcore: registered new interface driver rndis_host
[  294.765709] rndis_host 1-4:1.0 enp0s21f0u4: renamed from usb0
[  294.770315] usb-storage 1-4:1.2: USB Mass Storage device detected
[  294.770429] scsi host2: usb-storage 1-4:1.2
[  294.771475] usbcore: registered new interface driver usb-storage
[  294.774167] usbcore: registered new interface driver uas
[  294.786861] IPv6: ADDRCONF(NETDEV_UP): enp0s21f0u4: link is not ready
[  295.788681] scsi 2:0:0:0: Direct-Access     Linux    File-Stor Gadget 0409 PQ: 0 ANSI: 2
[  295.789385] scsi 2:0:0:1: Direct-Access     Linux    File-Stor Gadget 0409 PQ: 0 ANSI: 2
[  295.964526] scsi 2:0:0:0: Attached scsi generic sg0 type 0
[  295.964666] scsi 2:0:0:1: Attached scsi generic sg1 type 0
[  295.971717] sd 2:0:0:0: [sda] Attached SCSI removable disk
[  295.971958] sd 2:0:0:1: [sdb] Attached SCSI removable disk
[  298.872434] usb 1-4: USB disconnect, device number 12
[  298.872756] rndis_host 1-4:1.0 enp0s21f0u4: unregister 'rndis_host' usb-0000:00:15.0-4, RNDIS device
[  298.889965] cdc_acm 1-4:1.4: acm_ctrl_irq - usb_submit_urb failed: -19
[  299.020263] cdc_acm 1-4:1.4: failed to set dtr/rts

It was possible to resolve the video stream to the RC controller?