Having trouble at least with sending data from a Jetson TK1 dev board to a Pixhawk flight controller over a USB serial connection (unclear if there is trouble receiving since the Pixhawk won’t send anything unless commanded to do so).
The Pixhawk shows up as /dev/ttyACM0 with the alias /dev/serial/by-idusb-3D_Robotics_PX4_FMU_v2.x_0-if00
Works ONLY when I use the command “cat /dev/ttyACM0” quickly after plugging in the device. Then I can use, e.g., “echo ‘whatever’ > /dev/ttyACM0” in another terminal and get back data in the terminal running the cat command.
If I wait too long after plugging the device in or kill the cat command and try it again, I get nothing when trying to send commands out using echo as above. My knowledge of Linux’s inner working is somewhat shallow, that it only works when it does because I get to the device before some service kicks in and screws things up. On the Pixhawk site it’s mentioned that the modemmanager package can cause issues but I’ve already purged it from the system and that did not help.
Output from lsusb (Pixhawk is first device):
Bus 002 Device 006: ID 26ac:0011
Bus 002 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Relevant dmesg info (looks the same as it does on when connected to a desktop and working properly):
[ 809.886035] usb 2-1.2: new full-speed USB device number 5 using tegra-ehci
[ 809.904840] usb 2-1.2: string descriptor 0 malformed (err = 2), defaulting to 0x0409
[ 809.915489] usb 2-1.2: New USB device found, idVendor=26ac, idProduct=0011
[ 809.915542] usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 809.915586] usb 2-1.2: Product: PX4 BL FMU v2.x
[ 809.915625] usb 2-1.2: Manufacturer: 3D Robotics
[ 809.915662] usb 2-1.2: SerialNumber: 0
[ 809.929989] cdc_acm 2-1.2:1.0: This device cannot do calls on its own. It is not a modem.
[ 809.941960] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device
[ 814.813519] usb 2-1.2: USB disconnect, device number 5
[ 816.285030] usb 2-1.2: new full-speed USB device number 6 using tegra-ehci
[ 816.483316] usb 2-1.2: New USB device found, idVendor=26ac, idProduct=0011
[ 816.483366] usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 816.483406] usb 2-1.2: Product: PX4 FMU v2.x
[ 816.483443] usb 2-1.2: Manufacturer: 3D Robotics
[ 816.483476] usb 2-1.2: SerialNumber: 0
[ 816.497378] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device