could not open port /dev/ttyUSB0

Klipper log ends with:

mcu 'mcu': Starting serial connect
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'
webhooks client 548017919504: New connection
webhooks client 548017919504: Client info {'program': 'Moonraker', 'version': 'v0.8.0-138-gfe12095'}
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'

mcu 'mcu': Starting serial connect
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'
webhooks client 548017919504: New connection
webhooks client 548017919504: Client info {'program': 'Moonraker', 'version': 'v0.8.0-138-gfe12095'}
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'

When I look for the device it is detected:

[Sat Aug 12 10:39:48 2023] usb 1-1.2: USB disconnect, device number 4
[Sat Aug 12 10:40:02 2023] usb 1-1.2: new full-speed USB device number 5 using xhci_hcd
[Sat Aug 12 10:40:02 2023] usb 1-1.2: New USB device found, idVendor=1d50, idProduct=614e, bcdDevice= 1.00
[Sat Aug 12 10:40:02 2023] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[Sat Aug 12 10:40:02 2023] usb 1-1.2: Product: stm32f446xx
[Sat Aug 12 10:40:02 2023] usb 1-1.2: Manufacturer: Klipper
[Sat Aug 12 10:40:02 2023] usb 1-1.2: SerialNumber: btt-octopus-11
[Sat Aug 12 10:40:02 2023] cdc_acm 1-1.2:1.0: ttyACM2: USB ACM device

[Sat Aug 12 10:39:48 2023] usb 1-1.2: USB disconnect, device number 4
[Sat Aug 12 10:40:02 2023] usb 1-1.2: new full-speed USB device number 5 using xhci_hcd
[Sat Aug 12 10:40:02 2023] usb 1-1.2: New USB device found, idVendor=1d50, idProduct=614e, bcdDevice= 1.00
[Sat Aug 12 10:40:02 2023] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[Sat Aug 12 10:40:02 2023] usb 1-1.2: Product: stm32f446xx
[Sat Aug 12 10:40:02 2023] usb 1-1.2: Manufacturer: Klipper
[Sat Aug 12 10:40:02 2023] usb 1-1.2: SerialNumber: btt-octopus-11
[Sat Aug 12 10:40:02 2023] cdc_acm 1-1.2:1.0: ttyACM2: USB ACM device

But there is no USB0 device only:

root@vcore-3:/dev/serial/by-id# ls -al
total 0
drwxr-xr-x 2 root root 80 Aug 12 10:40 .
drwxr-xr-x 4 root root 80 Aug 12 10:17 ..
lrwxrwxrwx 1 root root 13 Aug 12 10:40 usb-Klipper_stm32f446xx_btt-octopus-11-if00 -> ../../ttyACM2
lrwxrwxrwx 1 root root 13 Aug 12 10:17 usb-Klipper_stm32g0b1xx_btt-ebb42-11-if00 -> ../../ttyACM0
root@vcore-3:/dev/serial/by-id#

root@vcore-3:/dev/serial/by-id# ls -al
total 0
drwxr-xr-x 2 root root 80 Aug 12 10:40 .
drwxr-xr-x 4 root root 80 Aug 12 10:17 ..
lrwxrwxrwx 1 root root 13 Aug 12 10:40 usb-Klipper_stm32f446xx_btt-octopus-11-if00 -> ../../ttyACM2
lrwxrwxrwx 1 root root 13 Aug 12 10:17 usb-Klipper_stm32g0b1xx_btt-ebb42-11-if00 -> ../../ttyACM0
root@vcore-3:/dev/serial/by-id#

When I look in the RatOS/boards/btt-octopus-11/config.cfg it actually uses

[mcu]
serial: /dev/btt-octopus-11

[mcu]
serial: /dev/btt-octopus-11

What is the "RatOS" way to fix this?

4 Replies

Nebulator•11mo ago

Oke sorry but after a reboot its working again. I notice my Pi has trouble rebooting too. When I watch the 'disk activity led', it stops blinking and I can wait an hour but nothing happens. When I unplug USB cables (toolboard and mcu), it suddenly wakes up and within seconds, I get ping reply again. It was after that disconnect/reconnect that the USB enumeration started working again So Im not sure what is going on ... either way its working again

miklschmidt•11mo ago

This has been reported before with some pi's (and is also a problem with powered usb ports that connect their 5V rail to VBUS). I believe there may have been some pi's produced during the chip shortage (theory is that some components may have been replaced temporarily) which exhibit this problem.

Nebulator•11mo ago

Thanks, good to hear Im not the only one ;). It may not just be the chip shortage though, these are much older though, well before Covid.

ptegler•11mo ago

an easy way around power problems with a an RPi due to USB power drain is simply use a powered USB 3 hub. All my problems disappeared with one. Plus I have 5 things plugged into USB ports, more than the RPi had!

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could not open port /dev/ttyUSB0