Spresense does detect /dev/ttyUSB0

[Matha 1]

Hello,

When I connect my desktop (Ubuntu 22.04) to the Spresense main board, the Arduino IDE (v1.8.19) detects the port as /dev/ttyUSB0.

When I connect to Spresense (Arduino) Extension board, no corresponding port is detected (i.e. neither USB0 nor any /dev/ttyACMn). The previously download sketch resumes the run (i.e. power is indeed transferred to the main board from the Extension board).

Connecting via the main board is consistently working as expected (connect/disconnect) - repeatable, reliably reproducible. Unfortunately, connecting via Extension board seems to transfer power to the main board (PWR LED turns on) but Arduino IDE does not display any corresponding (new) port identifier.

What configuration changes are needed to enable a port for Arduino use when connected to the Extension board? I have tried USB 2.0 and 3.0 hubs as well as connecting to a USB 2.0 port on the motherboard itself. Thanks.

Kind regards.

P.S.
I had to uninstall brltty to get Arduino to recognize the port when connecting through the main board.

[Matha 1]

@Matha-1
Some more information for your review, please:

This is what I can view even when /dev/ttyUSB0 is not detected by Arduino IDE:

$ sudo dmesg | grep "cp21.*attached"
[ 2351.552509] usb 1-7: cp210x converter now attached to ttyUSB0

and

$ ls /dev/tty* | grep USB
$

No /dev/ttyUSB* entry

[CamilaSouza]

@Matha-1

This is actually the expected behavior for the boards. By default, the extension board is not recognized as a device.

The USB connector in the extension board can provide USB MSC (Mass Storage Class) function allowing access to the SD card on the extension board directly from the PC.
Example on how to do that with Arduino IDE: https://github.com/sonydevworld/spresense-arduino-compatible/blob/master/Arduino15/packages/SPRESENSE/hardware/spresense/1.0.0/libraries/SDHCI/examples/UsbMsc/UsbMsc.ino

[Matha 1]

@CamilaSouza
Thanks for the quick response.

If I understand your assertion correctly then I can connect both microUSB ports (main board and extension board) to a desktop concurrently?

Please indulge by affirming or correction my understanding. Hope to accelerate my modest work quickly based on your forthcoming response. Thanks again.

Kind regards.

[Matha 1]

@CamilaSouza

Must confess this Spresense solution (UsbMsc function) is great for transferring images (for my planned ML tests). Did a quick sanity check successfully for an image file.

Many thanks to the Spresense architects.

Kind regards.

[CamilaSouza]

Hey, @Matha-1
Yes, you can connect both USB ports at the same time.

I'm so glad you're pleased with the solution. I'll be sure to share your compliment with the responsible parties.