How to enable mini-USB as a serial port for BBB?

Allen_Walker · June 10, 2022, 7:44pm

Recently I’m trying to bring up my BBB board, and I want to develop linux drivers on it, so I need to compile kernel by myself.

Before I use my customized linux, I tried the BeagleBoard.org - getting-started imgs to boot my BBB.
When the BBB boot done, I can find a COM port on my win10.( I just use the miniUSB port connected to my laptop). Then, I can use mobaXterm or putty to login it.

However, when I use my own linux img to boot my BBB, I can not find such COM port. I doubt I need do some specical configurations to compile the kernel again. But I don’t know how to do it.

Can any experts help me here?

Thanks

RobertCNelson · June 10, 2022, 7:57pm

Hi @Allen_Walker in Bullseye install this debian package “bb-usb-gadgets”…

Then enable this service:

github.com

rcn-ee/repos/blob/master/bb-usb-gadgets/suite/bullseye/debian/bb-usb-gadgets.bb-usb-gadgets.service

[Unit]
Description=BeagleBoard.org USB gadgets
After=usb-gadget.target
ConditionFileIsExecutable=/usr/bin/bb-start-usb-gadgets

[Service]
Type=forking
ExecStartPre=/sbin/modprobe libcomposite
ExecStart=/usr/bin/bb-start-usb-gadgets

[Install]
WantedBy=multi-user.target

Then edit this file:

/usr/bin/bb-start-usb-gadgets

to enable custom options:

github.com

rcn-ee/repos/blob/master/bb-usb-gadgets/suite/bullseye/debian/bb-start-usb-gadgets

#!/bin/bash

log="bb-usb-gadgets"

#Examples
#https://github.com/linux-usb-gadgets/libusbgx/tree/master/examples

#built_in="gadget-acm-ecm"
#built_in="gadget-ffs"
#built_in="gadget-hid"
#built_in="gadget-midi"
#built_in="gadget-ms"
#built_in="gadget-printer"
#built_in="gadget-rndis-os-desc"
#built_in="gadget-uac2"
#built_in="gadget-uvc"

#/usr/bin/gadget-export
#/usr/bin/gadget-import
#/usr/bin/gadget-vid-pid-remove

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or just use the factory default:

github.com

rcn-ee/repos/blob/master/bb-usb-gadgets/suite/bullseye/debian/bb-start-acm-ncm-rndis-old-gadget

#!/bin/sh -e
#
# Copyright (c) 2013-2021 Robert Nelson <robertcnelson@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

This file has been truncated. show original

Regards,

Allen_Walker · June 13, 2022, 3:20am

Thanks for support!

So you mean this feature is not only configurations in kernel ? I need install above packages to enable it?
Or above package is default enabled in the imgs from BeagleBoard.org - getting-started ?

Thanks.

RobertCNelson · June 13, 2022, 2:02pm

Hi @Allen_Walker it’s a user-space side configuration. While it requires the Kernel to have specific config’s enabled, the “USB Configuration” is purely in user-space thru configfs.

https://www.kernel.org/doc/Documentation/usb/gadget_configfs.txt

Regards,

Allen_Walker · June 14, 2022, 1:56am

Thanks a lot ! Maybe I need learn more about some knowledge about above links : )