Recently, I connected a serial device to the NXP board, which is LS1012ARDB, see the figure below.
after plugging in the serial device to the NXP board, the output of dmesg[1] is shown below
under /dev. I tried to use minicom[2] to connect ttyS0, ttyS1....ttyS3, all of them failed, I got no
response from them.
detected and attached, a new device name was created under /dev. 
Instead, I plugged the serial device to my laptop using USB to serial converter too. The diagram
shows the connection
The output of dmesg after plugging the serial device on my laptop is shown below, the serial device is
attached and I can access the serial device via minicom
It seems that the problem is happed because of the usb driver. The signal from switch console is not recognised by the NXP boardI am stuck on this problem.
Any help or suggestions will be much appreciated.
[1]dmesg: (display message or driver message) is a command on most Unix-like operating
systems that prints the message buffer of the kernel. The output of this command typically
contains the messages produced by the device drivers.
[2]minicom: Minicom is a text-based modem control and terminal emulation program for Unix-like
operating systems.
Is USB Serial converter support enabled in kernel menu for your board?
For example see attached snapshot from LSDK 1809 kernel menu.
This menu is available using the following in kernel menu:
Device Drivers --->
[*] USB support --->
<*> USB Serial Converter support --->
Have a great day,
Pavel Chubakov
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------