I use the minicom to connect my board but can not open /dev/ttyUSB0

I check /dev list
cuse loop3 sdd tty26 tty61 ttyUSB0
it is exist ,but when i use sudo minicom it shows can not open /dev/ttyUSB0 and print U

My serial port setting is :
| A - Serial Device : /dev/ttyUSB0 |
| B - Lockfile Location : /var/lock |
| C - Callin Program : |
| D - Callout Program : |
| E - Bps/Par/Bits : 9600 8N1 |
| F - Hardware Flow Control : Yes |
| G - Software Flow Control : No |
| |
| Change which setting? |
where is wrong?Thanks a lot.

You have to set speed to 115200 8N1 and disable any flow control. However this does not explain why you are not able to open to open the tty. Maybe something else use this tty, what happens I you simply perform ‘sudo cat /dev/ttyUSB0’, do you have same opening issue?

Thanks for your commit.
I set speed to 115200 8N1 and disable any flow control ,but it doesn’t work.I m installing Debian on the board and i referenced https://wiki.debian.org/InstallingDebianOn/96Boards/HiKey960.
In the page ,it seems that a FT232 needed.I m not sure is that for the reason ?

The /dev/ttyUSB0 they are talking about is the endpoint for the FTDI USB-SERIAL bridge, connecting the console 1.8V UART6 (CPU-wise) to your host machine.