Cannot open Serial Port using CuteCom

houmingc

I am using Cutecom to connect to my device
When i "open device", Error "could not open /dev/ttyUSB0

sudo apt-get install cutecom
may i know where is cutecom installed. <Which CuteCom not working>

Finding ports ttyUSB0 connected
dmesg |grep tty shows ttyUSB0 connected
usb 2-1.3:pl203 now attached to ttyUSB0

I have check with lsusb, and device is connected

I set the baud rate, data bits, stops bits and hex input at the right bottom.
I tried with minicom, but i can't open serial port too

SGaist

Hi,

Not really a Qt question but anyway, do you have the rights to access your device ?

houmingc

sudo chmod a+rw /dev/ttyUSB0

works

SGaist

And that's a security hole wide open.

You should rather add your user to the correct group.

houmingc

It is troublesome to run this command everytimes.
Is there other alternatives?

SGaist

Yes there is. What I suggested in my last message

houmingc

I do not know what is the benefit of doing so.
Below is the steps on 'how to add user to correct Group'?
What is the difference between primary and secondary group

@
First, list all group $ cut -d: -f1 /etc/group
Second, login as root user, $ su -
Third, add user: $ sudo adduser new_username
& add group: $ groupadd groupname
& add user into group $ useradd -G groupname new_username
Fouth, grant sudo privilege $visudo
below root, add newuser ALL=(ALL:ALL) ALL
Fifth, save and closed Ctrl + X
@

SGaist

The benefit ? You don't allow everybody and anybody the rights to access the serial port.

The secondary groups are just the additional groups your user is part of e.g. dial out

@useradd -G dialout username@
is a bit simpler

houmingc

CuteCom can always open serial port but Qt program open serial port sometimes. What is the solution

SGaist

Is there a pattern when it fails to open the device ? Did you check if there's an error message returned by QSerialPort ?