Multi serial port application

veera

yes having two ports only ttyS4 and ttyS5 i am not using any usb to serial converter i am directly connecting with serial port only .....i have tried terminal example its giving the permission error means sudo permission .....

veera

permission is denied error while opening the port in Terminal Sample...

jsulm

@veera What does

ls -lh /dev/ttyS4

say?

mrdebug

Are you in dialout group?

veera

i tried using this command on the qt project path also not able to open the serial ports.....

veera

yes i am in dialout group....

veera

crw-rw---- 1 root dialout 4, 68 Dec 11 13:22 /dev/ttyS4

veera

@jsulm said in multi serial port application:

ls -lh /dev/ttyS4

crw-rw---- 1 root dialout 4, 68 Dec 11 13:22 /dev/ttyS4

mrdebug

Are you sure you really have 4 serial ports? Which kind of machine have you got?
In some case, with a beaglebone board for example, you have to enable the third and fourth serial port with a special kernel parameter.

mrjj

Hi
Often you have to add your user to the dialout group to be allowed to use it

usermod -a -G dialout MY_USER_NAME

as @mrdebug asks/says

veera

@mrdebug
I have only two serial ports i am connecting slot machine to my desktop computer.....need to connect from desktop to slot machine i am struggling to open the serial port please help me i have added like this

veera

sudo usermod -a -G dialout veera

veera

in my desktop using two serial ports using right now may be in built its four i guess.....

jsulm

@veera Make sure your user is member of dialout group

mrjj

Also if you are having ONLY 2 serial ports why are you then
trying the /dev/ttyS4 port ???
i would giess on
/dev/ttyS0
or
/dev/ttyS1

veera

i have verified with minicom slot machine cable is connected with ttyS4 so i am trying with this port

veera

i have tried ttyS0 and ttyS1 also it is not able to open the serial port....

mrjj

@veera

ok. not sure what could be wrong with your linux if you have added
yourself (your username) to dial out group and you are sure that the port exists.

What linux are you using ?

veera

ubuntu 16.04 LTS ,i opened serial port now if i choose the run in terminal its opening please help how to set sudo password in qt instead of choosing run in terminal directly need to open

aha_1980

@veera said in multi serial port application:

ubuntu 16.04 LTS ,i opened serial port now if i choose the run in terminal its opening please help how to set sudo password in qt instead of choosing run in terminal directly need to open

If you need the sudo password than setting yourself into dialout group did not work!

Have your rebooted your PC after you put yourself into dialout?

Hint: call error() when opening the serial port fails to get more information about the error.