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LAUNCHXL-F280049C: Consistent naming for serial port on macOS/Windows

Kustaa Nyholm
Expert 2005 points
Part Number: LAUNCHXL-F280049C

Hi,

I'm working with TWO LAUNCHXL-F280049C.

When I plug one of them in (on macOS) I get two serial ports in '/dev'

ls /dev/tty.usbmodem*

/dev/tty.usbmodemCL4910351 /dev/tty.usbmodemCL4910354

The ...51 works, ...54 does not.

What is the later one for?

If I plug in the second one I get two more:

ls /dev/tty.usbmodem*

/dev/tty.usbmodem3 /dev/tty.usbmodemCL4910351

/dev/tty.usbmodem4 /dev/tty.usbmodemCL4910354

Again the first one (...3) works, the second one does not (...4)

 

My problem is that the first device that is plugged in always gets the tty.usbmodemCL4910351/4 name and the second device plugged in gets the tty.usbmodem3/4 name, regardless which physical LAUNCHXL board I plug in.

Is there a way to get consistent naming?

Better yet, specify the names?

What about Windows, can we get consistent port numbering there?

  • 0
    TI__Guru 55700 points

    Kustaa,

    I shall forward this question to some one in CCS team. Please give couple of business days for them to answer this question.

    Regards,

    Manoj

  • 0
    TI__Guru**** 464301 points

    Hello,

    The assignment of port numbers is something that is handled by the OS and is OS specific. On Windows, COM port numbers are assigned based in VID/PID and probably a serial number of sorts. Once a port number is assigned, that device should get the same COM port number the next time it is plugged in. However a variable is of there are two devices with the same hardware IDs that are plugged in at the same time. The system will see them as the same device hence no guarantee that a specific device will be assigned the same COM port number. I think it will depend on the order that the devices are plugged in (as you are observing on Linux). And also if the system is rebooted with both devices plugged in, what is the enumeration order of the devices? I assume this is the issue you are running into since you mentioned you are working with TWO identical launchpads. I don't have much experience with Linux regarding this so I can't comment much on how it works on Linux. 

    In any case, I believe this issue is more on how the OS assigns port numbers for USB devices. There are likely some tips and tricks on how to deal with this, though it is beyond my area of expertise.

    ki

  • 0 in reply to Ki
    Expert 2005 points

    Thanks. 

    Yes I understand the problem that the devices look identical to the OS. 

    I was looking for experience/confirmation that the OS will 'remember' the USB tree so that if the port/hub of a USB device does not change then it will be assigned that same name.

    Or better yet, if there is a way to assign the serial number for the LAUNCHXL serial port.


    I'm working with a test setup that needs to be rebooted remotely and I have to guarantee somehow that the LAUNCHXLs attached to the computer are not mixed up.

    BTW as stated I'm on macOS but indeed the test setup will most likely run on Linux.

  • 0 in reply to Kustaa Nyholm
    TI__Guru**** 464301 points
    Kustaa Nyholm said:
    I'm working with a test setup that needs to be rebooted remotely and I have to guarantee somehow that the LAUNCHXLs attached to the computer are not mixed up.

    Assuming both launchpads are ready for enumeration at the same time I expect this to be the case. This is my experience also when I have multiple launchpads of the same type plugged in. But I am hardly on expert on this topic so I cannot guarantee anything. I will search around some more to see if I get find more conclusive information and will update this thread with  any relevant data I find.

    Thanks

    ki