• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 99 subscribers
  • Views 909 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

USB-serial on DM365

Joel Carlson
Intellectual 305 points

I'm working with the DM365 EVM, and we're going to need to use the serial port for something else but still need access to the console.  So we're trying to get USB-serial support working.  So far, we've re-built the kernel with USB-serial drivers support, and we've changed part of the U-boot bootargs from:
console=ttyS0,115200n8
to
console=ttyUSB0,115200n8
The jumpers on the EVM are set for USB Host mode and the ID pin is pulled low.

At this point, when I let the system boot, the output is sent correctly over ttyUSB0 and I can see the boot sequence running on my terminal.  However, as soon as the process finishes and I'm left at the Arago Project login screen, the output is back to ttyS0 (in fact, it goes back to ttyS0 before the "Arago Project" stuff prints).  I switch back to serial and can then interact again (and beneath the "Arago Project" logo it indicates ttyS0).

Is there something else I can change so that the output will default to ttyUSB0 and not use ttyS0?  If not, is there a way I can redirect ttyS0 to ttyUSB0 after the system finishes booting?  I came across one thing while searching Google that suggested these commands:
rm /dev/ttyS0
ln -s /dev/ttyUSB0 /dev/ttyS0
but that didn't work for me.

Thanks.
Joel

  • 0
    TI__Genius 15510 points

    Take a look at /etc/inittab in your target root file system. You should see a line similar to

    S:2345respawn:/sbin/getty 115200 ttyS0

    This line starts a login session on ttyS0. If you add a line or change it to ttyUSB0 then you should see a login prompt on ttyUSB0. I have not tested this, but seems like it should work.

    Steve K.

  • 0 in reply to Steve Kipisz
    Intellectual 305 points

    That worked.

    There are lots of things about Linux I don't know, including a lot about the initial startup sequence.  I never would have thought of that.

    Thanks, Steve!

  • 0 in reply to Steve Kipisz
    Prodigy 20 points

    I'm following the same path as the previous poster, but do not seem to be able to get a /dev/ttyUSB0 device available.  In the make 'menuconfig' step I have enabled USB SERIAL, but when I make the kernel & boot there is no ttyUSB available in /dev.  Please can you confirm which kernel options I need to enable to get the ttyUSB0 available on my DM365?

    Regards

    Dave

  • 0
    Intellectual 710 points

    hey joel

    we r also installing dm365 but we r using isb to serial converter to communicate becauz there is no serial port there

    we have set minicom and settinfg is done ttyusb0 and baud rate is also same but we r not getting any boot sequences from board

    and also that EVM# console window

    can u suggest whats the problem?

    thanks

    kailash

  • 0 in reply to Dave Gwilt
    Intellectual 305 points

    Dave Gwilt said:
    Please can you confirm which kernel options I need to enable to get the ttyUSB0 available on my DM365?

    From 'make menuconfig', I then went to the following:
    Device Drivers > USB Support > USB Serial Converter Support (press Y and enter)
        > then press Y on:
            > USB Serial Console Support
            >  USB Generic Serial Driver
            >  USB Prolific 2303 Single Port Serial Driver

  • 0 in reply to kailash negi
    Intellectual 305 points

    kailash negi said:

    we r also installing dm365 but we r using isb to serial converter to communicate becauz there is no serial port there

    we have set minicom and settinfg is done ttyusb0 and baud rate is also same but we r not getting any boot sequences from board

    and also that EVM# console window

    can u suggest whats the problem?

    Hey Kailash,

    I'm not sure I understand.  Which direction are you using the USB-serial converter in?  Our setup was using the USB connection on the DM365 EVM, and a serial connection on the laptop we were working on.  Therefore, our minicom settings were still set to use ttyS0.

    If you are using a USB connection on your computer and the serial connection end with the DM365, then your minicom will need to use ttyUSB0, and the EVM will use ttyS0.

    -Joel