Need help with USB to Serial (RS-232) Adapter

Discussion in 'Troubleshooting' started by mablabs, Dec 5, 2013.

  1. mablabs

    mablabs New Member

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    I have a UDOO quad running Ubuntu 12.04 and am trying to get a USB to Serial cable to recognize as /dev/ttyUSB0. When I do a lsusb I get this additional line:

    Bus 002 Device 003: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

    I have tried using the modprobe command (modprobe usbserial vendor=0x067b product=0x2303) but notice no changes to my /dev directory. While searching the forum I found someone with a similar issue trying to set up a GPS device (roadancer @ viewtopic.php?f=17&t=136&p=1347&hilit=gps#p1347) but did not see a solution for my problem.

    My usb to serial console port on the UDOO is working fine but I need to connect to equipment with a 9 pin rs-232 port.

    Any help would be greatly appreciated.
     
  2. mablabs

    mablabs New Member

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    I made some progress and now see ttyUSB0. I first had to remove the ftdi_sio module from the kernel with the following command:

    sudo modprobe -r ftdi_sio

    Then I added it to my device with:

    sudo modprobe ftdi_sio vendor=0x067b product=0x2303

    Voila, I now see /dev/ttyUSB0

    I added this line to my /etc/modules file so it will assign the module at boot time to the kernel.

    ftdi_sio vendor=0x067b product=0x2303

    I'm still testing and had to chmod privileges and getty parameters to /dev/ttyUSB0. I can cat to this device.

    My concern is what did I disable (if anything) by assigning this module to my device. Still doing research and testing so I'm not in solved status yet.
     
  3. mablabs

    mablabs New Member

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    Bump

    I'm still not able to communicate to /dev/ttyUSB0. I can change settings and privileges but still no communication.

    Am I the only one trying to get a serial device hooked to the UDOO? Still looking for alternatives.
     
  4. kenr

    kenr New Member

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    I have successfully connected a USB to Serial adapter using the FT232RL chip to Udoo Quad running Ubuntu. There would appear to drivers for this available in the kernel.
    I can sea the NMEA data stream form my gps module (UBLOX NEO-6M) on /dev/ttyUB0 using PUTTY, but I can not see the gps data using gpsmon.
    I had previously connected the module via Arduino serial1 using a simple script to echo the received data to /dev/ttyMXC3 and all worked well on gpsmon and xgps. I also installed FoxtrotGPS and mapped position correctly.
    The problem appears to be accessing /dev/ttyUSB0.
    I have tried the fixes using modprobe suggested above but with zero success.
    It seems wasteful to use the Arduino as a serial converter and I would prefer to use a USB input.
    Any help would be appreciated
     
  5. kenr

    kenr New Member

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    Following further research around the internet I eventually found a solution:

    Change permissions for /dev/ttyUSB0 as follows:

    sudo chmod 777 /dev/ttyUSB0
    cat /dev/ttyUSB0

    Not sure this is the correct way to resolve the issue, but what the heck, it works.

    Terminal nows shows stream from GPS via USB to Serial converter, gpsmon, xps and FoxtrotGPS work OK.
    Have ordered a new USB Serial converter using the CP1202 chip to seeif there are drivers for this in the build. Will report back after it arrives from China.
     
  6. napule77

    napule77 New Member

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    Have you tried with Cp1202 cable?
     
  7. kenr

    kenr New Member

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    Module using CP1202 arrived today.
    Same result as with PL2303, no drivers available.
     
  8. obueno

    obueno New Member

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    I have the same problem right here with PL2303, is there any update of this issue?
    In my computer it uses the usbserial driver but I cannot find it in UDOO, neither Debian or Ubuntu.
     
  9. mablabs

    mablabs New Member

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    Thanks to the advice of kenr I am now able to communicate between the UDOO usb and external rs232 equipment. I purchased a cable at http://www.amazon.com/gp/product/B00B5T ... UTF8&psc=1 (disclaimer: not promoting this item just know this item works). Its chipset is a FT232RL and this driver appears to be configured properly for the UDOO.

    Then all I needed to do was chmod 777 /dev/ttyUSB0

    Since I am using the UDOO to collect data from serial acquisition equipment I can now reduce the hardware size needed for collection. I am happy.
     
  10. islander

    islander New Member

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    Thanks guys for sharing. Shame that the modules aren't already compiled.

    I'm ordering one as well, hopefully it'll be ok.
     

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