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Problem connecting the bq76PL455EVM via an FTDI USB-to-TTL (5V) Unable to open COM port

BRAHIM SOLTANI
Prodigy 20 points
Other Parts Discussed in Thread: BQ76PL455EVM

Hello,

I am trying to connect the bq76PL455EVM via an FTDI USB-to-TTL provided with the board. The drivers of the cable are installed correctly and evrything seems fine in the device manager.

But everytime I try to connect it to my laptop using the GUI, I get en error message "Unable to open COM port". I used the same cable with the same driver in another laptop and it works.
I tried to uninstall/install restart my laptop a lot of times but it did not work.

Could anyone help me please?

  • 0
    TI__Intellectual 2795 points

    If the EVM is connected to 16 series batteries, the only thing I can think of is that you may need to run the FT Clean utility from FTDI. It can happen that there are conflicting registry entries for the same virtual com port in Windows. FTClean will remove all entries assigned to a particular VID. Here is a link to the utility:

    www.ftdichip.com/.../index.html

    After running this you will need to download the latest virtual com port drivers from FTDI and install them. The latest VCP drivers can be found here:

    www.ftdichip.com/.../VCP.htm

  • 0 in reply to Stephen Holland
    Prodigy 20 points
    Thank you for you answer. The problem is that I can't find FTClean is FTDI utilities. I tried CDMUninstaller instead but it did not work after uninstalling re-installing the driver.
    I am temporarily using another laptop and the same setup is working fine. So I do not think that the problem relates to the board or the cable.
    I have been struggling with this problem for more than 3 days now and I have no clue how to resolve it.
  • 0 in reply to BRAHIM SOLTANI
    TI__Intellectual 2795 points

    I think FTClean may only be supported on older versions of Windows. You may want to try contacting FTDI for a solution. CDMUninstaller sounds like it should fix the issue.

  • 0
    Prodigy 70 points
    I have an exactly same problem with the board wired to resistor ladder (16 pcs).

    The green LED burns on the board but GUI gives "Unable to open COM port" error.

    The COM port can be opened with any other terminal software so I'm really not suspecting any device problem here. Is there any way to see if the device is really operating?
  • 0 in reply to Janne Kjellamn
    TI__Genius 11480 points

    Hi Janne,

    If D22 lights up, the board is most likely operating, since it is powered by the external npn regulator driven by the PL455 EVM. You could also measure the various power supplies as a check ( ie, the 5VAO pin is ~5V, Vref, VIO, VP,  etc). Depending on the wake status of the part, that will give you a good indication if the part is at least functional.

    This may be a low hanging fruit, but can you verify that both actuators 1  and 2  of SW are switched towards the single ended mode?

  • 0 in reply to David Wiest Jr
    Prodigy 70 points
    Hi David,

    Thank you for your response but both switches are towards the single ended mode.

    It seems that the board lights up (D22) when the USB driver is initialised on the PC, possibly giving the wakeup signal?

    5VAO = 5.28V
    VDIG = 5.31V
    VIO = 4.94V
    VP1 = 5.31V
    VREF = 2.49V

    Anything which seems out of ordinary?

    // Janne
  • 0 in reply to Janne Kjellamn
    TI__Genius 11480 points
    Janne,

    I would say this looks fine, and all the supplies are up indicating that the 455 received a wakeup signal. Can you try to capture the signals on TX,RX, FAULTN, and nWakeup?

    If you have the switch actuators 1 and 2 shifted towards "single" and a 16s connection, the GUI should be able to detect the board. Can you measure the voltage across BAT16 and BAT0? Perhaps there is a bad connection there, and the 455 is not actually fully powered on.
  • 0 in reply to David Wiest Jr
    Prodigy 70 points
    Hello David,

    Faultn and wakeup seem to be 0 volts but TX and RX 5.0V. Unfortunately I don't have scope at hand to measure the TX and RX signals more accurately, can try this tomorrow.

    Voltage between BAT0 and BAT16 is 55.5 volts which is right.

    Could the board be just faulty?

    // Janne
  • 0 in reply to Janne Kjellamn
    TI__Genius 11480 points
    Hi Janne,

    If Faultn is low, that would indicate that the device either has not been woken up, or is in a fault condition, which could be something like a communication fault....

    If the setup works on other PC's as you reported earlier, I would say the board is fine. It sounds like a driver on your PC needs to be reinstalled, or something similar.
  • 0 in reply to David Wiest Jr
    Prodigy 70 points

    Hi David,

    Seems that GUI software has some problems on certain machines (three tested total). It does not send anything to the COM port (tested with oscilloscope) but we can use normal terminal software (putty.exe) to open the port and send data without problems.

    I installed fresh version of Windows, FTDI driver and GUI and that works now.

    Thanks for the support anyway!

    // Janne

  • 0 in reply to Janne Kjellamn
    TI__Genius 11480 points
    Janne,


    Thanks for following up on that! That is good to know.... if you don't mind me asking, could you provide some details about the machine it doesn't work on? I'd like to see if that's a known issue or not.
  • 0 in reply to David Wiest Jr
    Prodigy 70 points

    Dear David,

    All non working machines were Windows 7 Pro SP1 / .NET framework 4 or 4.5 installations running on:

    - Lenovo B50-80

    - Virtualbox 5.1.6 environment on Macbook Pro

    - Parallel Desktop 11 environment on Macbook Pro

    With fresh vanilla installation of Windows 7 Pro SP1 (.NET Framework 4) the software now runs on Macbook Pro under Parallels Desktop 11 for Mac

    // Janne

  • 0 in reply to David Wiest Jr
    Prodigy 70 points
    Hi David,

    I return to this issue. I installed .NET framework 4.5 to a working machine with the GUI and the GUI stopped working so the .NET framework seems to be the source of the problems.

    // Janne
  • 0 in reply to Janne Kjellamn
    TI__Genius 11480 points

    Janne,

    Thank you for taking the time to confirm this! It will be helpful for the future.... 

    Please let me know if you need further help.