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BQ769X0EVM with EV2300: unable to detect a connected device

sevendays
Prodigy 40 points
Other Parts Discussed in Thread: BQ76920EVM, BQ76940EVM, BQ76940, BQSTUDIO, EV2400, BQ78350

Hello,


I tried to connect via I2c to the BQ76920EVM and BQ76940EVM boards through the EV2300 interface, but I always get the "unable to detect a connected device" error from the bq76940 evaluation software.

Since it's mentioned that the EV2400 has got problems when using bqStudio to evaluate the fuel gauge, I ordered the EV2300.

I have tried using Windows 7 64 bit and Windows 7 32 bit. Both with .NET 4 installed.

  • The EV2300 drivers have been installed prior to connecting the EV2300 interface.
  • I have removed the shunts connecting the AFE to the fuel gauge (bq78350).
  • I have left the pull-up SCL&SDA shunts on, since I'm using the EV2300.
  • The switches are closed.
  • The EV2300 usb cable is plugged in the PC.
  • The I2C cable is connected both to the bq769x0EVM and the EV2300.
  • The bq769x0EVM is powered with a 18V source connected to the "BATT" terminals. A red led is lighted.
  • I have pressed and released the bq769x0EVM BOOT switch.
  • Upon starting the bq76940 evaluation software the above error message appears.

I'm confident I didn't miss any steps, and I even installed Windows 7 32 bit to rule out any EV2300 driver issue I might be having on Win 7 64 bit. I don't really know how to debug the issue. Both the bq76920evm and the bq76940evm show the same exact error (the only difference being the applied voltage).

I searched the forums because I presumed not to be the only one having this problem, but apparently I am.

What should I do now to debug the issue? The bq76940 evaluation software prints out nothing in the command line.

Thanks in advance.

  • 0
    TI__Guru 54715 points

    With drivers installed on the system and starting the bq76940 Evaluation Software without an adapter (EV2300), the following error window is typical:

    When this is "ok'd" or if the adapter was found but the device was not found, Another error window is displayed:

    When this is "ok'd" the software windown will open, without data of course.  In the bottom border there is a status line:

    The right side is the error message area. The view pictured was with no adapter.  If the adapter was found but the device was not, this will typicaly read "No acknowledge from the device".

    From your description I expect you are not seeing the second error box and not the first.  If this is true your drivers are working and the problem is between the adapter and the board.

    Some suggested debug steps:

    • Be sure the 4 pin cable is connected from the EV2300 I2C connector to the EVM I2C connector.  It will not talk
    • After pressing the boot button, measure the voltage of REGOUT with respect to GND.  It should be 2.5V.
    • Check the voltage on the SCL and SDA signals, each should be pulled up to 2.5V also.  There are board test points and these same signals should get to the 4 pin connector, but sometimes it is good to check multiple places.
    • If there is no 2.5V, check to see that the lower dip switches are closed, the top one must be if you have the red LED.  Refer to the schematic in the EVM user guide to find the missing IC supply voltage.  Check for board damage from shipping or handling.
    • Check that CAP1 voltage is 3.3V after boot.  If not, look for shorts/opens.
    • Ohm the 4 pin cable.  The boards are tested, I don't know about the cables.
    • Try a different 4 pin cable, there should be one with each EVM.  A deformed or contaminated pin could prevent contact.  It has been some years since I saw a bad cable but it is possible and has happened. 
    • Check for bent or contaminated pins on the EV2300 I2C connector.  EV2300's are supposed to be tested also.
    • Check the value in the "I2C Target Device Address" box at the right top of the bq76940 evaluation software window.  This should be "08" for the EVM.  If a value was somehow wrong it won't talk.  It will remember the last used value.
    • If you have voltage on the I2C lines and the right address, check the SCL and SDA signals on the board with an oscilloscope.  You should see the signals move when you read with the tool such as "Read Byte" or "Update Display"
    • If you have the EV2400, try it instead of the EV2300.  The EV2400 should talk to the bq769x0 through I2C.  (Also, a firmware update is now available for the EV2400 also to allow it to work with the bq78350 and bqStudio, see "EV2400 Firmware Updater" in the Software section of www.ti.com/tool/EV2400 The text on the EVM pages has not been updated yet.)

     

    Please let us know what you find, as you noted, it can be very helpful to other users.  If it does not help, please let us know where in the process the error message occurs and any other message or status apparent in the software window.  Also any relevant voltages or signal sequences on the board.

  • 0
    Prodigy 40 points
    To provide more info:

    When trying to communicate with the AFE with the bq76940 evaluation software, after the popup error the status bar reports "no acknowledge from the device".

    The same thing happens when using the Battery Management Studio (bqStudio): there's a "Proceed?" popup complaining that "the detected device is not compatible with this application", but the bq76920EVm says to "acknowledge the Proceed" window.

    Then, in the Firmware screen, after having chosen the downloaded firmware for the bq78350 (bq78350FirmwareBundle-0.06\bq78350_v0_06_build_16.srec) and ha ving clicked the "Program" button, the status bar displays a red error message: "Program Srec : No acknowledge from device".
  • 0 in reply to WM5295
    Prodigy 40 points

    Ok, thanks for the steps.


    Here are the results:

    • Preliminary check: the EV2300 is powered and I can measure 3.29V on the VCC output pin
    • the cable is connected: i2c to i2c
    • after pressing the BOOT button, REGOUT measures 2.51V
    • SCL and SDA measure 2.5V too (both at TP and connector)
    • The dip switches are closed, and the board looks good. The carton package shows no signs of improper handling too.
    • CAP1 voltage measures 3.29V

    ...

    Well, and now since I was impatient I started the bq76940 evaluation software again: it is working now. I cannot even guess why it wasn't.
     The most probable hypotesis that comes to my mind is that I was pressing the "display" button and not the "boot" button...

    Thanks again, I will come back here to confirm that bqStudio works too.

  • 0 in reply to sevendays
    Prodigy 40 points
    Yes, the bqStudio software works. However the debug steps are so useful that I flagged those as answer.