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bq20z65 fuel gauge cell no 4 reading 0V

gerhard peter
Prodigy 30 points

Hi,

I have gone through the calibration process using bqeasy several times and can not get a reading on cell no 4.

I have run the calibration with 4 x1k resistors and a power supply to simulate the cells. All cell voltages

are reading correctly when measured with a voltmeter. (4.0V)

And yes I did set the number of cells to 4 during calibration.

Please advice.

Thank you in advance,

Gerhard

  • 0
    TI__Expert 6470 points

    Gerhard,

    I think I would first verify that the CC0, CC1 bits in Operation Cfg. A are set correctly for 4 cells. They should both be = 1. Have you confirmed?

    If they were not set correctly, then we should find out why. Maybe the gauge just needs a reset - type 41 in Manufacturer Access on SBS screen and then hit Enter.

    If there is still no Cell 4 measurement, then you could have a bad IC, bad EVM, or perhaps a loose wire on your resistor ladder.

    Rgds,

    Doug

  • 0 in reply to Doug Williams4811
    Prodigy 30 points

    Doug,

     

        I forgot to mention one other problem. When I start BQeasy with the gauge attached and powered up

        I get the message, :"unrecognized device or bqeasy can not find the .encr file for the connected device.

        this file is needed to configure the dataflash."

        I can still proceed to calibration though.

        I have tried to follow your suggestions and went to "Operation cfg A" to check the bit settings, but

        left clicking on "Operation cfg A" only results in a row of bit names but I not able to see any bit settings

        no matter what I click on.

        I entered the no 41 in the manufacturers access. There was no change.

        I checked the resistor ladder as well as the cell voltages right at the IC. They were all there.

        On a sidenote, I inspected the back side of the gas gauge pc board for assembly errors against your

        layout documentation. I noticed R23 was missing, (don't think it is related to the problem but strange

        in any case). Also R6 looks like somebody moved it with a soldering iron. ( it is not exactly sitting on

        the pads)

        At this point I don't know what else to do. I either need to talk with a technician live to troubleshoot

        or get an RMA? Please advice.

     

        Regards,

     

        Gerhard

  • 0 in reply to gerhard peter
    TI__Expert 3865 points

    Gerhard,

    When you left click on Operation cfg A, the bit setting is indicated by color, green = 0, red = 1, grey = not communicating to the device.

    The value column also shows the setting of the register. For 4-cell, CC0 and CC1 should both be 1.

     

    If you get the error message from bqEASY, it is likely that the tool is not configuring the setting for you probably. I'll contact out tools team to look into that.

  • 0 in reply to Jackie Hui
    Prodigy 30 points

    Jackie,

     

    As far as I remember  only one of the two bits was green the other red. Unfortunately I can not double check

    because now I am getting an all gray readout even though the program (bqeasy) says "communication ok".

    I really need to get resolution to this problem and some direction from TI as far as what to do next.

    Best regards,

    Gerhard

     

     

     

  • 0 in reply to gerhard peter
    TI__Genius 10235 points

    Gerhard,

    The first thing you need to do is try another known good board and see if it is having communication issues. 

    If it is having problems, you need to replace your USB cable, EV2300, and SMBus cable one by one to see if any of those are causing communication issues.

    If none of that works, it is time to uninstall EVSW. You need to make sure to delete the Texas Instruments folder after uninstalling from Add/Remove Programs.

    Then, reinstall the latest EVSW from the web for your device.

     

    After you get communication working again, you need to capture a GG file and a screenshot of the SBS screen in EVSW with the 'Keep Scanning' box checked.

    Once we have this, we can help in troubleshooting your issue.