• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 587 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.

BQ40Z50: Problems communicating with NI 8451 and Labview

Alex N
Prodigy 240 points
Part Number: BQ40Z50
Other Parts Discussed in Thread: BQSTUDIO, EV2400

Hello,

We are currently using the BQ40z50 chipset in one of our smart battery packs, and are developing several new packs which will use that same chipset.

We built a labview based test system to electrically test and verify communications and certain data fields in our smart batteries. We are using a national instruments usb8451 for the system communications to the battery pack.

We have encountered a problem with this setup that we cannot figure out. We test the 20z75 and the 34z100 without any problems.

When we test the packs using the 40z50, it causes the usb8451 to "lock" up and the labview test environment to crash. These crashes will happen about every 3 to 4 packs we try to communicate with.

We are at a loss to why this is occurring and need help solving it.

  • 0
    TI__Guru* 76230 points
    Hi Alex

    These are third party tools and there is limited help which we can provide in that regard. I would recommend you use ev2400 and bqstudio and then sniff the comm lines to understand what bqstudio does. Then compare that to what your tool is doing.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 240 points
    We used an logic analyzer to monitor the databus on the 40z50. We found that when plugged on a bus, there was a voltage spike up to 6.5V. When this happens, it is tricking our usb8451 into thinking that a slave is trying to transmit data and it will no longer communicate with the host computer.
    After the chipset has been plugged onto a positive databus, it will no longer spike across the data lines.
    Is there a solution to mitigate this problem?
  • 0 in reply to Alex N
    TI__Guru* 76230 points
    I have not run into this kind of issue in the past. Can you try using zeners to clamp the voltage?

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 240 points
    We will not have another production of batteries for two more weeks. I will have to try it then.

    This only happens with boards that are freshly programmed from the manufacturer. After being communicated with, the chipset no longer pulses.

    We also saw this behavior with the EV2400. When a newly programmed board was plugged up to the EV2400, the computer would say the usb device was not recognized and the EV2400 would lock up and not communicate until power cycled. Have you seen any of this behavior before?
  • 0 in reply to Alex N
    TI__Guru* 76230 points
    that is strange. I have not seen that behavior with the ev2400. Thankfully the spikes are you seeing doesn't damage the board.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 240 points

    After some further testing, I have discovered that sometimes when a newly programmed bq40z50 is plugged onto the SMBus lines. It appears that the bq40z50 is "loading" the bus lines for an extended period of time.

    Please see screenshots below:

     

    Have you ever seen behavior like this from a chipset?

  • 0 in reply to Alex N
    TI__Mastermind 24870 points
    Is this using EV2400?