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BQ40Z80: Timeout/failed to communicate

Shailender kumar
Prodigy 80 points
Part Number: BQ40Z80
Other Parts Discussed in Thread: EV2400, BQSTUDIO

Hi

i am using bq40z80 in my customised designed board.

Battery management studio 1.3.86 software detects the bq40z80 Ic part no. automatically.

initially it works fine able to read 7 cells voltage and exact pack voltage.

Tools use here are:

1) EV2400

2)battery management studio 1.3.86

Observation during further test

1) After removing pack voltage it will not able to communicate(.i.e. failed to communicate or timeout error).

2) now it shows

pack voltage = 65535 mV

cell voltage[1..7]=0 mV

Average current = 0 to 8156

3) Now Battery management studio 1.3.86 software unable to detects the bq40z80 Ic part no.

4)Only after manual selection faces this kind of problem. 

5)No auto detection is working with bq40z80

6)getting pulses on TS1 & TS2.

I am also uploading the schematic and a screenshot of the software. 8424.bq40z80.pdf

 

  

  • 0
    TI__Mastermind 42060 points

    Hello Shailender,

    Could you explain your set-up? Do you have a charger/power supply connected to PACK? Then it loses communication once you remove the charger/power supply?

    Is NR set to 1? You need this in order for the device to remain awake after removing PACK voltage. Otherwise you'd need to short SysPres to PACK- in order for the device to stay awake after removing PACK voltage. Check the EVM User Guide to make sure your design follows our design.

    Also, make sure you have the latest firmware installed.

    Best Regards,

    Luis Hernandez Salomon

  • 0 in reply to Luis H. S.
    Prodigy 80 points

    Hi Luis Hernandez Salomon

    Thanks for your reply.

     

    Setup brief:

    i am using power supply with a voltage divider circuit. (i.e. 7 resistance in series & each having 10 Ohm resistance)

    Is NR set to 1?

    Unable to access their value because communication failure/timeout error.

    Short SysPres to PACK- nothing happens or it didn't resolved my problem.   

    Generally following the EVM User guide schematic and bq40z80 datasheet while making the customised schematic. 

    Also tested with the latest firmware but failed to resolve the problem (i.e. bqstudio 1.3.86).

    Due you suggest me anything else or where/what should i look to resolve this problem.

    Best Regards

    Shailender

  • 0 in reply to Shailender kumar
    TI__Mastermind 42060 points

    Hello Shailender, 

    The BQ40Z80-EVM User Guide indicates to use 1-kOhm resistors for cell simulation. I would advice that your set-up is similar to how it's shown in the user guide(Section 2.3).

    When shorting the top of the cell-stack(7P) to PACK+, do you get any connection?

    By firmware, I mean the latest BQ40Z80 firmware, found under Software Development in its product page. You can find how to update the firmware of the BQ40Z80 in Section 2.4 of the EVM user guide.

    Best Regards,

    Luis Hernandez Salomon