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Original question:

BQ79616EVM-021: BQ79616 EVM: Not receiving any message on UART

BQ79616EVM-021: How can I address the INVALID_CBCONF flag when initiating automatic balancing on the bq79616?

S Naik
Prodigy 120 points
Part Number: BQ79616EVM-021
Other Parts Discussed in Thread: BQ79616

I was about to start the balancing with bq79616 evm, as soon is put evm in auto balancing mode, we read Bal_STAT register and this returns the  INVALID_CBCONF flag set. As per the data sheet its during manual balancing that this bit is set, i am trying following combinations;

Following is our approach,

we have enabled ADC and read ADC val

ues that all set,

Enabled TSREF,

// SET DUTY cycle for CELL

WriteCmd(CB_CELL1_CTRL, 0x7);// 30 min

WriteCmd(CB_CELL3_CTRL, 0x7);

WriteCmd( BAL_CTRL1 , 0x3);// duty 0x3 = 60 s

WriteCmd( BAL_CTRL2 , 0x3); // set auto mode and start balancing

//Next we are reading this after few ms delay

ReadCmd(BAL_STAT, 1);

this return INVALID_CBCONF set always

 EDIT: i also added NO_ADJ_CB before starting balancing part;

WriteCmd( DEV_CONF, FCOMM_EN|NFAULT_EN); // just en FCOMM and FAULT_EN

but still getting same .

Here is Every cell voltage that we have read,

// 0------------1-----------------2------------------3------------4---------------5------------------6---------------7---------------8--------------9

3.12434816, 2.92732406, 3.05244303, 2.9509747, 2.99369812, 3.97652984, 4.01047993, 3.95287943, 3.9711895, 3.94658518, 3.94715738, 3.94257998, 4.02154207, 3.93704867, 3.86914873, 3.87887597

  • 0
    TI__Prodigy 440 points

    Good afternoon,
    Thank you for reaching out to us. The INVALID_CBCONF flag triggers when more than eight channels are enabled for cell balancing, or with improper adjacent channel set up. But that doesn't seem to be the case with your set up.

    I would like to ask some questions about your set up.
    Does this only happen with Cells 1 and 3, or does it happen with other cells?
    Is the fault already triggered before starting cell balancing?
    Does this fault also appear in manual mode?
    Also try setting the Auto_BAL mode before setting the BAL_GO bit (i.e., WriteCmd( BAL_CTRL2, 0x1) then WriteCmd( BAL_CTRL2, 0x3)).

    Best,
    Fernando Dominguez

  • 0 in reply to Fernando Dominguez
    Prodigy 120 points
    Fernando Dominguez said:
    I would like to ask some questions about your set up.
    Does this only happen with Cells 1 and 3, or does it happen with other cells?
    Is the fault already triggered before starting cell balancing?
    Does this fault also appear in manual mode?
    Also try setting the Auto_BAL mode before setting the BAL_GO bit (i.e., WriteCmd( BAL_CTRL2, 0x1) then WriteCmd( BAL_CTRL2, 0x3)).

    1. i tried CELL1 only, and CELL 1 to 8

    2. I read the BAL_STAT before starting cell balancing and its 0, as soon as i send command , and read again bal_stat its 1 (INVALID_CBCONF)

    3. i haven't tried manual mode, we are currently just going ahead with Auto mode

    4. i will try this

  • 0 in reply to S Naik
    TI__Prodigy 440 points

    Good afternoon, 

    Thank you for the information. Just another question, if you don't mind, are you using a bridge device (such as the BQ79600 EVM) or is it just a single BQ79616 EVM? And what program are you currently using to communicate with the device(s)?

    Best,

    Fernando Dominguez

  • 0 in reply to Fernando Dominguez
    Prodigy 120 points

    Thanks for Assistance

    Not using BQ79600 EVM.

    We got the balancing run, while starting balancing we set the rest of the timer 0 and set desired cell timer value for balancing.

  • 0 in reply to Fernando Dominguez
    Prodigy 120 points

    BUT there is another issue when we start balancing, for first time we ran the balancing for 30min and it was done proper, now on 2nd run, when we start balancing, This our guess work, after certain we dont receive response on UART, but balancing is running we checked the current on individual cell, but UART response stops, we are thinking that BQ is entering sleep mode.

    However, there is no command send for sleep from MCU, or CTL and CTS timer are 0. we also set BAL_ACT to 0x0 when starting balancing. Other than this we didnt find any reason to goto sleep.

    AS soon as we restart MCU the communication is UP, our guess is that on start we send wake tone, so BQ also wakes up from sleep.

    However you can guide us in this to diagnose the issue.

  • 0 in reply to S Naik
    TI__Prodigy 440 points

    Good morning,
    Thank you for providing more information on your set up. We are currently working in our lab to help you find a solution for this issue.
    One way to check if the device is in sleep mode is through the LDOIN current. Within our datasheet, in the Electrical Characteristics section under Supply Currents, you are able to see the different current measurements for the different power states of the device.
    You also stated that by restarting the MCU, you are able to gain back communication. Please verify if there is a communication timeout with the MCU you are currently using.


    Best,
    Fernando Dominguez

  • 0 in reply to S Naik
    TI__Prodigy 440 points

    Good morning,

    I would like to add a couple of things you could check in your set up.
    Where you able to check the current of LDOIN to verify if the device is in sleep mode?
    How are you setting up the second cell balancing? Do you restart the device or set up the timers again and clear the flags, or is there another set up you follow?
    And are you able to see commands being sent or received through the TX/RX pins in the device when it potentially goes into sleep mode?

    Best,
    Fernando Dominguez