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Original question:

BQ35100: Li-SOCL2 chemical and measured impedance

BQ35100: EOS mode, wait for [GA] bit?

user4867287
Intellectual 435 points
Part Number: BQ35100
Other Parts Discussed in Thread: BQSTUDIO

Hi,

In the TRM I can not find any recommendations on waiting for [GA] after the GAUGE_STARTt() command has been sent.

I have however found some reference code and some TI threads that do wait for [GA].

Is it required to wait for the [GA] bit in EOS mode?

I would like to:
1. Send GAUGE_START(), t=0ms
2. start 100ms high current load (100mA), t~10ms
3. Send GAUGE_STOP(), t~110ms
4. Shut down my processor (to save energy), t~120ms
5. Wait for G_DONE=1 (when my processor is in low current mode), t~120-16000ms
6. Wake up my uP and do some stuff, t~16000ms

Regards

CHA

  • 0
    TI__Mastermind 24870 points
    It depends on the battery relaxation, I would log the battery relaxation time for the delays.
  • 0 in reply to Kang Kang
    Intellectual 435 points
    Hi,

    Please give relevant instructions if/when it is required to wait for the [GA] bit (in EOS mode).

    Do I have to wait for the [GA] bit to be set efter I have issued a GAUGE_START() command?
    Or can I send a GAUGE_STOP() 110ms after the start command?


    As far as I can see the bqStudio does not wait for [GA] after a GAUGE_START() command.


    Regards
    CHA
  • 0 in reply to user4867287
    TI__Guru* 76230 points
    Hi Cha
    Why would you want to send the gauge start and stop back to back? The gauge would not have had time to take any reasonable data. Do not do that. In EOS mode, the gauge stop should be sent after load has been removed.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Intellectual 435 points

    Hi,

    As I understand the TRM the gauge will complete a started measuring sequence (1024ms) before it enters the Data Update Phase, even if start and stop are sent back to back.

    Please see flow chart in TRM, page 26. Is the flow chart wrong?

    I would also appreciate if you could adress my questions in your answers:

    Do I have to wait for the [GA] bit to be set efter I have issued a GAUGE_START() command?
    Or can I send a GAUGE_STOP() 110ms after the start command?

    Kind Regards

    CHA

  • 0 in reply to user4867287
    TI__Genius 10370 points

    CHA,

    When [GA] is active the gauge is sampling voltage and current extremely fast (ms) when the [Gauge stop] command is sent it will transition to a slower data collection sampling to save power. The burst load needs to be started and completed during the active phase. 

    The [GA] bit is the only reference you have to know that that gauge received the [Gauge_Start] Command. Technically no you do no need to wait for the [GA] bit to set. However when waiting for it to set you do no know if the gauge is actively measuring, had an error in the communication, had a delay is starting...ect... So it is recommended to wait for the [GA ] bit.

    Thanks,

    Eric Vos