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bq24392 / Timing chart between bq24392 and host controller

S.Satoshi
Guru 21685 points
Other Parts Discussed in Thread: BQ24392

Hi,

Our customer is evaluating bq24392 now and they hope to understand the following operation of bq24392 well. Can you prepare any documentation which explain them?

1, They hope to understand the detection sequence will stated in P7 in datasheet.
Can you have or prepare the timing chart between host and bq24392 at detection sequence?

2, Do you have or prepare any documentation which states the notes or consideration when they design their system by using bq24392?
They hope to know what they need to care because bq24392 need to be placed on USB data pass.

Please let me know if you need to know about detailed business information.


Best Regards,
Sonoki / Japan Disty

  • 0
    TI__Expert 6395 points

    Hello Sonoki,

    For item one, the BQ24392 will take approximately 140 ms to complete a primary and secondary detection sequence(left branch in the flow chart). If DCD fails then detection will take 600 ms.  

    With this in mind the customer should always prepare for a 600 ms detection sequence due to a slow plug in event. A slow plug event can cause a VBUS and GND presence without the DP and DM making full contact, due to the mechanical nature of USB plugs.  If the plug is not fully inserted before the 600 ms timeout, detection will fail.

    For item two, here is a generic guide to routing USB from TI and the section pertaining to the DP and DM lines is 2.2.7. http://www.ti.com/lit/an/spraar7/spraar7.pdf

    Regards,

    Andrew

  • 0 in reply to Andrew_Mason
    Guru 21685 points

    Hi Andrew-san,

    Thank you for your response. I would like to ask more about item one.

    Our customer hope  to know and understand well what handshake is doing during detection sequence. Concretely they are looking forward to have the figure like one stated in BC1.2 specification document in P34 3.4.2 Detection Timing, CDP. Is it difficult to prepare like this?


    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    Guru 21685 points

    Please let me attach the link in case.

    http://kinetis.pl/sites/default/files/BC1.2_FINAL.pdf

    Best Regards,

    Sonoki