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DM8148: Different behavior of USB host/device switching between RevB and RevC.

Kaka
Guru 24520 points

Hi community member,

Please let me confirm the following question.

[Question]

Is there any change about USB controller by Device revision change?

[Background]

When they had used the revision B, there was not any problem for  USB (Hsot/Device modes) behavior.  However, even though they used the same USB driver which supports Host mode and Device mode with using Revision C, the DM8148 could not work correctly in case of Host mode. 

  Note:"not work" means that DM8148 could not mount the USB device  And in case of device mode, there is not any problem for USB behavior.   If change the USB  driver which supports only host mode, there was not any problem for USB behavior.

According to them, the pin of "USB0_VBSUIN" was outputted the voltage(Approximately 2.8V) even though this pin type was "input pin".  I got the USB pins waveforms which the both cases Rev C and Rev B from customer. Please check them. 

And If you need their schematic, please let me know. This documents is under the NDA.

[Request]

If you need to take some times in order to verify, would you please the schedule which you can response by end of Tuesday in US time?

If you have any question, please let me know.

Best regards.

Kaka

  • 0
    TI__Guru**** 170625 points

    Kaka,

    Kato Motoki said:

    [Question]

    Is there any change about USB controller by Device revision change?

    If you ask about changes in the USB controller between DM814x silicon version 2.1 and 3.0, then the answer is no, there is no change.

    The changes are related to DMM arbitration, DDR Symmetry, HDVPSS lock up when accessed from CCS/JTAG, IO latch up, SATA gen3 (no USB changes). See the DM814x silicon errata for mode details.

    In the Linux based PSP, we have some patches for 3.0 support, see the below e2e thread:

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/p/222257/783204.aspx#783204

    Best regards,
    Pavel 

  • 0 in reply to Pavel Botev
    Guru 24520 points

    Hi Pavel,

    Thank you for your response.

    I reported your comments to customer.  I have a question for USB controller behavior.

    [Question]

    What is the reason why the USB0_VBUSIN was outputted the voltage even though this pin type could be only  define as "input pin"?

    Do you have any ideas why this phenomenon was occurred?

    If you have any questions, please let me know.

    Best regards,

    Kaka

  • 0 in reply to Kaka
    TI__Guru**** 170625 points

    Kaka,

    Kato Motoki said:

    [Question]

    What is the reason why the USB0_VBUSIN was outputted the voltage even though this pin type could be only  define as "input pin"?

    Do you have any ideas why this phenomenon was occurred?

    I suspect this should be hardware design issue. Please double check your hardware design. You can use as reference the DM814x documentation (TRM, datasheet, SiliconErrata), DM8148 EVM reference design schematics. Have a look also in the below links:

    https://processors.wiki.ti.com/index.php/DM814x_Hardware_Design_Guide

    https://processors.wiki.ti.com/index.php/AM387x_/_C6A814x_Schematic_Review_Checklist

    http://www.ti.com/lit/an/spraar7a/spraar7a.pdf

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/223771.aspx

    http://e2e.ti.com/support/embedded/linux/f/354/p/187730/686868.aspx

    Best regards,
    Pavel

  • 0 in reply to Pavel Botev
    Guru 24520 points

    Hi Pavel,

    Thank you for your advices.

    I will inform your advices to customer.  If I get some feedbacks from customer, I will report to you again.

    By the way, does this device have a USB setting sequence(Initilazation of USB core) in order to use USB function?

    I read the TRM and TI wiki but I could not find out this sequence.  So, if you know this, please let me know.

    Best regards,

    Kaka

  • 0 in reply to Kaka
    TI__Guru**** 170625 points

    Kaka,

    Kato Motoki said:
    By the way, does this device have a USB setting sequence(Initilazation of USB core) in order to use USB function?

    May be you can find useful information here below:

    https://lwn.net/images/pdf/LDD3/ch13.pdf

    Best regards,
    Pavel

  • 0 in reply to Pavel Botev
    Guru 24520 points

    Hi Pavel,

    Thank you for your response.

    I think that this is a general sequence by using USB function.

    I would like to know the unique initialization sequence for each devices such as below.

     Note: The following sequence is C5000 family.

    If you have any questions, please let me know.

    Best regards.

    Kaka

  • 0 in reply to Kaka
    TI__Guru**** 170625 points

    Kaka,

    I can find the below USB initialization sequences in the DM814x TRM:

    chapter 25 USBSS

    25.5.8 Clock, PLL, and PHY Initialization
    25.8.6.1.1 CPPI DMA Scheduler Initialization
    25.8.9.1.1 Transmit Initialization
    25.8.9.2.1 Receive Initialization

    Best regards,
    Pavel

  • 0 in reply to Pavel Botev
    Guru 24520 points

    Hi Pavel,


    Thank you for your response.  I did not find them at that time.

    I will check them.

    * Just for your information

      I have already informed to customer to check the PSP in order to confirm the USB initialization sequence. 

    Best regards.

    Kaka