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AM3352: Errata advisory 1.0.33

Kanae
Guru 10295 points

Part Number: AM3352
Other Parts Discussed in Thread: AM3358

Hi Sitara support Team,

Regarding the following errata, my customer need to know more detailed information.

"Advisory 1.0.33: USB Host: USB Low-Speed Receive-to-Transmit Inter-Packet Delay"

In customer's application, it is an important use for the low speed mode,
such as a bar code reader limited to the USB low speed mode.

Could you please advise how to confirm that the errata status will be problem,
or not by using AM3358 starter kit?

Best regards,
kanae

  • 0
    TI__Guru**** 393215 points
    Hi,

    The Errata advisory states:

    "The absence of the required minimum 2-bit time 'J' state as part of a USB low-speed RX-to-TX bus transition can result in the failure of some low-speed peripheral devices to function."

    Your customer will need to check if their low-speed peripheral device is affected. There is no workaround on the AM335x side. The Starter Kit USB1 port (connector J5) is a Host port.
  • 0 in reply to Biser Gatchev-XID
    Guru 10295 points

     

    Hi Biser,

     

    Thank you for your quick reply!

     

    My customer would like to know how come the failure is occurred

    at using USB low-speed mode device.

    Are there any explanations for this outside of the errata?

     

    I also need to make sure if the low-speed peripheral device is

    in more than 2-bit time 'J' state during the idle period,

    it can be able to use the function as the low-speed device.

    On other words, does it depend on the low-speed peripheral device condition

    during the idle period which should be required minimum 2-bit time 'J' state.

     

    Is my understanding correct?

     

    Best regards,

    Kanae

  • 0 in reply to Kanae
    TI__Mastermind 27890 points

    Hello Kanae,
    The result of this erratum depends on the peripheral attached, and whether or not it is tolerant of the reduced bus turn-around time. As this issue occurs 100% of the time, it would immediately be evident if an attached peripheral has an issue with it or not so I'd recommend testing it beforehand on any TI or community EVM.

    I think you will find it is not a problem.

  • 0 in reply to -DK-
    Guru 10295 points

    Hi DK,

    Thank you for your reply.
    My customer does not know what kind of the USB low speed mode device are used by the end customer.
    They would like to know whether AM335x's USB fail if it is taken the USB compliance test on the host side
    in Low-speed mode?

    This issue is 100% detectable if the USB device does not meet the AM335x SPEC
    however there is no workaround on AM 335 x side,as you explained,
    does it means that the most devices distributed in the market can be connected,
    in other words, is the issue occurence rate very low?

    Best regards,
    Kanae

  • 0 in reply to Kanae
    TI__Mastermind 27890 points
    Hello Kanae,
    This erratum does not prevent AM335x from passing USB-IF Compliance testing.

    As for your second question, there has only been a single instance of a single device that has ever been verified as having a problem with this erratum, and this occurred ~4 years ago. No further problematic devices have been reported.
  • 0 in reply to -DK-
    Guru 10295 points

    Hi DK,

    Thank you for your reply.
    I think my customer would judge to accept this errata, or not.

    Best regards,
    Kanae