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MSP430F5505: USB BSL and USB PLL

DDdoor
Expert 2435 points

Part Number: MSP430F5505

Hello,

What is the USB operation that can disable the USB PLL?



Best regards,
DDdoor

  • 0
    TI__Mastermind 30406 points

    Hi DDdoor,

    This is means the voltage range supported between enable USB PLL and disable USB PLL is different when you use USB module.

    Best Regards

    Johnson

  • 0 in reply to Johnson He
    Expert 2435 points

    Hello Johnson,

    Thank you for your reply.
    It turned out to be used in bus-powered configurations.
    Is it possible to use the USB BSL in this state?
    Is it impossible because the PLL is disabled?

    Best regards,
    DDdoor

  • 0 in reply to DDdoor
    Guru 34973 points

    DDdoor said:

    Is it possible to use the USB BSL in this state?
    Is it impossible because the PLL is disabled?

    Don't know what is your target, but USB can not work without 48 MHz clock.

    This clock can be sourced by XT2 over PLL or directly by 48MHz XT2 with bypassed and disabled PLL (undocumented and out of spec).

  • 0 in reply to DDdoor
    TI__Mastermind 30406 points

    Hi DDdoor,

    Could you sharing some details about your requirement? 

    Best Regards

    Johnson

  • 0 in reply to Johnson He
    Expert 2435 points

    Hello Johnson,

    Thank you for your reply.

    The background is below.
    Customers were considering firmware updates using USB BSL.
    There was a problem that firmware update could not be done. Upon investigation, it was found that the supply voltage to the MSP430 was 1.9V.
    However, with the MSP430F5505's revD, the firmware update worked.
    Also, even in RevF where firmware update is not possible, the USB function (CDC class) in normal operation is currently operating at VCC1.9V, USB PLL enable.


    If USB firmware update is not possible, at worst, the customer wants to do the following:
    As an essential operation in normal operation, they want to notify the USB Discriptor information when connecting to a PC and read the Discriptor information on the PC. Specifically, read PID, VID, Serial Number. The purpose is to record it on the production line and manage it in association with the inspection results.

    The USB function (CDC class) in normal operation is currently operating with VCC1.9V and USB PLL enable, so there is a desire to proceed if possible.
    First of all, it would be helpful if you could tell me the possible reason why it works even if it is out of specs.
    Since the customers have confirmed the operation on the actual machine, they would like to proceed as they are, but it would be helpful if you could let us know if there are any risks if the customers proceed as they are.

    Best regards,

    DDdoor

  • 0 in reply to DDdoor
    TI__Mastermind 30406 points

    Hi DDdoor,

    USB BSL firmware RevF default enable UPLLEN, thus customer need provide more than 2.2V voltage as description in datasheet.

    For the case of over specs, unpredictable problems may occur, it is recommended that customers use within the range of specs.

    Best Regards

    Johnson

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