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Thread: Understanding The USB Specification

  1. #1

    Understanding The USB Specification

    Howdy folks,
    I'm trying to understand how USB works as a whole [for implementing Devices]. Currently, I'm trying to dive through the teensy4 usb.c code, but I'm having trouble interpreting it.

    In usb.c, "Device Controller Initialization, page 3161" is referenced[1]. Where can I find the document that this is referencing? I'm not familiar with where USB specifications live.

    Many Thanks,
    ~kp

    [1] https://github.com/PaulStoffregen/co...sy4/usb.c#L165

  2. #2
    Senior Member PaulStoffregen's Avatar
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    That's the IMXRT1060 Manual, which you can get here.

    https://www.pjrc.com/teensy/datasheets.html

    However, page 3161 is from an oldest public version of the manual for the chip used in the beta test last year: IMXRT1050, Rev 1, 03/2018. In IMXRT1060, Rev 2, 12/2019, turn to page 2351 to find that info. All the USB info is the same, just on a different page.


    Edit: I've updated that page number in the comment. The code is filled with lots of other page numbers that are probably also out of date, since the newer manuals rearranged all the sections (into a much better order than the early ones).

  3. #3
    Junior Member
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    Quote Originally Posted by kubernetespleb View Post
    I'm trying to understand how USB works as a whole [for implementing Devices].
    My go to resources for USB are:
    http://www.janaxelson.com/usb.htm
    https://www.beyondlogic.org/usbnutshell/usb1.shtml

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