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Thread: Teensy 4.1 USB Pads Tested

  1. #1

    Teensy 4.1 USB Pads Tested

    Hi al, i made a little breakout board to test the USB pads with pogo pins, it works well, i'm able to upload sketches without any issues.

    Is there a test i should do to make sure that USB is working as intended over those pads? i had read that the 4.0 doesn't have pads for USB because of concerns with the high speed usb pads being exposed but again in my test it worked great.

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  2. #2
    Senior Member PaulStoffregen's Avatar
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    Yes, I will admit, my concern about bottom side pads & signal integrity was overly conservative. Several other decisions that went into Teensy 4.0 could probably also, in hindsight, be considered on the too conservative side.

    But still, everything took so much longer than I had wanted. I started working on the IMXRT chip in late 2017. My initial goal was to release Teensy 4.0 by November 2018. It turned out we just barely got the beta test started in the final days of December 2018. The beta test ran for nearly 8 months, during which time we switched from the 1052 to 1062 chip. Even with so many small design choices to limit risk, we still didn't manage to get it properly released until August 2019.

    Teensy 4.1 design started in January 2020, building on a couple years of development, 8 months of beta testing, and 4 months of experience and feedback from Teensy 4.0 being widely used. Now that those days seem long in the past, the only visible difference seems to be the form factor.

  3. #3
    Senior Member
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    A pair of 4 inch long wires with du Pont connectors work fine too apparently. This is what one of the buyers of TSynth used to connect to the PCB.
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  4. #4
    Senior Member
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    I totally agree with being a bit conservative when designing a core product.

    If it incorporates relaxed design rules, the user may add just very little "exception" to good design, because errors sum up and sometimes even multiply.

    Surely, USB for example "can" work with flying wires, unsymmetric unmatched traces and stubs, but such things quickly eat up all the safety margin, so even unexpected environmental noise/influence could just turn it unusable or unreliable at best.

    So keep on making well-designed Teensy! Please!

  5. #5
    Its understandable, im hoping to see a 4.0 with usb pads and host pads or even just with usb pads instead of host pads, ill post pics of my breakout that uses a usb cable for a 4.0

  6. #6
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    Hi there, I'm having some issues with Teensy 4.1 and the pogo pins, made a PCB design which uses pogo pins to bring the USB connector to the front panel, but when the pogo pins are in contact, the USB port of the Teensy 4.1 does not work...of course the connector on the front panel of my hardware does not work too,
    I've been testing for shorts or mistakes in the routing and everything looks to be fine, so my theory is that I've placed the traces of the USB crossing with other signals and not enough isolated so it's making some disturbance and spoiling it,
    does anyone has some experience here who could confirm my thoughts?
    after doing some search in the forum I've seen that there are routing requirements for USB 480 Mbit ...which I have obviously not followed.

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