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Thread: USB device insertion sequencer

  1. #1
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    USB device insertion sequencer

    Hi everyone.
    I need a USB device insertion sequencer so I'm thinking of a TeensyLC in a box with a row of USB-B connectors on the back, a corresponding row of Host sockets on the front with the LC enabling respective connections between back and front, in the correct order and time delay before the next one is enabled.

    The whole lot is to be plugged in between a host PC and a growing range of currently 9 Audio/Midi USB devices so that when the system is booted, everybody gets woken up, identified, re-mapped etc. in an orderly manner.

    Given that we're thinking more or less RF transmission lines I'm looking for ideas as to what kind of switch element would suit this job. A pair of reed relays, or a 74HCTxxx analog switch elements.
    Thanks in advance, any suggestions greatly appreciated.
    Teensy rocks!

  2. #2
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    Basic option is probably to leave the USB data lines connected through, and just use a relay or FET to control the 5V power. One option would be a row of USB extension cables (or OEM cables for that matter) cut open to allow access to the power wire, but it could probably also be done by opening up a hub and doing some surgery on the 5V tracks and using FETs. The hub would work as normal. Depending on the hub design there may already be switching components for the port current limiting you can tap into for this.

  3. #3
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by MatrixRat View Post
    I'm looking for ideas as to what kind of switch element would suit this job.
    I've used this part with good results.

    https://www.onsemi.com/products/inte...itches/fsusb30

    But it only comes in fine pitch SMT packages.


    Also agree, just switching the device's power might be good enough.

  4. #4
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    Thanks GremlinWrangler. Five of the devices require their own wallwarts due to their power consumption or other idiosyncracies and four are not designed to work out of a hub. Ok, will damage a cable and see what I can do with the red wire.

    Thanks Paul, the FSUSB30 looks like the perfect choice. My tweezers are too large and glasses too small.


    Ok. The red wire and FET will do the trick. Now for the detail drawingboard, thanks for the tip.
    Last edited by MatrixRat; 10-04-2019 at 12:54 AM. Reason: Solution

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