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Thread: teensy 3.2 - using usb lead

  1. #1
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    teensy 3.2 - using usb lead

    Is it possible to connect the teesny directly to a usb lead using tx1(pin1) and rx1(pin0)

    the Usb connector is a bit delicate and i would prefer a more robust solution

    does something need to be done to make the teesny recognisable over usb

    is there a performance loss using this method ?

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    You can connect Teensy 3.2 directly to an USB cable using the pads on the bottom side:

    This is what I suggested a few weeks ago in this post to someone who had already damaged their USB connector.

    Note that the USB support in Teensies is native, and not via an USB-serial chip like in most Arduino boards. This means that on Teensy, pins 0 and 1 are not involved in the USB communications in any way.

  3. #3
    Senior Member+ MichaelMeissner's Avatar
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    This board was published some time ago (3-4 years ago). It includes a PCB you can have oshpark make (3 boards for $2.60 for USA delivery), and then you solder in a USB-B board:


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    thanks for the suggestions guys

    might be a nice feature to add pins to the Teensy 4.0

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    Senior Member+ MichaelMeissner's Avatar
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    Quote Originally Posted by Gadget999 View Post
    thanks for the suggestions guys

    might be a nice feature to add pins to the Teensy 4.0
    At this point the Teensy 4 hardware is frozen, and it presumably will be officially announced in a bit (only Paul/Robin know precisely when). There will be extra pads underneath the Teensy 4 just like there are for the Teensy 3.x series, but the pins will be laid out in a different fashion than the layout used for the 3.2. While many of the outer row pins will have the same features, there will be differences. You can read the beta thread if you want to get an idea of what it will look like. I'm sure there will be PCB boards that will allow you to get access to those pins.

  6. #6
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by Gadget999 View Post
    Is it possible to connect the teesny directly to a usb lead using tx1(pin1) and rx1(pin0)
    ...
    Also note: The Teensy pins " tx1(pin1) and rx1(pin0) " are wholly separate from USB Serial.

    On Teensy they are independent interface for Serial1 UART, or as other GPIO pins. The follow up posts indeed show the USB pins for the Teensy 3.2 native USB hardware that mirror the USB connector.

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    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by MichaelMeissner View Post
    0nly Paul/Robin know precisely when
    Oh how I wish we could know this precisely. We most definitely do not, at least not yet. Delays in manufacturing beyond our control add uncertainty. Even we don't yet know a definite release date.


    The Teensy 4.0 hardware design absolutely is frozen at this point, actually since several weeks ago.

    We did not put alternate (duplicate) pads for the main USB port on the bottom side, as we've done for other Teensy 3.x boards. Part of the reason is lack of space, but another concern is the 20X faster speed of 480 Mbit/sec USB makes this sort of routing (branches, stubs, etc) quite risky for the signal quality. With 12 Mbit/sec speed on Teensy 3.x boards, a short stub for those 2 pads does not substantially impact the signal quality. This might also be able to work at 480 Mbit/sec, but that's a huge risk that we're not willing to take.

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    Quote Originally Posted by PaulStoffregen View Post
    Oh how I wish we could know this precisely. We most definitely do not, at least not yet. Delays in manufacturing beyond our control add uncertainty. Even we don't yet know a definite release date.


    The Teensy 4.0 hardware design absolutely is frozen at this point, actually since several weeks ago.

    We did not put alternate (duplicate) pads for the main USB port on the bottom side, as we've done for other Teensy 3.x boards. Part of the reason is lack of space, but another concern is the 20X faster speed of 480 Mbit/sec USB makes this sort of routing (branches, stubs, etc) quite risky for the signal quality. With 12 Mbit/sec speed on Teensy 3.x boards, a short stub for those 2 pads does not substantially impact the signal quality. This might also be able to work at 480 Mbit/sec, but that's a huge risk that we're not willing to take.
    Hi Paul - i do not have my hands on a T4.0 yet

    the backside appears to have the USB pads - did you decide to include them after all ?

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    Quote Originally Posted by Gadget999 View Post
    Hi Paul - i do not have my hands on a T4.0 yet

    the backside appears to have the USB pads - did you decide to include them after all ?
    The pads are for USB2, that can and has be used for USBHost SW

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    Thank you WMXZ

    can USB2 be used as a serial port ?

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    yes,
    I have done it but only Serial is implemented
    Needs a 2nd usb SW stack (see also the huge T4-beta thread where Paul commented on that)

    Edit: I was referring for the USB2 as USB-device and not hosting external serial devices (I think this is what Paul refers to in next post)

  12. #12
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by Gadget999 View Post
    can USB2 be used as a serial port ?
    Yes, it can. In fact, it can be used as many serial ports. Just connect a USB hub (or network of hubs) and plug as many USB serial cables as you like into the hub(s).

    For each hub and each serial cable you wish to use, you have to put 1 instance of the USBHost_t36 hub driver / serial driver into your program. When a serial cable is plugged in, it will be assigned to one of the drivers. Then you can use that driver's instance name for serial communication, the same way you'd use Serial, Serial1, Serial2, etc.

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    wow - that's awesome - I might have to rethink a communication strategy !

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