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  4. VOXL as usb2 host not working via j8

VOXL as usb2 host not working via j8

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  • NirgeN Offline
    NirgeN Offline
    Nirge
    wrote on last edited by
    #1

    Hi,
    Connecting my laptop to voxl via adb works on j8 connecter.
    However, an STM based device is not recognized when connecting a client device to voxl using micro-usb to micro-usb cable.
    The same device is recognized when connecting via the usb expander (https://docs.modalai.com/usb-expander-and-debug-datasheet/)

    Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
    Bus 001 Device 002: ID 0483:5740 STMicroelectronics STM32F407
    Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    

    https://docs.modalai.com/voxl-as-usb-host/ does not specify any special requirements.
    Am I missing something? is the micro-usb cable needs to be an OTG cable with ID pin?
    Best regards,
    Nir

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    • modaltbM Offline
      modaltbM Offline
      modaltb
      ModalAI Team
      wrote on last edited by
      #2

      Hi @Nirge ,

      A standard cable won't work.

      Some info here:
      https://docs.modalai.com/voxl-datasheets-connectors/#notes-3

      From here: https://docs.modalai.com/voxl-as-usb-host/#background

      Because the USB3.0 SS pins on the VOXL (Snapdragon 821) cannot support TX/RX swapping, they were set to peripheral mode since the 821 is used mainly in phones and peripheral mode is way more commonly used in a phone configuration.
      
      In order for systems to use the standard micro-b to type A female OTG cables, they need to do TX/RX swapping.
      
      Since VOXL can't do this, it needs to use a non-standard pinout as its default configuration is peripheral mode in order to get the SS.
      
      NirgeN 1 Reply Last reply
      0
      • modaltbM modaltb

        Hi @Nirge ,

        A standard cable won't work.

        Some info here:
        https://docs.modalai.com/voxl-datasheets-connectors/#notes-3

        From here: https://docs.modalai.com/voxl-as-usb-host/#background

        Because the USB3.0 SS pins on the VOXL (Snapdragon 821) cannot support TX/RX swapping, they were set to peripheral mode since the 821 is used mainly in phones and peripheral mode is way more commonly used in a phone configuration.
        
        In order for systems to use the standard micro-b to type A female OTG cables, they need to do TX/RX swapping.
        
        Since VOXL can't do this, it needs to use a non-standard pinout as its default configuration is peripheral mode in order to get the SS.
        
        NirgeN Offline
        NirgeN Offline
        Nirge
        wrote on last edited by
        #3

        @modaltb Using USB 2.
        Got my hands on an OTG adapter, seems to be doing the trick.

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