VOXL as usb2 host not working via j8

Nirge

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

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.

Nirge

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