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USB Host Guide

Omega4 EVB USB-C

The Omega4 EVB has a single USB-C port that can be configured as Host or Device (Gadget). Omega4 official firmware defaults to USB host mode. The port supports USB 2.0 only.

1. Verify host mode​

cat /sys/class/usb_role/20b00000.usb-role-switch/role
cat /sys/devices/platform/20e10000.usb2-phy/otg_mode

Expected values are host and host.

2. List connected devices​

lsusb
dmesg | tail -n 50

You should see enumeration logs when you plug in a device.

3. Common use cases​

3.1 USB storage​

blkid
ls /dev/sd*

Mount (example):

mkdir -p /mnt/usb
mount /dev/sda1 /mnt/usb

3.2 USB serial adapters​

ls /dev/ttyUSB* /dev/ttyACM* 2>/dev/null

Use screen, minicom, or picocom to connect as needed.

3.3 USB Ethernet adapters​

ip link

Bring the interface up and configure DHCP or a static address.

4. Switch back to host mode (if changed)​

If the port was switched to device mode for gadget testing, force host mode:

echo host > /sys/class/usb_role/20b00000.usb-role-switch/role
echo host > /sys/devices/platform/20e10000.usb2-phy/otg_mode

5. Power notes​

  • The Omega4 EVB provides 5 V on the USB-A host port, but high-draw peripherals (spinning disks, Wi-Fi dongles) may need a powered hub.
  • If devices enumerate and immediately drop, check the 5 V rail and use shorter cables.

6. Troubleshooting​

  • No devices show up: verify host mode, confirm the USB 2.0 Host support is enabled in your firmware, and check dmesg.
  • Enumeration errors: try a different cable or a powered hub.