USB Host Interface

The USB Host interface on the ESP32-S3 and ESP32-S2 is used to connect to USB peripheral devices. Multiple devices may be configured, but only one can be connected at any time. By default the device must be directly connected to the ESP32, but this can be changed by setting the enable_hubs option to true.

This component is used by the usb_uart component to allow the ESP32 to connect to USB-serial devices. It is also possible to configure devices directly in this component, but this has no application other than for debug purposes.

# Example configuration entry
usb_host:
  enable_hubs: true
  max_transfer_requests: 32  # For high-throughput devices like USB UART at 115200+ baud
  devices:
    - id: device_0
      vid: 0x1725
      pid: 0x1234

Configuration variables

id (Optional, ID): The id to use for this component.
enable_hubs (Optional, boolean): Whether to include support for hubs. Defaults to false.
max_transfer_requests (Optional, int): Maximum number of concurrent USB transfer requests. Range: 1-32. Defaults to 16. Increase this value for high-throughput devices (e.g., USB UART at 115200+ baud) if you see “All X transfer slots in use” errors.
devices (Optional, list): A list of devices to configure.

Device configuration options

id (Optional, ID): An id to assign to the device.
vid (Required, int): The vendor ID of the device. Use 0 as a wildcard.
pid (Required, int): The product ID of the device. Use 0 as a wildcard.

Setting both vid and pid to 0 will match any device.

If a device is configured and a device is connected that matches the configuration, the device will be connected to the ESP32 and log entries will appear at the DEBUG level. If the log level is set to VERBOSE, then the configuration descriptors of the device will be dumped. The device will remain connected until it is disconnected or the ESP32 is reset.

If a device is plugged in that does not match any configured device, the device will be disconnected and a log entry will appear at the DEBUG level.