USB Host UART Interface

This component allows an ESP32-S3 or ESP32-S2 to host USB-serial peripheral devices. It uses the Usb Host component to interface to the device as a USB-OTG host.

Currently supported devices are listed in the table below:

Supported Devices

Name	VID	PID	Description
CDC_ACM	0x0000	0x0000	USB CDC ACM (Abstract Control Model)
CH34X	0x1A86	0x55D5	USB to serial adapter, multi-channel
CH340	0x1A86	0x7523	USB to serial adapter, single channel
CP210X	0x10C4	0xEA60	Silicon Labs USB to UART Bridge
ESP_JTAG	0x303A	0x1001	ESP32 JTAG interface
FT232	0x0403	0x6001	FTDI USB to serial adapter single port
FT2232	0x0403	0x6010	FTDI USB to serial adapter dual port
FT4232	0x0403	0x6011	FTDI USB to serial adapter dual port
PL2303	0x067B	0x2303	Prolific USB to serial adapter
PL2303GC	0x067B	0x23A3	Prolific PL2303 G-series (GC)
PL2303GB	0x067B	0x23B3	Prolific PL2303 G-series (GB)
PL2303GT	0x067B	0x23C3	Prolific PL2303 G-series (GT)
PL2303GL	0x067B	0x23D3	Prolific PL2303 G-series (GL)
PL2303GE	0x067B	0x23E3	Prolific PL2303 G-series (GE)
PL2303GS	0x067B	0x23F3	Prolific PL2303 G-series (GS)
STM32_VCP	0x0483	0x5740	STM32 Virtual COM Port

Note that devices with 4 channels will only allow 3 channels to be used at any one time on an ESP32-S3 due to hardware limitations. The ESP32-P4 is not affected by this limitation and can use all 4 channels.

# Example minimal configuration entry
usb_uart:
  - type: cp210x
    channels:
      - id: uch_1
        baud_rate: 9600
        buffer_size: 1024

Configuration variables

• id (Optional, ID): The id to use for this component.
• type (Required, string): The type of USB-serial device to connect to. One of ft23xx, ch34x, ch340, esp_jtag, stm32_vcp, cdc_acm, cp210x, pl2303, pl2303gc, pl2303gb, pl2303gt, pl2303gl, pl2303ge, pl2303gs.
• channels (Required, list): A list of channels to configure.
• vid (Optional, int): The vendor ID of the device. Use 0 as a wildcard. Each type has a default VID which will be overridden if this is set.
• pid (Optional, int): The product ID of the device. Use 0 as a wildcard. Each type has a default PID which will be overridden if this is set.

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

Channel configuration options

• id (Optional, ID): An id to assign to the channel. This id may be used anywhere a uart component is required.
• baud_rate (Required, int): The baud rate to use for the channel. This is optional for the stm32_vcp, esp_jtag and cdc_acm types.
• buffer_size (Optional, int): The size of the buffer to use for the channel. Defaults to 256 bytes.
• stop_bits (Optional, float): The number of stop bits to use. Defaults to 1. Other options are 1.5 and 2.
• data_bits (Optional, int): The number of data bits to use in the range 5-8. Defaults to 8.
• parity (Optional, string): The parity to use. One of NONE, EVEN, ODD, MARK and SPACE. Defaults to NONE.
• dummy_receiver (Optional, boolean): If set to true, the channel will consume any data received. This is useful for debugging purposes. Defaults to false.
• debug (Optional, boolean): If set to true, the channel will log all data sent and received. Defaults to false.
• debug_prefix (Optional, string): A string prepended to every debug log line for this channel. Useful when multiple channels have debugging enabled, to distinguish their output in the log. Defaults to "".
• flush_timeout (Optional, Time): The maximum time to wait for the USB output queue to drain when flush() is called. If the queue does not drain within this time, flush() returns a TIMEOUT result. Defaults to 100ms.

Device types

The cdc_acm type is a generic USB CDC ACM (Abstract Control Model) device. This is a common USB device class for serial communication. This driver does not strictly enforce the CDC-ACM configuration specification, so it may work with devices that do not properly implement that specification. It expects to find a single interrupt endpoint, a single bulk in endpoint, and a single bulk out endpoint.

See Also

• USB Host Interface
• API Reference: usb_uart.h