USB UART Interface

This component allows an ESP32-S3 or ESP32-S2 to connect to USB-serial devices. It uses the USB Host Interface component to connect to the device.

Currently supported devices are listed in the table below:

Supported Devices

Name

VID

PID

Description

CH34X

0x1A86

0x55D5

USB to serial adapter, multi-channel (up to 3 channels)

CH340

0x1A86

0x7523

USB to serial adapter, single channel

ESP_JTAG

0x303A

0x1001

ESP32 JTAG interface

STM32_VCP

0x0483

0x5740

STM32 Virtual COM Port

CDC_ACM

0x0000

0x0000

USB CDC ACM (Abstract Control Model)

CP210X

0x10C4

0xEA60

Silicon Labs USB to UART Bridge

 
# 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 ch34x, ch340, esp_jtag, stm32_vcp, cdc_acm, cp210x.

  • 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 (and ignored) 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.

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. The cdc_acm, esp_jtag and stm32_vcp types do not support changing baud rate, stop bits or number of data bits, as they implement a virtual channel not typically associated with a physical UART.

See Also