[usb_cdc_acm] New component documentation

Author: kbx81

content/components/_index.md

@@ -168,6 +168,7 @@ Create update entities simplifying management of OTA updates.
 "OpenTherm","components/opentherm","opentherm.png",""
 "SPI Bus","components/spi","spi.svg",""
 "UART","components/uart","uart.svg",""
+"USB CDC-ACM","components/usb_cdc_acm","usb.svg","dark-invert"
 "USB Host","components/usb_host","usb.svg","dark-invert"
 "USB UART","components/usb_uart","usb.svg","dark-invert"
 {{< /imgtable >}}

content/components/usb_cdc_acm.md

@@ -0,0 +1,70 @@
+---
+description: "Instructions for setting up USB CDC-ACM virtual serial ports on ESP32 variants in ESPHome"
+title: "USB CDC-ACM Interface"
+params:
+  seo:
+    description: Instructions for setting up USB CDC-ACM virtual serial ports on ESP32 variants in ESPHome
+    image: usb.svg
+---
+
+The USB CDC-ACM (Communications Device Class - Abstract Control Model) component enables ESP32-S2 and ESP32-S3 devices
+to function as USB virtual serial ports. When connected to a host computer, the microcontroller will appear as one or
+more standard serial/COM ports, allowing serial communication with the application running on the microcontroller.
+
+You must have the TinyUSB component in your device's configuration to use this component.
+
+> [!NOTE]
+> This component is only compatible with ESP32-S2 and ESP32-S3 variants using the ESP-IDF framework.
+
+```yaml
+# Example minimal configuration entry
+usb_cdc_acm:
+  interfaces:
+    - number: 0
+```
+
+## Configuration variables
+
+- **usb_rx_buffer_size** (*Optional*, int): Size of the USB receive buffer in bytes. Range: 1-65535. Defaults to `256`.
+- **usb_tx_buffer_size** (*Optional*, int): Size of the USB transmit buffer in bytes. Range: 1-65535. Defaults to `256`.
+- **interfaces** (**Required**, list): List of CDC-ACM interface instances to configure; up to two are supported. At
+  least one is required.
+
+## Interface configuration variables
+
+Each interface in the `interfaces` list supports the following options:
+
+- **id** (*Optional*, [ID](#config-id)): The ID to use for this interface instance.
+- **number** (**Required**, int): Unique interface identifier. Valid values are `0` or `1`. Each configured interface
+  must have a unique number.
+
+## Multiple Interface Example
+
+The USB CDC-ACM component supports up to two simultaneous virtual serial port interfaces on a single device. This
+allows you to create multiple independent communication channels over a single physical USB connection.
+
+```yaml
+# Example configuration with two interfaces
+usb_cdc_acm:
+  interfaces:
+    - id: cdc_acm_1
+      number: 0
+    - id: cdc_acm_2
+      number: 1
+```
+
+In this configuration, the device will appear as two separate serial/COM ports to the host computer. Each interface
+operates independently with its own data buffers.
+
+## Buffer Size Considerations
+
+The buffer sizes determine how much data can be temporarily stored during USB transfers:
+
+- **Small buffers (256 bytes, default)**: Suitable for low-bandwidth applications and conserves RAM
+- **Large buffers (512-1024 bytes)**: Recommended for high-throughput applications or when handling bursts of data
+
+Increase buffer sizes if you experience data loss or need to handle larger data packets without frequent polling.
+
+## See Also
+
+- {{< apiref "usb_cdc_acm/usb_cdc_acm.h" "usb_cdc_acm/usb_cdc_acm.h" >}}