docs(uart): clarify example pins need a USB-to-UART bridge

docs/en/api-guides/stdio.rst

@@ -26,6 +26,10 @@ On {IDF_TARGET_NAME}, ESP-IDF provides implementations of VFS drivers for I/O ov
 
 Standard I/O is not limited to these options, though. See below on enabling custom destinations for standard I/O.
 
+.. note::
+
+    The console path is separate from an application UART that you open with the :doc:`UART driver <../api-reference/peripherals/uart>` on other pins. If a UART peripheral provides console output, a USB-to-UART bridge chip is required. Many development boards already include this bridge chip onboard for console communication between the PC and the default UART0. If a USB or USB Serial/JTAG peripheral provides console output, no adapter chip is needed. The USB connector on the development board connects directly to the chip's USB D+/D- pins. Traffic on other UART ports does not appear in ``idf.py monitor`` unless a given port is configured as the console. For details, see :doc:`Establish Serial Connection with {IDF_TARGET_NAME} <../get-started/establish-serial-connection>`.
+
 Configuration
 -------------
 

docs/en/api-reference/peripherals/uart.rst

@@ -150,6 +150,9 @@ The same macro :c:macro:`UART_PIN_NO_CHANGE` should be specified for pins that w
   // Set UART pins(TX: IO4, RX: IO5, RTS: IO18, CTS: IO19, DTR: UNUSED, DSR: UNUSED)
   ESP_ERROR_CHECK(uart_set_pin({IDF_TARGET_UART_EXAMPLE_PORT}, 4, 5, 18, 19, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE));
 
+.. note::
+
+    The pin numbers above are only an example. On many development boards, the onboard USB-to-UART bridge is connected to the UART0 default TX/RX pins. If you need to communicate with a PC over other ports or pins, connect a separate USB-to-UART bridge to those pins.
 
 .. _uart-api-running-uart-communication:
 

docs/en/get-started/establish-serial-connection.rst

@@ -20,6 +20,8 @@ Some development boards have the USB-to-UART bridge installed. If a board does n
 
     The {IDF_TARGET_NAME} supports the USB peripheral. In this case, the USB-to-UART bridge is not needed and the device can be flashed directly.
 
+    The USB peripheral and its USB PHY are separate from the UART controllers. UART controllers output UART signals on GPIOs, so connecting a UART to a PC over USB still requires an onboard or external USB-to-UART bridge.
+
     .. blockdiag::
         :scale: 70%
         :caption: SoC with Supported USB

docs/zh_CN/api-guides/stdio.rst

@@ -26,6 +26,10 @@ ESP-IDF 提供了 C 标准输入输出功能，如 ``stdin``、``stdout`` 和 ``
 
 不过，标准 I/O 并不限于这些选项。请参见下文，了解如何为标准 I/O 启用自定义目标。
 
+.. note::
+
+    控制台通路与通过 :doc:`UART 驱动 <../api-reference/peripherals/uart>` 在其他管脚上打开的应用 UART 彼此独立。若控制台输出由 UART 外设提供，则需要 USB 至 UART 桥芯片，许多开发板上已板载该桥芯片，用于 PC 与默认 UART0 之间的控制台通信；若控制台输出由 USB 或 USB Serial/JTAG 外设提供，则无需转接芯片，开发板上的 USB 接口直连芯片的 USB D+/D- 管脚。除非将某端口配置为控制台，否则其他 UART 端口上的数据不会出现在 ``idf.py monitor`` 中。有关详细信息，请参阅 :doc:`与 {IDF_TARGET_NAME} 创建串口连接 <../get-started/establish-serial-connection>`。
+
 配置
 -----
 

docs/zh_CN/api-reference/peripherals/uart.rst

@@ -150,6 +150,9 @@ UART 驱动程序函数通过 :cpp:type:`uart_port_t` 识别不同的 UART 控
   // Set UART pins(TX: IO4, RX: IO5, RTS: IO18, CTS: IO19, DTR: UNUSED, DSR: UNUSED)
   ESP_ERROR_CHECK(uart_set_pin({IDF_TARGET_UART_EXAMPLE_PORT}, 4, 5, 18, 19, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE));
 
+.. note::
+
+    上方管脚编号仅为示例。许多开发板的板载 USB 至 UART 桥接到 UART0 的默认 TX/RX 管脚。若需要通过其他端口或其他管脚与 PC 通信，则需在这些管脚上另接 USB 至 UART 桥。
 
 .. _uart-api-running-uart-communication:
 

docs/zh_CN/get-started/establish-serial-connection.rst

@@ -20,6 +20,8 @@
 
     {IDF_TARGET_NAME} 支持 USB 外设。无需 USB 至 UART 桥，便可直接烧录设备。
 
+    USB 外设及其 USB PHY 与 UART 控制器彼此独立。UART 控制器在 GPIO 上输出 UART 信号，因此若要通过 USB 将 UART 连接到 PC，仍需使用板载或外部的 USB 至 UART 桥。
+
     .. blockdiag::
         :scale: 70%
         :caption: 支持 USB 的 SoC