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third_party/tinyusb/examples/dual/dynamic_switch/README.md

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+# Dynamic Switch Example
+
+This example demonstrates TinyUSB's dual-role capability by allowing runtime switching between USB device and host modes.
+
+## Features
+
+- **Button-triggered mode switching**: Press the board button to switch between device and host modes
+- **Device Mode**: Acts as a USB CDC (Virtual Serial Port) that echoes all received data
+- **Host Mode**: Enumerates connected USB devices and prints device information
+- **Dynamic switching**: Deinitializes the current stack and reinitializes in the new mode
+
+## Configuration
+
+Notable `tusb_config.h` settings:
+
+```c
+#define CFG_TUD_CDC 1
+#define CFG_TUH_HUB 1
+#define CFG_TUH_DEVICE_MAX (CFG_TUH_HUB ? 4 : 1)
+#define CFG_TUH_ENUMERATION_BUFSIZE 256
+```
+
+## Usage
+
+1. **Build and flash** the example to your board
+2. **Default behavior**: The board starts in **Device mode**
+3. **Device mode**:
+   - Connect the board to a PC
+   - Open a serial terminal (e.g., `screen /dev/ttyACM0` or PuTTY)
+   - Type characters - they will be echoed back to you
+4. **Switch to Host mode**:
+   - Press the board button
+   - Connect a USB device to the board
+   - The board will enumerate the device and print its descriptors to the debug console
+5. **Switch back to Device mode**: Press the button again
+
+## LED Patterns
+
+The onboard LED indicates the USB connection status:
+
+- **Fast blink (250ms)**: Not mounted/connected
+- **Slow blink (1000ms)**: Successfully mounted/connected
+- **Very slow blink (2500ms)**: Suspended (device mode only)
+
+## Serial Output
+
+The example prints status messages to the debug UART:
+
+```
+======================================
+TinyUSB Dynamic Switch Example
+Press button to switch between device and host modes
+Starting in DEVICE mode...
+======================================
+
+[DEVICE] Mounted
+
+--- Switching USB mode ---
+Stopping DEVICE mode...
+Starting HOST mode...
+Mode switch complete!
+
+[HOST] Device attached, address = 1
+Device 1: ID 1234:5678 SN ABC123
+Device Descriptor:
+  bLength             18
+  bDescriptorType     1
+  bcdUSB              0200
+  bDeviceClass        239
+  ...
+```