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diff --git a/examples/device/cdc_dual_ports/README.md b/examples/device/cdc_dual_ports/README.md new file mode 100644 index 000000000..b0d1e5d97 --- /dev/null +++ b/examples/device/cdc_dual_ports/README.md @@ -0,0 +1,48 @@ +# CDC Dual Ports + +Enumerates as a USB device with two independent CDC virtual serial ports. + +## What it does + +- Exposes two CDC virtual COM ports. +- Echoes back any data received on either port to **both** ports: the first port echoes as lower case, the second as upper case. +- Sends a UART state notification (toggles the DSR line) on each press of the on-board button. +- Resets the board into the bootloader when the first port is opened at 1200 bps and then disconnected (touch-1200 trigger). +- Blinks the on-board LED: 250 ms when unmounted, 1000 ms when mounted. + +## USB Descriptors + +| Interface | Class driver | +|-----------|--------------| +| 0–1 | CDC (virtual serial port 1) | +| 2–3 | CDC (virtual serial port 2) | + +## Configuration + +Notable `tusb_config.h` settings: + +```c +#define CFG_TUD_CDC 2 // two CDC ports +#define CFG_TUD_CDC_RX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64) +#define CFG_TUD_CDC_TX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64) +``` + +## Building + +CMake: + +```bash +mkdir build && cd build +cmake -DBOARD=raspberry_pi_pico .. +cmake --build . +``` + +Make: + +```bash +make BOARD=raspberry_pi_pico all +``` + +## Try it + +After flashing, two serial ports appear on the host (e.g. `/dev/ttyACM0` and `/dev/ttyACM1` on Linux). Open either one in a terminal and type: characters come back lower-cased on the first port and upper-cased on the second. |