194 lines
3.5 KiB
ReStructuredText
194 lines
3.5 KiB
ReStructuredText
#######
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USB CDC
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#######
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About
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-----
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USB Communications Device Class API. This class is used to enable communication between the host and the device.
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This class is often used to enable serial communication and can be used to flash the firmware on the ESP32 without the external USB to Serial chip.
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APIs
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****
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onEvent
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^^^^^^^
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Event handling functions.
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.. code-block:: arduino
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void onEvent(esp_event_handler_t callback);
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.. code-block:: arduino
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void onEvent(arduino_usb_cdc_event_t event, esp_event_handler_t callback);
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Where ``event`` can be:
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* ARDUINO_USB_CDC_ANY_EVENT
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* ARDUINO_USB_CDC_CONNECTED_EVENT
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* ARDUINO_USB_CDC_DISCONNECTED_EVENT
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* ARDUINO_USB_CDC_LINE_STATE_EVENT
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* ARDUINO_USB_CDC_LINE_CODING_EVENT
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* ARDUINO_USB_CDC_RX_EVENT
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* ARDUINO_USB_CDC_TX_EVENT
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* ARDUINO_USB_CDC_RX_OVERFLOW_EVENT
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* ARDUINO_USB_CDC_MAX_EVENT
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setRxBufferSize
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^^^^^^^^^^^^^^^
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The ``setRxBufferSize`` function is used to set the size of the RX buffer.
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.. code-block:: arduino
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size_t setRxBufferSize(size_t size);
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setTxTimeoutMs
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^^^^^^^^^^^^^^
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This function is used to define the time to reach the timeout for the TX.
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.. code-block:: arduino
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void setTxTimeoutMs(uint32_t timeout);
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begin
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^^^^^
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This function is used to start the peripheral using the default CDC configuration.
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.. code-block:: arduino
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void begin(unsigned long baud);
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Where:
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* ``baud`` is the baud rate.
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end
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^^^
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This function will finish the peripheral as CDC and release all the allocated resources. After calling ``end`` you need to use ``begin`` again in order to initialize the USB CDC driver again.
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.. code-block:: arduino
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void end();
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available
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^^^^^^^^^
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This function will return if there are messages in the queue.
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.. code-block:: arduino
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int available(void);
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The return is the number of bytes available to read.
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availableForWrite
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^^^^^^^^^^^^^^^^^
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This function will return if the hardware is available to write data.
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.. code-block:: arduino
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int availableForWrite(void);
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peek
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^^^^
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This function is used to ``peek`` messages from the queue.
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.. code-block:: arduino
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int peek(void);
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read
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^^^^
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This function is used to read the bytes available.
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.. code-block:: arduino
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size_t read(uint8_t *buffer, size_t size);
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Where:
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* ``buffer`` is the pointer to the buffer to be read.
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* ``size`` is the number of bytes to be read.
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write
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^^^^^
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This function is used to write the message.
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.. code-block:: arduino
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size_t write(const uint8_t *buffer, size_t size);
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Where:
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* ``buffer`` is the pointer to the buffer to be written.
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* ``size`` is the number of bytes to be written.
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flush
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^^^^^
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This function is used to flush the data.
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.. code-block:: arduino
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void flush(void);
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baudRate
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^^^^^^^^
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This function is used to get the ``baudRate``.
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.. code-block:: arduino
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uint32_t baudRate();
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setDebugOutput
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^^^^^^^^^^^^^^
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This function will enable the debug output, usually from the `UART0`, to the USB CDC.
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.. code-block:: arduino
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void setDebugOutput(bool);
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enableReboot
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^^^^^^^^^^^^
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This function enables the device to reboot by the DTR as RTS signals.
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.. code-block:: arduino
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void enableReboot(bool enable);
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rebootEnabled
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^^^^^^^^^^^^^
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This function will return if the reboot is enabled.
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.. code-block:: arduino
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bool rebootEnabled(void);
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Example Code
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------------
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Here is an example of how to use the USB CDC.
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USBSerial
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*********
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.. literalinclude:: ../../../libraries/USB/examples/USBSerial/USBSerial.ino
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:language: arduino
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.. _USB.org: https://www.usb.org/developers
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