Mbed OS Reference | UARTSerial.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2006-2017 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef MBED_UARTSERIAL_H
 #define MBED_UARTSERIAL_H
 
 #include "platform/platform.h"
 
 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
 
 #include "platform/FileHandle.h"
 #include "SerialBase.h"
 #include "InterruptIn.h"
 #include "platform/PlatformMutex.h"
 #include "hal/serial_api.h"
 #include "platform/CircularBuffer.h"
 #include "platform/NonCopyable.h"
 
 #ifndef MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE
 #define MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE  256
 #endif
 
 #ifndef MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE
 #define MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE  256
 #endif
 
 namespace mbed {
 
 /** \addtogroup drivers */
 
 /** Class providing buffered UART communication functionality using separate circular buffer for send and receive channels
  *
  * @ingroup drivers
  */
 
 class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UARTSerial> {
 
 public:
 
     /** Create a UARTSerial port, connected to the specified transmit and receive pins, with a particular baud rate.
      *  @param tx Transmit pin
      *  @param rx Receive pin
      *  @param baud The baud rate of the serial port (optional, defaults to MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE)
      */
     UARTSerial(PinName tx, PinName rx, int baud = MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE);
     virtual ~UARTSerial();
 
     /** Equivalent to POSIX poll(). Derived from FileHandle.
      *  Provides a mechanism to multiplex input/output over a set of file handles.
      */
     virtual short poll(short events) const;
 
     /* Resolve ambiguities versus our private SerialBase
      * (for writable, spelling differs, but just in case)
      */
     using FileHandle::readable;
     using FileHandle::writable;
 
     /** Write the contents of a buffer to a file
      *
      *  Follows POSIX semantics:
      *
      * * if blocking, block until all data is written
      * * if no data can be written, and non-blocking set, return -EAGAIN
      * * if some data can be written, and non-blocking set, write partial
      *
      *  @param buffer   The buffer to write from
      *  @param length   The number of bytes to write
      *  @return         The number of bytes written, negative error on failure
      */
     virtual ssize_t write(const void *buffer, size_t length);
 
     /** Read the contents of a file into a buffer
      *
      *  Follows POSIX semantics:
      *
      *  * if no data is available, and non-blocking set return -EAGAIN
      *  * if no data is available, and blocking set, wait until data is available
      *  * If any data is available, call returns immediately
      *
      *  @param buffer   The buffer to read in to
      *  @param length   The number of bytes to read
      *  @return         The number of bytes read, 0 at end of file, negative error on failure
      */
     virtual ssize_t read(void *buffer, size_t length);
 
     /** Close a file
      *
      *  @return         0 on success, negative error code on failure
      */
     virtual int close();
 
     /** Check if the file in an interactive terminal device
      *
      *  @return         True if the file is a terminal
      *  @return         False if the file is not a terminal
      *  @return         Negative error code on failure
      */
     virtual int isatty();
 
     /** Move the file position to a given offset from from a given location
      *
      * Not valid for a device type FileHandle like UARTSerial.
      * In case of UARTSerial, returns ESPIPE
      *
      *  @param offset   The offset from whence to move to
      *  @param whence   The start of where to seek
      *      SEEK_SET to start from beginning of file,
      *      SEEK_CUR to start from current position in file,
      *      SEEK_END to start from end of file
      *  @return         The new offset of the file, negative error code on failure
      */
     virtual off_t seek(off_t offset, int whence);
 
     /** Flush any buffers associated with the file
      *
      *  @return         0 on success, negative error code on failure
      */
     virtual int sync();
 
     /** Set blocking or non-blocking mode
      *  The default is blocking.
      *
      *  @param blocking true for blocking mode, false for non-blocking mode.
      */
     virtual int set_blocking(bool blocking)
     {
         _blocking = blocking;
         return 0;
     }
 
     /** Check current blocking or non-blocking mode for file operations.
      *
      *  @return             true for blocking mode, false for non-blocking mode.
      */
     virtual bool is_blocking() const
     {
         return _blocking;
     }
 
     /** Enable or disable input
      *
      * Control enabling of device for input. This is primarily intended
      * for temporary power-saving; the overall ability of the device to operate for
      * input and/or output may be fixed at creation time, but this call can
      * allow input to be temporarily disabled to permit power saving without
      * losing device state.
      *
      *  @param enabled      true to enable input, false to disable.
      *
      *  @return             0 on success
      *  @return             Negative error code on failure
      */
     virtual int enable_input(bool enabled);
 
     /** Enable or disable output
      *
      * Control enabling of device for output. This is primarily intended
      * for temporary power-saving; the overall ability of the device to operate for
      * input and/or output may be fixed at creation time, but this call can
      * allow output to be temporarily disabled to permit power saving without
      * losing device state.
      *
      *  @param enabled      true to enable output, false to disable.
      *
      *  @return             0 on success
      *  @return             Negative error code on failure
      */
     virtual int enable_output(bool enabled);
 
     /** Register a callback on state change of the file.
      *
      *  The specified callback will be called on state changes such as when
      *  the file can be written to or read from.
      *
      *  The callback may be called in an interrupt context and should not
      *  perform expensive operations.
      *
      *  Note! This is not intended as an attach-like asynchronous api, but rather
      *  as a building block for constructing  such functionality.
      *
      *  The exact timing of when the registered function
      *  is called is not guaranteed and susceptible to change. It should be used
      *  as a cue to make read/write/poll calls to find the current state.
      *
      *  @param func     Function to call on state change
      */
     virtual void sigio(Callback<void()> func);
 
     /** Setup interrupt handler for DCD line
      *
      *  If DCD line is connected, an IRQ handler will be setup.
      *  Does nothing if DCD is NC, i.e., not connected.
      *
      *  @param dcd_pin         Pin-name for DCD
      *  @param active_high     a boolean set to true if DCD polarity is active low
      */
     void set_data_carrier_detect(PinName dcd_pin, bool active_high = false);
 
     /** Set the baud rate
      *
      *  @param baud   The baud rate
      */
     void set_baud(int baud);
 
     // Expose private SerialBase::Parity as UARTSerial::Parity
     using SerialBase::Parity;
     // In C++11, we wouldn't need to also have using directives for each value
     using SerialBase::None;
     using SerialBase::Odd;
     using SerialBase::Even;
     using SerialBase::Forced1;
     using SerialBase::Forced0;
 
     /** Set the transmission format used by the serial port
      *
      *  @param bits The number of bits in a word (5-8; default = 8)
      *  @param parity The parity used (None, Odd, Even, Forced1, Forced0; default = None)
      *  @param stop_bits The number of stop bits (1 or 2; default = 1)
      */
     void set_format(int bits = 8, Parity parity = UARTSerial::None, int stop_bits = 1);
 
 #if DEVICE_SERIAL_FC
     // For now use the base enum - but in future we may have extra options
     // such as XON/XOFF or manual GPIO RTSCTS.
     using SerialBase::Flow;
     // In C++11, we wouldn't need to also have using directives for each value
     using SerialBase::Disabled;
     using SerialBase::RTS;
     using SerialBase::CTS;
     using SerialBase::RTSCTS;
 
     /** Set the flow control type on the serial port
      *
      *  @param type the flow control type (Disabled, RTS, CTS, RTSCTS)
      *  @param flow1 the first flow control pin (RTS for RTS or RTSCTS, CTS for CTS)
      *  @param flow2 the second flow control pin (CTS for RTSCTS)
      */
     void set_flow_control(Flow type, PinName flow1 = NC, PinName flow2 = NC);
 #endif
 
 private:
 
     void wait_ms(uint32_t millisec);
 
     /** SerialBase lock override */
     virtual void lock(void);
 
     /** SerialBase unlock override */
     virtual void unlock(void);
 
     /** Acquire mutex */
     virtual void api_lock(void);
 
     /** Release mutex */
     virtual void api_unlock(void);
 
     /** Unbuffered write - invoked when write called from critical section */
     ssize_t write_unbuffered(const char *buf_ptr, size_t length);
 
     void enable_rx_irq();
     void disable_rx_irq();
     void enable_tx_irq();
     void disable_tx_irq();
 
     /** Software serial buffers
      *  By default buffer size is 256 for TX and 256 for RX. Configurable through mbed_app.json
      */
     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE> _rxbuf;
     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE> _txbuf;
 
     PlatformMutex _mutex;
 
     Callback<void()> _sigio_cb;
 
     bool _blocking;
     bool _tx_irq_enabled;
     bool _rx_irq_enabled;
     bool _tx_enabled;
     bool _rx_enabled;
     InterruptIn *_dcd_irq;
 
     /** Device Hanged up
      *  Determines if the device hanged up on us.
      *
      *  @return True, if hanged up
      */
     bool hup() const;
 
     /** ISRs for serial
      *  Routines to handle interrupts on serial pins.
      *  Copies data into Circular Buffer.
      *  Reports the state change to File handle.
      */
     void tx_irq(void);
     void rx_irq(void);
 
     void wake(void);
 
     void dcd_irq(void);
 
 };
 } //namespace mbed
 
 #endif //(DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
 #endif //MBED_UARTSERIAL_H
Important Information for this Arm website
