UARTSerial.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2017 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef MBED_UARTSERIAL_H
00018 #define MBED_UARTSERIAL_H
00019 
00020 #include "platform/platform.h"
00021 
00022 #if (DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
00023 
00024 #include "FileHandle.h"
00025 #include "SerialBase.h"
00026 #include "InterruptIn.h"
00027 #include "PlatformMutex.h"
00028 #include "serial_api.h"
00029 #include "CircularBuffer.h"
00030 #include "platform/NonCopyable.h"
00031 
00032 #ifndef MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE
00033 #define MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE  256
00034 #endif
00035 
00036 #ifndef MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE
00037 #define MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE  256
00038 #endif
00039 
00040 namespace mbed {
00041 
00042 class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UARTSerial> {
00043 
00044 public:
00045 
00046     /** Create a UARTSerial port, connected to the specified transmit and receive pins, with a particular baud rate.
00047      *  @param tx Transmit pin
00048      *  @param rx Receive pin
00049      *  @param baud The baud rate of the serial port (optional, defaults to MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE)
00050      */
00051     UARTSerial(PinName tx, PinName rx, int baud = MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE);
00052     virtual ~UARTSerial();
00053 
00054     /** Equivalent to POSIX poll(). Derived from FileHandle.
00055      *  Provides a mechanism to multiplex input/output over a set of file handles.
00056      */
00057     virtual short poll(short events) const;
00058 
00059     /* Resolve ambiguities versus our private SerialBase
00060      * (for writable, spelling differs, but just in case)
00061      */
00062     using FileHandle::readable;
00063     using FileHandle::writable;
00064 
00065     /** Write the contents of a buffer to a file
00066      *
00067      *  @param buffer   The buffer to write from
00068      *  @param length   The number of bytes to write
00069      *  @return         The number of bytes written, negative error on failure
00070      */
00071     virtual ssize_t write(const void* buffer, size_t length);
00072 
00073     /** Read the contents of a file into a buffer
00074      *
00075      *  Follows POSIX semantics:
00076      *
00077      *  * if no data is available, and non-blocking set return -EAGAIN
00078      *  * if no data is available, and blocking set, wait until data is available
00079      *  * If any data is available, call returns immediately
00080      *
00081      *  @param buffer   The buffer to read in to
00082      *  @param length   The number of bytes to read
00083      *  @return         The number of bytes read, 0 at end of file, negative error on failure
00084      */
00085     virtual ssize_t read(void* buffer, size_t length);
00086 
00087     /** Close a file
00088      *
00089      *  @return         0 on success, negative error code on failure
00090      */
00091     virtual int close();
00092 
00093     /** Check if the file in an interactive terminal device
00094      *
00095      *  @return         True if the file is a terminal
00096      *  @return         False if the file is not a terminal
00097      *  @return         Negative error code on failure
00098      */
00099     virtual int isatty();
00100 
00101     /** Move the file position to a given offset from from a given location
00102      *
00103      * Not valid for a device type FileHandle like UARTSerial.
00104      * In case of UARTSerial, returns ESPIPE
00105      *
00106      *  @param offset   The offset from whence to move to
00107      *  @param whence   The start of where to seek
00108      *      SEEK_SET to start from beginning of file,
00109      *      SEEK_CUR to start from current position in file,
00110      *      SEEK_END to start from end of file
00111      *  @return         The new offset of the file, negative error code on failure
00112      */
00113     virtual off_t seek(off_t offset, int whence);
00114 
00115     /** Flush any buffers associated with the file
00116      *
00117      *  @return         0 on success, negative error code on failure
00118      */
00119     virtual int sync();
00120 
00121     /** Set blocking or non-blocking mode
00122      *  The default is blocking.
00123      *
00124      *  @param blocking true for blocking mode, false for non-blocking mode.
00125      */
00126     virtual int set_blocking(bool blocking)
00127     {
00128         _blocking = blocking;
00129         return 0;
00130     }
00131 
00132     /** Register a callback on state change of the file.
00133      *
00134      *  The specified callback will be called on state changes such as when
00135      *  the file can be written to or read from.
00136      *
00137      *  The callback may be called in an interrupt context and should not
00138      *  perform expensive operations.
00139      *
00140      *  Note! This is not intended as an attach-like asynchronous api, but rather
00141      *  as a building block for constructing  such functionality.
00142      *
00143      *  The exact timing of when the registered function
00144      *  is called is not guaranteed and susceptible to change. It should be used
00145      *  as a cue to make read/write/poll calls to find the current state.
00146      *
00147      *  @param func     Function to call on state change
00148      */
00149     virtual void sigio(Callback<void()> func);
00150 
00151     /** Setup interrupt handler for DCD line
00152      *
00153      *  If DCD line is connected, an IRQ handler will be setup.
00154      *  Does nothing if DCD is NC, i.e., not connected.
00155      *
00156      *  @param dcd_pin         Pin-name for DCD
00157      *  @param active_high     a boolean set to true if DCD polarity is active low
00158      */
00159     void set_data_carrier_detect(PinName dcd_pin, bool active_high = false);
00160 
00161     /** Set the baud rate
00162      *
00163      *  @param baud   The baud rate
00164      */
00165     void set_baud(int baud);
00166 
00167 private:
00168 
00169     /** SerialBase lock override */
00170     virtual void lock(void);
00171 
00172     /** SerialBase unlock override */
00173     virtual void unlock(void);
00174 
00175     /** Acquire mutex */
00176     virtual void api_lock(void);
00177 
00178     /** Release mutex */
00179     virtual void api_unlock(void);
00180 
00181     /** Software serial buffers
00182      *  By default buffer size is 256 for TX and 256 for RX. Configurable through mbed_app.json
00183      */
00184     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE> _rxbuf;
00185     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE> _txbuf;
00186 
00187     PlatformMutex _mutex;
00188 
00189     Callback<void()> _sigio_cb;
00190 
00191     bool _blocking;
00192     bool _tx_irq_enabled;
00193     InterruptIn *_dcd_irq;
00194 
00195     /** Device Hanged up
00196      *  Determines if the device hanged up on us.
00197      *
00198      *  @return True, if hanged up
00199      */
00200     bool hup() const;
00201 
00202     /** ISRs for serial
00203      *  Routines to handle interrupts on serial pins.
00204      *  Copies data into Circular Buffer.
00205      *  Reports the state change to File handle.
00206      */
00207     void tx_irq(void);
00208     void rx_irq(void);
00209 
00210     void wake(void);
00211 
00212     void dcd_irq(void);
00213 
00214 };
00215 } //namespace mbed
00216 
00217 #endif //(DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
00218 #endif //MBED_UARTSERIAL_H