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 /** \addtogroup drivers */
00043 
00044 /** Class providing buffered UART communication functionality using separate circular buffer for send and receive channels
00045  *  
00046  * @ingroup drivers
00047  */
00048 
00049 class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UARTSerial> {
00050 
00051 public:
00052 
00053     /** Create a UARTSerial port, connected to the specified transmit and receive pins, with a particular baud rate.
00054      *  @param tx Transmit pin
00055      *  @param rx Receive pin
00056      *  @param baud The baud rate of the serial port (optional, defaults to MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE)
00057      */
00058     UARTSerial(PinName tx, PinName rx, int baud = MBED_CONF_PLATFORM_DEFAULT_SERIAL_BAUD_RATE);
00059     virtual ~UARTSerial();
00060 
00061     /** Equivalent to POSIX poll(). Derived from FileHandle.
00062      *  Provides a mechanism to multiplex input/output over a set of file handles.
00063      */
00064     virtual short poll(short events) const;
00065 
00066     /* Resolve ambiguities versus our private SerialBase
00067      * (for writable, spelling differs, but just in case)
00068      */
00069     using FileHandle::readable;
00070     using FileHandle::writable;
00071 
00072     /** Write the contents of a buffer to a file
00073      *
00074      *  @param buffer   The buffer to write from
00075      *  @param length   The number of bytes to write
00076      *  @return         The number of bytes written, negative error on failure
00077      */
00078     virtual ssize_t write(const void* buffer, size_t length);
00079 
00080     /** Read the contents of a file into a buffer
00081      *
00082      *  Follows POSIX semantics:
00083      *
00084      *  * if no data is available, and non-blocking set return -EAGAIN
00085      *  * if no data is available, and blocking set, wait until data is available
00086      *  * If any data is available, call returns immediately
00087      *
00088      *  @param buffer   The buffer to read in to
00089      *  @param length   The number of bytes to read
00090      *  @return         The number of bytes read, 0 at end of file, negative error on failure
00091      */
00092     virtual ssize_t read(void* buffer, size_t length);
00093 
00094     /** Close a file
00095      *
00096      *  @return         0 on success, negative error code on failure
00097      */
00098     virtual int close();
00099 
00100     /** Check if the file in an interactive terminal device
00101      *
00102      *  @return         True if the file is a terminal
00103      *  @return         False if the file is not a terminal
00104      *  @return         Negative error code on failure
00105      */
00106     virtual int isatty();
00107 
00108     /** Move the file position to a given offset from from a given location
00109      *
00110      * Not valid for a device type FileHandle like UARTSerial.
00111      * In case of UARTSerial, returns ESPIPE
00112      *
00113      *  @param offset   The offset from whence to move to
00114      *  @param whence   The start of where to seek
00115      *      SEEK_SET to start from beginning of file,
00116      *      SEEK_CUR to start from current position in file,
00117      *      SEEK_END to start from end of file
00118      *  @return         The new offset of the file, negative error code on failure
00119      */
00120     virtual off_t seek(off_t offset, int whence);
00121 
00122     /** Flush any buffers associated with the file
00123      *
00124      *  @return         0 on success, negative error code on failure
00125      */
00126     virtual int sync();
00127 
00128     /** Set blocking or non-blocking mode
00129      *  The default is blocking.
00130      *
00131      *  @param blocking true for blocking mode, false for non-blocking mode.
00132      */
00133     virtual int set_blocking(bool blocking)
00134     {
00135         _blocking = blocking;
00136         return 0;
00137     }
00138 
00139     /** Register a callback on state change of the file.
00140      *
00141      *  The specified callback will be called on state changes such as when
00142      *  the file can be written to or read from.
00143      *
00144      *  The callback may be called in an interrupt context and should not
00145      *  perform expensive operations.
00146      *
00147      *  Note! This is not intended as an attach-like asynchronous api, but rather
00148      *  as a building block for constructing  such functionality.
00149      *
00150      *  The exact timing of when the registered function
00151      *  is called is not guaranteed and susceptible to change. It should be used
00152      *  as a cue to make read/write/poll calls to find the current state.
00153      *
00154      *  @param func     Function to call on state change
00155      */
00156     virtual void sigio(Callback<void()> func);
00157 
00158     /** Setup interrupt handler for DCD line
00159      *
00160      *  If DCD line is connected, an IRQ handler will be setup.
00161      *  Does nothing if DCD is NC, i.e., not connected.
00162      *
00163      *  @param dcd_pin         Pin-name for DCD
00164      *  @param active_high     a boolean set to true if DCD polarity is active low
00165      */
00166     void set_data_carrier_detect(PinName dcd_pin, bool active_high = false);
00167 
00168     /** Set the baud rate
00169      *
00170      *  @param baud   The baud rate
00171      */
00172     void set_baud(int baud);
00173 
00174 private:
00175 
00176     void wait_ms(uint32_t millisec);
00177 
00178     /** SerialBase lock override */
00179     virtual void lock(void);
00180 
00181     /** SerialBase unlock override */
00182     virtual void unlock(void);
00183 
00184     /** Acquire mutex */
00185     virtual void api_lock(void);
00186 
00187     /** Release mutex */
00188     virtual void api_unlock(void);
00189 
00190     /** Software serial buffers
00191      *  By default buffer size is 256 for TX and 256 for RX. Configurable through mbed_app.json
00192      */
00193     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE>  _rxbuf;
00194     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE>  _txbuf;
00195 
00196     PlatformMutex _mutex;
00197 
00198     Callback<void()> _sigio_cb;
00199 
00200     bool _blocking;
00201     bool _tx_irq_enabled;
00202     InterruptIn *_dcd_irq;
00203 
00204     /** Device Hanged up
00205      *  Determines if the device hanged up on us.
00206      *
00207      *  @return True, if hanged up
00208      */
00209     bool hup() const;
00210 
00211     /** ISRs for serial
00212      *  Routines to handle interrupts on serial pins.
00213      *  Copies data into Circular Buffer.
00214      *  Reports the state change to File handle.
00215      */
00216     void tx_irq(void);
00217     void rx_irq(void);
00218 
00219     void wake(void);
00220 
00221     void dcd_irq(void);
00222 
00223 };
00224 } //namespace mbed
00225 
00226 #endif //(DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
00227 #endif //MBED_UARTSERIAL_H