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      *  Follows POSIX semantics:
00075      *
00076      * * if blocking, block until all data is written
00077      * * if no data can be written, and non-blocking set, return -EAGAIN
00078      * * if some data can be written, and non-blocking set, write partial
00079      *
00080      *  @param buffer   The buffer to write from
00081      *  @param length   The number of bytes to write
00082      *  @return         The number of bytes written, negative error on failure
00083      */
00084     virtual ssize_t write(const void* buffer, size_t length);
00085 
00086     /** Read the contents of a file into a buffer
00087      *
00088      *  Follows POSIX semantics:
00089      *
00090      *  * if no data is available, and non-blocking set return -EAGAIN
00091      *  * if no data is available, and blocking set, wait until data is available
00092      *  * If any data is available, call returns immediately
00093      *
00094      *  @param buffer   The buffer to read in to
00095      *  @param length   The number of bytes to read
00096      *  @return         The number of bytes read, 0 at end of file, negative error on failure
00097      */
00098     virtual ssize_t read(void* buffer, size_t length);
00099 
00100     /** Close a file
00101      *
00102      *  @return         0 on success, negative error code on failure
00103      */
00104     virtual int close();
00105 
00106     /** Check if the file in an interactive terminal device
00107      *
00108      *  @return         True if the file is a terminal
00109      *  @return         False if the file is not a terminal
00110      *  @return         Negative error code on failure
00111      */
00112     virtual int isatty();
00113 
00114     /** Move the file position to a given offset from from a given location
00115      *
00116      * Not valid for a device type FileHandle like UARTSerial.
00117      * In case of UARTSerial, returns ESPIPE
00118      *
00119      *  @param offset   The offset from whence to move to
00120      *  @param whence   The start of where to seek
00121      *      SEEK_SET to start from beginning of file,
00122      *      SEEK_CUR to start from current position in file,
00123      *      SEEK_END to start from end of file
00124      *  @return         The new offset of the file, negative error code on failure
00125      */
00126     virtual off_t seek(off_t offset, int whence);
00127 
00128     /** Flush any buffers associated with the file
00129      *
00130      *  @return         0 on success, negative error code on failure
00131      */
00132     virtual int sync();
00133 
00134     /** Set blocking or non-blocking mode
00135      *  The default is blocking.
00136      *
00137      *  @param blocking true for blocking mode, false for non-blocking mode.
00138      */
00139     virtual int set_blocking(bool blocking)
00140     {
00141         _blocking = blocking;
00142         return 0;
00143     }
00144 
00145     /** Check current blocking or non-blocking mode for file operations.
00146      *
00147      *  @return             true for blocking mode, false for non-blocking mode.
00148      */
00149     virtual bool is_blocking() const
00150     {
00151         return _blocking;
00152     }
00153 
00154     /** Register a callback on state change of the file.
00155      *
00156      *  The specified callback will be called on state changes such as when
00157      *  the file can be written to or read from.
00158      *
00159      *  The callback may be called in an interrupt context and should not
00160      *  perform expensive operations.
00161      *
00162      *  Note! This is not intended as an attach-like asynchronous api, but rather
00163      *  as a building block for constructing  such functionality.
00164      *
00165      *  The exact timing of when the registered function
00166      *  is called is not guaranteed and susceptible to change. It should be used
00167      *  as a cue to make read/write/poll calls to find the current state.
00168      *
00169      *  @param func     Function to call on state change
00170      */
00171     virtual void sigio(Callback<void()> func);
00172 
00173     /** Setup interrupt handler for DCD line
00174      *
00175      *  If DCD line is connected, an IRQ handler will be setup.
00176      *  Does nothing if DCD is NC, i.e., not connected.
00177      *
00178      *  @param dcd_pin         Pin-name for DCD
00179      *  @param active_high     a boolean set to true if DCD polarity is active low
00180      */
00181     void set_data_carrier_detect(PinName dcd_pin, bool active_high = false);
00182 
00183     /** Set the baud rate
00184      *
00185      *  @param baud   The baud rate
00186      */
00187     void set_baud(int baud);
00188 
00189     // Expose private SerialBase::Parity as UARTSerial::Parity
00190     using SerialBase::Parity;
00191     // In C++11, we wouldn't need to also have using directives for each value
00192     using SerialBase::None;
00193     using SerialBase::Odd;
00194     using SerialBase::Even;
00195     using SerialBase::Forced1;
00196     using SerialBase::Forced0;
00197 
00198     /** Set the transmission format used by the serial port
00199      *
00200      *  @param bits The number of bits in a word (5-8; default = 8)
00201      *  @param parity The parity used (None, Odd, Even, Forced1, Forced0; default = None)
00202      *  @param stop_bits The number of stop bits (1 or 2; default = 1)
00203      */
00204     void set_format(int bits=8, Parity parity=UARTSerial::None, int stop_bits=1);
00205 
00206 #if DEVICE_SERIAL_FC
00207     // For now use the base enum - but in future we may have extra options
00208     // such as XON/XOFF or manual GPIO RTSCTS.
00209     using SerialBase::Flow;
00210     // In C++11, we wouldn't need to also have using directives for each value
00211     using SerialBase::Disabled;
00212     using SerialBase::RTS;
00213     using SerialBase::CTS;
00214     using SerialBase::RTSCTS;
00215 
00216     /** Set the flow control type on the serial port
00217      *
00218      *  @param type the flow control type (Disabled, RTS, CTS, RTSCTS)
00219      *  @param flow1 the first flow control pin (RTS for RTS or RTSCTS, CTS for CTS)
00220      *  @param flow2 the second flow control pin (CTS for RTSCTS)
00221      */
00222     void set_flow_control(Flow type, PinName flow1=NC, PinName flow2=NC);
00223 #endif
00224 
00225 private:
00226 
00227     void wait_ms(uint32_t millisec);
00228 
00229     /** SerialBase lock override */
00230     virtual void lock(void);
00231 
00232     /** SerialBase unlock override */
00233     virtual void unlock(void);
00234 
00235     /** Acquire mutex */
00236     virtual void api_lock(void);
00237 
00238     /** Release mutex */
00239     virtual void api_unlock(void);
00240 
00241     /** Software serial buffers
00242      *  By default buffer size is 256 for TX and 256 for RX. Configurable through mbed_app.json
00243      */
00244     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_RXBUF_SIZE>  _rxbuf;
00245     CircularBuffer<char, MBED_CONF_DRIVERS_UART_SERIAL_TXBUF_SIZE>  _txbuf;
00246 
00247     PlatformMutex _mutex;
00248 
00249     Callback<void()> _sigio_cb;
00250 
00251     bool _blocking;
00252     bool _tx_irq_enabled;
00253     bool _rx_irq_enabled;
00254     InterruptIn *_dcd_irq;
00255 
00256     /** Device Hanged up
00257      *  Determines if the device hanged up on us.
00258      *
00259      *  @return True, if hanged up
00260      */
00261     bool hup() const;
00262 
00263     /** ISRs for serial
00264      *  Routines to handle interrupts on serial pins.
00265      *  Copies data into Circular Buffer.
00266      *  Reports the state change to File handle.
00267      */
00268     void tx_irq(void);
00269     void rx_irq(void);
00270 
00271     void wake(void);
00272 
00273     void dcd_irq(void);
00274 
00275 };
00276 } //namespace mbed
00277 
00278 #endif //(DEVICE_SERIAL && DEVICE_INTERRUPTIN) || defined(DOXYGEN_ONLY)
00279 #endif //MBED_UARTSERIAL_H