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