BufferedSerial.h

00001 
00002 /**
00003  * @file    BufferedSerial.h
00004  * @brief   Software Buffer - Extends mbed Serial functionallity adding irq driven TX and RX
00005  * @author  sam grove
00006  * @version 1.0
00007  * @see     
00008  *
00009  * Copyright (c) 2013
00010  *
00011  * Licensed under the Apache License, Version 2.0 (the "License");
00012  * you may not use this file except in compliance with the License.
00013  * You may obtain a copy of the License at
00014  *
00015  *     http://www.apache.org/licenses/LICENSE-2.0
00016  *
00017  * Unless required by applicable law or agreed to in writing, software
00018  * distributed under the License is distributed on an "AS IS" BASIS,
00019  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00020  * See the License for the specific language governing permissions and
00021  * limitations under the License.
00022  */
00023 
00024 #ifndef BUFFEREDSERIAL_H
00025 #define BUFFEREDSERIAL_H
00026  
00027 #include "mbed.h"
00028 #include "Buffer.h"
00029 
00030 // Base Class
00031 #define SERIAL_BASE  RawSerial
00032 
00033 #define XBEE_WAIT_TIME    3800
00034 
00035 /** A serial port (UART) for communication with other serial devices
00036  *
00037  * Can be used for Full Duplex communication, or Simplex by specifying
00038  * one pin as NC (Not Connected)
00039  *
00040  * Example:
00041  * @code
00042  *  #include "mbed.h"
00043  *  #include "BufferedSerial.h"
00044  *
00045  *  BufferedSerial pc(USBTX, USBRX);
00046  *
00047  *  int main()
00048  *  { 
00049  *      while(1)
00050  *      {
00051  *          Timer s;
00052  *        
00053  *          s.start();
00054  *          pc.printf("Hello World - buffered\n");
00055  *          int buffered_time = s.read_us();
00056  *          wait(0.1f); // give time for the buffer to empty
00057  *        
00058  *          s.reset();
00059  *          printf("Hello World - blocking\n");
00060  *          int polled_time = s.read_us();
00061  *          s.stop();
00062  *          wait(0.1f); // give time for the buffer to empty
00063  *        
00064  *          pc.printf("printf buffered took %d us\n", buffered_time);
00065  *          pc.printf("printf blocking took %d us\n", polled_time);
00066  *          wait(0.5f);
00067  *      }
00068  *  }
00069  * @endcode
00070  */
00071 
00072 /**
00073  *  @class BufferedSerial
00074  *  @brief Software buffers and interrupt driven tx and rx for Serial
00075  */  
00076 class BufferedSerial : public SERIAL_BASE 
00077 {
00078 private:
00079     InterruptIn   _cts;
00080     Timer         _cts_timer;
00081     Buffer <char>  _rxbuf;
00082     Buffer <char>  _txbuf;
00083     uint32_t      _buf_size;
00084     uint32_t      _tx_multiple;
00085  
00086     void rxIrq(void);
00087     void txIrq(void);
00088     void prime(void);
00089     
00090     bool checkCTS(void);
00091     void ctsInterrupt(void);
00092     
00093 public:
00094     /** Create a BufferedSerial port, connected to the specified transmit and receive pins
00095      *  @param tx Transmit pin
00096      *  @param rx Receive pin
00097      *  @param cts CTS pin
00098      *  @param buf_size printf() buffer size
00099      *  @param tx_multiple amount of max printf() present in the internal ring buffer at one time
00100      *  @param name optional name
00101      *  @note Either tx or rx may be specified as NC if unused
00102      */
00103     BufferedSerial(PinName tx, PinName rx, PinName cts, uint32_t buf_size = 256, uint32_t tx_multiple = 4,const char* name=NULL);
00104     
00105     /** Destroy a BufferedSerial port
00106      */
00107     virtual ~BufferedSerial(void);
00108     
00109     /** Check on how many bytes are in the rx buffer
00110      *  @return 1 if something exists, 0 otherwise
00111      */
00112     virtual int readable(void);
00113     
00114     /** Check to see if the tx buffer has room
00115      *  @return 1 always has room and can overwrite previous content if too small / slow
00116      */
00117     virtual int writeable(void);
00118     
00119     /** Get a single byte from the BufferedSerial Port.
00120      *  Should check readable() before calling this.
00121      *  @return A byte that came in on the Serial Port
00122      */
00123     virtual int getc(void);
00124     
00125     /** Write a single byte to the BufferedSerial Port.
00126      *  @param c The byte to write to the Serial Port
00127      *  @return The byte that was written to the Serial Port Buffer
00128      */
00129     virtual int putc(int c);
00130     
00131     /** Write a string to the BufferedSerial Port. Must be NULL terminated
00132      *  @param s The string to write to the Serial Port
00133      *  @return The number of bytes written to the Serial Port Buffer
00134      */
00135     virtual int puts(const char *s);
00136     
00137     /** Write a formatted string to the BufferedSerial Port.
00138      *  @param format The string + format specifiers to write to the Serial Port
00139      *  @return The number of bytes written to the Serial Port Buffer
00140      */
00141     virtual int printf(const char* format, ...);
00142     
00143     /** Write data to the Buffered Serial Port
00144      *  @param s A pointer to data to send
00145      *  @param length The amount of data being pointed to
00146      *  @return The number of bytes written to the Serial Port Buffer
00147      */
00148     virtual ssize_t write(const void *s, std::size_t length);
00149 };
00150 
00151 #endif