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 "MyBuffer.h"
00029 
00030 /** A serial port (UART) for communication with other serial devices
00031  *
00032  * Can be used for Full Duplex communication, or Simplex by specifying
00033  * one pin as NC (Not Connected)
00034  *
00035  * Example:
00036  * @code
00037  *  #include "mbed.h"
00038  *  #include "BufferedSerial.h"
00039  *
00040  *  BufferedSerial pc(USBTX, USBRX);
00041  *
00042  *  int main()
00043  *  { 
00044  *      while(1)
00045  *      {
00046  *          Timer s;
00047  *        
00048  *          s.start();
00049  *          pc.printf("Hello World - buffered\n");
00050  *          int buffered_time = s.read_us();
00051  *          wait(0.1f); // give time for the buffer to empty
00052  *        
00053  *          s.reset();
00054  *          printf("Hello World - blocking\n");
00055  *          int polled_time = s.read_us();
00056  *          s.stop();
00057  *          wait(0.1f); // give time for the buffer to empty
00058  *        
00059  *          pc.printf("printf buffered took %d us\n", buffered_time);
00060  *          pc.printf("printf blocking took %d us\n", polled_time);
00061  *          wait(0.5f);
00062  *      }
00063  *  }
00064  * @endcode
00065  */
00066 
00067 /**
00068  *  @class BufferedSerial
00069  *  @brief Software buffers and interrupt driven tx and rx for Serial
00070  */  
00071 class BufferedSerial : public RawSerial 
00072 {
00073 private:
00074     MyBuffer <char> _rxbuf;
00075     MyBuffer <char> _txbuf;
00076     uint32_t      _buf_size;
00077     uint32_t      _tx_multiple;
00078  
00079     void rxIrq(void);
00080     void txIrq(void);
00081     void prime(void);
00082     
00083 public:
00084     /** Create a BufferedSerial port, connected to the specified transmit and receive pins
00085      *  @param tx Transmit pin
00086      *  @param rx Receive pin
00087      *  @param buf_size printf() buffer size
00088      *  @param tx_multiple amount of max printf() present in the internal ring buffer at one time
00089      *  @param name optional name
00090      *  @note Either tx or rx may be specified as NC if unused
00091      */
00092     BufferedSerial(PinName tx, PinName rx, uint32_t buf_size = 256, uint32_t tx_multiple = 4,const char* name=NULL);
00093     
00094     /** Destroy a BufferedSerial port
00095      */
00096     virtual ~BufferedSerial(void);
00097     
00098     /** Check on how many bytes are in the rx buffer
00099      *  @return 1 if something exists, 0 otherwise
00100      */
00101     virtual int readable(void);
00102     
00103     /** Check to see if the tx buffer has room
00104      *  @return 1 always has room and can overwrite previous content if too small / slow
00105      */
00106     virtual int writeable(void);
00107     
00108     /** Get a single byte from the BufferedSerial Port.
00109      *  Should check readable() before calling this.
00110      *  @return A byte that came in on the Serial Port
00111      */
00112     virtual int getc(void);
00113     
00114     /** Write a single byte to the BufferedSerial Port.
00115      *  @param c The byte to write to the Serial Port
00116      *  @return The byte that was written to the Serial Port Buffer
00117      */
00118     virtual int putc(int c);
00119     
00120     /** Write a string to the BufferedSerial Port. Must be NULL terminated
00121      *  @param s The string to write to the Serial Port
00122      *  @return The number of bytes written to the Serial Port Buffer
00123      */
00124     virtual int puts(const char *s);
00125     
00126     /** Write a formatted string to the BufferedSerial Port.
00127      *  @param format The string + format specifiers to write to the Serial Port
00128      *  @return The number of bytes written to the Serial Port Buffer
00129      */
00130     virtual int printf(const char* format, ...);
00131     
00132     /** Write data to the Buffered Serial Port
00133      *  @param s A pointer to data to send
00134      *  @param length The amount of data being pointed to
00135      *  @return The number of bytes written to the Serial Port Buffer
00136      */
00137     virtual ssize_t write(const void *s, std::size_t length);
00138 };
00139 
00140 #endif