SerialHalfDuplex.h

00001 
00002 /* mbed Microcontroller Library
00003  * Copyright (c) 2006-2012 ARM Limited
00004  *
00005  * Permission is hereby granted, free of charge, to any person obtaining a copy
00006  * of this software and associated documentation files (the "Software"), to deal
00007  * in the Software without restriction, including without limitation the rights
00008  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00009  * copies of the Software, and to permit persons to whom the Software is
00010  * furnished to do so, subject to the following conditions:
00011  *
00012  * The above copyright notice and this permission notice shall be included in
00013  * all copies or substantial portions of the Software.
00014  *
00015  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00016  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00017  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00018  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00019  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00020  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00021  * SOFTWARE.
00022  *
00023  * NOTE: This is an unsupported legacy untested library.
00024  */
00025 #ifndef MBED_SERIALHALFDUPLEX_H
00026 #define MBED_SERIALHALFDUPLEX_H
00027 
00028 #include "device.h"
00029  
00030 #if DEVICE_SERIAL
00031  
00032 #include "Serial.h"
00033 #include "PinNames.h"
00034 #include "PeripheralNames.h"
00035  
00036 namespace mbed {
00037  
00038 /* Class: SerialHalfDuplex
00039  * A serial port (UART) for communication with other devices using  
00040  * Half-Duplex, allowing transmit and receive on a single
00041  * shared transmit and receive line. Only one end should be transmitting 
00042  * at a time.
00043  * 
00044  * Both the tx and rx pin should be defined, and wired together. 
00045  * This is in addition to them being wired to the other serial 
00046  * device to allow both read and write functions to operate.
00047  *
00048  *  Example:
00049  *  > // Send a byte to a second HalfDuplex device, and read the response
00050  *  >
00051  *  > #include "mbed.h"
00052  *  >
00053  *  > // p9 and p10 should be wired together to form "a"
00054  *  > // p28 and p27 should be wired together to form "b"
00055  *  > // p9/p10 should be wired to p28/p27 as the Half Duplex connection
00056  *  >
00057  *  > SerialHalfDuplex a(p9, p10);
00058  *  > SerialHalfDuplex b(p28, p27);
00059  *  >
00060  *  > void b_rx() { // second device response
00061  *  >     b.putc(b.getc() + 4);
00062  *  > }
00063  *  >   
00064  *  > int main() {
00065  *  >     b.attach(&b_rx);
00066  *  >     for(int c = 'A'; c < 'Z'; c++) {
00067  *  >         a.putc(c);
00068  *  >         printf("sent [%c]\n", c);
00069  *  >         wait(0.5);   // b should respond
00070  *  >         if(a.readable()) {
00071  *  >             printf("received [%c]\n", a.getc());
00072  *  >         }
00073  *  >     }
00074  *  > }
00075  * 
00076  * For Simplex and Full-Duplex Serial communication, see <Serial>
00077  */
00078 class SerialHalfDuplex : public Serial {
00079  
00080 public:
00081     /* Constructor: SerialHalfDuplex
00082      * Create a half-duplex serial port, connected to the specified transmit
00083      * and receive pins.
00084      *
00085      * These pins should be wired together, as well as to the target device
00086      *
00087      * Variables:
00088      *  tx - Transmit pin
00089      *  rx - Receive pin
00090      */
00091     SerialHalfDuplex(PinName tx, PinName rx, const char *name = NULL);
00092  
00093 #if 0       // Inherited from Serial class, for documentation
00094     /* Function: baud
00095      *  Set the baud rate of the serial port
00096      *
00097      * Variables:
00098      *  baudrate - The baudrate of the serial port (default = 9600).
00099      */
00100     void baud(int baudrate);
00101  
00102     enum Parity {
00103         None = 0
00104         , Odd
00105         , Even
00106         , Forced1
00107         , Forced0
00108     };
00109  
00110     /* Function: format
00111      *  Set the transmission format used by the Serial port
00112      *
00113      * Variables:
00114      *  bits - The number of bits in a word (5-8; default = 8)
00115      *  parity - The parity used (Serial::None, Serial::Odd, 
00116 Serial::Even, Serial::Forced1, Serial::Forced0; default = Serial::None)
00117      *  stop - The number of stop bits (1 or 2; default = 1)
00118      */
00119     void format(int bits = 8, Parity parity = Serial::None, int stop_bits 
00120 = 1);
00121  
00122     /* Function: putc
00123      *  Write a character
00124      *
00125      * Variables:
00126      *  c - The character to write to the serial port
00127      */
00128     int putc(int c);
00129  
00130     /* Function: getc
00131      *  Read a character
00132      *
00133      * Read a character from the serial port. This call will block
00134      * until a character is available. For testing if a character is
00135      * available for reading, see <readable>.
00136      *
00137      * Variables:
00138      *  returns - The character read from the serial port
00139      */
00140     int getc();
00141  
00142     /* Function: printf
00143      *  Write a formated string
00144      *
00145      * Variables:
00146      *  format - A printf-style format string, followed by the
00147      *      variables to use in formating the string.
00148      */
00149     int printf(const char* format, ...);
00150  
00151     /* Function: scanf
00152      *  Read a formated string
00153      *
00154      * Variables:
00155      *  format - A scanf-style format string,
00156      *      followed by the pointers to variables to store the results.
00157      */
00158     int scanf(const char* format, ...);
00159  
00160     /* Function: readable
00161      *  Determine if there is a character available to read
00162      *
00163      * Variables:
00164      *  returns - 1 if there is a character available to read, else 0
00165      */
00166     int readable();
00167  
00168     /* Function: writeable
00169      *  Determine if there is space available to write a character
00170      *
00171      * Variables:
00172      *  returns - 1 if there is space to write a character, else 0
00173      */
00174     int writeable();
00175  
00176     /* Function: attach
00177      *  Attach a function to call whenever a serial interrupt is generated
00178      *
00179      * Variables:
00180      *  fptr - A pointer to a void function, or 0 to set as none
00181      */
00182     void attach(void (*fptr)(void));
00183  
00184     /* Function: attach
00185      *  Attach a member function to call whenever a serial interrupt is generated
00186      *
00187      * Variables:
00188      *  tptr - pointer to the object to call the member function on
00189      *  mptr - pointer to the member function to be called
00190      */
00191     template<typename T>
00192     void attach(T* tptr, void (T::*mptr)(void));
00193  
00194 #endif
00195  
00196 protected:
00197     PinName     _txpin;
00198  
00199     virtual int _putc(int c);
00200     virtual int _getc(void);
00201  
00202 }; // End class SerialHalfDuplex
00203  
00204 } // End namespace
00205  
00206 #endif
00207  
00208 #endif