SerialHalfDuplex.h

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