BusInOut.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 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 #ifndef MBED_BUSINOUT_H
00017 #define MBED_BUSINOUT_H
00018 
00019 #include "DigitalInOut.h"
00020 #include "PlatformMutex.h"
00021 
00022 namespace mbed {
00023 
00024 /** A digital input output bus, used for setting the state of a collection of pins
00025  *
00026  * @Note Synchronization level: Thread safe
00027  */
00028 class BusInOut {
00029 
00030 public:
00031 
00032     /** Create an BusInOut, connected to the specified pins
00033      *
00034      *  @param p<n> DigitalInOut pin to connect to bus bit p<n> (p5-p30, NC)
00035      *
00036      *  @note
00037      *  It is only required to specify as many pin variables as is required
00038      *  for the bus; the rest will default to NC (not connected)
00039      */
00040     BusInOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00041              PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00042              PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00043              PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00044 
00045     BusInOut(PinName pins[16]);
00046 
00047     virtual ~BusInOut();
00048 
00049     /* Group: Access Methods */
00050 
00051     /** Write the value to the output bus
00052      *
00053      *  @param value An integer specifying a bit to write for every corresponding DigitalInOut pin
00054      */
00055     void write(int value);
00056 
00057     /** Read the value currently output on the bus
00058      *
00059      *  @returns
00060      *    An integer with each bit corresponding to associated DigitalInOut pin setting
00061      */
00062     int read();
00063 
00064     /** Set as an output
00065      */
00066     void output();
00067 
00068     /** Set as an input
00069      */
00070     void input();
00071 
00072     /** Set the input pin mode
00073      *
00074      *  @param mode PullUp, PullDown, PullNone
00075      */
00076     void mode(PinMode pull);
00077 
00078     /** Binary mask of bus pins connected to actual pins (not NC pins)
00079      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00080      *
00081      *  @returns
00082      *    Binary mask of connected pins
00083      */
00084     int mask() {
00085         // No lock needed since _nc_mask is not modified outside the constructor
00086         return _nc_mask;
00087     }
00088 
00089      /** A shorthand for write()
00090      */
00091     BusInOut& operator= (int v);
00092     BusInOut& operator= (BusInOut& rhs);
00093 
00094     /** Access to particular bit in random-iterator fashion
00095     */
00096     DigitalInOut& operator[] (int index);
00097 
00098     /** A shorthand for read()
00099      */
00100     operator int();
00101 
00102 protected:
00103     virtual void lock();
00104     virtual void unlock();
00105     DigitalInOut* _pin[16];
00106 
00107     /** Mask of bus's NC pins
00108      * If bit[n] is set to 1 - pin is connected
00109      * if bit[n] is cleared - pin is not connected (NC)
00110      */
00111     int _nc_mask;
00112 
00113     PlatformMutex _mutex;
00114 
00115     /* disallow copy constructor and assignment operators */
00116 private:
00117     BusInOut(const BusInOut&);
00118     BusInOut & operator = (const BusInOut&);
00119 };
00120 
00121 } // namespace mbed
00122 
00123 #endif