BusIn.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_BUSIN_H
00017 #define MBED_BUSIN_H
00018 
00019 #include "platform/platform.h"
00020 #include "drivers/DigitalIn.h"
00021 #include "platform/PlatformMutex.h"
00022 #include "platform/NonCopyable.h"
00023 
00024 namespace mbed {
00025 /** \addtogroup drivers */
00026 
00027 /** A digital input bus, used for reading the state of a collection of pins
00028  *
00029  * @note Synchronization level: Thread safe
00030  * @ingroup drivers
00031  */
00032 class BusIn : private NonCopyable<BusIn> {
00033 
00034 public:
00035     /* Group: Configuration Methods */
00036 
00037     /** Create an BusIn, connected to the specified pins
00038      *
00039      * @param p0 DigitalIn pin to connect to bus bit
00040      * @param p1 DigitalIn pin to connect to bus bit
00041      * @param p2 DigitalIn pin to connect to bus bit
00042      * @param p3 DigitalIn pin to connect to bus bit
00043      * @param p4 DigitalIn pin to connect to bus bit
00044      * @param p5 DigitalIn pin to connect to bus bit
00045      * @param p6 DigitalIn pin to connect to bus bit
00046      * @param p7 DigitalIn pin to connect to bus bit
00047      * @param p8 DigitalIn pin to connect to bus bit
00048      * @param p9 DigitalIn pin to connect to bus bit
00049      * @param p10 DigitalIn pin to connect to bus bit
00050      * @param p11 DigitalIn pin to connect to bus bit
00051      * @param p12 DigitalIn pin to connect to bus bit
00052      * @param p13 DigitalIn pin to connect to bus bit
00053      * @param p14 DigitalIn pin to connect to bus bit
00054      * @param p15 DigitalIn pin to connect to bus bit
00055      *
00056      * @note
00057      *  It is only required to specify as many pin variables as is required
00058      *  for the bus; the rest will default to NC (not connected)
00059      */
00060     BusIn(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00061           PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00062           PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00063           PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00064 
00065     
00066     /** Create an BusIn, connected to the specified pins
00067      *
00068      * @param pins An array of pins to connect to bus bit
00069      */
00070      BusIn(PinName pins[16]);
00071 
00072     virtual ~BusIn();
00073 
00074     /** Read the value of the input bus
00075      *
00076      *  @returns
00077      *   An integer with each bit corresponding to the value read from the associated DigitalIn pin
00078      */
00079     int read();
00080 
00081     /** Set the input pin mode
00082      *
00083      *  @param pull PullUp, PullDown, PullNone
00084      */
00085     void mode(PinMode pull);
00086 
00087     /** Binary mask of bus pins connected to actual pins (not NC pins)
00088      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00089      *
00090      *  @returns
00091      *    Binary mask of connected pins
00092      */
00093     int mask() {
00094         // No lock needed since _nc_mask is not modified outside the constructor
00095         return _nc_mask;
00096     }
00097 
00098     /** A shorthand for read()
00099      *  \sa DigitalIn::read()
00100      */
00101     operator int();
00102 
00103     /** Access to particular bit in random-iterator fashion
00104      * @param index  Position of bit
00105      */
00106     DigitalIn & operator[] (int index);
00107 
00108 protected:
00109     DigitalIn* _pin[16];
00110 
00111     /* Mask of bus's NC pins
00112      * If bit[n] is set to 1 - pin is connected
00113      * if bit[n] is cleared - pin is not connected (NC)
00114      */
00115     int _nc_mask;
00116 
00117     PlatformMutex _mutex;
00118 
00119 private:
00120     virtual void lock();
00121     virtual void unlock();
00122 };
00123 
00124 } // namespace mbed
00125 
00126 #endif
00127