BusIn.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #ifndef MBED_BUSIN_H
00018 #define MBED_BUSIN_H
00019 
00020 #include "platform/platform.h"
00021 #include "drivers/DigitalIn.h"
00022 #include "platform/PlatformMutex.h"
00023 #include "platform/NonCopyable.h"
00024 
00025 namespace mbed {
00026 /** \addtogroup drivers */
00027 
00028 /** A digital input bus, used for reading the state of a collection of pins
00029  *
00030  * @note Synchronization level: Thread safe
00031  * @ingroup drivers
00032  */
00033 class BusIn : private NonCopyable<BusIn> {
00034 
00035 public:
00036     /* Group: Configuration Methods */
00037 
00038     /** Create an BusIn, connected to the specified pins
00039      *
00040      * @param p0 DigitalIn pin to connect to bus bit
00041      * @param p1 DigitalIn pin to connect to bus bit
00042      * @param p2 DigitalIn pin to connect to bus bit
00043      * @param p3 DigitalIn pin to connect to bus bit
00044      * @param p4 DigitalIn pin to connect to bus bit
00045      * @param p5 DigitalIn pin to connect to bus bit
00046      * @param p6 DigitalIn pin to connect to bus bit
00047      * @param p7 DigitalIn pin to connect to bus bit
00048      * @param p8 DigitalIn pin to connect to bus bit
00049      * @param p9 DigitalIn pin to connect to bus bit
00050      * @param p10 DigitalIn pin to connect to bus bit
00051      * @param p11 DigitalIn pin to connect to bus bit
00052      * @param p12 DigitalIn pin to connect to bus bit
00053      * @param p13 DigitalIn pin to connect to bus bit
00054      * @param p14 DigitalIn pin to connect to bus bit
00055      * @param p15 DigitalIn pin to connect to bus bit
00056      *
00057      * @note
00058      *  It is only required to specify as many pin variables as is required
00059      *  for the bus; the rest will default to NC (not connected)
00060      */
00061     BusIn(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00062           PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00063           PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00064           PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00065 
00066 
00067     /** Create an BusIn, connected to the specified pins
00068      *
00069      * @param pins An array of pins to connect to bus bit
00070      */
00071     BusIn(PinName pins[16]);
00072 
00073     virtual ~BusIn();
00074 
00075     /** Read the value of the input bus
00076      *
00077      *  @returns
00078      *   An integer with each bit corresponding to the value read from the associated DigitalIn pin
00079      */
00080     int read();
00081 
00082     /** Set the input pin mode
00083      *
00084      *  @param pull PullUp, PullDown, PullNone
00085      */
00086     void mode(PinMode pull);
00087 
00088     /** Binary mask of bus pins connected to actual pins (not NC pins)
00089      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00090      *
00091      *  @returns
00092      *    Binary mask of connected pins
00093      */
00094     int mask()
00095     {
00096         // No lock needed since _nc_mask is not modified outside the constructor
00097         return _nc_mask;
00098     }
00099 
00100     /** A shorthand for read()
00101      *  \sa DigitalIn::read()
00102      */
00103     operator int();
00104 
00105     /** Access to particular bit in random-iterator fashion
00106      * @param index  Position of bit
00107      */
00108     DigitalIn &operator[](int index);
00109 
00110 #if !defined(DOXYGEN_ONLY)
00111 protected:
00112     DigitalIn *_pin[16];
00113 
00114     /* Mask of bus's NC pins
00115      * If bit[n] is set to 1 - pin is connected
00116      * if bit[n] is cleared - pin is not connected (NC)
00117      */
00118     int _nc_mask;
00119 
00120     PlatformMutex _mutex;
00121 
00122 private:
00123     virtual void lock();
00124     virtual void unlock();
00125 #endif
00126 };
00127 
00128 } // namespace mbed
00129 
00130 #endif
00131