BusInOut.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_BUSINOUT_H
00018 #define MBED_BUSINOUT_H
00019 
00020 #include "drivers/DigitalInOut.h"
00021 #include "platform/PlatformMutex.h"
00022 #include "platform/NonCopyable.h"
00023 
00024 namespace mbed {
00025 /** \addtogroup drivers */
00026 
00027 /** A digital input output bus, used for setting the state of a collection of pins
00028  *
00029  * @note Synchronization level: Thread safe
00030  * @ingroup drivers
00031  */
00032 class BusInOut : private NonCopyable<BusInOut> {
00033 
00034 public:
00035 
00036     /** Create an BusInOut, connected to the specified pins
00037      *
00038      *  @param p0 DigitalInOut pin to connect to bus bit
00039      *  @param p1 DigitalInOut pin to connect to bus bit
00040      *  @param p2 DigitalInOut pin to connect to bus bit
00041      *  @param p3 DigitalInOut pin to connect to bus bit
00042      *  @param p4 DigitalInOut pin to connect to bus bit
00043      *  @param p5 DigitalInOut pin to connect to bus bit
00044      *  @param p6 DigitalInOut pin to connect to bus bit
00045      *  @param p7 DigitalInOut pin to connect to bus bit
00046      *  @param p8 DigitalInOut pin to connect to bus bit
00047      *  @param p9 DigitalInOut pin to connect to bus bit
00048      *  @param p10 DigitalInOut pin to connect to bus bit
00049      *  @param p11 DigitalInOut pin to connect to bus bit
00050      *  @param p12 DigitalInOut pin to connect to bus bit
00051      *  @param p13 DigitalInOut pin to connect to bus bit
00052      *  @param p14 DigitalInOut pin to connect to bus bit
00053      *  @param p15 DigitalInOut pin to connect to bus bit
00054      *
00055      *  @note
00056      *  It is only required to specify as many pin variables as is required
00057      *  for the bus; the rest will default to NC (not connected)
00058      */
00059     BusInOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00060              PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00061              PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00062              PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00063 
00064     /** Create an BusInOut, connected to the specified pins
00065      *
00066      *  @param pins An array of pins to construct a BusInOut from
00067      */
00068     BusInOut(PinName pins[16]);
00069 
00070     virtual ~BusInOut();
00071 
00072     /* Group: Access Methods */
00073 
00074     /** Write the value to the output bus
00075      *
00076      *  @param value An integer specifying a bit to write for every corresponding DigitalInOut pin
00077      */
00078     void write(int value);
00079 
00080     /** Read the value currently output on the bus
00081      *
00082      *  @returns
00083      *    An integer with each bit corresponding to associated DigitalInOut pin setting
00084      */
00085     int read();
00086 
00087     /** Set all the pins in bus as output
00088      */
00089     void output();
00090 
00091     /** Set all the pins in bus as an input
00092      */
00093     void input();
00094 
00095     /** Set the input pin mode for all the pins in bus
00096      *
00097      *  @param pull PullUp, PullDown, PullNone
00098      */
00099     void mode(PinMode pull);
00100 
00101     /** Binary mask of bus pins connected to actual pins (not NC pins)
00102      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00103      *
00104      *  @returns
00105      *    Binary mask of connected pins
00106      */
00107     int mask()
00108     {
00109         // No lock needed since _nc_mask is not modified outside the constructor
00110         return _nc_mask;
00111     }
00112 
00113     /** A shorthand for write()
00114     * \sa BusInOut::write()
00115      */
00116     BusInOut &operator= (int v);
00117     BusInOut &operator= (BusInOut &rhs);
00118 
00119     /** Access to particular bit in random-iterator fashion
00120      * @param index  Bit Position
00121      */
00122     DigitalInOut &operator[](int index);
00123 
00124     /** A shorthand for read()
00125      * \sa BusInOut::read()
00126      */
00127     operator int();
00128 #if !defined(DOXYGEN_ONLY)
00129 protected:
00130     virtual void lock();
00131     virtual void unlock();
00132     DigitalInOut *_pin[16];
00133 
00134     /* Mask of bus's NC pins
00135      * If bit[n] is set to 1 - pin is connected
00136      * if bit[n] is cleared - pin is not connected (NC)
00137      */
00138     int _nc_mask;
00139 
00140     PlatformMutex _mutex;
00141 #endif
00142 };
00143 
00144 } // namespace mbed
00145 
00146 #endif