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