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 /**
00026  * \defgroup drivers_BusInOut BusInOut class
00027  * \ingroup drivers-public-api-gpio
00028  * @{
00029  */
00030 
00031 /** A digital input output bus, used for setting the state of a collection of pins.
00032  *  Implemented as an array of DigitalInOut pins, the bus can be constructed by any
00033  *  pins without restriction other than being capable of digital input or output
00034  *  capabilities
00035  *
00036  * @note Synchronization level: Thread safe
00037  */
00038 class BusInOut : private NonCopyable<BusInOut> {
00039 
00040 public:
00041 
00042     /** Create a BusInOut, connected to the specified pins
00043      *
00044      *  @param p0 DigitalInOut pin to connect to bus bit
00045      *  @param p1 DigitalInOut pin to connect to bus bit
00046      *  @param p2 DigitalInOut pin to connect to bus bit
00047      *  @param p3 DigitalInOut pin to connect to bus bit
00048      *  @param p4 DigitalInOut pin to connect to bus bit
00049      *  @param p5 DigitalInOut pin to connect to bus bit
00050      *  @param p6 DigitalInOut pin to connect to bus bit
00051      *  @param p7 DigitalInOut pin to connect to bus bit
00052      *  @param p8 DigitalInOut pin to connect to bus bit
00053      *  @param p9 DigitalInOut pin to connect to bus bit
00054      *  @param p10 DigitalInOut pin to connect to bus bit
00055      *  @param p11 DigitalInOut pin to connect to bus bit
00056      *  @param p12 DigitalInOut pin to connect to bus bit
00057      *  @param p13 DigitalInOut pin to connect to bus bit
00058      *  @param p14 DigitalInOut pin to connect to bus bit
00059      *  @param p15 DigitalInOut pin to connect to bus bit
00060      *
00061      *  @note
00062      *  It is only required to specify as many pin variables as is required
00063      *  for the bus; the rest will default to NC (not connected)
00064      */
00065     BusInOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00066              PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00067              PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00068              PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00069 
00070     /** Create a BusInOut, connected to the specified pins
00071      *
00072      *  @param pins An array of pins (PinName) to construct a BusInOut from. The maximum
00073      *  number of pins in the array is 16 and any pins that are unspecified or are not to be
00074      *  connected must be specified as NC in the array that is passed in
00075      */
00076     BusInOut(PinName pins[16]);
00077 
00078     virtual ~BusInOut();
00079 
00080     /* Group: Access Methods */
00081 
00082     /** Write the value to the output bus
00083      *
00084      *  @param value An integer specifying a bit to write for every corresponding DigitalInOut pin
00085      */
00086     void write(int value);
00087 
00088     /** Read the value currently output on the bus
00089      *
00090      *  @returns
00091      *    An integer with each bit corresponding to associated DigitalInOut pin setting
00092      */
00093     int read();
00094 
00095     /** Set all the pins in bus as output
00096      */
00097     void output();
00098 
00099     /** Set all the pins in bus as an input
00100      */
00101     void input();
00102 
00103     /** Set the input pin mode for all the pins in bus
00104      *
00105      *  @param pull PullUp, PullDown, PullNone
00106      */
00107     void mode(PinMode pull);
00108 
00109     /** Binary mask of bus pins connected to actual pins (not NC pins)
00110      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00111      *
00112      *  @returns
00113      *    Binary mask of connected pins
00114      */
00115     int mask()
00116     {
00117         // No lock needed since _nc_mask is not modified outside the constructor
00118         return _nc_mask;
00119     }
00120 
00121     /** A shorthand for write()
00122      * \sa BusInOut::write()
00123      */
00124     BusInOut &operator= (int v);
00125     BusInOut &operator= (BusInOut &rhs);
00126 
00127     /** Access to particular bit in random-iterator fashion
00128      * @param index  Bit Position
00129      */
00130     DigitalInOut &operator[](int index);
00131 
00132     /** A shorthand for read()
00133      * \sa BusInOut::read()
00134      */
00135     operator int();
00136 
00137 protected:
00138 #if !defined(DOXYGEN_ONLY)
00139     virtual void lock();
00140     virtual void unlock();
00141     DigitalInOut *_pin[16];
00142 
00143     /* Mask of bus's NC pins
00144      * If bit[n] is set to 1 - pin is connected
00145      * if bit[n] is cleared - pin is not connected (NC)
00146      */
00147     int _nc_mask;
00148 
00149     PlatformMutex _mutex;
00150 #endif //!defined(DOXYGEN_ONLY)
00151 };
00152 
00153 /** @}*/
00154 
00155 } // namespace mbed
00156 
00157 #endif