BusInOut.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_BUSINOUT_H
00017 #define MBED_BUSINOUT_H
00018 
00019 #include "drivers/DigitalInOut.h"
00020 #include "platform/PlatformMutex.h"
00021 #include "platform/NonCopyable.h"
00022 
00023 namespace mbed {
00024 /** \addtogroup drivers */
00025 
00026 /** A digital input output bus, used for setting the state of a collection of pins
00027  *
00028  * @note Synchronization level: Thread safe
00029  * @ingroup drivers
00030  */
00031 class BusInOut : private NonCopyable<BusInOut> {
00032 
00033 public:
00034 
00035     /** Create an BusInOut, connected to the specified pins
00036      *
00037      *  @param p0 DigitalInOut pin to connect to bus bit
00038      *  @param p1 DigitalInOut pin to connect to bus bit
00039      *  @param p2 DigitalInOut pin to connect to bus bit
00040      *  @param p3 DigitalInOut pin to connect to bus bit
00041      *  @param p4 DigitalInOut pin to connect to bus bit
00042      *  @param p5 DigitalInOut pin to connect to bus bit
00043      *  @param p6 DigitalInOut pin to connect to bus bit
00044      *  @param p7 DigitalInOut pin to connect to bus bit
00045      *  @param p8 DigitalInOut pin to connect to bus bit
00046      *  @param p9 DigitalInOut pin to connect to bus bit
00047      *  @param p10 DigitalInOut pin to connect to bus bit
00048      *  @param p11 DigitalInOut pin to connect to bus bit
00049      *  @param p12 DigitalInOut pin to connect to bus bit
00050      *  @param p13 DigitalInOut pin to connect to bus bit
00051      *  @param p14 DigitalInOut pin to connect to bus bit
00052      *  @param p15 DigitalInOut pin to connect to bus bit
00053      *
00054      *  @note
00055      *  It is only required to specify as many pin variables as is required
00056      *  for the bus; the rest will default to NC (not connected)
00057      */
00058     BusInOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00059              PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00060              PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00061              PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00062 
00063     /** Create an BusInOut, connected to the specified pins
00064      *
00065      *  @param pins An array of pins to construct a BusInOut from
00066      */
00067     BusInOut(PinName pins[16]);
00068 
00069     virtual ~BusInOut();
00070 
00071     /* Group: Access Methods */
00072 
00073     /** Write the value to the output bus
00074      *
00075      *  @param value An integer specifying a bit to write for every corresponding DigitalInOut pin
00076      */
00077     void write(int value);
00078 
00079     /** Read the value currently output on the bus
00080      *
00081      *  @returns
00082      *    An integer with each bit corresponding to associated DigitalInOut pin setting
00083      */
00084     int read();
00085 
00086     /** Set as an output
00087      */
00088     void output();
00089 
00090     /** Set as an input
00091      */
00092     void input();
00093 
00094     /** Set the input pin mode
00095      *
00096      *  @param pull PullUp, PullDown, PullNone
00097      */
00098     void mode(PinMode pull);
00099 
00100     /** Binary mask of bus pins connected to actual pins (not NC pins)
00101      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00102      *
00103      *  @returns
00104      *    Binary mask of connected pins
00105      */
00106     int mask()
00107     {
00108         // No lock needed since _nc_mask is not modified outside the constructor
00109         return _nc_mask;
00110     }
00111 
00112     /** A shorthand for write()
00113     * \sa BusInOut::write()
00114      */
00115     BusInOut &operator= (int v);
00116     BusInOut &operator= (BusInOut &rhs);
00117 
00118     /** Access to particular bit in random-iterator fashion
00119      * @param index  Bit Position
00120      */
00121     DigitalInOut &operator[](int index);
00122 
00123     /** A shorthand for read()
00124      * \sa BusInOut::read()
00125      */
00126     operator int();
00127 
00128 protected:
00129     virtual void lock();
00130     virtual void unlock();
00131     DigitalInOut *_pin[16];
00132 
00133     /* Mask of bus's NC pins
00134      * If bit[n] is set to 1 - pin is connected
00135      * if bit[n] is cleared - pin is not connected (NC)
00136      */
00137     int _nc_mask;
00138 
00139     PlatformMutex _mutex;
00140 };
00141 
00142 } // namespace mbed
00143 
00144 #endif