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