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 
00022 namespace mbed {
00023 /** \addtogroup drivers */
00024 /** @{*/
00025 
00026 /** A digital output bus, used for setting the state of a collection of pins
00027  */
00028 class BusOut {
00029 
00030 public:
00031 
00032     /** Create an BusOut, connected to the specified pins
00033      *
00034      *  @param p<n> DigitalOut pin to connect to bus bit <n> (p5-p30, NC)
00035      *
00036      *  @Note Synchronization level: Thread safe
00037      *
00038      *  @note
00039      *  It is only required to specify as many pin variables as is required
00040      *  for the bus; the rest will default to NC (not connected)
00041      */
00042     BusOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00043            PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00044            PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00045            PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00046 
00047     BusOut(PinName pins[16]);
00048 
00049     virtual ~BusOut();
00050 
00051     /** Write the value to the output bus
00052      *
00053      *  @param value An integer specifying a bit to write for every corresponding DigitalOut pin
00054      */
00055     void write(int value);
00056 
00057     /** Read the value currently output on the bus
00058      *
00059      *  @returns
00060      *    An integer with each bit corresponding to associated DigitalOut pin setting
00061      */
00062     int read();
00063 
00064     /** Binary mask of bus pins connected to actual pins (not NC pins)
00065      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00066      *
00067      *  @returns
00068      *    Binary mask of connected pins
00069      */
00070     int mask() {
00071         // No lock needed since _nc_mask is not modified outside the constructor
00072         return _nc_mask;
00073     }
00074 
00075     /** A shorthand for write()
00076      */
00077     BusOut& operator= (int v);
00078     BusOut& operator= (BusOut& rhs);
00079 
00080     /** Access to particular bit in random-iterator fashion
00081      */
00082     DigitalOut& operator[] (int index);
00083 
00084     /** A shorthand for read()
00085      */
00086     operator int();
00087 
00088 protected:
00089     virtual void lock();
00090     virtual void unlock();
00091     DigitalOut* _pin[16];
00092 
00093     /** Mask of bus's NC pins
00094      * If bit[n] is set to 1 - pin is connected
00095      * if bit[n] is cleared - pin is not connected (NC)
00096      */
00097     int _nc_mask;
00098 
00099     PlatformMutex _mutex;
00100 
00101    /* disallow copy constructor and assignment operators */
00102 private:
00103     BusOut(const BusOut&);
00104     BusOut & operator = (const BusOut&);
00105 };
00106 
00107 } // namespace mbed
00108 
00109 #endif
00110 
00111 /** @}*/