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 "DigitalOut.h"
00020 
00021 namespace mbed {
00022 
00023 /** A digital output bus, used for setting the state of a collection of pins
00024  */
00025 class BusOut {
00026 
00027 public:
00028 
00029     /** Create an BusOut, connected to the specified pins
00030      *
00031      *  @param p<n> DigitalOut pin to connect to bus bit <n> (p5-p30, NC)
00032      *
00033      *  @note
00034      *  It is only required to specify as many pin variables as is required
00035      *  for the bus; the rest will default to NC (not connected)
00036      */
00037     BusOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00038            PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00039            PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00040            PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00041 
00042     BusOut(PinName pins[16]);
00043 
00044     virtual ~BusOut();
00045 
00046     /** Write the value to the output bus
00047      *
00048      *  @param value An integer specifying a bit to write for every corresponding DigitalOut pin
00049      */
00050     void write(int value);
00051 
00052     /** Read the value currently output on the bus
00053      *
00054      *  @returns
00055      *    An integer with each bit corresponding to associated DigitalOut pin setting
00056      */
00057     int read();
00058 
00059     /** Binary mask of bus pins connected to actual pins (not NC pins)
00060      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00061      *
00062      *  @returns
00063      *    Binary mask of connected pins
00064      */
00065     int mask() {
00066         return _nc_mask;
00067     }
00068 
00069 #ifdef MBED_OPERATORS
00070     /** A shorthand for write()
00071      */
00072     BusOut& operator= (int v);
00073     BusOut& operator= (BusOut& rhs);
00074 
00075     /** Access to particular bit in random-iterator fashion
00076      */
00077     DigitalOut& operator[] (int index);
00078 
00079     /** A shorthand for read()
00080      */
00081     operator int();
00082 #endif
00083 
00084 protected:
00085     DigitalOut* _pin[16];
00086 
00087     /** Mask of bus's NC pins
00088      * If bit[n] is set to 1 - pin is connected
00089      * if bit[n] is cleared - pin is not connected (NC)
00090      */
00091     int _nc_mask;
00092 
00093    /* disallow copy constructor and assignment operators */
00094 private:
00095     BusOut(const BusOut&);
00096     BusOut & operator = (const BusOut&);
00097 };
00098 
00099 } // namespace mbed
00100 
00101 #endif