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 
00022 namespace mbed {
00023 /** \addtogroup drivers */
00024 /** @{*/
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  */
00030 class BusInOut {
00031 
00032 public:
00033 
00034     /** Create an BusInOut, connected to the specified pins
00035      *
00036      *  @param p<n> DigitalInOut pin to connect to bus bit p<n> (p5-p30, NC)
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     BusInOut(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     BusInOut(PinName pins[16]);
00048 
00049     virtual ~BusInOut();
00050 
00051     /* Group: Access Methods */
00052 
00053     /** Write the value to the output bus
00054      *
00055      *  @param value An integer specifying a bit to write for every corresponding DigitalInOut pin
00056      */
00057     void write(int value);
00058 
00059     /** Read the value currently output on the bus
00060      *
00061      *  @returns
00062      *    An integer with each bit corresponding to associated DigitalInOut pin setting
00063      */
00064     int read();
00065 
00066     /** Set as an output
00067      */
00068     void output();
00069 
00070     /** Set as an input
00071      */
00072     void input();
00073 
00074     /** Set the input pin mode
00075      *
00076      *  @param mode PullUp, PullDown, PullNone
00077      */
00078     void mode(PinMode pull);
00079 
00080     /** Binary mask of bus pins connected to actual pins (not NC pins)
00081      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00082      *
00083      *  @returns
00084      *    Binary mask of connected pins
00085      */
00086     int mask() {
00087         // No lock needed since _nc_mask is not modified outside the constructor
00088         return _nc_mask;
00089     }
00090 
00091      /** A shorthand for write()
00092      */
00093     BusInOut& operator= (int v);
00094     BusInOut& operator= (BusInOut& rhs);
00095 
00096     /** Access to particular bit in random-iterator fashion
00097     */
00098     DigitalInOut& operator[] (int index);
00099 
00100     /** A shorthand for read()
00101      */
00102     operator int();
00103 
00104 protected:
00105     virtual void lock();
00106     virtual void unlock();
00107     DigitalInOut* _pin[16];
00108 
00109     /** Mask of bus's NC pins
00110      * If bit[n] is set to 1 - pin is connected
00111      * if bit[n] is cleared - pin is not connected (NC)
00112      */
00113     int _nc_mask;
00114 
00115     PlatformMutex _mutex;
00116 
00117     /* disallow copy constructor and assignment operators */
00118 private:
00119     BusInOut(const BusInOut&);
00120     BusInOut & operator = (const BusInOut&);
00121 };
00122 
00123 } // namespace mbed
00124 
00125 #endif
00126 
00127 /** @}*/