BusIn.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_BUSIN_H
00017 #define MBED_BUSIN_H
00018 
00019 #include "platform/platform.h"
00020 #include "drivers/DigitalIn.h"
00021 #include "platform/PlatformMutex.h"
00022 
00023 namespace mbed {
00024 /** \addtogroup drivers */
00025 /** @{*/
00026 
00027 /** A digital input bus, used for reading the state of a collection of pins
00028  *
00029  * @Note Synchronization level: Thread safe
00030  */
00031 class BusIn {
00032 
00033 public:
00034     /* Group: Configuration Methods */
00035 
00036     /** Create an BusIn, connected to the specified pins
00037      *
00038      * @param <n> DigitalIn pin to connect to bus bit <n> (p5-p30, NC)
00039      *
00040      * @note
00041      *  It is only required to specify as many pin variables as is required
00042      *  for the bus; the rest will default to NC (not connected)
00043      */
00044     BusIn(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC,
00045           PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC,
00046           PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC,
00047           PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC);
00048 
00049     BusIn(PinName pins[16]);
00050 
00051     virtual ~BusIn();
00052 
00053     /** Read the value of the input bus
00054      *
00055      *  @returns
00056      *   An integer with each bit corresponding to the value read from the associated DigitalIn pin
00057      */
00058     int read();
00059 
00060     /** Set the input pin mode
00061      *
00062      *  @param mode PullUp, PullDown, PullNone
00063      */
00064     void mode(PinMode pull);
00065 
00066     /** Binary mask of bus pins connected to actual pins (not NC pins)
00067      *  If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1
00068      *
00069      *  @returns
00070      *    Binary mask of connected pins
00071      */
00072     int mask() {
00073         // No lock needed since _nc_mask is not modified outside the constructor
00074         return _nc_mask;
00075     }
00076 
00077     /** A shorthand for read()
00078      */
00079     operator int();
00080 
00081     /** Access to particular bit in random-iterator fashion
00082      */
00083     DigitalIn & operator[] (int index);
00084 
00085 protected:
00086     DigitalIn* _pin[16];
00087 
00088     /** Mask of bus's NC pins
00089      * If bit[n] is set to 1 - pin is connected
00090      * if bit[n] is cleared - pin is not connected (NC)
00091      */
00092     int _nc_mask;
00093 
00094     PlatformMutex _mutex;
00095 
00096     /* disallow copy constructor and assignment operators */
00097 private:
00098     virtual void lock();
00099     virtual void unlock();
00100     BusIn(const BusIn&);
00101     BusIn & operator = (const BusIn&);
00102 };
00103 
00104 } // namespace mbed
00105 
00106 #endif
00107 
00108 /** @}*/