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.h"
00020 #include "DigitalIn.h"
00021 #include "PlatformMutex.h"
00022 
00023 namespace mbed {
00024 
00025 /** A digital input bus, used for reading the state of a collection of pins
00026  *
00027  * @Note Synchronization level: Thread safe
00028  */
00029 class BusIn {
00030 
00031 public:
00032     /* Group: Configuration Methods */
00033 
00034     /** Create an BusIn, connected to the specified pins
00035      *
00036      * @param <n> DigitalIn pin to connect to bus bit <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     BusIn(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     BusIn(PinName pins[16]);
00048 
00049     virtual ~BusIn();
00050 
00051     /** Read the value of the input bus
00052      *
00053      *  @returns
00054      *   An integer with each bit corresponding to the value read from the associated DigitalIn pin
00055      */
00056     int read();
00057 
00058     /** Set the input pin mode
00059      *
00060      *  @param mode PullUp, PullDown, PullNone
00061      */
00062     void mode(PinMode pull);
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 read()
00076      */
00077     operator int();
00078 
00079     /** Access to particular bit in random-iterator fashion
00080      */
00081     DigitalIn & operator[] (int index);
00082 
00083 protected:
00084     DigitalIn* _pin[16];
00085 
00086     /** Mask of bus's NC pins
00087      * If bit[n] is set to 1 - pin is connected
00088      * if bit[n] is cleared - pin is not connected (NC)
00089      */
00090     int _nc_mask;
00091 
00092     PlatformMutex _mutex;
00093 
00094     /* disallow copy constructor and assignment operators */
00095 private:
00096     virtual void lock();
00097     virtual void unlock();
00098     BusIn(const BusIn&);
00099     BusIn & operator = (const BusIn&);
00100 };
00101 
00102 } // namespace mbed
00103 
00104 #endif