1 /* mbed Microcontroller Library 2 * Copyright (c) 2006-2013 ARM Limited 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 #ifndef MBED_BUSOUT_H 17 #define MBED_BUSOUT_H 18 19 #include "drivers/DigitalOut.h" 20 #include "platform/PlatformMutex.h" 21 22 namespace mbed { 23 /** \addtogroup drivers */ 24 /** @{*/ 25 26 /** A digital output bus, used for setting the state of a collection of pins 27 */ 28 class BusOut { 29 30 public: 31 32 /** Create an BusOut, connected to the specified pins 33 * 34 * @param p<n> DigitalOut pin to connect to bus bit <n> (p5-p30, NC) 35 * 36 * @Note Synchronization level: Thread safe 37 * 38 * @note 39 * It is only required to specify as many pin variables as is required 40 * for the bus; the rest will default to NC (not connected) 41 */ 42 BusOut(PinName p0, PinName p1 = NC, PinName p2 = NC, PinName p3 = NC, 43 PinName p4 = NC, PinName p5 = NC, PinName p6 = NC, PinName p7 = NC, 44 PinName p8 = NC, PinName p9 = NC, PinName p10 = NC, PinName p11 = NC, 45 PinName p12 = NC, PinName p13 = NC, PinName p14 = NC, PinName p15 = NC); 46 47 BusOut(PinName pins[16]); 48 49 virtual ~BusOut(); 50 51 /** Write the value to the output bus 52 * 53 * @param value An integer specifying a bit to write for every corresponding DigitalOut pin 54 */ 55 void write(int value); 56 57 /** Read the value currently output on the bus 58 * 59 * @returns 60 * An integer with each bit corresponding to associated DigitalOut pin setting 61 */ 62 int read(); 63 64 /** Binary mask of bus pins connected to actual pins (not NC pins) 65 * If bus pin is in NC state make corresponding bit will be cleared (set to 0), else bit will be set to 1 66 * 67 * @returns 68 * Binary mask of connected pins 69 */ mask()70 int mask() { 71 // No lock needed since _nc_mask is not modified outside the constructor 72 return _nc_mask; 73 } 74 75 /** A shorthand for write() 76 */ 77 BusOut& operator= (int v); 78 BusOut& operator= (BusOut& rhs); 79 80 /** Access to particular bit in random-iterator fashion 81 */ 82 DigitalOut& operator[] (int index); 83 84 /** A shorthand for read() 85 */ 86 operator int(); 87 88 protected: 89 virtual void lock(); 90 virtual void unlock(); 91 DigitalOut* _pin[16]; 92 93 /** Mask of bus's NC pins 94 * If bit[n] is set to 1 - pin is connected 95 * if bit[n] is cleared - pin is not connected (NC) 96 */ 97 int _nc_mask; 98 99 PlatformMutex _mutex; 100 101 /* disallow copy constructor and assignment operators */ 102 private: 103 BusOut(const BusOut&); 104 BusOut & operator = (const BusOut&); 105 }; 106 107 } // namespace mbed 108 109 #endif 110 111 /** @}*/ 112