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| 1 | +// --------------------------------------------------------------------------- |
| 2 | +// Created by Francisco Malpartida on 20/08/11. |
| 3 | +// Copyright 2011 - Under creative commons license 3.0: |
| 4 | +// Attribution-ShareAlike CC BY-SA |
| 5 | +// |
| 6 | +// This software is furnished "as is", without technical support, and with no |
| 7 | +// warranty, express or implied, as to its usefulness for any purpose. |
| 8 | +// |
| 9 | +// Thread Safe: No |
| 10 | +// Extendable: Yes |
| 11 | +// |
| 12 | +// @file I2CIO.h |
| 13 | +// This file implements a basic IO library using the PCF8574 I2C IO Expander |
| 14 | +// chip. |
| 15 | +// |
| 16 | +// @brief |
| 17 | +// Implement a basic IO library to drive the PCF8574* I2C IO Expander ASIC. |
| 18 | +// The library implements basic IO general methods to configure IO pin direction |
| 19 | +// read and write uint8_t operations and basic pin level routines to set or read |
| 20 | +// a particular IO port. |
| 21 | +// |
| 22 | +// |
| 23 | +// @version API 1.0.0 |
| 24 | +// |
| 25 | +// @author F. Malpartida - fmalpartida@gmail.com |
| 26 | +// --------------------------------------------------------------------------- |
| 27 | +#if (ARDUINO < 100) |
| 28 | +#include <WProgram.h> |
| 29 | +#else |
| 30 | +#include <Arduino.h> |
| 31 | +#endif |
| 32 | + |
| 33 | +#include <inttypes.h> |
| 34 | + |
| 35 | +#include "./Wire.h" |
| 36 | +#include "./I2CIO.h" |
| 37 | + |
| 38 | +// CLASS VARIABLES |
| 39 | +// --------------------------------------------------------------------------- |
| 40 | + |
| 41 | + |
| 42 | +// CONSTRUCTOR |
| 43 | +// --------------------------------------------------------------------------- |
| 44 | +I2CIO::I2CIO ( ) |
| 45 | +{ |
| 46 | + _i2cAddr = 0x0; |
| 47 | + _dirMask = 0xFF; // mark all as INPUTs |
| 48 | + _shadow = 0x0; // no values set |
| 49 | + _initialised = false; |
| 50 | +} |
| 51 | + |
| 52 | +// PUBLIC METHODS |
| 53 | +// --------------------------------------------------------------------------- |
| 54 | + |
| 55 | +// |
| 56 | +// begin |
| 57 | +int I2CIO::begin ( uint8_t i2cAddr ) |
| 58 | +{ |
| 59 | + _i2cAddr = i2cAddr; |
| 60 | + |
| 61 | + Wire.begin ( ); |
| 62 | + |
| 63 | + _initialised = Wire.requestFrom ( _i2cAddr, (uint8_t)1 ); |
| 64 | + |
| 65 | +#if (ARDUINO < 100) |
| 66 | + _shadow = Wire.receive (); |
| 67 | +#else |
| 68 | + _shadow = Wire.read (); // Remove the byte read don't need it. |
| 69 | +#endif |
| 70 | + |
| 71 | + return ( _initialised ); |
| 72 | +} |
| 73 | + |
| 74 | +// |
| 75 | +// pinMode |
| 76 | +void I2CIO::pinMode ( uint8_t pin, uint8_t dir ) |
| 77 | +{ |
| 78 | + if ( _initialised ) |
| 79 | + { |
| 80 | + if ( OUTPUT == dir ) |
| 81 | + { |
| 82 | + _dirMask &= ~( 1 << pin ); |
| 83 | + } |
| 84 | + else |
| 85 | + { |
| 86 | + _dirMask |= ( 1 << pin ); |
| 87 | + } |
| 88 | + } |
| 89 | +} |
| 90 | + |
| 91 | +// |
| 92 | +// portMode |
| 93 | +void I2CIO::portMode ( uint8_t dir ) |
| 94 | +{ |
| 95 | + |
| 96 | + if ( _initialised ) |
| 97 | + { |
| 98 | + if ( dir == INPUT ) |
| 99 | + { |
| 100 | + _dirMask = 0xFF; |
| 101 | + } |
| 102 | + else |
| 103 | + { |
| 104 | + _dirMask = 0x00; |
| 105 | + } |
| 106 | + } |
| 107 | +} |
| 108 | + |
| 109 | +// |
| 110 | +// read |
| 111 | +uint8_t I2CIO::read ( void ) |
| 112 | +{ |
| 113 | + uint8_t retVal = 0; |
| 114 | + |
| 115 | + if ( _initialised ) |
| 116 | + { |
| 117 | + Wire.requestFrom ( _i2cAddr, (uint8_t)1 ); |
| 118 | +#if (ARDUINO < 100) |
| 119 | + retVal = ( _dirMask & Wire.receive ( ) ); |
| 120 | +#else |
| 121 | + retVal = ( _dirMask & Wire.read ( ) ); |
| 122 | +#endif |
| 123 | + |
| 124 | + } |
| 125 | + return ( retVal ); |
| 126 | +} |
| 127 | + |
| 128 | +// |
| 129 | +// write |
| 130 | +int I2CIO::write ( uint8_t value ) |
| 131 | +{ |
| 132 | + int status = 0; |
| 133 | + |
| 134 | + if ( _initialised ) |
| 135 | + { |
| 136 | + // Only write HIGH the values of the ports that have been initialised as |
| 137 | + // outputs updating the output shadow of the device |
| 138 | + _shadow = ( value & ~(_dirMask) ); |
| 139 | + |
| 140 | + Wire.beginTransmission ( _i2cAddr ); |
| 141 | +#if (ARDUINO < 100) |
| 142 | + Wire.send ( _shadow ); |
| 143 | +#else |
| 144 | + Wire.write ( _shadow ); |
| 145 | +#endif |
| 146 | + status = Wire.endTransmission (); |
| 147 | + } |
| 148 | + return ( (status == 0) ); |
| 149 | +} |
| 150 | + |
| 151 | +// |
| 152 | +// digitalRead |
| 153 | +uint8_t I2CIO::digitalRead ( uint8_t pin ) |
| 154 | +{ |
| 155 | + uint8_t pinVal = 0; |
| 156 | + |
| 157 | + // Check if initialised and that the pin is within range of the device |
| 158 | + // ------------------------------------------------------------------- |
| 159 | + if ( ( _initialised ) && ( pin <= 7 ) ) |
| 160 | + { |
| 161 | + // Remove the values which are not inputs and get the value of the pin |
| 162 | + pinVal = this->read() & _dirMask; |
| 163 | + pinVal = ( pinVal >> pin ) & 0x01; // Get the pin value |
| 164 | + } |
| 165 | + return (pinVal); |
| 166 | +} |
| 167 | + |
| 168 | +// |
| 169 | +// digitalWrite |
| 170 | +int I2CIO::digitalWrite ( uint8_t pin, uint8_t level ) |
| 171 | +{ |
| 172 | + uint8_t writeVal; |
| 173 | + int status = 0; |
| 174 | + |
| 175 | + // Check if initialised and that the pin is within range of the device |
| 176 | + // ------------------------------------------------------------------- |
| 177 | + if ( ( _initialised ) && ( pin <= 7 ) ) |
| 178 | + { |
| 179 | + // Only write to HIGH the port if the port has been configured as |
| 180 | + // an OUTPUT pin. Add the new state of the pin to the shadow |
| 181 | + writeVal = ( 1 << pin ) & ~_dirMask; |
| 182 | + if ( level == HIGH ) |
| 183 | + { |
| 184 | + _shadow |= writeVal; |
| 185 | + |
| 186 | + } |
| 187 | + else |
| 188 | + { |
| 189 | + _shadow &= ~writeVal; |
| 190 | + } |
| 191 | + status = this->write ( _shadow ); |
| 192 | + } |
| 193 | + return ( status ); |
| 194 | +} |
| 195 | + |
| 196 | +// |
| 197 | +// PRIVATE METHODS |
| 198 | +// --------------------------------------------------------------------------- |
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