Basic library of routines to interface to a Microchip MCP23017 16-bit I/O expander using an I2C interface.
Dependents: acd52832_beep_buzzer_ints
Fork of MCP23017 by
MCP23017.cpp@0:a6a5d942b58f, 2010-11-28 (annotated)
- Committer:
- jimherd
- Date:
- Sun Nov 28 20:41:49 2010 +0000
- Revision:
- 0:a6a5d942b58f
- Child:
- 2:2a17f52c550a
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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jimherd | 0:a6a5d942b58f | 1 | /* MCP23017 library for Arduino |
jimherd | 0:a6a5d942b58f | 2 | Copyright (C) 2009 David Pye <davidmpye@gmail.com |
jimherd | 0:a6a5d942b58f | 3 | |
jimherd | 0:a6a5d942b58f | 4 | This program is free software: you can redistribute it and/or modify |
jimherd | 0:a6a5d942b58f | 5 | it under the terms of the GNU General Public License as published by |
jimherd | 0:a6a5d942b58f | 6 | the Free Software Foundation, either version 3 of the License, or |
jimherd | 0:a6a5d942b58f | 7 | (at your option) any later version. |
jimherd | 0:a6a5d942b58f | 8 | |
jimherd | 0:a6a5d942b58f | 9 | This program is distributed in the hope that it will be useful, |
jimherd | 0:a6a5d942b58f | 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
jimherd | 0:a6a5d942b58f | 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
jimherd | 0:a6a5d942b58f | 12 | GNU General Public License for more details. |
jimherd | 0:a6a5d942b58f | 13 | |
jimherd | 0:a6a5d942b58f | 14 | You should have received a copy of the GNU General Public License |
jimherd | 0:a6a5d942b58f | 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
jimherd | 0:a6a5d942b58f | 16 | */ |
jimherd | 0:a6a5d942b58f | 17 | #include "MCP23017.h" |
jimherd | 0:a6a5d942b58f | 18 | #include "mbed.h" |
jimherd | 0:a6a5d942b58f | 19 | |
jimherd | 0:a6a5d942b58f | 20 | union { |
jimherd | 0:a6a5d942b58f | 21 | uint8_t value8[2]; |
jimherd | 0:a6a5d942b58f | 22 | uint16_t value16; |
jimherd | 0:a6a5d942b58f | 23 | } tmp_data; |
jimherd | 0:a6a5d942b58f | 24 | |
jimherd | 0:a6a5d942b58f | 25 | using namespace mbed; |
jimherd | 0:a6a5d942b58f | 26 | /* |
jimherd | 0:a6a5d942b58f | 27 | * |
jimherd | 0:a6a5d942b58f | 28 | */ |
jimherd | 0:a6a5d942b58f | 29 | MCP23017::MCP23017(PinName sda, PinName scl, int i2cAddress) : _i2c(sda, scl) { |
jimherd | 0:a6a5d942b58f | 30 | MCP23017_i2cAddress = i2cAddress; |
jimherd | 0:a6a5d942b58f | 31 | reset(); // initialise chip to power-on condition |
jimherd | 0:a6a5d942b58f | 32 | } |
jimherd | 0:a6a5d942b58f | 33 | |
jimherd | 0:a6a5d942b58f | 34 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 35 | * reset |
jimherd | 0:a6a5d942b58f | 36 | * Set configuration (IOCON) and direction(IODIR) registers to initial state |
jimherd | 0:a6a5d942b58f | 37 | */ |
jimherd | 0:a6a5d942b58f | 38 | void MCP23017::reset() { |
jimherd | 0:a6a5d942b58f | 39 | // |
jimherd | 0:a6a5d942b58f | 40 | // First make sure that the device is in BANK=0 mode |
jimherd | 0:a6a5d942b58f | 41 | // |
jimherd | 0:a6a5d942b58f | 42 | writeRegister(0x05, (unsigned char)0x00); |
jimherd | 0:a6a5d942b58f | 43 | // |
jimherd | 0:a6a5d942b58f | 44 | // set direction registers to inputs |
jimherd | 0:a6a5d942b58f | 45 | // |
jimherd | 0:a6a5d942b58f | 46 | writeRegister(IODIR, (unsigned short)0xFFFF); |
jimherd | 0:a6a5d942b58f | 47 | // |
jimherd | 0:a6a5d942b58f | 48 | // set all other registers to zero (last od 10 registers is OLAT) |
jimherd | 0:a6a5d942b58f | 49 | // |
jimherd | 0:a6a5d942b58f | 50 | for (int reg_addr = 2 ; reg_addr <= OLAT ; reg_addr+=2) { |
jimherd | 0:a6a5d942b58f | 51 | writeRegister(reg_addr, (unsigned short)0x0000); |
jimherd | 0:a6a5d942b58f | 52 | } |
jimherd | 0:a6a5d942b58f | 53 | // |
jimherd | 0:a6a5d942b58f | 54 | // Set the shadow registers to power-on state |
jimherd | 0:a6a5d942b58f | 55 | // |
jimherd | 0:a6a5d942b58f | 56 | shadow_IODIR = 0xFFFF; |
jimherd | 0:a6a5d942b58f | 57 | shadow_GPIO = 0; |
jimherd | 0:a6a5d942b58f | 58 | shadow_GPPU = 0; |
jimherd | 0:a6a5d942b58f | 59 | shadow_IPOL = 0; |
jimherd | 0:a6a5d942b58f | 60 | } |
jimherd | 0:a6a5d942b58f | 61 | |
jimherd | 0:a6a5d942b58f | 62 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 63 | * pinMode |
jimherd | 0:a6a5d942b58f | 64 | */ |
jimherd | 0:a6a5d942b58f | 65 | void MCP23017::pinMode(int pin, int mode) { |
jimherd | 0:a6a5d942b58f | 66 | if (DIR_INPUT) { |
jimherd | 0:a6a5d942b58f | 67 | shadow_IODIR |= 1 << pin; |
jimherd | 0:a6a5d942b58f | 68 | } else { |
jimherd | 0:a6a5d942b58f | 69 | shadow_IODIR &= ~(1 << pin); |
jimherd | 0:a6a5d942b58f | 70 | } |
jimherd | 0:a6a5d942b58f | 71 | writeRegister(IODIR, (unsigned short)shadow_IODIR); |
jimherd | 0:a6a5d942b58f | 72 | } |
jimherd | 0:a6a5d942b58f | 73 | |
jimherd | 0:a6a5d942b58f | 74 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 75 | * digitalRead |
jimherd | 0:a6a5d942b58f | 76 | */ |
jimherd | 0:a6a5d942b58f | 77 | int MCP23017::digitalRead(int pin) { |
jimherd | 0:a6a5d942b58f | 78 | shadow_GPIO = readRegister(GPIO); |
jimherd | 0:a6a5d942b58f | 79 | if ( shadow_GPIO & (1 << pin)) { |
jimherd | 0:a6a5d942b58f | 80 | return 1; |
jimherd | 0:a6a5d942b58f | 81 | } else { |
jimherd | 0:a6a5d942b58f | 82 | return 0; |
jimherd | 0:a6a5d942b58f | 83 | } |
jimherd | 0:a6a5d942b58f | 84 | } |
jimherd | 0:a6a5d942b58f | 85 | |
jimherd | 0:a6a5d942b58f | 86 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 87 | * write_bit |
jimherd | 0:a6a5d942b58f | 88 | * Write a 1/0 to a single bit of the 16-bit port |
jimherd | 0:a6a5d942b58f | 89 | */ |
jimherd | 0:a6a5d942b58f | 90 | void MCP23017::write_bit(int value, int bit_number) { |
jimherd | 0:a6a5d942b58f | 91 | if (value == 0) { |
jimherd | 0:a6a5d942b58f | 92 | shadow_GPIO &= ~(1 << bit_number); |
jimherd | 0:a6a5d942b58f | 93 | } else { |
jimherd | 0:a6a5d942b58f | 94 | shadow_GPIO |= 1 << bit_number; |
jimherd | 0:a6a5d942b58f | 95 | } |
jimherd | 0:a6a5d942b58f | 96 | writeRegister(GPIO, (unsigned short)shadow_GPIO); |
jimherd | 0:a6a5d942b58f | 97 | } |
jimherd | 0:a6a5d942b58f | 98 | |
jimherd | 0:a6a5d942b58f | 99 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 100 | * Write a combination of bits to the 16-bit port |
jimherd | 0:a6a5d942b58f | 101 | */ |
jimherd | 0:a6a5d942b58f | 102 | void MCP23017::write_mask(unsigned short data, unsigned short mask) { |
jimherd | 0:a6a5d942b58f | 103 | shadow_GPIO = (shadow_GPIO & ~mask) | data; |
jimherd | 0:a6a5d942b58f | 104 | writeRegister(GPIO, (unsigned short)shadow_GPIO); |
jimherd | 0:a6a5d942b58f | 105 | } |
jimherd | 0:a6a5d942b58f | 106 | |
jimherd | 0:a6a5d942b58f | 107 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 108 | * read_bit |
jimherd | 0:a6a5d942b58f | 109 | * Read a single bit from the 16-bit port |
jimherd | 0:a6a5d942b58f | 110 | */ |
jimherd | 0:a6a5d942b58f | 111 | int MCP23017::read_bit(int bit_number) { |
jimherd | 0:a6a5d942b58f | 112 | shadow_GPIO = readRegister(GPIO); |
jimherd | 0:a6a5d942b58f | 113 | return ((shadow_GPIO >> bit_number) & 0x0001); |
jimherd | 0:a6a5d942b58f | 114 | } |
jimherd | 0:a6a5d942b58f | 115 | |
jimherd | 0:a6a5d942b58f | 116 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 117 | * read_mask |
jimherd | 0:a6a5d942b58f | 118 | */ |
jimherd | 0:a6a5d942b58f | 119 | int MCP23017::read_mask(unsigned short mask) { |
jimherd | 0:a6a5d942b58f | 120 | shadow_GPIO = readRegister(GPIO); |
jimherd | 0:a6a5d942b58f | 121 | return (shadow_GPIO & mask); |
jimherd | 0:a6a5d942b58f | 122 | } |
jimherd | 0:a6a5d942b58f | 123 | |
jimherd | 0:a6a5d942b58f | 124 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 125 | * Config |
jimherd | 0:a6a5d942b58f | 126 | * set direction and pull-up registers |
jimherd | 0:a6a5d942b58f | 127 | */ |
jimherd | 0:a6a5d942b58f | 128 | void MCP23017::config(unsigned short dir_config, unsigned short pullup_config, unsigned short polarity_config) { |
jimherd | 0:a6a5d942b58f | 129 | shadow_IODIR = dir_config; |
jimherd | 0:a6a5d942b58f | 130 | writeRegister(IODIR, (unsigned short)shadow_IODIR); |
jimherd | 0:a6a5d942b58f | 131 | shadow_GPPU = pullup_config; |
jimherd | 0:a6a5d942b58f | 132 | writeRegister(GPPU, (unsigned short)shadow_GPPU); |
jimherd | 0:a6a5d942b58f | 133 | shadow_IPOL = polarity_config; |
jimherd | 0:a6a5d942b58f | 134 | writeRegister(IPOL, (unsigned short)shadow_IPOL); |
jimherd | 0:a6a5d942b58f | 135 | } |
jimherd | 0:a6a5d942b58f | 136 | |
jimherd | 0:a6a5d942b58f | 137 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 138 | * digitalWrite |
jimherd | 0:a6a5d942b58f | 139 | */ |
jimherd | 0:a6a5d942b58f | 140 | void MCP23017::digitalWrite(int pin, int val) { |
jimherd | 0:a6a5d942b58f | 141 | //If this pin is an INPUT pin, a write here will |
jimherd | 0:a6a5d942b58f | 142 | //enable the internal pullup |
jimherd | 0:a6a5d942b58f | 143 | //otherwise, it will set the OUTPUT voltage |
jimherd | 0:a6a5d942b58f | 144 | //as appropriate. |
jimherd | 0:a6a5d942b58f | 145 | bool isOutput = !(shadow_IODIR & 1<<pin); |
jimherd | 0:a6a5d942b58f | 146 | |
jimherd | 0:a6a5d942b58f | 147 | if (isOutput) { |
jimherd | 0:a6a5d942b58f | 148 | //This is an output pin so just write the value |
jimherd | 0:a6a5d942b58f | 149 | if (val) shadow_GPIO |= 1 << pin; |
jimherd | 0:a6a5d942b58f | 150 | else shadow_GPIO &= ~(1 << pin); |
jimherd | 0:a6a5d942b58f | 151 | writeRegister(GPIO, (unsigned short)shadow_GPIO); |
jimherd | 0:a6a5d942b58f | 152 | } else { |
jimherd | 0:a6a5d942b58f | 153 | //This is an input pin, so we need to enable the pullup |
jimherd | 0:a6a5d942b58f | 154 | if (val) { |
jimherd | 0:a6a5d942b58f | 155 | shadow_GPPU |= 1 << pin; |
jimherd | 0:a6a5d942b58f | 156 | } else { |
jimherd | 0:a6a5d942b58f | 157 | shadow_GPPU &= ~(1 << pin); |
jimherd | 0:a6a5d942b58f | 158 | } |
jimherd | 0:a6a5d942b58f | 159 | writeRegister(GPPU, (unsigned short)shadow_GPPU); |
jimherd | 0:a6a5d942b58f | 160 | } |
jimherd | 0:a6a5d942b58f | 161 | } |
jimherd | 0:a6a5d942b58f | 162 | |
jimherd | 0:a6a5d942b58f | 163 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 164 | * digitalWordRead |
jimherd | 0:a6a5d942b58f | 165 | */ |
jimherd | 0:a6a5d942b58f | 166 | unsigned short MCP23017::digitalWordRead() { |
jimherd | 0:a6a5d942b58f | 167 | shadow_GPIO = readRegister(GPIO); |
jimherd | 0:a6a5d942b58f | 168 | return shadow_GPIO; |
jimherd | 0:a6a5d942b58f | 169 | } |
jimherd | 0:a6a5d942b58f | 170 | |
jimherd | 0:a6a5d942b58f | 171 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 172 | * digitalWordWrite |
jimherd | 0:a6a5d942b58f | 173 | */ |
jimherd | 0:a6a5d942b58f | 174 | void MCP23017::digitalWordWrite(unsigned short w) { |
jimherd | 0:a6a5d942b58f | 175 | shadow_GPIO = w; |
jimherd | 0:a6a5d942b58f | 176 | writeRegister(GPIO, (unsigned short)shadow_GPIO); |
jimherd | 0:a6a5d942b58f | 177 | } |
jimherd | 0:a6a5d942b58f | 178 | |
jimherd | 0:a6a5d942b58f | 179 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 180 | * inputPolarityMask |
jimherd | 0:a6a5d942b58f | 181 | */ |
jimherd | 0:a6a5d942b58f | 182 | void MCP23017::inputPolarityMask(unsigned short mask) { |
jimherd | 0:a6a5d942b58f | 183 | writeRegister(IPOL, mask); |
jimherd | 0:a6a5d942b58f | 184 | } |
jimherd | 0:a6a5d942b58f | 185 | |
jimherd | 0:a6a5d942b58f | 186 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 187 | * inputoutputMask |
jimherd | 0:a6a5d942b58f | 188 | */ |
jimherd | 0:a6a5d942b58f | 189 | void MCP23017::inputOutputMask(unsigned short mask) { |
jimherd | 0:a6a5d942b58f | 190 | shadow_IODIR = mask; |
jimherd | 0:a6a5d942b58f | 191 | writeRegister(IODIR, (unsigned short)shadow_IODIR); |
jimherd | 0:a6a5d942b58f | 192 | } |
jimherd | 0:a6a5d942b58f | 193 | |
jimherd | 0:a6a5d942b58f | 194 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 195 | * internalPullupMask |
jimherd | 0:a6a5d942b58f | 196 | */ |
jimherd | 0:a6a5d942b58f | 197 | void MCP23017::internalPullupMask(unsigned short mask) { |
jimherd | 0:a6a5d942b58f | 198 | shadow_GPPU = mask; |
jimherd | 0:a6a5d942b58f | 199 | writeRegister(GPPU, (unsigned short)shadow_GPPU); |
jimherd | 0:a6a5d942b58f | 200 | } |
jimherd | 0:a6a5d942b58f | 201 | |
jimherd | 0:a6a5d942b58f | 202 | |
jimherd | 0:a6a5d942b58f | 203 | |
jimherd | 0:a6a5d942b58f | 204 | //PRIVATE |
jimherd | 0:a6a5d942b58f | 205 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 206 | * writeRegister |
jimherd | 0:a6a5d942b58f | 207 | * write a byte |
jimherd | 0:a6a5d942b58f | 208 | */ |
jimherd | 0:a6a5d942b58f | 209 | void MCP23017::writeRegister(int regAddress, unsigned char data) { |
jimherd | 0:a6a5d942b58f | 210 | char buffer[2]; |
jimherd | 0:a6a5d942b58f | 211 | |
jimherd | 0:a6a5d942b58f | 212 | buffer[0] = regAddress; |
jimherd | 0:a6a5d942b58f | 213 | buffer[1] = data; |
jimherd | 0:a6a5d942b58f | 214 | _i2c.write(MCP23017_i2cAddress, buffer, 2); |
jimherd | 0:a6a5d942b58f | 215 | } |
jimherd | 0:a6a5d942b58f | 216 | |
jimherd | 0:a6a5d942b58f | 217 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 218 | * writeRegister |
jimherd | 0:a6a5d942b58f | 219 | * write two bytes |
jimherd | 0:a6a5d942b58f | 220 | */ |
jimherd | 0:a6a5d942b58f | 221 | void MCP23017::writeRegister(int regAddress, unsigned short data) { |
jimherd | 0:a6a5d942b58f | 222 | char buffer[3]; |
jimherd | 0:a6a5d942b58f | 223 | |
jimherd | 0:a6a5d942b58f | 224 | buffer[0] = regAddress; |
jimherd | 0:a6a5d942b58f | 225 | tmp_data.value16 = data; |
jimherd | 0:a6a5d942b58f | 226 | buffer[1] = tmp_data.value8[0]; |
jimherd | 0:a6a5d942b58f | 227 | buffer[2] = tmp_data.value8[1]; |
jimherd | 0:a6a5d942b58f | 228 | |
jimherd | 0:a6a5d942b58f | 229 | _i2c.write(MCP23017_i2cAddress, buffer, 3); |
jimherd | 0:a6a5d942b58f | 230 | } |
jimherd | 0:a6a5d942b58f | 231 | |
jimherd | 0:a6a5d942b58f | 232 | /******************************************************************************* |
jimherd | 0:a6a5d942b58f | 233 | * readRegister |
jimherd | 0:a6a5d942b58f | 234 | */ |
jimherd | 0:a6a5d942b58f | 235 | int MCP23017::readRegister(int regAddress) { |
jimherd | 0:a6a5d942b58f | 236 | char buffer[2]; |
jimherd | 0:a6a5d942b58f | 237 | |
jimherd | 0:a6a5d942b58f | 238 | buffer[0] = regAddress; |
jimherd | 0:a6a5d942b58f | 239 | _i2c.write(MCP23017_i2cAddress, buffer, 1); |
jimherd | 0:a6a5d942b58f | 240 | _i2c.read(MCP23017_i2cAddress, buffer, 2); |
jimherd | 0:a6a5d942b58f | 241 | |
jimherd | 0:a6a5d942b58f | 242 | return ((int)(buffer[0] + (buffer[1]<<8))); |
jimherd | 0:a6a5d942b58f | 243 | } |