Justin Howard / MCP23017

Basic library of routines to interface to a Microchip MCP23017 16-bit I/O expander using an I2C interface.

Dependents:   AdaFruit_RGBLCD SX1276_GPS

Fork of MCP23017 by jim herd

MCP23017.cpp@15:164d420bcbcf, 2014-08-07 (annotated)

Committer:
vtraveller
Date:
Thu Aug 07 19:59:32 2014 +0000
Revision:
15:164d420bcbcf
Parent:
14:c8d31c67ac27
Child:
16:9b5a51117afe
Updated with high speed clock support.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jimherd 0:a6a5d942b58f 1 /* MCP23017 library for Arduino
jimherd 0:a6a5d942b58f 2 Copyright (C) 2009 David Pye <davidmpye@gmail.com
jimherd 12:6d9d2b277f26 3 Modified for use on the MBED ARM platform
jimherd 0:a6a5d942b58f 4
jimherd 0:a6a5d942b58f 5 This program is free software: you can redistribute it and/or modify
jimherd 0:a6a5d942b58f 6 it under the terms of the GNU General Public License as published by
jimherd 0:a6a5d942b58f 7 the Free Software Foundation, either version 3 of the License, or
jimherd 0:a6a5d942b58f 8 (at your option) any later version.
jimherd 0:a6a5d942b58f 9
jimherd 0:a6a5d942b58f 10 This program is distributed in the hope that it will be useful,
jimherd 0:a6a5d942b58f 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
jimherd 0:a6a5d942b58f 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
jimherd 0:a6a5d942b58f 13 GNU General Public License for more details.
jimherd 0:a6a5d942b58f 14
jimherd 0:a6a5d942b58f 15 You should have received a copy of the GNU General Public License
jimherd 0:a6a5d942b58f 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
jimherd 0:a6a5d942b58f 17 */
jimherd 4:32fd6ee97dff 18
jimherd 4:32fd6ee97dff 19 #include "MCP23017.h"
jimherd 2:2a17f52c550a 20 #include "mbed.h"
jimherd 0:a6a5d942b58f 21
jimherd 0:a6a5d942b58f 22 union {
jimherd 0:a6a5d942b58f 23 uint8_t value8[2];
jimherd 0:a6a5d942b58f 24 uint16_t value16;
jimherd 0:a6a5d942b58f 25 } tmp_data;
jimherd 0:a6a5d942b58f 26
jimherd 12:6d9d2b277f26 27 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 28 *
jimherd 0:a6a5d942b58f 29 */
vtraveller 15:164d420bcbcf 30 MCP23017::MCP23017(PinName sda, PinName scl, int i2cAddress, bool hispeed) : _i2c(sda, scl) {
vtraveller 15:164d420bcbcf 31 // I2C can handle two different frequencies - switch to high speed if asked
vtraveller 15:164d420bcbcf 32 _i2c.frequency(hispeed ? 400000 : 100000);
vtraveller 15:164d420bcbcf 33
jimherd 0:a6a5d942b58f 34 MCP23017_i2cAddress = i2cAddress;
jimherd 0:a6a5d942b58f 35 reset(); // initialise chip to power-on condition
jimherd 0:a6a5d942b58f 36 }
jimherd 0:a6a5d942b58f 37
jimherd 12:6d9d2b277f26 38 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 39 * reset
jimherd 0:a6a5d942b58f 40 * Set configuration (IOCON) and direction(IODIR) registers to initial state
jimherd 0:a6a5d942b58f 41 */
jimherd 0:a6a5d942b58f 42 void MCP23017::reset() {
jimherd 0:a6a5d942b58f 43 //
jimherd 0:a6a5d942b58f 44 // First make sure that the device is in BANK=0 mode
jimherd 0:a6a5d942b58f 45 //
jimherd 0:a6a5d942b58f 46 writeRegister(0x05, (unsigned char)0x00);
jimherd 0:a6a5d942b58f 47 //
jimherd 0:a6a5d942b58f 48 // set direction registers to inputs
jimherd 0:a6a5d942b58f 49 //
jimherd 0:a6a5d942b58f 50 writeRegister(IODIR, (unsigned short)0xFFFF);
jimherd 0:a6a5d942b58f 51 //
jimherd 9:e08c29541bc4 52 // set all other registers to zero (last of 10 registers is OLAT)
jimherd 0:a6a5d942b58f 53 //
jimherd 0:a6a5d942b58f 54 for (int reg_addr = 2 ; reg_addr <= OLAT ; reg_addr+=2) {
jimherd 0:a6a5d942b58f 55 writeRegister(reg_addr, (unsigned short)0x0000);
jimherd 0:a6a5d942b58f 56 }
jimherd 0:a6a5d942b58f 57 //
jimherd 0:a6a5d942b58f 58 // Set the shadow registers to power-on state
jimherd 0:a6a5d942b58f 59 //
jimherd 0:a6a5d942b58f 60 shadow_IODIR = 0xFFFF;
jimherd 0:a6a5d942b58f 61 shadow_GPIO = 0;
jimherd 0:a6a5d942b58f 62 shadow_GPPU = 0;
jimherd 0:a6a5d942b58f 63 shadow_IPOL = 0;
jimherd 0:a6a5d942b58f 64 }
jimherd 0:a6a5d942b58f 65
jimherd 12:6d9d2b277f26 66 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 67 * write_bit
jimherd 0:a6a5d942b58f 68 * Write a 1/0 to a single bit of the 16-bit port
jimherd 0:a6a5d942b58f 69 */
jimherd 0:a6a5d942b58f 70 void MCP23017::write_bit(int value, int bit_number) {
jimherd 0:a6a5d942b58f 71 if (value == 0) {
jimherd 0:a6a5d942b58f 72 shadow_GPIO &= ~(1 << bit_number);
jimherd 0:a6a5d942b58f 73 } else {
jimherd 0:a6a5d942b58f 74 shadow_GPIO |= 1 << bit_number;
jimherd 0:a6a5d942b58f 75 }
jimherd 0:a6a5d942b58f 76 writeRegister(GPIO, (unsigned short)shadow_GPIO);
jimherd 0:a6a5d942b58f 77 }
jimherd 0:a6a5d942b58f 78
jimherd 12:6d9d2b277f26 79 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 80 * Write a combination of bits to the 16-bit port
jimherd 0:a6a5d942b58f 81 */
jimherd 0:a6a5d942b58f 82 void MCP23017::write_mask(unsigned short data, unsigned short mask) {
jimherd 0:a6a5d942b58f 83 shadow_GPIO = (shadow_GPIO & ~mask) | data;
jimherd 0:a6a5d942b58f 84 writeRegister(GPIO, (unsigned short)shadow_GPIO);
jimherd 0:a6a5d942b58f 85 }
jimherd 0:a6a5d942b58f 86
jimherd 12:6d9d2b277f26 87 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 88 * read_bit
jimherd 0:a6a5d942b58f 89 * Read a single bit from the 16-bit port
jimherd 0:a6a5d942b58f 90 */
jimherd 0:a6a5d942b58f 91 int MCP23017::read_bit(int bit_number) {
jimherd 0:a6a5d942b58f 92 shadow_GPIO = readRegister(GPIO);
jimherd 0:a6a5d942b58f 93 return ((shadow_GPIO >> bit_number) & 0x0001);
jimherd 0:a6a5d942b58f 94 }
jimherd 0:a6a5d942b58f 95
jimherd 12:6d9d2b277f26 96 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 97 * read_mask
jimherd 0:a6a5d942b58f 98 */
jimherd 0:a6a5d942b58f 99 int MCP23017::read_mask(unsigned short mask) {
jimherd 0:a6a5d942b58f 100 shadow_GPIO = readRegister(GPIO);
jimherd 0:a6a5d942b58f 101 return (shadow_GPIO & mask);
jimherd 0:a6a5d942b58f 102 }
jimherd 0:a6a5d942b58f 103
jimherd 12:6d9d2b277f26 104 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 105 * Config
jimherd 0:a6a5d942b58f 106 * set direction and pull-up registers
jimherd 0:a6a5d942b58f 107 */
jimherd 0:a6a5d942b58f 108 void MCP23017::config(unsigned short dir_config, unsigned short pullup_config, unsigned short polarity_config) {
jimherd 0:a6a5d942b58f 109 shadow_IODIR = dir_config;
jimherd 0:a6a5d942b58f 110 writeRegister(IODIR, (unsigned short)shadow_IODIR);
jimherd 0:a6a5d942b58f 111 shadow_GPPU = pullup_config;
jimherd 0:a6a5d942b58f 112 writeRegister(GPPU, (unsigned short)shadow_GPPU);
jimherd 0:a6a5d942b58f 113 shadow_IPOL = polarity_config;
jimherd 0:a6a5d942b58f 114 writeRegister(IPOL, (unsigned short)shadow_IPOL);
jimherd 0:a6a5d942b58f 115 }
jimherd 0:a6a5d942b58f 116
jimherd 12:6d9d2b277f26 117 /*-----------------------------------------------------------------------------
jimherd 12:6d9d2b277f26 118 * writeRegister
jimherd 12:6d9d2b277f26 119 * write a byte
jimherd 12:6d9d2b277f26 120 */
jimherd 12:6d9d2b277f26 121 void MCP23017::writeRegister(int regAddress, unsigned char data) {
jimherd 12:6d9d2b277f26 122 char buffer[2];
jimherd 12:6d9d2b277f26 123
jimherd 12:6d9d2b277f26 124 buffer[0] = regAddress;
jimherd 12:6d9d2b277f26 125 buffer[1] = data;
jimherd 12:6d9d2b277f26 126 _i2c.write(MCP23017_i2cAddress, buffer, 2);
jimherd 12:6d9d2b277f26 127 }
jimherd 12:6d9d2b277f26 128
jimherd 12:6d9d2b277f26 129 /*----------------------------------------------------------------------------
jimherd 12:6d9d2b277f26 130 * write Register
jimherd 12:6d9d2b277f26 131 * write two bytes
jimherd 12:6d9d2b277f26 132 */
jimherd 12:6d9d2b277f26 133 void MCP23017::writeRegister(int regAddress, unsigned short data) {
jimherd 12:6d9d2b277f26 134 char buffer[3];
jimherd 12:6d9d2b277f26 135
jimherd 12:6d9d2b277f26 136 buffer[0] = regAddress;
jimherd 12:6d9d2b277f26 137 tmp_data.value16 = data;
jimherd 12:6d9d2b277f26 138 buffer[1] = tmp_data.value8[0];
jimherd 12:6d9d2b277f26 139 buffer[2] = tmp_data.value8[1];
jimherd 12:6d9d2b277f26 140
jimherd 12:6d9d2b277f26 141 _i2c.write(MCP23017_i2cAddress, buffer, 3);
jimherd 12:6d9d2b277f26 142 }
jimherd 12:6d9d2b277f26 143
jimherd 12:6d9d2b277f26 144 /*-----------------------------------------------------------------------------
jimherd 12:6d9d2b277f26 145 * readRegister
jimherd 12:6d9d2b277f26 146 */
jimherd 12:6d9d2b277f26 147 int MCP23017::readRegister(int regAddress) {
jimherd 12:6d9d2b277f26 148 char buffer[2];
jimherd 12:6d9d2b277f26 149
jimherd 12:6d9d2b277f26 150 buffer[0] = regAddress;
jimherd 12:6d9d2b277f26 151 _i2c.write(MCP23017_i2cAddress, buffer, 1);
jimherd 12:6d9d2b277f26 152 _i2c.read(MCP23017_i2cAddress, buffer, 2);
jimherd 12:6d9d2b277f26 153
jimherd 12:6d9d2b277f26 154 return ((int)(buffer[0] + (buffer[1]<<8)));
jimherd 12:6d9d2b277f26 155 }
jimherd 12:6d9d2b277f26 156
jimherd 12:6d9d2b277f26 157 /*-----------------------------------------------------------------------------
jimherd 12:6d9d2b277f26 158 * pinMode
jimherd 12:6d9d2b277f26 159 */
jimherd 12:6d9d2b277f26 160 void MCP23017::pinMode(int pin, int mode) {
vtraveller 14:c8d31c67ac27 161 if (mode == DIR_INPUT) {
jimherd 12:6d9d2b277f26 162 shadow_IODIR |= 1 << pin;
jimherd 12:6d9d2b277f26 163 } else {
jimherd 12:6d9d2b277f26 164 shadow_IODIR &= ~(1 << pin);
jimherd 12:6d9d2b277f26 165 }
jimherd 12:6d9d2b277f26 166 writeRegister(IODIR, (unsigned short)shadow_IODIR);
jimherd 12:6d9d2b277f26 167 }
jimherd 12:6d9d2b277f26 168
jimherd 12:6d9d2b277f26 169 /*-----------------------------------------------------------------------------
jimherd 12:6d9d2b277f26 170 * digitalRead
jimherd 12:6d9d2b277f26 171 */
jimherd 12:6d9d2b277f26 172 int MCP23017::digitalRead(int pin) {
jimherd 12:6d9d2b277f26 173 shadow_GPIO = readRegister(GPIO);
jimherd 12:6d9d2b277f26 174 if ( shadow_GPIO & (1 << pin)) {
jimherd 12:6d9d2b277f26 175 return 1;
jimherd 12:6d9d2b277f26 176 } else {
jimherd 12:6d9d2b277f26 177 return 0;
jimherd 12:6d9d2b277f26 178 }
jimherd 12:6d9d2b277f26 179 }
jimherd 12:6d9d2b277f26 180
jimherd 12:6d9d2b277f26 181 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 182 * digitalWrite
jimherd 0:a6a5d942b58f 183 */
jimherd 0:a6a5d942b58f 184 void MCP23017::digitalWrite(int pin, int val) {
jimherd 0:a6a5d942b58f 185 //If this pin is an INPUT pin, a write here will
jimherd 0:a6a5d942b58f 186 //enable the internal pullup
jimherd 0:a6a5d942b58f 187 //otherwise, it will set the OUTPUT voltage
jimherd 0:a6a5d942b58f 188 //as appropriate.
jimherd 0:a6a5d942b58f 189 bool isOutput = !(shadow_IODIR & 1<<pin);
jimherd 0:a6a5d942b58f 190
jimherd 0:a6a5d942b58f 191 if (isOutput) {
jimherd 0:a6a5d942b58f 192 //This is an output pin so just write the value
jimherd 0:a6a5d942b58f 193 if (val) shadow_GPIO |= 1 << pin;
jimherd 0:a6a5d942b58f 194 else shadow_GPIO &= ~(1 << pin);
jimherd 0:a6a5d942b58f 195 writeRegister(GPIO, (unsigned short)shadow_GPIO);
jimherd 0:a6a5d942b58f 196 } else {
jimherd 0:a6a5d942b58f 197 //This is an input pin, so we need to enable the pullup
jimherd 0:a6a5d942b58f 198 if (val) {
jimherd 0:a6a5d942b58f 199 shadow_GPPU |= 1 << pin;
jimherd 0:a6a5d942b58f 200 } else {
jimherd 0:a6a5d942b58f 201 shadow_GPPU &= ~(1 << pin);
jimherd 0:a6a5d942b58f 202 }
jimherd 0:a6a5d942b58f 203 writeRegister(GPPU, (unsigned short)shadow_GPPU);
jimherd 0:a6a5d942b58f 204 }
jimherd 0:a6a5d942b58f 205 }
jimherd 0:a6a5d942b58f 206
jimherd 12:6d9d2b277f26 207 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 208 * digitalWordRead
jimherd 0:a6a5d942b58f 209 */
jimherd 0:a6a5d942b58f 210 unsigned short MCP23017::digitalWordRead() {
jimherd 0:a6a5d942b58f 211 shadow_GPIO = readRegister(GPIO);
jimherd 0:a6a5d942b58f 212 return shadow_GPIO;
jimherd 0:a6a5d942b58f 213 }
jimherd 0:a6a5d942b58f 214
jimherd 12:6d9d2b277f26 215 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 216 * digitalWordWrite
jimherd 0:a6a5d942b58f 217 */
jimherd 0:a6a5d942b58f 218 void MCP23017::digitalWordWrite(unsigned short w) {
jimherd 0:a6a5d942b58f 219 shadow_GPIO = w;
jimherd 0:a6a5d942b58f 220 writeRegister(GPIO, (unsigned short)shadow_GPIO);
jimherd 0:a6a5d942b58f 221 }
jimherd 0:a6a5d942b58f 222
jimherd 12:6d9d2b277f26 223 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 224 * inputPolarityMask
jimherd 0:a6a5d942b58f 225 */
jimherd 0:a6a5d942b58f 226 void MCP23017::inputPolarityMask(unsigned short mask) {
jimherd 0:a6a5d942b58f 227 writeRegister(IPOL, mask);
jimherd 0:a6a5d942b58f 228 }
jimherd 0:a6a5d942b58f 229
jimherd 12:6d9d2b277f26 230 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 231 * inputoutputMask
jimherd 0:a6a5d942b58f 232 */
jimherd 0:a6a5d942b58f 233 void MCP23017::inputOutputMask(unsigned short mask) {
jimherd 0:a6a5d942b58f 234 shadow_IODIR = mask;
jimherd 0:a6a5d942b58f 235 writeRegister(IODIR, (unsigned short)shadow_IODIR);
jimherd 0:a6a5d942b58f 236 }
jimherd 0:a6a5d942b58f 237
jimherd 12:6d9d2b277f26 238 /*-----------------------------------------------------------------------------
jimherd 0:a6a5d942b58f 239 * internalPullupMask
jimherd 0:a6a5d942b58f 240 */
jimherd 0:a6a5d942b58f 241 void MCP23017::internalPullupMask(unsigned short mask) {
jimherd 0:a6a5d942b58f 242 shadow_GPPU = mask;
jimherd 0:a6a5d942b58f 243 writeRegister(GPPU, (unsigned short)shadow_GPPU);
jimherd 0:a6a5d942b58f 244 }
jimherd 0:a6a5d942b58f 245