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MCP23017.cpp@0:d76c38ee24ab, 2012-04-13 (annotated)

Committer:: GobertPierre
Date:: Fri Apr 13 17:44:17 2012 +0000
Revision:: 0:d76c38ee24ab

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User	Revision	Line number	New contents of line
GobertPierre	0:d76c38ee24ab	1	/* MCP23017 library for Arduino
GobertPierre	0:d76c38ee24ab	2	Copyright (C) 2009 David Pye <davidmpye@gmail.com
GobertPierre	0:d76c38ee24ab	3	Modified for use on the MBED ARM platform
GobertPierre	0:d76c38ee24ab	4
GobertPierre	0:d76c38ee24ab	5	This program is free software: you can redistribute it and/or modify
GobertPierre	0:d76c38ee24ab	6	it under the terms of the GNU General Public License as published by
GobertPierre	0:d76c38ee24ab	7	the Free Software Foundation, either version 3 of the License, or
GobertPierre	0:d76c38ee24ab	8	(at your option) any later version.
GobertPierre	0:d76c38ee24ab	9
GobertPierre	0:d76c38ee24ab	10	This program is distributed in the hope that it will be useful,
GobertPierre	0:d76c38ee24ab	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
GobertPierre	0:d76c38ee24ab	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GobertPierre	0:d76c38ee24ab	13	GNU General Public License for more details.
GobertPierre	0:d76c38ee24ab	14
GobertPierre	0:d76c38ee24ab	15	You should have received a copy of the GNU General Public License
GobertPierre	0:d76c38ee24ab	16	along with this program. If not, see <http://www.gnu.org/licenses/>.
GobertPierre	0:d76c38ee24ab	17	*/
GobertPierre	0:d76c38ee24ab	18
GobertPierre	0:d76c38ee24ab	19	#include "MCP23017.h"
GobertPierre	0:d76c38ee24ab	20	#include "mbed.h"
GobertPierre	0:d76c38ee24ab	21
GobertPierre	0:d76c38ee24ab	22	union {
GobertPierre	0:d76c38ee24ab	23	uint8_t value8[2];
GobertPierre	0:d76c38ee24ab	24	uint16_t value16;
GobertPierre	0:d76c38ee24ab	25	} tmp_data;
GobertPierre	0:d76c38ee24ab	26
GobertPierre	0:d76c38ee24ab	27	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	28	*
GobertPierre	0:d76c38ee24ab	29	*/
GobertPierre	0:d76c38ee24ab	30	MCP23017::MCP23017(PinName sda, PinName scl, int i2cAddress) : _i2c(sda, scl) {
GobertPierre	0:d76c38ee24ab	31	MCP23017_i2cAddress = i2cAddress;
GobertPierre	0:d76c38ee24ab	32	reset(); // initialise chip to power-on condition
GobertPierre	0:d76c38ee24ab	33	}
GobertPierre	0:d76c38ee24ab	34
GobertPierre	0:d76c38ee24ab	35	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	36	* reset
GobertPierre	0:d76c38ee24ab	37	* Set configuration (IOCON) and direction(IODIR) registers to initial state
GobertPierre	0:d76c38ee24ab	38	*/
GobertPierre	0:d76c38ee24ab	39	void MCP23017::reset() {
GobertPierre	0:d76c38ee24ab	40	//
GobertPierre	0:d76c38ee24ab	41	// First make sure that the device is in BANK=0 mode
GobertPierre	0:d76c38ee24ab	42	//
GobertPierre	0:d76c38ee24ab	43	writeRegister(0x05, (unsigned char)0x00);
GobertPierre	0:d76c38ee24ab	44	//
GobertPierre	0:d76c38ee24ab	45	// set direction registers to inputs
GobertPierre	0:d76c38ee24ab	46	//
GobertPierre	0:d76c38ee24ab	47	writeRegister(IODIR, (unsigned short)0xFFFF);
GobertPierre	0:d76c38ee24ab	48	//
GobertPierre	0:d76c38ee24ab	49	// set all other registers to zero (last of 10 registers is OLAT)
GobertPierre	0:d76c38ee24ab	50	//
GobertPierre	0:d76c38ee24ab	51	for (int reg_addr = 2 ; reg_addr <= OLAT ; reg_addr+=2) {
GobertPierre	0:d76c38ee24ab	52	writeRegister(reg_addr, (unsigned short)0x0000);
GobertPierre	0:d76c38ee24ab	53	}
GobertPierre	0:d76c38ee24ab	54	//
GobertPierre	0:d76c38ee24ab	55	// Set the shadow registers to power-on state
GobertPierre	0:d76c38ee24ab	56	//
GobertPierre	0:d76c38ee24ab	57	shadow_IODIR = 0xFFFF;
GobertPierre	0:d76c38ee24ab	58	shadow_GPIO = 0;
GobertPierre	0:d76c38ee24ab	59	shadow_GPPU = 0;
GobertPierre	0:d76c38ee24ab	60	shadow_IPOL = 0;
GobertPierre	0:d76c38ee24ab	61	}
GobertPierre	0:d76c38ee24ab	62
GobertPierre	0:d76c38ee24ab	63	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	64	* write_bit
GobertPierre	0:d76c38ee24ab	65	* Write a 1/0 to a single bit of the 16-bit port
GobertPierre	0:d76c38ee24ab	66	*/
GobertPierre	0:d76c38ee24ab	67	void MCP23017::write_bit(int value, int bit_number) {
GobertPierre	0:d76c38ee24ab	68	if (value == 0) {
GobertPierre	0:d76c38ee24ab	69	shadow_GPIO &= ~(1 << bit_number);
GobertPierre	0:d76c38ee24ab	70	} else {
GobertPierre	0:d76c38ee24ab	71	shadow_GPIO \|= 1 << bit_number;
GobertPierre	0:d76c38ee24ab	72	}
GobertPierre	0:d76c38ee24ab	73	writeRegister(GPIO, (unsigned short)shadow_GPIO);
GobertPierre	0:d76c38ee24ab	74	}
GobertPierre	0:d76c38ee24ab	75
GobertPierre	0:d76c38ee24ab	76	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	77	* Write a combination of bits to the 16-bit port
GobertPierre	0:d76c38ee24ab	78	*/
GobertPierre	0:d76c38ee24ab	79	void MCP23017::write_mask(unsigned short data, unsigned short mask) {
GobertPierre	0:d76c38ee24ab	80	shadow_GPIO = (shadow_GPIO & ~mask) \| data;
GobertPierre	0:d76c38ee24ab	81	writeRegister(GPIO, (unsigned short)shadow_GPIO);
GobertPierre	0:d76c38ee24ab	82	}
GobertPierre	0:d76c38ee24ab	83
GobertPierre	0:d76c38ee24ab	84	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	85	* read_bit
GobertPierre	0:d76c38ee24ab	86	* Read a single bit from the 16-bit port
GobertPierre	0:d76c38ee24ab	87	*/
GobertPierre	0:d76c38ee24ab	88	int MCP23017::read_bit(int bit_number) {
GobertPierre	0:d76c38ee24ab	89	shadow_GPIO = readRegister(GPIO);
GobertPierre	0:d76c38ee24ab	90	return ((shadow_GPIO >> bit_number) & 0x0001);
GobertPierre	0:d76c38ee24ab	91	}
GobertPierre	0:d76c38ee24ab	92
GobertPierre	0:d76c38ee24ab	93	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	94	* read_mask
GobertPierre	0:d76c38ee24ab	95	*/
GobertPierre	0:d76c38ee24ab	96	int MCP23017::read_mask(unsigned short mask) {
GobertPierre	0:d76c38ee24ab	97	shadow_GPIO = readRegister(GPIO);
GobertPierre	0:d76c38ee24ab	98	return (shadow_GPIO & mask);
GobertPierre	0:d76c38ee24ab	99	}
GobertPierre	0:d76c38ee24ab	100
GobertPierre	0:d76c38ee24ab	101	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	102	* Config
GobertPierre	0:d76c38ee24ab	103	* set direction and pull-up registers
GobertPierre	0:d76c38ee24ab	104	*/
GobertPierre	0:d76c38ee24ab	105	void MCP23017::config(unsigned short dir_config, unsigned short pullup_config, unsigned short polarity_config) {
GobertPierre	0:d76c38ee24ab	106	shadow_IODIR = dir_config;
GobertPierre	0:d76c38ee24ab	107	writeRegister(IODIR, (unsigned short)shadow_IODIR);
GobertPierre	0:d76c38ee24ab	108	shadow_GPPU = pullup_config;
GobertPierre	0:d76c38ee24ab	109	writeRegister(GPPU, (unsigned short)shadow_GPPU);
GobertPierre	0:d76c38ee24ab	110	shadow_IPOL = polarity_config;
GobertPierre	0:d76c38ee24ab	111	writeRegister(IPOL, (unsigned short)shadow_IPOL);
GobertPierre	0:d76c38ee24ab	112	}
GobertPierre	0:d76c38ee24ab	113
GobertPierre	0:d76c38ee24ab	114	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	115	* writeRegister
GobertPierre	0:d76c38ee24ab	116	* write a byte
GobertPierre	0:d76c38ee24ab	117	*/
GobertPierre	0:d76c38ee24ab	118	void MCP23017::writeRegister(int regAddress, unsigned char data) {
GobertPierre	0:d76c38ee24ab	119	char buffer[2];
GobertPierre	0:d76c38ee24ab	120
GobertPierre	0:d76c38ee24ab	121	buffer[0] = regAddress;
GobertPierre	0:d76c38ee24ab	122	buffer[1] = data;
GobertPierre	0:d76c38ee24ab	123	_i2c.write(MCP23017_i2cAddress, buffer, 2);
GobertPierre	0:d76c38ee24ab	124	}
GobertPierre	0:d76c38ee24ab	125
GobertPierre	0:d76c38ee24ab	126	/*----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	127	* write Register
GobertPierre	0:d76c38ee24ab	128	* write two bytes
GobertPierre	0:d76c38ee24ab	129	*/
GobertPierre	0:d76c38ee24ab	130	void MCP23017::writeRegister(int regAddress, unsigned short data) {
GobertPierre	0:d76c38ee24ab	131	char buffer[3];
GobertPierre	0:d76c38ee24ab	132
GobertPierre	0:d76c38ee24ab	133	buffer[0] = regAddress;
GobertPierre	0:d76c38ee24ab	134	tmp_data.value16 = data;
GobertPierre	0:d76c38ee24ab	135	buffer[1] = tmp_data.value8[0];
GobertPierre	0:d76c38ee24ab	136	buffer[2] = tmp_data.value8[1];
GobertPierre	0:d76c38ee24ab	137
GobertPierre	0:d76c38ee24ab	138	_i2c.write(MCP23017_i2cAddress, buffer, 3);
GobertPierre	0:d76c38ee24ab	139	}
GobertPierre	0:d76c38ee24ab	140
GobertPierre	0:d76c38ee24ab	141	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	142	* readRegister
GobertPierre	0:d76c38ee24ab	143	*/
GobertPierre	0:d76c38ee24ab	144	int MCP23017::readRegister(int regAddress) {
GobertPierre	0:d76c38ee24ab	145	char buffer[2];
GobertPierre	0:d76c38ee24ab	146
GobertPierre	0:d76c38ee24ab	147	buffer[0] = regAddress;
GobertPierre	0:d76c38ee24ab	148	_i2c.write(MCP23017_i2cAddress, buffer, 1);
GobertPierre	0:d76c38ee24ab	149	_i2c.read(MCP23017_i2cAddress, buffer, 2);
GobertPierre	0:d76c38ee24ab	150
GobertPierre	0:d76c38ee24ab	151	return ((int)(buffer[0] + (buffer[1]<<8)));
GobertPierre	0:d76c38ee24ab	152	}
GobertPierre	0:d76c38ee24ab	153
GobertPierre	0:d76c38ee24ab	154	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	155	* pinMode
GobertPierre	0:d76c38ee24ab	156	*/
GobertPierre	0:d76c38ee24ab	157	void MCP23017::pinMode(int pin, int mode) {
GobertPierre	0:d76c38ee24ab	158	if (DIR_INPUT) {
GobertPierre	0:d76c38ee24ab	159	shadow_IODIR \|= 1 << pin;
GobertPierre	0:d76c38ee24ab	160	} else {
GobertPierre	0:d76c38ee24ab	161	shadow_IODIR &= ~(1 << pin);
GobertPierre	0:d76c38ee24ab	162	}
GobertPierre	0:d76c38ee24ab	163	writeRegister(IODIR, (unsigned short)shadow_IODIR);
GobertPierre	0:d76c38ee24ab	164	}
GobertPierre	0:d76c38ee24ab	165
GobertPierre	0:d76c38ee24ab	166	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	167	* digitalRead
GobertPierre	0:d76c38ee24ab	168	*/
GobertPierre	0:d76c38ee24ab	169	int MCP23017::digitalRead(int pin) {
GobertPierre	0:d76c38ee24ab	170	shadow_GPIO = readRegister(GPIO);
GobertPierre	0:d76c38ee24ab	171	if ( shadow_GPIO & (1 << pin)) {
GobertPierre	0:d76c38ee24ab	172	return 1;
GobertPierre	0:d76c38ee24ab	173	} else {
GobertPierre	0:d76c38ee24ab	174	return 0;
GobertPierre	0:d76c38ee24ab	175	}
GobertPierre	0:d76c38ee24ab	176	}
GobertPierre	0:d76c38ee24ab	177
GobertPierre	0:d76c38ee24ab	178	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	179	* digitalWrite
GobertPierre	0:d76c38ee24ab	180	*/
GobertPierre	0:d76c38ee24ab	181	void MCP23017::digitalWrite(int pin, int val) {
GobertPierre	0:d76c38ee24ab	182	//If this pin is an INPUT pin, a write here will
GobertPierre	0:d76c38ee24ab	183	//enable the internal pullup
GobertPierre	0:d76c38ee24ab	184	//otherwise, it will set the OUTPUT voltage
GobertPierre	0:d76c38ee24ab	185	//as appropriate.
GobertPierre	0:d76c38ee24ab	186	bool isOutput = !(shadow_IODIR & 1<<pin);
GobertPierre	0:d76c38ee24ab	187
GobertPierre	0:d76c38ee24ab	188	if (isOutput) {
GobertPierre	0:d76c38ee24ab	189	//This is an output pin so just write the value
GobertPierre	0:d76c38ee24ab	190	if (val) shadow_GPIO \|= 1 << pin;
GobertPierre	0:d76c38ee24ab	191	else shadow_GPIO &= ~(1 << pin);
GobertPierre	0:d76c38ee24ab	192	writeRegister(GPIO, (unsigned short)shadow_GPIO);
GobertPierre	0:d76c38ee24ab	193	} else {
GobertPierre	0:d76c38ee24ab	194	//This is an input pin, so we need to enable the pullup
GobertPierre	0:d76c38ee24ab	195	if (val) {
GobertPierre	0:d76c38ee24ab	196	shadow_GPPU \|= 1 << pin;
GobertPierre	0:d76c38ee24ab	197	} else {
GobertPierre	0:d76c38ee24ab	198	shadow_GPPU &= ~(1 << pin);
GobertPierre	0:d76c38ee24ab	199	}
GobertPierre	0:d76c38ee24ab	200	writeRegister(GPPU, (unsigned short)shadow_GPPU);
GobertPierre	0:d76c38ee24ab	201	}
GobertPierre	0:d76c38ee24ab	202	}
GobertPierre	0:d76c38ee24ab	203
GobertPierre	0:d76c38ee24ab	204	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	205	* digitalWordRead
GobertPierre	0:d76c38ee24ab	206	*/
GobertPierre	0:d76c38ee24ab	207	unsigned short MCP23017::digitalWordRead() {
GobertPierre	0:d76c38ee24ab	208	shadow_GPIO = readRegister(GPIO);
GobertPierre	0:d76c38ee24ab	209	return shadow_GPIO;
GobertPierre	0:d76c38ee24ab	210	}
GobertPierre	0:d76c38ee24ab	211
GobertPierre	0:d76c38ee24ab	212	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	213	* digitalWordWrite
GobertPierre	0:d76c38ee24ab	214	*/
GobertPierre	0:d76c38ee24ab	215	void MCP23017::digitalWordWrite(unsigned short w) {
GobertPierre	0:d76c38ee24ab	216	shadow_GPIO = w;
GobertPierre	0:d76c38ee24ab	217	writeRegister(GPIO, (unsigned short)shadow_GPIO);
GobertPierre	0:d76c38ee24ab	218	}
GobertPierre	0:d76c38ee24ab	219
GobertPierre	0:d76c38ee24ab	220	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	221	* inputPolarityMask
GobertPierre	0:d76c38ee24ab	222	*/
GobertPierre	0:d76c38ee24ab	223	void MCP23017::inputPolarityMask(unsigned short mask) {
GobertPierre	0:d76c38ee24ab	224	writeRegister(IPOL, mask);
GobertPierre	0:d76c38ee24ab	225	}
GobertPierre	0:d76c38ee24ab	226
GobertPierre	0:d76c38ee24ab	227	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	228	* inputoutputMask
GobertPierre	0:d76c38ee24ab	229	*/
GobertPierre	0:d76c38ee24ab	230	void MCP23017::inputOutputMask(unsigned short mask) {
GobertPierre	0:d76c38ee24ab	231	shadow_IODIR = mask;
GobertPierre	0:d76c38ee24ab	232	writeRegister(IODIR, (unsigned short)shadow_IODIR);
GobertPierre	0:d76c38ee24ab	233	}
GobertPierre	0:d76c38ee24ab	234
GobertPierre	0:d76c38ee24ab	235	/*-----------------------------------------------------------------------------
GobertPierre	0:d76c38ee24ab	236	* internalPullupMask
GobertPierre	0:d76c38ee24ab	237	*/
GobertPierre	0:d76c38ee24ab	238	void MCP23017::internalPullupMask(unsigned short mask) {
GobertPierre	0:d76c38ee24ab	239	shadow_GPPU = mask;
GobertPierre	0:d76c38ee24ab	240	writeRegister(GPPU, (unsigned short)shadow_GPPU);
GobertPierre	0:d76c38ee24ab	241	}
GobertPierre	0:d76c38ee24ab	242

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Type:	Library
Created:	13 Apr 2012
Imports:	29
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	0
Followers:	5

MCP23017.cpp@0:d76c38ee24ab, 2012-04-13 (annotated)

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