File content as of revision 0:371773dd3dd1:

/* MCP23017 - drive the Microchip MCP23017 16-bit Port Extender using I2C
* Copyright (c) 2010 Wim Huiskamp, Romilly Cocking (original version for SPI)
*
* Released under the MIT License: http://mbed.org/license/mit
*
* version 0.2 Initial Release
* version 0.3 Cleaned up
*/

#include "mbed.h"
#include "MCP23017.h"

DigitalOut Busy(LED4);

/** Create an MCP23017 object connected to the specified I2C object and using the specified deviceAddress
*
* @param I2C &i2c the I2C port to connect to
* @param char deviceAddress the address of the MSC23017
*/
MCP23017::MCP23017(I2C &i2c, char deviceAddress) : _i2c(i2c) {
printf("creating mcp23017\n");
    _writeOpcode = deviceAddress & 0xFE; // low order bit = 0 for write
    _readOpcode  = deviceAddress | 0x01; // low order bit = 1 for read
    busy = false;
    posted = false;
    _init();
    readW(INTFA);
    readW(GPIOA);
printf("mcp23017 created\n");
}

/** Read from specified MCP23017 register
*
* @param char address the internal registeraddress of the MSC23017
* @returns data from register
*/
short MCP23017::_read(char address) {//blocks on busy and still waits for completion
    char data[2];
    i2c_status s;
    data[0] = address;
    do {
        s = _read(address, data, 1);
    } while (s == i2c_busy);
    return (s == i2c_ok) ? data[0] : -2;
}

MCP23017::i2c_status MCP23017::_read(char reg, char *data, int size) {//returns on busy but still waits for completion
    if (testbusy()) return i2c_busy;
    _i2c.write(_writeOpcode, &reg, 1, true); //in a future version of the i2c lib write should return a status like ACK or NACK or busy
    int result = _i2c.read(_readOpcode, data, size);
    releasebusy();
    return result ? i2c_nack : i2c_ok;
}

int MCP23017::readW(char address) {//blocks on busy and still waits for completion
    char data[2];
    i2c_status s;
    data[0] = address;
    do {
        s = _read(address, data, 2);
    } while (s == i2c_busy);
    return (s == i2c_ok) ? *(unsigned short*)data : -1;
}


/** Write to specified MCP23017 register
*
* @param char address the internal registeraddress of the MSC23017
*/
void MCP23017::_write(char address, char byte) {//blocks on busy and still waits for completion
    i2c_status s;
    char data[2];
    data[0] = address;
    data[1] = byte;
    do {
        s = _write(data, 2);
    } while (s == i2c_busy);
//    _i2c.write(_writeOpcode, data, 2);    // Write data to selected Register
    return ; //s; //in the future return the status
}

MCP23017::i2c_status MCP23017::_write(char *data, int size, bool rpt) {//returns on busy but still waits for completion
    if (testbusy()) return i2c_busy;
    int result = 0;
    _i2c.write(_writeOpcode, data, size, rpt);    // Write data to selected Register
    releasebusy();
    return result ? i2c_nack : i2c_ok;
}

/** Init MCP23017
*
* @param
* @returns
*/
void MCP23017::_init() {
    _write(IOCON, (IOCON_BYTE_MODE | IOCON_ODR )); // Open drain interrupt, operations toggle between A and B registers

}

/** Set I/O direction of specified MCP23017 Port
*
* @param Port Port address (Port_A or Port_B)
* @param char direction pin direction (0 = output, 1 = input)
*/
void MCP23017::direction(Port port, char direction) {
    _write(port + IODIRA, direction);
}

/** Set Pull-Up Resistors on specified MCP23017 Port
*
* @param Port Port address (Port_A or Port_B)
* @param char offOrOn per pin (0 = off, 1 = on)
*/
void MCP23017::configurePullUps(Port port, char offOrOn) {
    _write(port + GPPUA, offOrOn);
}

void MCP23017::interruptEnable(Port port, char interruptsEnabledMask) {
    _write(port + GPINTENA, interruptsEnabledMask);
}

void MCP23017::mirrorInterrupts(bool mirror) {
    char iocon = _read(IOCON);
    if (mirror) {
        iocon = iocon | INTERRUPT_MIRROR_BIT;
    } else {
        iocon = iocon & ~INTERRUPT_MIRROR_BIT;
    }
    _write(IOCON, iocon);

}

void  MCP23017::interruptPolarity(Polarity polarity) {
    char iocon = _read(IOCON);
    if (polarity == ACTIVE_LOW) {
        iocon = iocon & ~INTERRUPT_POLARITY_BIT;
    } else {
        iocon = iocon | INTERRUPT_POLARITY_BIT;
    }
    _write(IOCON, iocon);
}

void MCP23017::defaultValue(Port port, char valuesToCompare) {
    _write(port + DEFVALA, valuesToCompare);
}

void MCP23017::interruptControl(Port port, char interruptControlBits) {
    _write(port + INTCONA, interruptControlBits);
}

/** Write to specified MCP23017 Port
*
* @param Port Port address (Port_A or Port_B)
* @param char byte data to write
*/
void MCP23017::write(Port port, char byte) {
    _write(port + OLATA, byte);
}

/** Read from specified MCP23017 Port
*
* @param Port Port address (Port_A or Port_B)
* @returns data from Port
*/
char MCP23017::read(Port port) {
    return _read(port + GPIOA);
}

void MCP23017::write(Port port, const char *buffer, int len, bool rpt) {
    len++;
    char *data = new char[len];
    data[0] = port+OLATA;
    i2c_status s;
    for (int k=1; k< len; k++) data[k] = buffer[k-1];
    do {
      s = _write(data, len, rpt);//toggle A and B, start with port
    } while (s == i2c_busy);
    delete[] data;
}