File content as of revision 2:e575d390c730:

/*
    SD21 - 21 Channel Servo Driver Module Library
    Copyright (c) 2011 Jim Herd
    Based on Arduino code by Richie Reynolds

    The MD25 motor controller uses a +5v I2C interfaced with a protocol
    similar to 24C04 EEPROM device.  Reading data uses a
    WRITE/RESTART/READ sequence.

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "MD25.h"
#include "mbed.h"

/*-----------------------------------------------------------------------------
 * Constructors
 */
MD25::MD25(PinName sda, PinName scl) : _i2c(sda, scl) {
    MD25_i2cAddress =  MD25_DEFAULT_ADDRESS;
    current_mode = MODE_0;
};

MD25::MD25(PinName sda, PinName scl, int i2cAddress) :  _i2c(sda, scl) {
    MD25_i2cAddress = i2cAddress;
    current_mode = MODE_0;
};

/*-----------------------------------------------------------------------------
 * Public Methods
 */

int32_t MD25::getEncoder1(void) {
    union {
        char buffer[4];
        int32_t data;
    } value;

    readRegisterbyte(MD25_ENCODER1_REG);   // dummy read high byte to get current encoder value
    value.buffer[0] = readRegisterbyte(MD25_ENCODER1_REG + 3);
    value.buffer[1] = readRegisterbyte(MD25_ENCODER1_REG + 2);
    value.buffer[2] = readRegisterbyte(MD25_ENCODER1_REG + 1);
    value.buffer[3] = readRegisterbyte(MD25_ENCODER1_REG + 0);

    return value.data;
}

int32_t MD25::getEncoder2(void) {
    union {
        uint8_t  buffer[4];
        int32_t  data;
    } value;
    
    readRegisterbyte(MD25_ENCODER2_REG);   // dummy read high byte to get current encoder value
    value.buffer[0] = readRegisterbyte(MD25_ENCODER2_REG + 3);
    value.buffer[1] = readRegisterbyte(MD25_ENCODER2_REG + 2);
    value.buffer[2] = readRegisterbyte(MD25_ENCODER2_REG + 1);
    value.buffer[3] = readRegisterbyte(MD25_ENCODER2_REG + 0);

    return value.data;
}

uint32_t MD25::getSoftwareVersion(void) {
    return readRegisterbyte(MD25_SOFTWAREVER_REG);
}

float MD25::getBatteryVolts(void) {
    return (float)(readRegisterbyte(MD25_VOLTAGE_REG))/10.0;
}

uint8_t MD25::getAccelerationRate() {
    return readRegisterbyte(MD25_ACCELRATE_REG);
}

uint8_t MD25::getMotor1Speed(void) {
    return readRegisterbyte(MD25_SPEED1_REG);
}

uint8_t MD25::getMotor2Speed(void) {
    return readRegisterbyte(MD25_SPEED2_REG);
}

uint8_t MD25::getMotor1Current(void) {
    return readRegisterbyte(MD25_CURRENT1_REG);
}

uint8_t MD25::getMotor2Current(void) {
    return readRegisterbyte(MD25_CURRENT2_REG);
}

uint8_t MD25::getMode(void) {
    return readRegisterbyte(MD25_MODE_REG);
}

void MD25::setSpeedRegisters(uint8_t speed_1, uint8_t speed_2) {
    writeRegisterbyte(MD25_SPEED1_REG, speed_1);
    writeRegisterbyte(MD25_SPEED2_REG, speed_2);
}

void MD25::stopMotor1(void) {
    switch (current_mode) {
        case MODE_0 :
        case MODE_2 :
            writeRegisterbyte(MD25_SPEED1_REG, 128);
            break;
        case MODE_1 :
        case MODE_3 :
            writeRegisterbyte(MD25_SPEED1_REG, 0);
            break;
    }
}

void MD25::stopMotor2(void) {
    switch (current_mode) {
        case MODE_0 :
        case MODE_2 :
            writeRegisterbyte(MD25_SPEED2_REG, 128);
            break;
        case MODE_1 :
        case MODE_3 :
            writeRegisterbyte(MD25_SPEED2_REG, 0);
            break;
    }
}

void MD25::stopMotors(void) {
    stopMotor1();
    stopMotor2();
}

void MD25::setMode(uint8_t mode) {
    writeRegisterbyte(MD25_MODE_REG, mode);
    current_mode = mode;
}

void MD25::setAccelerationRate(uint8_t rate) {
    writeRegisterbyte(MD25_ACCELRATE_REG, rate);
}

void MD25::setCommand(uint8_t command) {
    writeRegisterbyte(MD25_CMD_REG, command);
}

/*
 * Private Methods
 */

uint8_t MD25::readRegisterbyte(uint8_t reg) {
    char  buffer;

    buffer = reg;
    _i2c.write(MD25_i2cAddress, &buffer, 1, true);       // suppress STOP condition
    _i2c.read(MD25_i2cAddress, &buffer, 1, false);
    return buffer;
}

void MD25::writeRegisterbyte(uint8_t reg, uint8_t value) {
    char  buffer[2];

    buffer[0] = reg;
    buffer[1] = value;
    _i2c.write(MD25_i2cAddress, &buffer[0], 2);
    return;
}