File content as of revision 4:d850da8732c1:

#include "adxl345.h"

I2C i2c(PB_9, PB_8);

#define ADXL345_DEVICE (0xA6)    // Device Address for ADXL345
#define ADXL345_TO_READ (6)      // Number of chars Read - Two chars Per Axis

ADXL345::ADXL345() {
    status = ADXL345_OK;
    error_code = ADXL345_NO_ERROR;
    
    gains[0] = 0.00376390;      // Original gain 0.00376390 
    gains[1] = 0.00376009;      // Original gain 0.00376009
    gains[2] = 0.00349265;      // Original gain 0.00349265
}


void ADXL345::powerOn() {

    //ADXL345 TURN ON
    writeToI2C(ADXL345_POWER_CTL, 0);  // Wakeup     
    writeToI2C(ADXL345_POWER_CTL, 16); // Auto_Sleep
    writeToI2C(ADXL345_POWER_CTL, 8);  // Measure
    
}


/*********************** READING ACCELERATION ***********************/
/*    Reads Acceleration into Three Variables:  x, y and z          */

void ADXL345::readAccel(int *xyz){
    readAccel(xyz, xyz + 1, xyz + 2);
}

void ADXL345::readAccel(int *x, int *y, int *z) {
    readFromI2C(ADXL345_DATAX0, ADXL345_TO_READ, _buff);   // Read Accel Data from ADXL345
    
    // Each Axis @ All g Ranges: 10 Bit Resolution (2 chars)
    
    *x = (int16_t)((((int)_buff[1]) << 8) | _buff[0]);
    *y = (int16_t)((((int)_buff[3]) << 8) | _buff[2]);
    *z = (int16_t)((((int)_buff[5]) << 8) | _buff[4]);
        
}

void ADXL345::get_Gxyz(double *xyz){
    int i;
    int xyz_int[3];
    readAccel(xyz_int);
    for(i=0; i<3; i++){
        xyz[i] = xyz_int[i] * gains[i];
    }
}


/*************************** WRITE TO I2C ***************************/
/*      Start; Send Register Address; Send Value To Write; End      */
void ADXL345::writeToI2C(char _address, char _val) {
    
    char data_write[2];
    data_write[0] = _address;
    data_write[1] = _val;
    
    i2c.write(ADXL345_DEVICE, data_write, 2, 0);     
}

/*************************** READ FROM I2C **************************/
/*                Start; Send Address To Read; End                  */
void ADXL345::readFromI2C(char address, int num, char _buff[]) {
    
    char data_write[1];
    data_write[0] = address;
    i2c.write(ADXL345_DEVICE, data_write, 1, 1); 
    i2c.read(ADXL345_DEVICE, _buff, num, 0);    
}

void ADXL345::setRangeSetting(int val) {
    char _s;
    char _b;
    
    switch (val) {
        case 2:  
            _s = 00000000; 
            break;
        case 4:  
            _s = 00000001; 
            break;
        case 8:  
            _s = 00000010; 
            break;
        case 16: 
            _s = 00000011; 
            break;
        default: 
            _s = 00000000;
    }
    readFromI2C(ADXL345_DATA_FORMAT, 1, &_b);
    _s |= (_b & 11101100);
    writeToI2C(ADXL345_DATA_FORMAT, _s);
}

/*************************** SELF_TEST BIT **************************/
/*                            ~ GET & SET                           */
bool ADXL345::getSelfTestBit() {
    return getRegisterBit(ADXL345_DATA_FORMAT, 7);
}

// If Set (1) Self-Test Applied. Electrostatic Force exerted on the sensor
//  causing a shift in the output data.
// If Set (0) Self-Test Disabled.
void ADXL345::setSelfTestBit(bool selfTestBit) {
    setRegisterBit(ADXL345_DATA_FORMAT, 7, selfTestBit);
}


/*********************** INT_INVERT BIT STATE ***********************/
/*                           ~ GET & SET                            */
bool ADXL345::getInterruptLevelBit() {
    return getRegisterBit(ADXL345_DATA_FORMAT, 5);
}

// If Set (0) Sets the Interrupts to Active HIGH
// If Set (1) Sets the Interrupts to Active LOW
void ADXL345::setInterruptLevelBit(bool interruptLevelBit) {
    setRegisterBit(ADXL345_DATA_FORMAT, 5, interruptLevelBit);
}

/************************* FULL_RES BIT STATE ***********************/
/*                           ~ GET & SET                            */
bool ADXL345::getFullResBit() {
    return getRegisterBit(ADXL345_DATA_FORMAT, 3);
}

// If Set (1) Device is in Full Resolution Mode: Output Resolution Increase with G Range
//  Set by the Range Bits to Maintain a 4mg/LSB Scale Factor
// If Set (0) Device is in 10-bit Mode: Range Bits Determine Maximum G Range
//  And Scale Factor
void ADXL345::setFullResBit(bool fullResBit) {
    setRegisterBit(ADXL345_DATA_FORMAT, 3, fullResBit);
}

/*************************** JUSTIFY BIT STATE **************************/
/*                           ~ GET & SET                            */
bool ADXL345::getJustifyBit() {
    return getRegisterBit(ADXL345_DATA_FORMAT, 2);
}

// If Set (1) Selects the Left Justified Mode
// If Set (0) Selects Right Justified Mode with Sign Extension
void ADXL345::setJustifyBit(bool justifyBit) {
    setRegisterBit(ADXL345_DATA_FORMAT, 2, justifyBit);
}

/*********************** THRESH_TAP char VALUE **********************/
/*                          ~ SET & GET                             */
// Should Set Between 0 and 255
// Scale Factor is 62.5 mg/LSB
// A Value of 0 May Result in Undesirable Behavior
void ADXL345::setTapThreshold(int tapThreshold) {
    if(tapThreshold < 0)
    {
        tapThreshold = 0;
    }
    if(tapThreshold > 255)
    {
        tapThreshold = 255;
    }
    
    char _b = char (tapThreshold);
    writeToI2C(ADXL345_THRESH_TAP, _b);  
}

// Return Value Between 0 and 255
// Scale Factor is 62.5 mg/LSB
int ADXL345::getTapThreshold() {
    char _b;
    readFromI2C(ADXL345_THRESH_TAP, 1, &_b);  
    return int (_b);
}

/****************** GAIN FOR EACH AXIS IN Gs / COUNT *****************/
/*                           ~ SET & GET                            */
void ADXL345::setAxisGains(double *_gains){
    int i;
    for(i = 0; i < 3; i++){
        gains[i] = _gains[i];
    }
}
void ADXL345::getAxisGains(double *_gains){
    int i;
    for(i = 0; i < 3; i++){
        _gains[i] = gains[i];
    }
}

/********************* OFSX, OFSY and OFSZ charS ********************/
/*                           ~ SET & GET                            */
// OFSX, OFSY and OFSZ: User Offset Adjustments in Twos Complement Format
// Scale Factor of 15.6mg/LSB
void ADXL345::setAxisOffset(int x, int y, int z) {
    writeToI2C(ADXL345_OFSX, char (x));  
    writeToI2C(ADXL345_OFSY, char (y));  
    writeToI2C(ADXL345_OFSZ, char (z));  
}

void ADXL345::getAxisOffset(int* x, int* y, int*z) {
    char _b;
    readFromI2C(ADXL345_OFSX, 1, &_b);  
    *x = int (_b);
    readFromI2C(ADXL345_OFSY, 1, &_b);  
    *y = int (_b);
    readFromI2C(ADXL345_OFSZ, 1, &_b);  
    *z = int (_b);
}

/****************************** DUR char ****************************/
/*                           ~ SET & GET                            */
// DUR char: Contains an Unsigned Time Value Representing the Max Time 
//  that an Event must be Above the THRESH_TAP Threshold to qualify 
//  as a Tap Event
// The scale factor is 625µs/LSB
// Value of 0 Disables the Tap/Double Tap Funcitons. Max value is 255.
void ADXL345::setTapDuration(int tapDuration) {
    if(tapDuration < 0)
    {
        tapDuration = 0;
    }
    if(tapDuration > 255)
    {
        tapDuration = 255;
    }
    char _b = char (tapDuration);
    writeToI2C(ADXL345_DUR, _b);  
}

int ADXL345::getTapDuration() {
    char _b;
    readFromI2C(ADXL345_DUR, 1, &_b);  
    return int (_b);
}

/************************** LATENT REGISTER *************************/
/*                           ~ SET & GET                            */
// Contains Unsigned Time Value Representing the Wait Time from the Detection
//  of a Tap Event to the Start of the Time Window (defined by the Window 
//  Register) during which a possible Second Tap Even can be Detected.
// Scale Factor is 1.25ms/LSB. 
// A Value of 0 Disables the Double Tap Function.
// It Accepts a Maximum Value of 255.
void ADXL345::setDoubleTapLatency(int doubleTapLatency) {
    char _b = char (doubleTapLatency);
    writeToI2C(ADXL345_LATENT, _b);  
}

int ADXL345::getDoubleTapLatency() {
    char _b;
    readFromI2C(ADXL345_LATENT, 1, &_b);  
    return int (_b);
}

/************************** WINDOW REGISTER *************************/
/*                           ~ SET & GET                            */
// Contains an Unsigned Time Value Representing the Amount of Time 
//  After the Expiration of the Latency Time (determined by Latent register)
//  During which a Second Valid Tape can Begin. 
// Scale Factor is 1.25ms/LSB. 
// Value of 0 Disables the Double Tap Function. 
// It Accepts a Maximum Value of 255.
void ADXL345::setDoubleTapWindow(int doubleTapWindow) {
    if(doubleTapWindow < 0)
    {
        doubleTapWindow = 0;
    }
    if(doubleTapWindow > 255)
    {
        doubleTapWindow = 255;
    }
    char _b = char (doubleTapWindow);
    writeToI2C(ADXL345_WINDOW, _b);  
}

int ADXL345::getDoubleTapWindow() {
    char _b;
    readFromI2C(ADXL345_WINDOW, 1, &_b);  
    return int (_b);
}

/*********************** THRESH_ACT REGISTER ************************/
/*                          ~ SET & GET                             */
// Holds the Threshold Value for Detecting Activity.
// Data Format is Unsigned, so the Magnitude of the Activity Event is Compared 
//  with the Value is Compared with the Value in the THRESH_ACT Register. 
// The Scale Factor is 62.5mg/LSB. 
// Value of 0 may Result in Undesirable Behavior if the Activity Interrupt Enabled. 
// It Accepts a Maximum Value of 255.
void ADXL345::setActivityThreshold(int activityThreshold) {
    if(activityThreshold < 0)
    {
        activityThreshold = 0;
    }
    if(activityThreshold > 255)
    {
        activityThreshold = 255;
    }
    char _b = char (activityThreshold);
    writeToI2C(ADXL345_THRESH_ACT, _b);  
}

// Gets the THRESH_ACT char
int ADXL345::getActivityThreshold() {
    char _b;
    readFromI2C(ADXL345_THRESH_ACT, 1, &_b);  
    return int (_b);
}

/********************** THRESH_INACT REGISTER ***********************/
/*                          ~ SET & GET                             */
// Holds the Threshold Value for Detecting Inactivity.
// The Data Format is Unsigned, so the Magnitude of the INactivity Event is 
//  Compared with the value in the THRESH_INACT Register. 
// Scale Factor is 62.5mg/LSB. 
// Value of 0 May Result in Undesirable Behavior if the Inactivity Interrupt Enabled. 
// It Accepts a Maximum Value of 255.
void ADXL345::setInactivityThreshold(int inactivityThreshold) {
    if(inactivityThreshold < 0)
    {
        inactivityThreshold = 0;
    }
    if(inactivityThreshold > 255)
    {
        inactivityThreshold = 255;
    }
    char _b = char (inactivityThreshold);
    writeToI2C(ADXL345_THRESH_INACT, _b);  
}

int ADXL345::getInactivityThreshold() {
    char _b;
    readFromI2C(ADXL345_THRESH_INACT, 1, &_b);  
    return int (_b);
}

/*********************** TIME_INACT RESIGER *************************/
/*                          ~ SET & GET                             */
// Contains an Unsigned Time Value Representing the Amount of Time that
//  Acceleration must be Less Than the Value in the THRESH_INACT Register
//  for Inactivity to be Declared. 
// Uses Filtered Output Data* unlike other Interrupt Functions
// Scale Factor is 1sec/LSB. 
// Value Must Be Between 0 and 255. 
void ADXL345::setTimeInactivity(int timeInactivity) {
    if(timeInactivity < 0)
    {
        timeInactivity = 0;
    }
    if(timeInactivity > 255)
    {
        timeInactivity = 255;
    }
    char _b = char (timeInactivity);
    writeToI2C(ADXL345_TIME_INACT, _b);  
}

int ADXL345::getTimeInactivity() {
    char _b;
    readFromI2C(ADXL345_TIME_INACT, 1, &_b);  
    return int (_b);
}

/*********************** THRESH_FF Register *************************/
/*                          ~ SET & GET                             */
// Holds the Threshold Value, in Unsigned Format, for Free-Fall Detection
// The Acceleration on all Axes is Compared with the Value in THRES_FF to
//  Determine if a Free-Fall Event Occurred. 
// Scale Factor is 62.5mg/LSB. 
// Value of 0 May Result in Undesirable Behavior if the Free-Fall interrupt Enabled.
// Accepts a Maximum Value of 255.
void ADXL345::setFreeFallThreshold(int freeFallThreshold) {
    if(freeFallThreshold < 0)
    {
        freeFallThreshold = 0;
    }
    if(freeFallThreshold > 255)
    {
        freeFallThreshold = 255;
    }
    char _b = char (freeFallThreshold);
    writeToI2C(ADXL345_THRESH_FF, _b);  
}

int ADXL345::getFreeFallThreshold() {
    char _b;
    readFromI2C(ADXL345_THRESH_FF, 1, &_b);  
    return int (_b);
}

/************************ TIME_FF Register **************************/
/*                          ~ SET & GET                             */
// Stores an Unsigned Time Value Representing the Minimum Time that the Value 
//  of all Axes must be Less Than THRES_FF to Generate a Free-Fall Interrupt.
// Scale Factor is 5ms/LSB. 
// Value of 0 May Result in Undesirable Behavior if the Free-Fall Interrupt Enabled.
// Accepts a Maximum Value of 255.
void ADXL345::setFreeFallDuration(int freeFallDuration) {
    if(freeFallDuration < 0)
    {
        freeFallDuration = 0;
    }
    if(freeFallDuration > 255)
    {
        freeFallDuration = 255;
    }
    char _b = char (freeFallDuration);
    writeToI2C(ADXL345_TIME_FF, _b);  
}

int ADXL345::getFreeFallDuration() {
    char _b;
    readFromI2C(ADXL345_TIME_FF, 1, &_b);  
    return int (_b);
}

/************************** ACTIVITY BITS ***************************/
/*                                                                  */
bool ADXL345::isActivityXEnabled() {  
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 6); 
}
bool ADXL345::isActivityYEnabled() {  
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 5); 
}
bool ADXL345::isActivityZEnabled() {  
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 4); 
}
bool ADXL345::isInactivityXEnabled() {  
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 2); 
}
bool ADXL345::isInactivityYEnabled() {  
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 1); 
}
bool ADXL345::isInactivityZEnabled() {  
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 0); 
}

void ADXL345::setActivityX(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 6, state); 
}
void ADXL345::setActivityY(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 5, state); 
}
void ADXL345::setActivityZ(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 4, state); 
}
void ADXL345::setActivityXYZ(bool stateX, bool stateY, bool stateZ) {
    setActivityX(stateX);
    setActivityY(stateY);
    setActivityZ(stateZ);
}
void ADXL345::setInactivityX(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 2, state); 
}
void ADXL345::setInactivityY(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 1, state); 
}
void ADXL345::setInactivityZ(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 0, state); 
}
void ADXL345::setInactivityXYZ(bool stateX, bool stateY, bool stateZ) {
    setInactivityX(stateX);
    setInactivityY(stateY);
    setInactivityZ(stateZ);
}

bool ADXL345::isActivityAc() { 
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 7); 
}
bool ADXL345::isInactivityAc(){ 
    return getRegisterBit(ADXL345_ACT_INACT_CTL, 3); 
}

void ADXL345::setActivityAc(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 7, state); 
}
void ADXL345::setInactivityAc(bool state) {  
    setRegisterBit(ADXL345_ACT_INACT_CTL, 3, state); 
}

/************************* SUPPRESS BITS ****************************/
/*                                                                  */
bool ADXL345::getSuppressBit(){ 
    return getRegisterBit(ADXL345_TAP_AXES, 3); 
}
void ADXL345::setSuppressBit(bool state) {  
    setRegisterBit(ADXL345_TAP_AXES, 3, state); 
}

/**************************** TAP BITS ******************************/
/*                                                                  */
bool ADXL345::isTapDetectionOnX(){ 
    return getRegisterBit(ADXL345_TAP_AXES, 2); 
}
void ADXL345::setTapDetectionOnX(bool state) {  
    setRegisterBit(ADXL345_TAP_AXES, 2, state); 
}
bool ADXL345::isTapDetectionOnY(){ 
    return getRegisterBit(ADXL345_TAP_AXES, 1); 
}
void ADXL345::setTapDetectionOnY(bool state) {  
    setRegisterBit(ADXL345_TAP_AXES, 1, state); 
}
bool ADXL345::isTapDetectionOnZ(){ 
    return getRegisterBit(ADXL345_TAP_AXES, 0); 
}
void ADXL345::setTapDetectionOnZ(bool state) {  
    setRegisterBit(ADXL345_TAP_AXES, 0, state); 
}

void ADXL345::setTapDetectionOnXYZ(bool stateX, bool stateY, bool stateZ) {
    setTapDetectionOnX(stateX);
    setTapDetectionOnY(stateY);
    setTapDetectionOnZ(stateZ);
}

bool ADXL345::isActivitySourceOnX(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 6); 
}
bool ADXL345::isActivitySourceOnY(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 5); 
}
bool ADXL345::isActivitySourceOnZ(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 4); 
}

bool ADXL345::isTapSourceOnX(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 2); 
}
bool ADXL345::isTapSourceOnY(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 1); 
}
bool ADXL345::isTapSourceOnZ(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 0); 
}

/*************************** ASLEEP BIT *****************************/
/*                                                                  */
bool ADXL345::isAsleep(){ 
    return getRegisterBit(ADXL345_ACT_TAP_STATUS, 3); 
}

/************************** LOW POWER BIT ***************************/
/*                                                                  */
bool ADXL345::isLowPower(){ 
    return getRegisterBit(ADXL345_BW_RATE, 4); 
}
void ADXL345::setLowPower(bool state) {  
    setRegisterBit(ADXL345_BW_RATE, 4, state); 
}


/************************* TRIGGER CHECK  ***************************/
/*                                                                  */
// Check if Action was Triggered in Interrupts
// Example triggered(interrupts, ADXL345_SINGLE_TAP);
bool ADXL345::triggered(char interrupts, int mask){
    return ((interrupts >> mask) & 1);
}

/*
 ADXL345_DATA_READY
 ADXL345_SINGLE_TAP
 ADXL345_DOUBLE_TAP
 ADXL345_ACTIVITY
 ADXL345_INACTIVITY
 ADXL345_FREE_FALL
 ADXL345_WATERMARK
 ADXL345_OVERRUNY
 */


char ADXL345::getInterruptSource() {
    char _b;
    readFromI2C(ADXL345_INT_SOURCE, 1, &_b);
    return _b;
}

bool ADXL345::getInterruptSource(char interruptBit) {
    return getRegisterBit(ADXL345_INT_SOURCE,interruptBit);
}

bool ADXL345::getInterruptMapping(char interruptBit) {
    return getRegisterBit(ADXL345_INT_MAP,interruptBit);
}

/*********************** INTERRUPT MAPPING **************************/
/*         Set the Mapping of an Interrupt to pin1 or pin2          */
// eg: setInterruptMapping(ADXL345_INT_DOUBLE_TAP_BIT,ADXL345_INT2_PIN);
void ADXL345::setInterruptMapping(char interruptBit, bool interruptPin) {
    setRegisterBit(ADXL345_INT_MAP, interruptBit, interruptPin);
}

void ADXL345::setImportantInterruptMapping(int single_tap, int double_tap, int free_fall, int activity, int inactivity) {
    if(single_tap == 1) {
        setInterruptMapping( ADXL345_INT_SINGLE_TAP_BIT,   ADXL345_INT1_PIN );}
    else if(single_tap == 2) {
        setInterruptMapping( ADXL345_INT_SINGLE_TAP_BIT,   ADXL345_INT2_PIN );}

    if(double_tap == 1) {
        setInterruptMapping( ADXL345_INT_DOUBLE_TAP_BIT,   ADXL345_INT1_PIN );}
    else if(double_tap == 2) {
        setInterruptMapping( ADXL345_INT_DOUBLE_TAP_BIT,   ADXL345_INT2_PIN );}

    if(free_fall == 1) {
        setInterruptMapping( ADXL345_INT_FREE_FALL_BIT,   ADXL345_INT1_PIN );}
    else if(free_fall == 2) {
        setInterruptMapping( ADXL345_INT_FREE_FALL_BIT,   ADXL345_INT2_PIN );}

    if(activity == 1) {
        setInterruptMapping( ADXL345_INT_ACTIVITY_BIT,   ADXL345_INT1_PIN );}
    else if(activity == 2) {
        setInterruptMapping( ADXL345_INT_ACTIVITY_BIT,   ADXL345_INT2_PIN );}

    if(inactivity == 1) {
        setInterruptMapping( ADXL345_INT_INACTIVITY_BIT,   ADXL345_INT1_PIN );}
    else if(inactivity == 2) {
        setInterruptMapping( ADXL345_INT_INACTIVITY_BIT,   ADXL345_INT2_PIN );}
}

bool ADXL345::isInterruptEnabled(char interruptBit) {
    return getRegisterBit(ADXL345_INT_ENABLE,interruptBit);
}

void ADXL345::setInterrupt(char interruptBit, bool state) {
    setRegisterBit(ADXL345_INT_ENABLE, interruptBit, state);
}

void ADXL345::singleTapINT(bool status) {
    if(status) {
        setInterrupt( ADXL345_INT_SINGLE_TAP_BIT, 1);
    }
    else {
        setInterrupt( ADXL345_INT_SINGLE_TAP_BIT, 0);
    }
}
void ADXL345::doubleTapINT(bool status) {
    if(status) {
        setInterrupt( ADXL345_INT_DOUBLE_TAP_BIT, 1);
    }
    else {
        setInterrupt( ADXL345_INT_DOUBLE_TAP_BIT, 0);       
    }   
}
void ADXL345::FreeFallINT(bool status) {
    if(status) {
        setInterrupt( ADXL345_INT_FREE_FALL_BIT,  1);
    }
    else {
        setInterrupt( ADXL345_INT_FREE_FALL_BIT,  0);
    }   
}
void ADXL345::ActivityINT(bool status) {
    if(status) {
        setInterrupt( ADXL345_INT_ACTIVITY_BIT,   1);
    }
    else {
        setInterrupt( ADXL345_INT_ACTIVITY_BIT,   0);
    }
}
void ADXL345::InactivityINT(bool status) {
    if(status) {
        setInterrupt( ADXL345_INT_INACTIVITY_BIT, 1);
    }
    else {
        setInterrupt( ADXL345_INT_INACTIVITY_BIT, 0);
    }
}

void ADXL345::setRegisterBit(char regAdress, int bitPos, bool state) {
    char _b;
    readFromI2C(regAdress, 1, &_b);
    if (state) {
        _b |= (1 << bitPos);  // Forces nth Bit of _b to 1. Other Bits Unchanged.  
    } 
    else {
        _b &= ~(1 << bitPos); // Forces nth Bit of _b to 0. Other Bits Unchanged.
    }
    writeToI2C(regAdress, _b);  
}

bool ADXL345::getRegisterBit(char regAdress, int bitPos) {
    char _b;
    readFromI2C(regAdress, 1, &_b);
    return ((_b >> bitPos) & 1);
}