CCS/MSP430FR5969: accessing accelerometer by using i2c in msp430fr5969

#include <msp430.h>
#include "hal_ADXL345.h"

unsigned char RxData = 0;
unsigned char TxData = 0;
unsigned char TxAddr = 0;

void eUSCIB0_Config()
{
    // Configure pins for I2C
    PORT_I2C_SEL |= BIT_SCL + BIT_SDA;

    //configure eUSCI for I2C
    UCB0CTL1 |= UCSWRST;                            //Software reset enabled
    UCB0CTLW0 |= UCMODE_3  + UCMST + UCSYNC + UCTR; //I2C mode, Master mode, sync, transmitter
    UCB0CTLW0 |= UCSSEL_2;                          // SMCLK = 1.04MHz

    UCB0BRW = 10;                       // Baudrate = SMLK/10 = 100kHz

    UCB0I2CSA  = 0x001D;                //slave address
    UCB0CTL1  &= ~UCSWRST;

    UCB0IFG  = 0x0000;
    UCB0CTL1  |= UCSWRST;
}

// Reads the register at reg_addr, returns the result
signed char I2C_Read_Register(unsigned char reg_addr)
{
    UCB0CTLW1 = UCASTP_1;
    UCB0TBCNT = 0x0001;
    UCB0CTL1  &= ~UCSWRST;
    UCB0CTL1 |= UCTXSTT + UCTR;     // Start i2c write operation
    while(!(UCB0IFG & UCTXIFG0));
    UCB0TXBUF = reg_addr;
    while(!(UCB0IFG & UCBCNTIFG));
    UCB0CTL1 &= ~UCTR;              // I2C read operation
    UCB0CTL1 |= UCTXSTT;            // Repeated start
    while(!(UCB0IFG & UCRXIFG0));
    RxData = UCB0RXBUF;
    UCB0CTLW0 |= UCTXSTP;           // Send stop after next RX
    while (!(UCB0IFG & UCSTPIFG));  // Ensure stop condition got sent
    UCB0CTL1  |= UCSWRST;
    return RxData;
}

//Continuous read data_length bytes and store in the area "read_data"
void I2C_Read_Continuous(unsigned char reg_addr, signed char* read_data, unsigned char data_length)
{
    unsigned int i;

    UCB0CTLW1 = UCASTP_1;
    UCB0TBCNT = 0x0001;
    UCB0CTL1  &= ~UCSWRST;
    UCB0CTL1 |= UCTXSTT + UCTR;     // Start i2c write operation

    while(!(UCB0IFG & UCTXIFG0));
    UCB0TXBUF = reg_addr;
    while(!(UCB0IFG & UCBCNTIFG));
    UCB0CTL1 &= ~UCTR;          //i2c read operation
    UCB0CTL1 |= UCTXSTT;        //repeated start
    while(!(UCB0IFG & UCRXIFG0));

    for(i = 0; i < data_length-1; i++)
    {
        while(!(UCB0IFG & UCRXIFG0));
        read_data[i] = UCB0RXBUF;
        if(i == data_length-1)
            UCB0CTL1 |= UCTXSTP;    //send stop after next RX
    }

    UCB0CTLW0 |= UCTXSTP;           //send stop after next RX
    while(!(UCB0IFG & UCRXIFG0));
    read_data[i] = UCB0RXBUF;
    while (!(UCB0IFG & UCSTPIFG));  // Ensure stop condition got sent
    UCB0CTL1  |= UCSWRST;
}

//writes the register at reg_addr with value
void I2C_Write_Register(unsigned char reg_addr, signed char value)
{
    UCB0CTLW1 = UCASTP_1;
    UCB0TBCNT = 0x0002;
    UCB0CTL1  &= ~UCSWRST;
    UCB0CTL1 |= UCTXSTT + UCTR;     // Start i2c write operation
    //write the address
    while(!(UCB0IFG & UCTXIFG0));
    UCB0TXBUF = reg_addr;
    //write the data
    while(!(UCB0IFG & UCTXIFG0));
    UCB0TXBUF = value;
    while (!(UCB0IFG & UCBCNTIFG));
    UCB0CTL1 |= UCTXSTP;
    while (!(UCB0IFG & UCSTPIFG));  // Ensure stop condition got sent
    UCB0CTL1  |= UCSWRST;
}

void ADXL345_Calibration()
{
    signed int Data_XYZ[3];
    signed int Offset_x = 0;
    signed int Offset_y = 0;
    signed int Offset_z = 0;
    signed char Data_ready = 0;
    unsigned char i;

    for(i=0;i<64;i++)
    {
        do
        {
            Data_ready = I2C_Read_Register(0x30);
        }
        while(!(Data_ready & 0x80));
        ADXL345_Update(Data_XYZ);
        Offset_x += Data_XYZ[0];
        Offset_y += Data_XYZ[1];
        Offset_z += Data_XYZ[2];
    }
    Offset_x = -Offset_x >> 8;
    Offset_y = -Offset_y >> 8;
    Offset_z = -((Offset_z >> 6) - 256) >> 2;

    I2C_Write_Register(0x1E, (signed char)Offset_x);
    I2C_Write_Register(0x1F, (signed char)Offset_y);
    I2C_Write_Register(0x20, (signed char)Offset_z);
}

void Init_ADXL345()
{
    char temp;

    eUSCIB0_Config();

    /****************************************************************************/
    /* Configure ADXL345 for Typical Usage Scenario                             */
    /****************************************************************************/

    temp = I2C_Read_Register(0x00);
    if(temp == 0xE5) // Check device ID
    {
        I2C_Write_Register(0x2C, 0x08); // 25Hz output
        I2C_Write_Register(0x2D, 0x08); // Measure
        I2C_Write_Register(0x2E, 0x00); // Disable interrupt
        I2C_Write_Register(0x2F, 0x00); //
        I2C_Write_Register(0x31, 0x20); // +/- 2g, 10 bit, LSB
    }

//    __delay_cycles(100000);

    temp = I2C_Read_Register(0x1e);
    if(temp == 0)    // Check if calibrated ?
    {
        P1OUT |= BIT0; P4OUT |= BIT0;
        ADXL345_Calibration();
        P1OUT &= ~BIT0; P4OUT &= ~BIT0;
    }
}

void ADXL345_Update(signed int *data_XYZ)
{
    signed char Data[8];

    I2C_Read_Continuous(0x32, Data, 6);

    data_XYZ[0] = (((signed int)Data[1] << 8) & 0xFF00) | ((signed int)Data[0] & 0x00FF);
    data_XYZ[1] = (((signed int)Data[3] << 8) & 0xFF00) | ((signed int)Data[2] & 0x00FF);
    data_XYZ[2] = (((signed int)Data[5] << 8) & 0xFF00) | ((signed int)Data[4] & 0x00FF);
}