MSP430FR2433: I2C: Hung up on "Poll for transmit interrupt flag"

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//******************************************************************************
//
//! This example shows how to configure the I2C module as a master for
//! multi byte transmission in interrupt driven mode. The address of the slave
//! module is set in this example.
//!
//!  Demo - EUSCI_B0 I2C Master TX multiple bytes to MSP430 Slave
//!
//!  Description: This demo connects two MSP430's via the I2C bus. The master
//!  transmits to the slave. This is the MASTER CODE. It cntinuously
//!  transmits an array of data and demonstrates how to implement an I2C
//!  master transmitter sending multiple bytes using the USCI_B0 TX interrupt.
//!  ACLK = n/a, MCLK = SMCLK = BRCLK = default DCO = ~1MHz
//!
//!                                /|\  /|\
//!          MSP430FR2xx_4xx Board 10k  10k MSP430FR2xx_4xx Board
//!                   slave         |    |         master
//!             -----------------   |    |   -----------------
//!            |          UCB0SDA|<-|----+->|UCB0SDA          |
//!            |                 |  |       |                 |
//!            |                 |  |       |                 |
//!            |          UCB0SCL|<-+------>|UCB0SCL          |
//!            |                 |          |                 |
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - I2C peripheral
//! - GPIO Port peripheral (for I2C pins)
//! - SCL
//! - SDA
//!
//! This example uses the following interrupt handlers.  To use this example
//! in your own application you must add these interrupt handlers to your
//! vector table.
//! - USCI_B0_VECTOR.
//
//******************************************************************************
#include "driverlib.h"
#include "Board.h"

//*****************************************************************************
//
//Set the address for slave module. This is a 7-bit address sent in the
//following format:
//[A6:A5:A4:A3:A2:A1:A0:RS]
//
//A zero in the "RS" position of the first byte means that the master
//transmits (sends) data to the selected slave, and a one in this position
//means that the master receives data from the slave.
//
//*****************************************************************************
#define SLAVE_ADDRESS 0x77

//*****************************************************************************
//
//Target frequency for SMCLK in kHz
//
//*****************************************************************************
#define CS_SMCLK_DESIRED_FREQUENCY_IN_KHZ   1000

//*****************************************************************************
//
//SMCLK/FLLRef Ratio
//
//*****************************************************************************
#define CS_SMCLK_FLLREF_RATIO   30

// Pointer to TX data
uint8_t TXData[] = {0x06, 0x00, 0x02, 0xFF, 0x02, 0x00};
int i = 0;
uint8_t TXByteCtr;

void main(void)
{
    WDT_A_hold(WDT_A_BASE);

    //Set DCO FLL reference = REFO
    CS_initClockSignal(
            CS_FLLREF,
            CS_REFOCLK_SELECT,
            CS_CLOCK_DIVIDER_1
        );

    //Set Ratio and Desired MCLK Frequency and initialize DCO
    CS_initFLLSettle(
            CS_SMCLK_DESIRED_FREQUENCY_IN_KHZ,
            CS_SMCLK_FLLREF_RATIO
            );

    //Set ACLK = VLO with frequency divider of 1
    CS_initClockSignal(
            CS_ACLK,
            CS_VLOCLK_SELECT,
            CS_CLOCK_DIVIDER_1
            );

    //Set SMCLK = DCO with frequency divider of 1
    CS_initClockSignal(
            CS_SMCLK,
            CS_DCOCLKDIV_SELECT,
            CS_CLOCK_DIVIDER_1
            );

    //Set MCLK = DCO with frequency divider of 1
    CS_initClockSignal(
            CS_MCLK,
            CS_DCOCLKDIV_SELECT,
            CS_CLOCK_DIVIDER_1
            );

    // Configure Pins for I2C
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_UCB0SCL,
        GPIO_PIN_UCB0SCL,
        GPIO_FUNCTION_UCB0SCL
    );
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_UCB0SDA,
        GPIO_PIN_UCB0SDA,
        GPIO_FUNCTION_UCB0SDA
    );

    /*
     * Disable the GPIO power-on default high-impedance mode to activate
     * previously configured port settings
     */
    PMM_unlockLPM5();

    EUSCI_B_I2C_initMasterParam param = {0};
    param.selectClockSource = EUSCI_B_I2C_CLOCKSOURCE_SMCLK;
    param.i2cClk = CS_getSMCLK();
    param.dataRate = EUSCI_B_I2C_SET_DATA_RATE_400KBPS;
    param.byteCounterThreshold = 0;
    param.autoSTOPGeneration = EUSCI_B_I2C_NO_AUTO_STOP;
    EUSCI_B_I2C_initMaster(EUSCI_B0_BASE, &param);

    //Specify slave address
    EUSCI_B_I2C_setSlaveAddress(EUSCI_B0_BASE,
            SLAVE_ADDRESS
            );

    //Set Master in receive mode
    EUSCI_B_I2C_setMode(EUSCI_B0_BASE,
            EUSCI_B_I2C_TRANSMIT_MODE
            );

    //Enable I2C Module to start operations
    EUSCI_B_I2C_enable(EUSCI_B0_BASE);

    EUSCI_B_I2C_clearInterrupt(EUSCI_B0_BASE,
            EUSCI_B_I2C_TRANSMIT_INTERRUPT0 +
            EUSCI_B_I2C_NAK_INTERRUPT
            );
    //Enable master Receive interrupt
    EUSCI_B_I2C_enableInterrupt(EUSCI_B0_BASE,
            EUSCI_B_I2C_TRANSMIT_INTERRUPT0 +
            EUSCI_B_I2C_NAK_INTERRUPT
            );
    while (EUSCI_B_I2C_SENDING_STOP == EUSCI_B_I2C_masterIsStopSent(EUSCI_B0_BASE));

    EUSCI_B_I2C_masterSendMultiByteStart(EUSCI_B0_BASE, TXData[i]);

    while(1)
    {
        __delay_cycles(5000);                   // Delay between transmissions
        TXByteCtr = 1;                          // Load TX byte counter
        if(i == 4) i = 2;


        while (EUSCI_B_I2C_SENDING_STOP == EUSCI_B_I2C_masterIsStopSent(EUSCI_B0_BASE));

        EUSCI_B_I2C_masterSendMultiByteStart(EUSCI_B0_BASE, TXData[i]);

        __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts
        // Remain in LPM0 until all data
        // is TX'd
        // Increment data byte
    }
}

//------------------------------------------------------------------------------
// The USCIAB0TX_ISR is structured such that it can be used to transmit any
// number of bytes by pre-loading TXByteCtr with the byte count. Also, TXData
// points to the next byte to transmit.
//------------------------------------------------------------------------------
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_B0_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(USCI_B0_VECTOR)))
#endif
void USCIB0_ISR(void)
{
    switch(__even_in_range(UCB0IV, USCI_I2C_UCBIT9IFG))
  {
        case USCI_NONE:             // No interrupts break;
            break;
        case USCI_I2C_UCALIFG:      // Arbitration lost
            break;
        case USCI_I2C_UCNACKIFG:    // NAK received (master only)
            //resend start if NACK
            EUSCI_B_I2C_masterSendStart(EUSCI_B0_BASE);
            break;
        case USCI_I2C_UCTXIFG0:     // TXIFG0
            // Check TX byte counter
            if (TXByteCtr)
            {
                i++;
                EUSCI_B_I2C_masterSendMultiByteNext(EUSCI_B0_BASE, TXData[i]);
                // Decrement TX byte counter
                TXByteCtr--;

            }
            else
            {
                EUSCI_B_I2C_masterSendMultiByteStop(EUSCI_B0_BASE);

                // Exit LPM0
                __bic_SR_register_on_exit(CPUOFF);
            }
            break;
        default:
            break;
  }
}