Compiler/MSP430FR2676: MSP430FR2676 locking up on a switch input interrupt.

Going to isr_trap means you got an interrupt which doesn't have an ISR. One way to do this is to make a typo in the vector= name; this will get a warning, but you might not notice.

Can you post or attach your code?

Thanks for the Response!!

When you mentioned: "One way to do this is to make a typo in the vector= name; this will get a warning, but you might not notice."
Where exactly do I add that?

Also, here is my code, if you see something that stands out (Or, if you need to see more code from a function), please let me know - Thanks!!!

===================
Main.c:
===================

void main(void)
{
    /* Set the watchdog timer */
    WDTCTL = WDTPW | WDTHOLD;

    /* Initialize the MCU:
    BSP_configureMCU() sets up the device IO and clocking
    The global interrupt enable is set to allow peripherals
    to wake the MCU. */
    BSP_configureMCU();

    /* open the port for communication */
    UART_openPort(&UARTPort);

    /* Setup LED pins */
    GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN7);
    GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN6);
    GPIO_setAsOutputPin(GPIO_PORT_P5, GPIO_PIN7);

    /* LED initial settings */
    GPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN7);
    GPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN6);
    GPIO_setOutputLowOnPin(GPIO_PORT_P5, GPIO_PIN7);

    /* Configure buttons */
    buttonConfigure();

    static uint32_t delayCounter = 0;
    static uint16_t loopCounter = 0;

    /* When this is in, CRASH!! */
    static uint8_t msg[] = {"Program Start"};
    UART_transmitBuffer(msg, sizeof(msg));

    /*  Main Loop */
    while(1)
    {
        /* Process the Buttons */
        buttonProcess();

        if (delayCounter++ > MAX_COUNTER)
        {
            delayCounter = 0;
            GPIO_toggleOutputOnPin(GPIO_PORT_P1, GPIO_PIN6);

            loopCounter++;
        }
    }
}

===================
Button.c
===================

void buttonConfigure( void )
{
    GPIO_setAsInputPinWithPullUpResistor(GPIO_PORT_P5, GPIO_PIN3);

    /* Set the edge */
    GPIO_selectInterruptEdge(GPIO_PORT_P5, GPIO_PIN3, GPIO_HIGH_TO_LOW_TRANSITION);

    /* Enable the interrupts for this port/pin */
    GPIO_enableInterrupt(GPIO_PORT_P5, GPIO_PIN3);

    /* Clear the interrupt */
    GPIO_clearInterrupt(GPIO_PORT_P5, GPIO_PIN3);
}

void buttonProcess( void )
{
    /* Clear the bitmap */
    buttonInterruptStatusVal = 0x0000;

    buttonInterruptStatusVal = GPIO_getInterruptStatus(GPIO_PORT_P5, GPIO_PIN3);

    /* Check if a button was pressed */
    if (buttonInterruptStatusVal)
    {
        GPIO_clearInterrupt(GPIO_PORT_P5, GPIO_PIN3);

        /* Toggle LED */
        GPIO_toggleOutputOnPin(GPIO_PORT_P1, GPIO_PIN7);
    }
}

===================
Structure for UART setup:
===================

//Sets all the parameters for UART transmission
const tUARTPort UARTPort =
{
     //does not receive messages, so no callback needed
    .pbReceiveCallback = NULL,

    //does not receive messages, so no callback needed
    .pbErrorCallback = 0,

    //choose clock source
    .peripheralParameters.selectClockSource = EUSCI_A_UART_CLOCKSOURCE_SMCLK,

    //clockPrescalar is UCBRx = int(N / 16), where N = clock_frequency / baud_rate
    // N = 2000000 / 115200 = 17.36111
    //int(N / 16) = int(17.36111 / 16) = int(1.0850694) = 1;
    .peripheralParameters.clockPrescalar = SMCLK_FREQ_MHZ * 1000000 / 115200 / 16,

    //controls UCBRF bits for oversampling mode
    //UCBRF = int(((N/16) - int(N/16)) * 16) = int(((17.36111/16) - int(17.36111/16)) * 16) = int(1.36111) = 1
    .peripheralParameters.firstModReg = 1,

    //consult table 22-4 in the user's guide to find the register value corresponding to UCBRF number
    //fraction portion of N = 0.36111
    //in the table, 0.36111 <---> 0x4A or 0x52
    .peripheralParameters.secondModReg = 0x4A,

    //controls parity bit - NOTE the eZ-FET does not support a parity bit
    .peripheralParameters.parity = EUSCI_A_UART_NO_PARITY,

    //least or most significant bit first
    .peripheralParameters.msborLsbFirst = EUSCI_A_UART_LSB_FIRST,

    //select either one or two stop bits
    .peripheralParameters.numberofStopBits = EUSCI_A_UART_ONE_STOP_BIT,

    //select whether to use multiprocessor/autobaud modes
    .peripheralParameters.uartMode = EUSCI_A_UART_MODE,

    //selects oversampling vs low-freq baud rate modes
    .peripheralParameters.overSampling = EUSCI_A_UART_OVERSAMPLING_BAUDRATE_GENERATION

};

To answer your question: You can define an ISR (Interrupt Service Routine) using "#pragma vector=<something>_VECTOR" and the __interrupt keyword.

But I don't think you want to do that. This code (buttonProcess) is polling the interrupt flags (IFG). That's fine, but in that case you should Not enable those interrupts (IE). The IFG bits are set independent of their corresponding IE bits. (It is routine to see IFG bits set for events you don't care about.)

Summary: Remove this line:

>    GPIO_enableInterrupt(GPIO_PORT_P5, GPIO_PIN3);