MSP430FR2433: 使用DCO时，是否需要对DCOFFG进行处理？

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//******************************************************************************
//!  EUSCI_A0 External Loopback test using EUSCI_A_UART_init API
//!
//!  Description: This demo connects TX to RX of the MSP430 UART
//!  The example code shows proper initialization of registers
//!  and interrupts to receive and transmit data.
//!
//!  SMCLK = MCLK = BRCLK = DCOCLKDIV = ~1MHz, ACLK = 32.768kHz
//!
//!
//!            Tested on MSP430FR4133
//!             -----------------
//!       RST -|     P1.0/UCA0TXD|----|
//!            |                 |    |
//!            |                 |    |
//!            |     P1.1/UCA0RXD|----|
//!            |                 |
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - UART peripheral
//! - GPIO Port peripheral (for UART pins)
//! - UCA0TXD
//! - UCA0RXD
//!
//! 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_A0_VECTOR.
//******************************************************************************
#include "driverlib.h"

uint16_t i;
uint8_t RXData = 0, TXData = 0;
uint8_t check = 0;
uint32_t clockValue;

void main(void)
{
    // stop watchdog
    WDT_A_hold(WDT_A_BASE);

    // XT1 Setup
    //Set P4.1 and P4.2 as Function Input.
    /*

     * Select Port 4
     * Set Pin 1, 2 to input Module Function, XT1.
     */
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_P2,
        GPIO_PIN0 + GPIO_PIN1,
        GPIO_PRIMARY_MODULE_FUNCTION
        );

    //Set external clock frequency to 32.768 KHz
    CS_setExternalClockSource(32768);
    //Set ACLK=XT1
    CS_initClockSignal(CS_ACLK,CS_XT1CLK_SELECT,CS_CLOCK_DIVIDER_1);
    //Start XT1 with no time out
    CS_turnOnXT1(CS_XT1_DRIVE_0);
    //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 UART pins
    //Set P1.0 and P1.1 as Secondary Module Function Input.
    /*

     * Select Port 1
     * Set Pin 0, 1 to input with function, (UCA0TXD/UCA0SIMO, UCA0RXD/UCA0SOMI).
     */
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_P1,
        GPIO_PIN4 + GPIO_PIN5,
        GPIO_PRIMARY_MODULE_FUNCTION
        );

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

    //Configure UART
    //SMCLK = 1MHz, Baudrate = 115200
    //UCBRx = 8, UCBRFx = 0, UCBRSx = 0xD6, UCOS16 = 0
    EUSCI_A_UART_initParam param = {0};
    param.selectClockSource = EUSCI_A_UART_CLOCKSOURCE_SMCLK;
    param.clockPrescalar = 8;
    param.firstModReg = 0;
    param.secondModReg = 0xD6;
    param.parity = EUSCI_A_UART_NO_PARITY;
    param.msborLsbFirst = EUSCI_A_UART_LSB_FIRST;
    param.numberofStopBits = EUSCI_A_UART_ONE_STOP_BIT;
    param.uartMode = EUSCI_A_UART_MODE;
    param.overSampling = EUSCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION;

    if(STATUS_FAIL == EUSCI_A_UART_init(EUSCI_A0_BASE, &param))
    {
        return;
    }

    EUSCI_A_UART_enable(EUSCI_A0_BASE);

    EUSCI_A_UART_clearInterrupt(EUSCI_A0_BASE,
                                EUSCI_A_UART_RECEIVE_INTERRUPT);

    // Enable USCI_A0 RX interrupt
    EUSCI_A_UART_enableInterrupt(EUSCI_A0_BASE,
                                 EUSCI_A_UART_RECEIVE_INTERRUPT);      // Enable interrupt

    //Verify if the Clock settings are as expected
    clockValue = CS_getMCLK();
    clockValue = CS_getACLK();
    clockValue = CS_getSMCLK();

    __enable_interrupt();
    while(1)
    {
        TXData = TXData + 1;                            // Increment TX data
        // Load data onto buffer
        EUSCI_A_UART_transmitData(EUSCI_A0_BASE,
                                  TXData);
        while(check != 1)
        {
            ;
        }
        check = 0;
    }
}

//******************************************************************************
//
//This is the USCI_A0 interrupt vector service routine.
//
//******************************************************************************
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A0_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(USCI_A0_VECTOR)))
#endif
void EUSCI_A0_ISR(void)
{
    switch(__even_in_range(UCA0IV,USCI_UART_UCTXCPTIFG))
    {
    case USCI_NONE: break;
    case USCI_UART_UCRXIFG:
        RXData = EUSCI_A_UART_receiveData(EUSCI_A0_BASE);
        if(!(RXData == TXData))                       // Check value
        {
            while(1)
            {
                ;
            }
        }
        check = 1;
        break;
    case USCI_UART_UCTXIFG: break;
    case USCI_UART_UCSTTIFG: break;
    case USCI_UART_UCTXCPTIFG: break;
    }
}