[参考译文] MSP430FR2111：请告诉我如何使用 UART 进行串行通信。

Other Parts Discussed in Thread: MSP430FR2111

https://e2e.ti.com/support/microcontrollers/msp-low-power-microcontrollers-group/msp430/f/msp-low-power-microcontroller-forum/1596034/msp430fr2111-please-tell-me-how-to-communicate-serially-using-uart

器件型号： MSP430FR2111

感谢 E2E 论坛的所有人的帮助。

我目前正在开发一个使用 Texas Instruments MSP430FR2111 MCU 的系统。

系统​​大约每天向外部 PC 发送一次测量值、以 UART 作为通信方法。

我创建了端口初始化和数据传输的源代码,并试图通过 FT232RL 使用 PC 终端应用程序接收数据,但出于某种原因,当 P1.6 (RxD) 连接到 FT232RL 的 TxD,数据无法从 P1.7 (TxD) 发送。

我被这个神秘的现象困扰:如果我断开连接 P1.6 (RxD) 到 FT232RL 的 TxD,数据可以从 P1.7 (TxD) 发送。

我有多个 FT232RL、所以我尝试了几个、但每个 FT232RL 的结果相同。
我随附了当前的源代码、虽然我很抱歉在您繁忙的日程安排期间打扰您、但如果您能告诉我如何解决问题、我将不胜感激。
提前感谢您。

#include <msp430.h>
#include <stdint.h> 

#pragma DATA_SECTION(accumulated_distance, ".myFRAM")
volatile uint32_t accumulated_distance;

#pragma DATA_SECTION(magic_flag, ".myFRAM")
volatile uint32_t magic_flag;

#define MAGIC_INITIALIZED   0xFFFFFFF0      // 2025.12.03
#define SMCLK_FREQ_HZ       1000000UL       // 2025.12.09
#define UART_BRW_VALUE      104
#define UART_MCTLW_VALUE    (UCOS16 | (2 << 4) | (0 << 8))

volatile uint8_t inc_flag = 0;

__interrupt void Port_1(void);

void uart_putc(char c);
void uart_puts(const char *s);

#define MCLK_FREQ_MHZ 1                     // MCLK = 1MHz

int main(void) {
    WDTCTL = WDTPW | WDTHOLD;               // Stop watchdog timer
    SYSCFG0 = FRWPPW;                       // 

    __bis_SR_register(SCG0);                // Disable FLL
    CSCTL3 = SELREF__REFOCLK;               // Set REFO as FLL reference source
    CSCTL1 = DCOFTRIMEN_0 | DCORSEL_0;      // DCO Range = 1MHz
    CSCTL2 = FLLD_0 + 30;                   // DCODIV = 1MHz
    __delay_cycles(3);
    __bic_SR_register(SCG0);                // Enable FLL
    CSCTL4 = SELMS__DCOCLKDIV | SELA__REFOCLK; // set default REFO(~32768Hz) as ACLK source, ACLK = 32768Hz
                                               // default DCODIV as MCLK and SMCLK source

    //
    // P1.0 / A0
    P1SEL0 |= BIT0; P1SEL1 |= BIT0;

    // P1.1 / A1
    P1DIR |= BIT1;

    // P1.3 / A3
    P1SEL0 &= ~BIT3; P1SEL1 &= ~BIT3;   //
    P1DIR &= ~BIT3;                     //
    P1IES |= BIT3;                      //
    P1IFG &= ~BIT3;                     //
    P1IE |= BIT3;                       //

    // P1.4 / A4
    P1SEL0 &= ~BIT4; P1SEL1 &= ~BIT4;   //
    P1DIR |= BIT4;                      //
    P1OUT &= ~BIT4;                     //

    // P1.5 / A5
    P1SEL0 &= ~BIT5; P1SEL1 &= ~BIT5;   //
    P1DIR |= BIT5;                      //
    P1OUT &= ~BIT5;                     //

    // P2.0
    P2SEL0 &= ~BIT0; P2SEL1 &= ~BIT0;   //
    P2DIR  |= BIT0;                     //
    P2OUT  |= BIT0;                     //

    // P2.1
    P2SEL0 &= ~BIT1; P2SEL1 &= ~BIT1;   //
    P2DIR &= ~BIT1;                     //

    // UART
    // P1.6 = UCA0RXD, P1.7 = UCA0TXD
    // 1) stop eUSCI_A
    
    //----------------------------------------------------------
    // (1) RXD (P1.6)
    //----------------------------------------------------------
    P1DIR &= ~BIT6;      // RXD input
    P1OUT |= BIT6;       // pull-up
    P1REN |= BIT6;       // enable pull-up

    //
    __delay_cycles(200000);   // 200ms @1MHz

    //----------------------------------------------------------
    // (2) Function change
    //----------------------------------------------------------
    P1REN &= ~BIT6;            //
    P1SEL0 |=  BIT6 | BIT7;    //
    P1SEL1 &= ~(BIT6 | BIT7);

    //----------------------------------------------------------
    // (3) DIR
    //----------------------------------------------------------
    P1DIR &= ~BIT6;     //
    P1DIR |=  BIT7;     //

    //----------------------------------------------------------
    // (4)
    //----------------------------------------------------------
    UCA0CTLW0  =  UCSWRST;        //
    UCA0CTLW0 |=  UCSSEL__SMCLK;  // SMCLK = 1MHz

    // 9600bps @ 1MHz
    UCA0BR0 = 104;
    UCA0BR1 = 0;
    UCA0MCTLW = 0;                //

    UCA0CTLW0 &= ~UCSWRST;        // UART start

    // UCA0IE |= UCRXIE;                //

    // ADC
    ADCCTL0 &= ~ADCENC;                 //
    ADCCTL1 |= ADCSHP | ADCSSEL_2;      //
    ADCCTL2 |= ADCRES_2;                //

    ADCMCTL0 |= ADCINCH_0;              //

    ADCCTL0 |= ADCON;                   //
    ADCIE |= ADCIE0;                    //
    
    PM5CTL0 &= ~LOCKLPM5;                   // Disable the GPIO power-on default high-impedance mode
                                            // to activate previously configured port settings

    // Check if this is first-ever run
    if (magic_flag != MAGIC_INITIALIZED){
        accumulated_distance = 0;           // Initialize on first run only
        magic_flag = MAGIC_INITIALIZED;
    }

    __delay_cycles(500000);

// Example
    uart_puts("U");

    while(1)							//
    {
        __low_power_mode_3();           //
        //
        if (inc_flag){
            accumulated_distance++;
            inc_flag = 0;
        }
    }
}

void uart_putc(char c) {
    while (! (UCA0IFG & UCTXIFG));      //
    UCA0TXBUF = c;                      // send
}

void uart_puts(const char *s){
    while (*s){
        uart_putc(*s++);
    }
}

// Port 1.x interrupt service routine
#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void)
{    
   if (P1IFG & BIT3){                   //
        inc_flag = 1;                   //
        P1IFG &= ~BIT3;                 //
        __bic_SR_register_on_exit(LPM3_bits);
    }
}