msp430超声波测距代码

下面是 MSP430 超声波测距的代码，仅供参考：

#include "msp430g2553.h"

#define TRIGGER BIT0    //P1.0
#define ECHO    BIT1    //P1.1

void delay_us(unsigned int us)
{
    __delay_cycles(us);
}

void delay_ms(unsigned int ms)
{
    __delay_cycles(1000*ms);
}

void main(void)
{
    WDTCTL = WDTPW + WDTHOLD; // stop WDT

    P1DIR |= TRIGGER;       //P1.0 as output
    P1DIR &= ~ECHO;         //P1.1 as input

    P1OUT &= ~TRIGGER;      //P1.0 output low

    while (1)
    {
        unsigned int distance = 0;
        unsigned int time = 0;

        P1OUT &= ~TRIGGER;  //P1.0 output low
        delay_us(2);
        P1OUT |= TRIGGER;   //P1.0 output high
        delay_us(10);
        P1OUT &= ~TRIGGER;  //P1.0 output low

        while(!(P1IN & ECHO));  //wait for the rising edge
        TACCR0 = 0;
        TACTL = TASSEL_2 + MC_2; //SMCLK, continuous mode
        while(P1IN & ECHO);
        TACTL = MC_0;   //stop the timer

        time = TAR;
        distance = time / 58; //calculate the distance

        delay_ms(1000); //wait for 1s
    }
}

这段代码使用 MSP430G2553 控制器进行超声波测距，将超声波测距的距离计算公式 `distance = time / 58` 写在了代码中。具体的使用方法可以参考代码中的注释。