msp430超声波测距代码
时间: 2023-07-09 08:34:59 浏览: 55
以下是一个简单的 MSP430 超声波测距代码,可以用于测量距离:
```c
#include "msp430g2553.h"
#include <stdio.h>
#define TRIG BIT0
#define ECHO BIT1
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
P1OUT &= ~TRIG; // Ensure TRIG is low
P1DIR |= TRIG; // Set TRIG as output
P1DIR &= ~ECHO; // Set ECHO as input
P1IES &= ~ECHO; // Set ECHO interrupt to trigger on rising edge
P1IE |= ECHO; // Enable ECHO interrupt
__enable_interrupt(); // Enable global interrupts
while(1) {
P1OUT |= TRIG; // Send a 10us pulse to TRIG
__delay_cycles(10);
P1OUT &= ~TRIG;
__delay_cycles(30000); // Wait for the ECHO pin to settle
// Calculate distance
int distance = (int)((long)echo_pulse / 58);
// Print distance to serial console
printf("Distance: %d cm\r\n", distance);
__delay_cycles(500000); // Wait for next measurement
}
}
long echo_pulse = 0;
int echo_start_time = 0;
// ECHO pin interrupt service routine
#pragma vector=PORT1_VECTOR
__interrupt void Port_1(void)
{
if(P1IFG & ECHO) {
if(P1IN & ECHO) {
// Start timer
TA0CTL = TASSEL_2 + MC_2 + TACLR;
echo_start_time = TA0R;
} else {
// Stop timer and record pulse duration
TA0CTL = TACLR;
echo_pulse = TA0R - echo_start_time;
}
P1IFG &= ~ECHO;
}
}
```
在这个代码中,TRIG 和 ECHO 分别连接到 MSP430 的 P1.0 和 P1.1 引脚上。当需要进行测距时,代码会向 TRIG 引脚发送一个 10us 的脉冲,然后等待 ECHO 引脚上的信号。当收到 ECHO 引脚上的信号时,代码会记录下信号的持续时间,然后根据声音传播速度和信号持续时间计算出距离。最后,代码会将距离输出到串口上,然后等待下一次测距。