c - ATMEGA168A-使用计时器

我正在尝试了解如何在我的ATMEGA168A中使用计时器，但是我有(link)的示例似乎不起作用，因为它始终返回0。

我的想法是使HC-SR04 (link)超声波传感器正常工作。

#define F_CPU   1000000UL
#include <avr/io.h>
#include <util/delay.h>

long measure(){
    //Setting up the timer
    TCCR1B |= (1 << CS12) | (1 << CS11) | (1 << CS10);

    //Setting trigger as output
    DDRD |= (1 << PD1);

    //Setting echo as input
    PORTD |= (1 << PD2);

    //Triggering the hardware
    PORTD ^= (1 << PD1);
    _delay_us(10);
    PORTD ^= (1 << PD1);

    //Waiting until echo goes low
    TCNT1 = 0;
    while(bit_is_clear(PIND, PD2));
    long timer_value = TCNT1;

    //Calculating and returning the distance
    long distance = timer_value / 58.82;
    return distance;
}

如何成功测量PD2处于高电平的时间？

最佳答案

要测量PD2处于高电平的时间，请编写一些代码来完成此操作，然后编译，将其写入微控制器并打开它。

未经测试，请尝试以下操作：

#define F_CPU   1000000UL
#include <avr/io.h>
#include <util/delay.h>

long measure(){
    //Setting up the timer
    TCCR1B |= (1 << CS12) | (1 << CS11) | (1 << CS10);

    //Setting trigger as output
    DDRD |= (1 << PD1);

    //Setting echo as input
    PORTD |= (1 << PD2);

    //Triggering the hardware
    PORTD ^= (1 << PD1);
    _delay_us(10);
    PORTD ^= (1 << PD1);

    //Waiting until echo goes low (after Initiate)
    while(!bit_is_clear(PIND, PD2));
    //Waiting until echo goes high (Echo back starts)
    while(bit_is_clear(PIND, PD2));
    TCNT1 = 0;
    //Waiting until echo goes low (Echo back ends)
    while(!bit_is_clear(PIND, PD2));
    long timer_value = TCNT1;

    //Calculating and returning the distance
    long distance = timer_value / 58.82;
    return distance;
}

关于c - ATMEGA168A-使用计时器，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/34471193/