Arduino Uno：当第二次按下时，While-loop 无法使用按钮重置计时器“重启”？答案

【问题标题】：Arduino Uno: While-loop fails to "restart" using Button to reset Timer when second-pressing?Arduino Uno：当第二次按下时，While-loop 无法使用按钮重置计时器“重启”？
【发布时间】：2020-11-07 17:45:17
【问题描述】：

代码的作用：

代码首先显示一个简短的“闪烁动画”，其中 A-F 段一次打开和关闭一个。
“闪烁动画”持续 3 到 10 秒，然后计时器开始计时。
数字 1 和 2 显示的计时器从 0 到 99 秒计数。而数字 3 和 4 分别显示第 10 和第 100 秒。
通过使用连接的按钮，您可以通过按下它来停止计时器。计时器停止并显示时间。
再次按下按钮应该会重新启动计时器并将我们送回第 1 步。

我的问题：当我进入代码中的第 5 步时，它不会重新启动。据我所知，该问题与 main 函数中的 while 循环有关，这是由函数“stopTimer”中的第二个 while 循环引起的。不能让它退出循环。至少这是我从无数次不成功的尝试中了解到的！尝试在“stopDisplay”函数中添加带有 if 语句的代码，包括 break；或返回；等等

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <avr/io.h>
#include <util/delay.h>

#define BUTTONPRESSED PINC & 1 << PC0

    /*
    - PORT = D
    Segment-A   Pin 1   PD1     0B00000010
    Segment-B   Pin 2   PD2     0B00000100
    Segment-C   Pin 3   PD3     0B00001000
    Segment-D   Pin 4   PD4     0B00010000
    Segment-E   Pin 5   PD5     0B00100000
    Segment-F   Pin 6   PD6     0B01000000
    Segment-G   Pin 7   PD7     0B10000000

    - PORT = B
    Digit 1     Pin 10  PB2     0B00000100
    Digit 2     Pin 11  PB3     0B00001000
    Digit 3     Pin 12  PB4     0B00010000
    Digit 4     Pin 13  PB5     0B00100000

    - PORT = C
    Button      Pin A0  PC0     0B00000001
    */

//Number: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9  in a array.
int segmentNumberArray[10] = {0B01111110, 0B00001100, 0B010110110, 0B10011110, 0B011001100, 0B11011010, 0B11111010, 0B00001110, 0B11111110, 0B11011110};

//Digit: 1, 2, 3, 4   in a array
int digitArrayOff[4] = {0B00000100, 0B00001000, 0B00010000, 0B00100000};
int digitArrayOn[4] = {0B11111011, 0B11110111, 0B11101111, 0B11011111};

//Blinking animation: segment-E, segment-D, segment-C, segment-G, segment-F, segment-A, segment-B, segment-G
int blinkingArray[8] = {0B00100000, 0B00010000, 0B00001000, 0B10000000, 0B01000000, 0B00000010, 0B00000100, 0B10000000};

long number = 0;
int recentTime;
int digit1, digit2, digit3, digit4;
int stopButton;

void startTimer();
void stopTimer();
void choseDigit(int x);
void showNumberOnDisplay(int x);
void blinkingAnimation();

int main()
{

  DDRC = 0;
  DDRD = 255;
  DDRB = 0B00111100; //DDRB = 28;

  srand(time(NULL));

  while (1)
  {
    if (number == 0)
    {
      int randomWaitTime = rand() % 10 + 3; //Calls random number between 3-10
      for (int i = 0; i < randomWaitTime; i++)
      {
        blinkingAnimation();
      }
    }
    startTimer();

    if (BUTTONPRESSED)
    {
      stopButton = 0;
      stopTimer();
    }
    
    if (BUTTONPRESSED)
    {
      break;
    }
  }

  return 0;
}

void startTimer()
{
  PORTD = 0B00000000;                   //Turn ALL segments off
  choseDigit(1);                        //Turn Display 1 on
  showNumberOnDisplay((number / 1000)); //Get value of thousand
  _delay_ms(1);                         //Delay 1 ms

  PORTD = 0B00000000;                         //Turn ALL segments off
  choseDigit(2);                              //Turn Display 2 on
  showNumberOnDisplay((number % 1000) / 100); //Get value of hundred
  _delay_ms(1);                               //Delay 1 ms

  PORTD = 0B00000000;                     //Turn ALL segments off
  choseDigit(3);                          //Turn Display 3 on
  showNumberOnDisplay(number % 100 / 10); //Get value of ten
  _delay_ms(1);                           //Delay 1 ms

  PORTD = 0B00000000;               //Turn ALL segments off
  choseDigit(4);                    //Turn Display 3 on
  showNumberOnDisplay(number % 10); //Get value of single digit
  _delay_ms(1);                     //Delay 1 ms

  number++;
  if (number == 9999) // Reset number count to 1;
  {
    number = 1;
  }
}

void stopTimer()
{
  recentTime = number;
  digit1 = recentTime / 1000;
  digit2 = (recentTime % 1000) / 100;
  digit3 = recentTime % 100 / 10;
  digit4 = recentTime % 10;

  while (stopButton == 0)
  {
    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(1);               //Turn Display 1 on
    showNumberOnDisplay(digit1); //Get value of thousand
    _delay_ms(1);                //Delay 1 ms

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(2);               //Turn Display 2 on
    showNumberOnDisplay(digit2); //Get value of hundred
    _delay_ms(1);                //Delay 1 ms

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(3);               //Turn Display 3 on
    showNumberOnDisplay(digit3); //Get value of ten
    _delay_ms(1);                //Delay 1 ms

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(4);               //Turn Display 3 on
    showNumberOnDisplay(digit4); //Get value of single digit
    _delay_ms(1);                //Delay 1 ms
  }
}

void choseDigit(int x)
{
  PORTB = 0B11111111;
  switch (x)
  {
  case 1:
    PORTB = digitArrayOn[0]; //Display 1 on
    break;

  case 2:
    PORTB = digitArrayOn[1]; //Display 2 on
    break;

  case 3:
    PORTB = digitArrayOn[2]; //Display 3 on
    break;

  case 4:
    PORTB = digitArrayOn[3]; //Display 4 on
    break;
  }
}

void showNumberOnDisplay(int x)
{
  switch (x)
  {
  case 1:
    PORTD = segmentNumberArray[1];
    break;

  case 2:
    PORTD = segmentNumberArray[2];
    break;

  case 3:
    PORTD = segmentNumberArray[3];
    break;

  case 4:
    PORTD = segmentNumberArray[4];
    break;

  case 5:
    PORTD = segmentNumberArray[5];
    break;

  case 6:
    PORTD = segmentNumberArray[6];
    break;

  case 7:
    PORTD = segmentNumberArray[7];
    break;

  case 8:
    PORTD = segmentNumberArray[8];
    break;

  case 9:
    PORTD = segmentNumberArray[9];
    break;

  default:
    PORTD = segmentNumberArray[0];
    break;
  }
}

void blinkingAnimation()
{
  for (int i = 0; i < 8; i++)
  {
    PORTD = blinkingArray[i];
    _delay_ms(125);
  }
}

【问题讨论】：

标签： c arduino arduino-uno

【解决方案1】：

变量stopButton的值还是0，结果stopButton == 0返回true。但我认为最好用变量来表示状态。

#define STATE_COUNT 1
#define STATE_STOP 2
int currentState = 1;
while(1){
  if(currentState == STATE_COUNT && BUTTONPRESSED){
     //do something

     currentState = STATE_STOP;
  }
  if(currentState == STATE_STOP && BUTTONPRESSED){
     //do something

     currentState = STATE_COUNT;
  }
}

编辑

所以，我的想法是使用 STATE 来定义要运行的代码。所以你可以消除第二个while循环。

while (1) {
  if(currentState == STATE_BLINK){
    blink(); //run code 1 time and change state
    currentState = STATE_COUNT;
  }
  if(currentState == STATE_COUNT){
    startTimer(); 
  }
  if(currentState == STATE_STOP){
    stopTimer(); // while loop inside is removed
  }


  if (BUTTONPRESSED) {
    //change state here
  }
}

void stopTimer() {
  recentTime = number;
  digit1 = recentTime / 1000;
  digit2 = (recentTime % 1000) / 100;
  digit3 = recentTime % 100 / 10;
  digit4 = recentTime % 10;

  PORTD = 0B00000000;          //Turn ALL segments off
  choseDigit(1);               //Turn Display 1 on
  showNumberOnDisplay(digit1); //Get value of thousand
  _delay_ms(1);                //Delay 1 ms

  PORTD = 0B00000000;          //Turn ALL segments off
  choseDigit(2);               //Turn Display 2 on
  showNumberOnDisplay(digit2); //Get value of hundred
  _delay_ms(1);                //Delay 1 ms

  PORTD = 0B00000000;          //Turn ALL segments off
  choseDigit(3);               //Turn Display 3 on
  showNumberOnDisplay(digit3); //Get value of ten
  _delay_ms(1);                //Delay 1 ms

  PORTD = 0B00000000;          //Turn ALL segments off
  choseDigit(4);               //Turn Display 3 on
  showNumberOnDisplay(digit4); //Get value of single digit
  _delay_ms(1);                //Delay 1 ms 
}

void blink(){
 if (number == 0) {
  int randomWaitTime = rand() % 10 + 3; //Calls random number between 3-10
  for (int i = 0; i < randomWaitTime; i++) {
    blinkingAnimation();
  }
 }
}

【讨论】：

我什至尝试使用 if 语句添加 stopButton = 1 来停止 while 循环，无论是否有 break 或 return 以强制它以某种方式退出。然而，这根本没有帮助，只是导致了其他不受欢迎的行为。为我缺乏知识而道歉，因为我是 C 的新手。我见过类似的东西，但我只是不知道如何实现它。我试过了，但没有成功 = 在我包含的if(currentState == STATE_COUNT && BUTTONPRESSED) 语句中：stopButton = 0, stopTime();，而在第二个语句中我不知道要包含什么，只是添加了 break;。困惑，对不起伙计。
Hermenstian IW - 我尝试了各种方式和组合。无法让它工作：/。它只是破坏了代码，一切都变得空白。不知道如何实现上述。感谢您能否详细说明。
对不起，如果我不能解释清楚，我编辑了我的答案。
我试过你上面的例子还是不行......这太令人沮丧了！我想知道，这可能是问题所在的按钮吗？但是我看不到那里有什么问题，并且按钮应该可以使用 Bit-operators 来激活它并且不需要任何类型的重置？我用一个新块编辑了你的答案，这样你就可以看到我在尝试你建议的代码时做了什么。看看那里有没有什么奇怪的事情发生？

【解决方案2】：

这里终于解决了我上面的问题。以为我发布它以防其他人遇到类似问题：

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <avr/io.h>
#include <util/delay.h>

#define BUTTONPRESSED PINC &(1 << PC0)

/*
    - PORT = D
    Segment-A   Pin 1   PD1     0B00000010
    Segment-B   Pin 2   PD2     0B00000100
    Segment-C   Pin 3   PD3     0B00001000
    Segment-D   Pin 4   PD4     0B00010000
    Segment-E   Pin 5   PD5     0B00100000
    Segment-F   Pin 6   PD6     0B01000000
    Segment-G   Pin 7   PD7     0B10000000

    - PORT = B
    Digit 1     Pin 10  PB2     0B00000100
    Digit 2     Pin 11  PB3     0B00001000
    Digit 3     Pin 12  PB4     0B00010000
    Digit 4     Pin 13  PB5     0B00100000

    - PORT = C
    Button      Pin A0  PC0     0B00000001
    */

//Number: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9  in a array
int segmentNumberArray[10] = {0B01111110, 0B00001100, 0B010110110, 0B10011110, 0B011001100, 0B11011010, 0B11111010, 0B00001110, 0B11111110, 0B11011110};

//Digit: 1, 2, 3, 4   in a array
int digitArrayOff[4] = {0B00000100, 0B00001000, 0B00010000, 0B00100000};
int digitArrayOn[4] = {0B11111011, 0B11110111, 0B11101111, 0B11011111};

//Blinking animation: segment-E, segment-D, segment-C, segment-G, segment-F, segment-A, segment-B, segment-G
int blinkingArray[8] = {0B00100000, 0B00010000, 0B00001000, 0B10000000, 0B01000000, 0B00000010, 0B00000100, 0B10000000};

long number = 0;
int recentTime;
int digit1, digit2, digit3, digit4;
int isCounting = 0;
int isButtonDown = 0;

void startTimer();
void stopTimer();
void choseDigit(int x);
void showNumberOnDisplay(int x);
void blinkingAnimation();

int main()
{

  DDRC = 0; // För knappen -->> alt. DDRC&= ~(1 << PC0);
  DDRD = 255;
  DDRB = 0B00111100; //DDRB = 28; -->> detta är för Displayerna

  srand(time(NULL));
  blinkingAnimation();

  while (1)
  {
    if (isCounting == 1)
    {
      startTimer();
    }

    if (BUTTONPRESSED)
    {
      if (isButtonDown == 0)  //Button has not been pressed before
      {
        isButtonDown = 1;
        if (isCounting == 0)
        {
          
          blinkingAnimation();
        }
        else
        {
        isCounting = 0;
        }
      }
    }
    else
    {
      isButtonDown = 0;  //Button has been released
    }

    stopTimer();
  }

  return 0;
}

void startTimer()
{
  PORTD = 0B00000000;                   //Turn ALL segments off
  choseDigit(1);                        //Turn Display 1 on
  showNumberOnDisplay((number / 1000)); //Get value of thousand
  _delay_ms(2.3);                       //Delay 1 ms

  PORTD = 0B00000000;                         //Turn ALL segments off
  choseDigit(2);                              //Turn Display 2 on
  showNumberOnDisplay((number % 1000) / 100); //Get value of hundred
  _delay_ms(2.3);                             //Delay 1 ms

  PORTD = 0B00000000;                     //Turn ALL segments off
  choseDigit(3);                          //Turn Display 3 on
  showNumberOnDisplay(number % 100 / 10); //Get value of ten
  _delay_ms(2.3);                         //Delay 1 ms

  PORTD = 0B00000000;               //Turn ALL segments off
  choseDigit(4);                    //Turn Display 4 on
  showNumberOnDisplay(number % 10); //Get value of single digit
  _delay_ms(2.3);                   //Delay 1 ms

  number++;
  if (number > 5999) // Reset number count to 1;
  {
    number = 1;
  }
}

void stopTimer()
{
  recentTime = number;
  digit1 = recentTime / 1000;
  digit2 = (recentTime % 1000) / 100;
  digit3 = recentTime % 100 / 10;
  digit4 = recentTime % 10;

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(1);               //Turn Display 1 on
    showNumberOnDisplay(digit1); //Get value of thousand
    _delay_ms(1);                //Delay 1 ms

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(2);               //Turn Display 2 on
    showNumberOnDisplay(digit2); //Get value of hundred
    _delay_ms(1);                //Delay 1 ms

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(3);               //Turn Display 3 on
    showNumberOnDisplay(digit3); //Get value of ten
    _delay_ms(1);                //Delay 1 ms

    PORTD = 0B00000000;          //Turn ALL segments off
    choseDigit(4);               //Turn Display 3 on
    showNumberOnDisplay(digit4); //Get value of single digit
    _delay_ms(1);                //Delay 1 ms
}

void choseDigit(int x)
{
  PORTB = 0B11111111;
  switch (x)
  {
  case 1:
    PORTB = digitArrayOn[0]; //Display 1 on
    break;

  case 2:
    PORTB = digitArrayOn[1]; //Display 2 on
    break;

  case 3:
    PORTB = digitArrayOn[2]; //Display 3 on
    break;

  case 4:
    PORTB = digitArrayOn[3]; //Display 4 on
    break;
  }
}

void showNumberOnDisplay(int x)
{
  switch (x)
  {
  case 1:
    PORTD = segmentNumberArray[1];
    break;

  case 2:
    PORTD = segmentNumberArray[2];
    break;

  case 3:
    PORTD = segmentNumberArray[3];
    break;

  case 4:
    PORTD = segmentNumberArray[4];
    break;

  case 5:
    PORTD = segmentNumberArray[5];
    break;

  case 6:
    PORTD = segmentNumberArray[6];
    break;

  case 7:
    PORTD = segmentNumberArray[7];
    break;

  case 8:
    PORTD = segmentNumberArray[8];
    break;

  case 9:
    PORTD = segmentNumberArray[9];
    break;

  default:
    PORTD = segmentNumberArray[0];
    break;
  }
}

void blinkingAnimation()
{
  PORTB = digitArrayOn[4];
  //Random wait time:
  int randomWaitTime = rand() % 10 + 3; //Calls random number between 3-10 seconds

  for (int i = 0; i < randomWaitTime; i++)
  {
    //Blink animation:
    for (int i = 0; i < 8; i++)
    {
      PORTD = blinkingArray[i];
      _delay_ms(125);
    }
  }
  number = 0;
  isCounting = 1;
}

【讨论】：