Arduino Uno不想写变量

Question

我正在写一个小草图来读取传感器值并将它们打印在 LCD 屏幕上。直到现在这都很好用，我不记得有什么改变，但突然我的 Arduino 不想再改变 ringbuf 变量的值，它现在总是在 8224。

这些是代码中最相关的部分：

const int RING_SIZE = 5;
double ringbuf[RING_SIZE]; // array for the ring buffer
unsigned int ringpos = 0; // position in the ring buffer - this will always be 8224 for some reason

// in loop()

ringbuf[ringpos] = readSensor();
ringpos++;
if (ringpos >= RING_SIZE) {
    ringpos = 0;
}

完整代码如下：

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

#include <Keypad.h>

#include <stdio.h>

int readpin = A2;
int irpin = 9;
const int BUFFER_SIZE = 20;
int buf[BUFFER_SIZE];
const int RING_SIZE = 5;
unsigned int ringpos = 0;
double ringbuf[RING_SIZE];
unsigned long lastRedTime = millis();
char text[20];

const byte ROWS = 4;
const byte COLS = 3;
const unsigned long BACKLIGHT_DURATION = 5000;
const double THRESHOLD = 245;

const double wattPerTurn = 1.666666667;
double lastUsage = 0;
bool currentState = LOW;

char keys[ROWS][COLS] = {{'1', '2', '3'},
  {'4', '5', '6'},
  {'7', '8', '9'},
  {'*', '0', '#'}
};

byte rowPins[] = {5, 4, 3, 2};
byte colPins[] = {8, 7, 6};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
LiquidCrystal_I2C lcd(0x20, 16, 2);

unsigned long lastKey = millis();
int turns = 0;


void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.home();

  pinMode(irpin, OUTPUT);
  analogReference(DEFAULT);
  digitalWrite(irpin, HIGH);
}

void loop() {
  Serial.print(ringpos);
  Serial.println();
  ringbuf[ringpos] = readSensor();
  ringpos++;
  if (ringpos >= RING_SIZE) {
    ringpos = 0;
  }

  double value = getAverage();
  if (value < THRESHOLD && currentState == HIGH) {
    currentState = LOW;

    lastUsage = wattPerTurn / (double) ((millis() - lastRedTime) / 1000) * (double) 3600;

    turns ++;
    lastRedTime = millis();
    lcd.clear();
    lcd.setCursor(10, 0);
    lcd.print("rot");
  }
  if (value > THRESHOLD && currentState == LOW) {
    currentState = HIGH;
    lcd.clear();
    lcd.setCursor(10, 0);
    lcd.print("silber");
  }
  lcd.setCursor(0, 0);

  sprintf(text, "%i W", lastUsage);
  lcd.print(text);

  lcd.setCursor(0, 1);
  sprintf(text, "s: %i, t: %i Wh   ", (int) value, (int) (((double) turns) * wattPerTurn));
  lcd.print(text);

  delay(20);
}

double getRelative(int r) {
  int v = ringpos + r;
  while (v < 0) {
    v += RING_SIZE;
  }
  while (v >= RING_SIZE) {
    v -= RING_SIZE;
  }
  return ringbuf[v];
}

double getAverage() {
  double sum = 0;
  for (int i = 0; i < RING_SIZE; i++) {
    sum += ringbuf[i];
  }
  return sum / (double) RING_SIZE;
}

double readSensor() {
  for (int i = 0; i < BUFFER_SIZE; i++) {
    buf[i] = analogRead(readpin);
  }

  int sum = 0;
  for (int i = 0; i < BUFFER_SIZE; i++) {
    sum += buf[i];
  }

  return (double) sum / (double) BUFFER_SIZE;
}

我可能漏掉了一些非常愚蠢的东西，但我不知道为什么它会停止工作。我还在另一个 Arduino 上测试了这个，同样的事情发生了。

Answer 1

请更新问题以直接包含所有相关代码，而不是在 pastie 上链接到它。错误不在您在此处显示的代码中，而是您的 text 变量

char text[10];

对于

来说太短了

sprintf(text, "s: %i, t: %i Wh   ", (int) value, (int) (((double) turns) * wattPerTurn));

你稍后再做，所以这会在 text 之外写入恰好位于 RAM 中 text 后面的变量。想必，ringpos恰好属于一种情况下被覆盖的那些，而另一种情况下则不会，但这当然会导致UB，无论哪种方式都是不可靠的。

要修复它，请使 text 足够大。

Arduino Uno不想写变量

Arduino Uno does not want to write variable

c++

arduino