byte led[7] = {13, 12, 11, 10, 9, 8, 7}; // a,b,c,d,e,f,g  共陰極 1=亮
byte digits[10][7] = {
  {1,1,1,1,1,1,0}, // 0
  {0,1,1,0,0,0,0}, // 1
  {1,1,0,1,1,0,1}, // 2
  {1,1,1,1,0,0,1}, // 3
  {0,1,1,0,0,1,1}, // 4
  {1,0,1,1,0,1,1}, // 5
  {1,0,1,1,1,1,1}, // 6
  {1,1,1,0,0,0,0}, // 7
  {1,1,1,1,1,1,1}, // 8
  {1,1,1,1,0,1,1}  // 9
};

#define BTN_STARTSTOP 5
#define BTN_RESET     6

bool running = false;
int number = 0;

void setup() {
  // 七段顯示器輸出
  for (int i = 0; i < 7; i++) pinMode(led[i], OUTPUT);

  // 按鍵輸入（使用內建上拉電阻）
  pinMode(BTN_STARTSTOP, INPUT_PULLUP);
  pinMode(BTN_RESET, INPUT_PULLUP);
}

void loop() {

  // ---- Start/Stop 按鍵（5 腳）----
  if (digitalRead(BTN_STARTSTOP) == LOW) {
    delay(50); // 按鍵去抖
    if (digitalRead(BTN_STARTSTOP) == LOW) {
      running = !running;   // 切換狀態
      while (digitalRead(BTN_STARTSTOP) == LOW); // 等放開
    }
  }

  // ---- Reset 按鍵（6 腳）----
  if (digitalRead(BTN_RESET) == LOW) {
    delay(50);
    if (digitalRead(BTN_RESET) == LOW) {
      number = 0;      // 回到 0
      running = false; // 停止
      showDigit(number);
      while (digitalRead(BTN_RESET) == LOW);
    }
  }

  // ---- 若正在運行就顯示並遞增 ----
  if (running) {
    showDigit(number);
    delay(800);  // 顯示間隔
    number++;
    if (number > 9) number = 0;
  } else {
    // 停止時保持原本顯示的數字
    showDigit(number);
  }
}

void showDigit(int n) {
  for (int i = 0; i < 7; i++) {
    digitalWrite(led[i], digits[n][i]);
  }
}