#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// 初始化 LiquidCrystal_I2C 类，参数依次为 I2C 地址，列数，行数
LiquidCrystal_I2C lcd(0x27, 16, 2);

// 定义按钮引脚
const int button1Pin = 25;
const int button2Pin = 32;
const int button3Pin = 34;

// 变量用于存储按钮按下的时间
volatile unsigned long button1PressedTime = 0;
volatile unsigned long button2PressedTime = 0;
volatile unsigned long button3PressedTime = 0;

void setup() {
  // 初始化 LCD
    lcd.init(); // 初始化 LCD
      lcd.backlight(); // 打开背光
        lcd.clear();
          lcd.setCursor(0, 0);
            lcd.print("Press buttons");
              lcd.setCursor(0, 1);
                lcd.print("to start timing");

                  // 设置按钮引脚为输入，并启用内部上拉电阻
                    pinMode(button1Pin, INPUT_PULLUP);
                      pinMode(button2Pin, INPUT_PULLUP);
                        pinMode(button3Pin, INPUT_PULLUP);

                          // 设置按钮的中断
                            attachInterrupt(digitalPinToInterrupt(button1Pin), button1Pressed, FALLING);
                              attachInterrupt(digitalPinToInterrupt(button2Pin), button2Pressed, FALLING);
                                attachInterrupt(digitalPinToInterrupt(button3Pin), button3Pressed, FALLING);
                                }

                                void loop() {
                                  // 在 LCD 上显示时间间隔
                                    lcd.setCursor(0, 0);
                                      lcd.print("Time1: ");
                                        lcd.print(button2PressedTime - button1PressedTime);
                                          lcd.print(" ms   ");

                                            lcd.setCursor(0, 1);
                                              lcd.print("Time2: ");
                                                lcd.print(button3PressedTime - button2PressedTime);
                                                  lcd.print(" ms   ");

                                                    // 添加小延迟，减少 CPU 使用率
                                                      delay(100);
                                                      }

                                                      // 按钮的中断服务程序
                                                      void button1Pressed() {
                                                        button1PressedTime = millis();
                                                          detachInterrupt(digitalPinToInterrupt(button1Pin)); // 禁用中断
                                                          }

                                                          void button2Pressed() {
                                                            button2PressedTime = millis();
                                                              detachInterrupt(digitalPinToInterrupt(button2Pin)); // 禁用中断
                                                              }

                                                              void button3Pressed() {
                                                                button3PressedTime = millis();
                                                                  detachInterrupt(digitalPinToInterrupt(button3Pin)); // 禁用中断
                                                                  }