// 新增：存储全局串口和读取器实例
    let port = null;
    let reader = null;
    let accumulatedData = ""; // 移到全局，便于关闭时重置

    async function connect() {
      if ("serial" in navigator) {
        try {
          port = await navigator.serial.requestPort(); // 修改为全局变量
          await port.open({ baudRate: 9600 });

          reader = port.readable.getReader(); // 修改为全局变量
          const decoder = new TextDecoder();
          accumulatedData = ""; // 重置累积数据

          console.log("串口连接成功，开始接收数据...");

          while (true) {
            const { value, done } = await reader.read();
            if (done) break;

            const decodedChunk = decoder.decode(value, { stream: true });
            accumulatedData += decodedChunk;
            console.log("接收到数据块:", decodedChunk);

            processAccumulatedData(accumulatedData);
          }
        } catch (error) {
          console.error("串口错误:", error);
        }
      }

      function processAccumulatedData(data) {
        if (data.includes("\n")) {
          const messages = data.split("\n");

          for (let i = 0; i < messages.length - 1; i++) {
            const completeMessage = messages[i];
            console.log("完整消息:", completeMessage);
            handleMessage(completeMessage);
          }

          accumulatedData = messages[messages.length - 1];
        }

        // 其他消息拆分示例保持不变
        /*
  while (accumulatedData.length >= 32) {
    const message = accumulatedData.substring(0, 32);
    accumulatedData = accumulatedData.substring(32);
    handleMessage(message);
  }
  */

        /*
  let startIndex = 0;
  while (true) {
    const start = accumulatedData.indexOf(0xAA, startIndex);
    if (start === -1) break;
    
    const end = accumulatedData.indexOf(0x55, start + 1);
    if (end === -1) break;
    
    const message = accumulatedData.substring(start, end + 1);
    accumulatedData = accumulatedData.substring(end + 1);
    handleMessage(message);
    startIndex = start;
  }
  */
      }
    }

    // 新增：关闭连接函数
    async function disconnect() {
      if (!port || !reader) {
        console.log("未建立连接，无需关闭");
        return;
      }

      try {
        // 先取消读取器
        await reader.cancel();
        // 再关闭串口
        await port.close();
        console.log("串口连接已关闭");

        // 重置全局变量
        port = null;
        reader = null;
        accumulatedData = "";
      } catch (error) {
        console.error("关闭连接失败:", error);
      }
    }

    export { connect, disconnect };