主题 : 串口接收文件数据丢失 复制链接 | 浏览器收藏 | 打印
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楼主  发表于: 2012-11-20 14:54
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 串口接收文件数据丢失

我在Android下想写一个串口接收文件的程序，通过Uart3来接收来自51单片机的文件数据，但是实际运行中，程序总是会丢失一小部分数据，比如300K的文件会丢失几百个字节。
因为之前的程序比较复杂，现在单独写了个简单的测试程序，通过定时器每隔几ms查询看串口有没有数据要读，如果有就关闭定时查询，进入while循环一直读取数据，并将数据写入文件，就这样一个简单的测试程序，还是会出现丢失数据的问题，想让大家帮忙看一下问题出在哪里（因为不知道串口缓冲有多大，所以我自己定义的buf是2048个字节）。

下面附上测试程序：

复制代码
  1. public class UartTestActivity extends Activity {
  2.     /** Called when the activity is first created. */
  3.     
  4.     private final int BAUDRATE_WIFI=115200;
  5.     private final int DATABITS_WIFI=8;
  6.     private final int STOPBITS_WIFI=1;
  7.     private final String SERIAL_PORT_WIFI="/dev/s3c2410_serial3";
  9.     private Handler mWifiHandler;
  10.     
  11.     private int serialToWifi;
  12.     Timer timer;
  13.     TimerTask task;
  14.     long totalLen=0;
  15.     
  16.     @Override
  17.     public void onCreate(Bundle savedInstanceState) {
  18.         super.onCreate(savedInstanceState);
  19.         setContentView(R.layout.main);
  20.         
  21.         
  22.         try{
  23.             serialToWifi=HardwareControler.openSerialPort(SERIAL_PORT_WIFI, BAUDRATE_WIFI, DATABITS_WIFI, STOPBITS_WIFI);
  24.         }catch(Exception e){
  25.             Toast.makeText(this, "Wifi串口错误!", 500).show();
  26.         }
  27.         
  28.         mWifiHandler = new Handler(){
  30.             @Override
  31.             public void handleMessage(Message msg) {
  32.                 // TODO Auto-generated method stub
  33.                 int readLen;
  34.                 
  35.                 byte[] buf = new byte[2048];
  36.                 FileOutputStream fos = null;
  37.                 if(msg.arg1 == 1){
  38.                     try{
  39.                         if(HardwareControler.select(serialToWifi, 0, 0) == 1){
  40.                             stopRead();//////////////////////////////////////
  41.                             Log.i("ReadWifi", "有数据啦");
  42.                         
  43.                             fos = openFileOutput("update.txt",MODE_PRIVATE);
  44.                             
  45.                             
  46.                             long time = System.currentTimeMillis();
  47.                             
  48.                             while((System.currentTimeMillis() - time) < 60*1000){  //读1s，这里确定发送端肯定发送完毕了
  49.                                 if((readLen = HardwareControler.read(serialToWifi, buf, buf.length)) > 0){
  50.                                     totalLen += readLen;
  51.                                     Log.i("读到" + readLen + "字节", "总共" + totalLen + "字节");
  52.         
  53.                                     fos.write(buf, 0, readLen);
  54.                                 }
  55.                                 Log.i("读到0字节", "读到0字节");
  56.                             
  57.                             }
  58.                             fos.flush();
  59.                             fos.close();
  60.                         }
  61.                         //initRead();///////////////////////
  62.                     }
  63.                     catch(Exception e){
  64.                         e.printStackTrace();
  65.                     }
  66.                     
  67.                 }//end of if
  68.             }    //end of public void handlerMessage()        
  69.         };//end of new
  70.         
  71.         initRead();
  72.     }
  73.     
  74.     
  75.     public void initRead(){
  76.         timer = new Timer();
  77.         task = new TimerTask() {
  78.             
  79.             @Override
  80.             public void run() {
  81.                 // TODO Auto-generated method stub
  82.                 Message msg=mWifiHandler.obtainMessage();
  83.                 msg.arg1=1;
  84.                 mWifiHandler.sendMessage(msg);        
  85.             }
  86.         };
  87.         
  88.         timer.schedule(task, 1, 1);
  89.     }
  90.     
  91.     public void stopRead(){
  92.         if(timer != null){
  93.             timer.cancel();
  94.             timer = null;
  95.         }
  96.         if(task != null){
  97.             task.cancel();
  98.             task = null;
  99.         }
  100.     }
  103.     @Override
  104.     protected void onDestroy() {
  105.         // TODO Auto-generated method stub
  106.         stopRead();
  107.         super.onDestroy();
  108.     }
  109.     
  110.     
  111.     }
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