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QtUSBHID—— 数据

date:2017/04/12 11:10

调用HIDAPI可实现读数据功能,但是功能十分单一,无法满足需求。

最简单的调用如下:

1 void Widget::myhid_read(){
2     res = hid_read(handle,buf_IN,2);
3     for(int i = 0;i < 2;i++){
4         qDebug("buf[%d]:0x%02x",i,buf_IN[i]);
5     }  
6 }

使用按钮click()操作调用该方法:

1 void Widget::on_readButton_clicked()
2 {
3     qDebug("read data.");
4     myhid_read();
5 }
 

 

但是使用的时候发现,每次点击read按钮运行一次myhid_read(),输出一个包的数据。hid设备产生了多少个数据包就要点多少次按钮才能全部接收。因此需要对它进行改造。

 1   void Widget::myhid_read(){
 2       qDebug("hid read start");
 3       res = hid_set_nonblocking(handle, 0);
 4   
 5       while (1) {
 6           res = hid_read(handle,buf_IN,2);
 7           for(int i = 0;i < 2;i++){
 8               qDebug("buf[%d]:0x%02x",i,buf_IN[i]);
 9           }        
10      }
11  }

这里第3行设置接收为阻塞式,HIDAPI文档说明如下:

        /** @brief Set the device handle to be non-blocking.

            In non-blocking mode calls to hid_read() will return
            immediately with a value of 0 if there is no data to be
            read. In blocking mode, hid_read() will wait (block) until
            there is data to read before returning.

            Nonblocking can be turned on and off at any time.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param nonblock enable or not the nonblocking reads
             - 1 to enable nonblocking
             - 0 to disable nonblocking.

            @returns
                This function returns 0 on success and -1 on error.
        */

 

设置阻塞后,点击read按钮,开始循环接收数据。但是未设置终止标志,即启动接收后软件一直等待接收数据直到退出软件。

现考虑:

1、提取报文数据总长度做判断量,接收包数与总包数相等则退出;

2、设置数据结束符,接收到特定结束符则退出接收。

 

QtUSBHID—— 数据