Qt下libusb-win32的使用(二)批量读写操作

一、概述

学习libusb-win32的使用。使用批量传输方式与USB开发板进行数据读、写操作。上位机使用Qt做界面，使用USB开发板的端点2作为批量传输端点。

二、实现

代码比较简单，直接给出，如下：

  1 #include "testlibusb.h"
  2 
  3 //for Tiny6410
  4 //#define MY_VID 0x5345
  5 //#define MY_PID 0x1234
  6 
  7 //for 51 USB Board
  8 #define MY_VID 0x8888
  9 #define MY_PID 0x0001
 10 
 11 // Device configuration and interface id.
 12 #define MY_CONFIG 1
 13 #define MY_INTF 0
 14 
 15 // Device endpoint 2
 16 #define EP_IN 0x82
 17 #define EP_OUT 0x02
 18 
 19 // Device of bytes to transfer.
 20 #define BUF_SIZE 64
 21 
 22 //#define DEBUG_GUI
 23 
 24 
 25 
 26 USB::USB()
 27 {
 28 #ifndef DEBUG_GUI
 29 
 30     usb_init(); /* initialize the library */
 31     //usb_set_debug(255);
 32     usb_find_busses(); /* find all busses */
 33     usb_find_devices(); /* find all connected devices */
 34 
 35     if (!(udev = open_dev())) {
 36         qDebug("error opening device: %s", usb_strerror());
 37         exit(1);
 38     } else
 39         qDebug("open success: device %04X:%04X opened", MY_VID, MY_PID);
 40 
 41     printf_device_descriptor(&dev->descriptor);
 42     my_init_usbdev();
 43 #endif
 44 
 45     textEdit = new QTextEdit(this);
 46     textEdit->setGeometry(50,20,230,40);
 47 
 48     sendButton = new QPushButton(this);
 49     sendButton->setText("send");
 50     sendButton->setGeometry(130,80,60,40);
 51     connect(sendButton,SIGNAL(clicked()),this,SLOT(send_slot()));
 52 
 53     readButton = new QPushButton(this);
 54     readButton->setText("read");
 55     readButton->setGeometry(130,140,60,40);
 56     connect(readButton,SIGNAL(clicked()),this,SLOT(read_slot()));
 57 
 58     recvLabel = new QLabel(this);
 59     recvLabel->setText("recv data:");
 60     recvLabel->setGeometry(20,180,280,40);
 61 
 62     //my_usb_get_device_list();
 63     resize(320, 240);
 64 }
 65 
 66 //关闭程序时被调用
 67 USB::~USB()
 68 {
 69 #ifndef DEBUG_GUI
 70     qDebug("close usb device.");
 71     usb_close(udev);
 72 #endif
 73 }
 74 
 75 //打开指定VID、PID的USB设备
 76 usb_dev_handle *USB::open_dev(void)
 77 {
 78     struct usb_bus *bus;
 79 
 80     for(bus = usb_get_busses(); bus; bus = bus->next) {
 81         for(dev = bus->devices; dev; dev = dev->next) {
 82             if((dev->descriptor.idVendor == MY_VID) && (dev->descriptor.idProduct == MY_PID)) {
 83                     return usb_open(dev);
 84             }
 85         }
 86     }
 87     return 0;
 88 }
 89 
 90 //打印USB设备描述符
 91 void USB::printf_device_descriptor(usb_device_descriptor *desc)
 92 {
 93         qDebug("bLength:             %u",     desc->bLength);
 94         qDebug("bDescriptorType:     %02Xh",  desc->bDescriptorType);
 95         qDebug("bcdUSB:              %04Xh",  desc->bcdUSB);
 96         qDebug("bDeviceClass:        %02Xh",  desc->bDeviceClass);
 97         qDebug("bDeviceSubClass:     %02Xh",  desc->bDeviceSubClass);
 98         qDebug("bDeviceProtocol:     %02Xh",  desc->bDeviceProtocol);
 99         qDebug("bMaxPacketSize0:     %02Xh",  desc->bMaxPacketSize0);
100         qDebug("idVendor:            %04Xh",  desc->idVendor);
101         qDebug("idProduct:           %04Xh",  desc->idProduct);
102         qDebug("bcdDevice:           %04Xh",  desc->bcdDevice);
103         qDebug("iManufacturer:       %u",     desc->iManufacturer);
104         qDebug("iProduct:            %u",     desc->iProduct);
105         qDebug("iSerialNumber:       %u",     desc->iSerialNumber);
106         qDebug("bNumConfigurations:  %u",     desc->bNumConfigurations);
107 }
108 
109 //指定USB设备的配置和接口
110 void USB::my_init_usbdev()
111 {
112     //libusb规定下面这两个函数必须要被调用
113     if (usb_set_configuration(udev, MY_CONFIG) < 0) {
114         qDebug("error setting config #%d: %s", MY_CONFIG, usb_strerror());
115         exit(1);
116     }
117     if (usb_claim_interface(udev, MY_INTF) < 0) {
118         qDebug("error claiming interface #%d:
%s", MY_INTF, usb_strerror());
119         exit(1);
120     }
121 }
122 
123 //发送按钮响应函数
124 void USB::send_slot()
125 {
126     int ret, num;
127     QString s = textEdit->toPlainText();
128     QByteArray a = s.toLatin1();
129     char *tmp = a.data();
130 
131     num = s.length();
132     //qDebug()<<"text: "<<tmp<<"length: "<<num;
133     //批量写(同步)
134     ret = usb_bulk_write(udev, EP_OUT, tmp, num, 5000);
135     if (ret < 0) {
136             qDebug("error writing: %s", usb_strerror());
137             exit(1);
138     }
139 }
140 
141 //读按钮响应函数
142 void USB::read_slot()
143 {
144     int ret;
145     char readdata[BUF_SIZE];
146 
147     //批量读(同步)
148     ret = usb_bulk_read(udev, EP_IN, readdata, sizeof(readdata), 5000);
149     if (ret < 0) {
150             qDebug("error reading:%s", usb_strerror());
151             exit(1);
152     }
153     readdata[ret] = '';
154     //将接收到的数据显示在Label上
155     recvLabel->setText("recv: " + QLatin1String(readdata));
156 }

三、结果

运行上位机程序，在编辑框输入一些字符(数字)，然后点击“send”按钮将数据发送给USB设备，点击“read”按钮将USB设备接收到的数据读回到上位机并显示在界面上，效果如下：