Arm板上usb接口热敏打印机控制

由于没有厂家的驱动，需要自己对usb口进行控制，主要有两种方式：

1.手写驱动，加载设备。2.采用libusb库进行无驱动配置

由于第一种较为麻烦，我采用了第二种。

主要步骤：

1.libusb配置：

　　官网下载，安装，发现config有问题，先安装依赖项。

　　主要参考：https://www.cnblogs.com/ettie999/p/8142973.html

　　

2.测试example里面的listudev.c，可运行代表安装成功

3.Qt开发：

　　1.首先需要在.pro文件中添加路径，用来访问libusb的库：

　　INCLUDEPATH += /usr/local/include?libusb-1.0

　　LIBS += -L"/usr/local/lib" -lusb-1.0

　　2.编写代码：

　　

   libusb_context *context = NULL;
    libusb_device_handle *dev_handle = NULL;
    libusb_device **devs;
    libusb_device *dev=NULL;
    int rc = 0;
    ssize_t count;

    //*****************Initial *********
    rc = libusb_init(&context);
 //   cout << "rc : " << rc << endl;
    assert(rc==0);
    //Enable debug
#ifndef NDEBUG
    libusb_set_debug(context,LIBUSB_LOG_LEVEL_WARNING);
#endif

    //Get device list
    count = libusb_get_device_list(context,&devs);
    cout << "count : " << count << endl;
    assert(count>0);
    for(ssize_t idx=0;idx<count;idx++)
    {
        libusb_device *device = devs[idx];
        libusb_device_descriptor desc = {0};

        rc = libusb_get_device_descriptor(device,&desc);
        assert(rc ==0);
        if((desc.idVendor == 0x0483) && (desc.idProduct == 0x5743))
        {
            cout << "get the device " << endl;
            dev = device;
        }
       // printf("Vendor:Device =  %04x:%04x\n",desc.idVendor,desc.idProduct);
        cout << "Vendor:Device = " << hex << desc.idVendor << "___" << desc.idProduct << endl;
    }

    //open usb device
    rc = libusb_open(dev,&dev_handle);
    //dev_handle = libusb_open_device_with_vid_pid(context,0x0483,0x5743);
    //dev_handle = libusb_open_device_with_vid_pid(context,0x17ef,0x602d);
    if(dev_handle == NULL)
    {
        cout << "Cann't Open device" << endl;
        return;
    }
    else
        cout << "Open Success " << endl;
  //  assert(dev_handle != NULL);
    //set privilige



    //Write data
    unsigned char *data = new unsigned char[0x30];
    int actual;
    data[0] = 0x0a;
    data[1] = 0x1b;
    data[2] = 0x21;
    data[3] = 0x00;
    data[4] = 0x55;

    data[6] = 0x66;
    data[7] = 0x23;
    data[8] = 0x45;
    data[9] = 0x0d;
    data[10] = 0x0a;

    if(libusb_kernel_driver_active(dev_handle,0) == 1)
    {
        cout << "Kernel_driver_active" << endl;
        rc = libusb_detach_kernel_driver(dev_handle,0);
        cout << "detach_kernel_driver __rc: " << rc << endl;
        assert(rc==0);
    }

    rc = libusb_claim_interface(dev_handle,0);
    cout << "libusb_claim_interface __rc: " << rc << endl;
  //  assert(rc<0);

    //  transfer *******
    libusb_config_descriptor* config_descriptor_in = NULL;
    libusb_get_config_descriptor(dev,0,&config_descriptor_in);

   // rc = libusb_control_transfer(dev_handle,0x21,0x09,0x0300,0x00,data+1,0x20,10000);
   // rc = libusb_bulk_transfer(dev_handle,(64|LIBUSB_ENDPOINT_OUT),data,4,&actual,0);
    rc = libusb_bulk_transfer(dev_handle,0x02,data,12,&actual,0);
    //rc = libusb_bulk_transfer(dev_handle,config_descriptor_in->interface->altsetting->endpoint->bEndpointAddress,data,4,&actual,10000);
    cout << "libusb_bulk_transfer __rc: " << rc << endl;
    cout << "actual num : " << actual << endl;
    assert(rc!=0 || actual !=5);


    rc = libusb_release_interface(dev_handle,0);
    cout << "libusb_release_interface __rc: " << rc << endl;
    //assert(rc!=0);

    cout << "close devices " << endl;

    //Free device list
    libusb_free_device_list(devs,1);

    libusb_attach_kernel_driver(dev_handle,0);
    libusb_close(dev_handle);
    libusb_exit(context);

　　用lsusb可查到usb设备的VID和PID，然后通过官网可以查询对应函数的用法，从而实现控制。

　　http://libusb.sourceforge.net/api-1.0/libusb_api.html