关于mini2440  usb device的问题

我从网上下载一个usb device的程序（据说是从uboot 的usb 下载功能移植到keil mdk的）。主程序大概如下:
int Main(void)
{
    char *mode;
    
    Port_Init();
    rGPHCON = rGPHCON&~(0xf<<18)|(0x5<<18);  
// USB device detection control
//    rGPGCON &= ~(3<<24);
//    rGPGCON |=  (1<<24); // output
//    rGPGUP  |=  (1<<12); // pullup disable
//    rGPGDAT |=  (1<<12); // output    
        
      rGPCCON &= ~(3<<10);
      rGPCCON |=  (1<<10); // output
      rGPCUP  |=  (1<<5);  // pullup disable
      rGPCDAT |=  (1<<5);  // ourtput
     //   rGPCCON = 0xAAAAA6AA;
     //   rGPCDAT &= ~(1<<5);



    //ChangeUPllValue(60,4,2);        // 48MHz
    //for(i=0; i<7; i++);
    //ChangeClockDivider(13,12);
    //ChangeMPllValue(97,1,2);        //296Mhz

    Isr_Init();

    consoleNum=1;        // Uart 1 select for debug.
    Uart_Init(0,115200);
    Uart_Select(0);

    rMISCCR=rMISCCR&~(1<<3); // USBD is selected instead of USBH1
    rMISCCR=rMISCCR&~(1<<13); // USB port 1 is enabled.

    
//  USBD should be initialized first of all.
//
    isUsbdSetConfiguration=0;


    pISR_SWI=(_ISR_STARTADDRESS+0xf0);    //for pSOS

    //Led_Display(0x6);

    
    UsbdMain();

    Delay(0);  //calibrate Delay()
    

#if USBDMA
    mode="DMA";
#else
    mode="Int";
#endif

    // CLKOUT0/1 select.
    //Uart_Printf("CLKOUT0:MPLL in, CLKOUT1:RTC clock.\n");
    //Clk0_Enable(0);    // 0:MPLLin, 1:UPLL, 2:FCLK, 3:HCLK, 4:PCLK, 5:DCLK0
    //Clk1_Enable(2);    // 0:MPLLout, 1:UPLL, 2:RTC, 3:HCLK, 4:PCLK, 5:DCLK1    
    Clk0_Disable();
    Clk1_Disable();
    
    //mpll_val = rMPLLCON;
    //Uart_Printf("DIVN_UPLL%x\n", divn_upll);
    //Uart_Printf("MPLLVal [M:%xh,P:%xh,S:%xh]\n", (mpll_val&(0xff<<12))>>12,(mpll_val&(0x3f<<4))>>4,(mpll_val&0x3));
    //Uart_Printf("CLKDIVN:%xh\n", rCLKDIVN);

    Uart_Printf("\n\n");
    Uart_Printf("+---------------------------------------------+\n");
    Uart_Printf("| S3C2440A USB Downloader ver R0.05 2008 August |\n");
    Uart_Printf("+---------------------------------------------+\n");
    Uart_Printf("FCLK=%4.1fMHz,%s mode\n",FCLK/1000000.,mode);
    //Uart_Printf("USB: IN_ENDPOINT:1 OUT_ENDPOINT:3\n");
    //Uart_Printf("FORMAT: <ADDR(DATA):4>+<SIZE(n+10):4>+<DATA:n>+<CS:2>\n");
    Uart_Printf("NOTE: 1. Power off/on or press the reset button for 1 sec\n");
    Uart_Printf("          in order to get a valid USB device address.\n");
    Uart_Printf("     2. For additional menu, Press any key. \n");
    Uart_Printf("\n");

    download_run=1; //The default menu is the Download & Run mode.

    while(1)
    {
        if(menuUsed==1)Menu();
        WaitDownload();    
    }

}

我将mini2440上电后连接PC机进行调试，PC机会发现硬件，但只会PC在右下角出现黄色背景的提示说:无法识别的USB设备。然后并没有弹出安装驱动的界面。
而串口打印的是:
+---------------------------------------------+
| S3C2440A USB Downloader ver R0.05 2008 August |
+---------------------------------------------+
FCLK=296NOTE: 1. Power off/on or press the reset button for 1 sec
                  in order to get a valid USB device address.
     2. For additional menu, Press any key.

USB host is not connected yet.


+---------------------------------------------+
| S3C2440A USB Downloader ver R0.05 2008 August |
+---------------------------------------------+
FCLK=296NOTE: 1. Power off/on or press the reset button for 1 sec
                  in order to get a valid USB device address.
     2. For additional menu, Press any key.

USB host is not connected yet.

我通过USBMonitor2_26来监测USB通信
发现只有如下信息：
000001: PnP Event: Query ID (UP), 15.08.2013 21:45:39.7187500 +97.7031250
Hardware IDs: USB\UNKNOWN
000002: PnP Event: Query ID (UP), 15.08.2013 21:45:39.7187500 +0.0
Compatible IDs: USB\UNKNOWN
000003: PnP Event: Device Disconnected (UP), 15.08.2013 21:45:39.7187500 +0.0
The USB device has just been removed from the system, all drivers unloaded.
000004: PnP Event: Query ID (UP), 15.08.2013 21:45:42.6718750 +2.9531250
Hardware IDs: USB\UNKNOWN
000005: PnP Event: Query ID (UP), 15.08.2013 21:45:42.6718750 +0.0
Compatible IDs: USB\UNKNOWN
并没有传说中的获取各描述符的命令。请各位大牛帮忙分析下。谢谢,完整代码如附:
usbdevice.zip (520 K) 下载次数:19