USBUART显示为未知USB设备

我使用的是PSoCYC8C4248AZI L45，并试图实现UsBuTART，但不管我做什么，我都无法使它在Windows中识别该设备。
我从样本UBUART项目开始，并做了很少的改动，超出了一些不执行的IFF代码，并添加了一个红色和绿色的状态。
4248是在3.3V，我是自供电它从外部来源。来自USB的5V应用于VBUS，并且我已经尝试了所有的VBUS监视的组合。我试过交换D+/D，但没什么区别。D线最初通过串联电阻，但后来我消除了它们。在当前原型上没有其他的过滤或静态保护。
每当我插入它时，在Windows（10）中得到一个错误消息，即设备描述符请求失败。它通常认识到我确实在USB端口上插入了一些东西，但是我会特别指出，在DEV周期中，它不会总是尝试加载驱动程序。沿途的某个地方，它对这个功能更加敏感。
我安装了生成的.INF文件作为项目的一部分（我必须引导到恢复模式，以允许Windows安装一个未签名的驱动程序）。这没有什么区别。
我还安装了一些我在旅途中发现的通用CyPress USB驱动程序，但这似乎也没什么区别。
附件是今天的项目，以及我在设备管理器中看到的错误消息的截图。
我对USB设备的开发是新的，所以我不太确定还有什么可以帮助其他人解决问题。看起来我离这件事只有一步之遥。
扎克
未知设备
39 K
USPFSU UART01. Cyrkkz.zip
3.7兆字节



     以下为原文
  I'm using a PSOC CY8C4248AZI-L485 and trying to implement the USBUART but no matter what I do, I can't get it to recognize the device in Windows.
    I started with the sample USBUART project, and made very few changes beyond stripping out some #ifdef code that wasn't executing, and adding a red and green status LED.  
    The 4248 is running at 3.3V, and I'm self-powering it from an external source.  The 5V from the USB is applied to the VBUS, and I've tried all combinations of VBUS monitoring both on and off.  I've tried swapping D+/D- and it made no difference.  The D lines were initially passed through series resistors, but I've since eliminated them.  There is no other filtering or static protection on the current prototype.
    Whenever I plug it in, I get an error message in Windows (10) that the Device Descriptor Request Failed.  It usually recognizes that I did plug something in to the USB port, but I will add that especially early on during the dev cycle, it wouldn't always attempt to load drivers.  Somewhere along the way it's gotten more responsive to that function.
    I installed the .inf file that is generated as part of the projct (I had to boot into the recovery mode to allow Windows to install an unsigned driver).  That made no difference.
    I had also installed some generic Cypress USB driver that I found during my travels, but that hasn't seemed to make any difference either.
    Attached is the project as it stands today, as well as a screenshot of the error message that I'm seeing in Device Manager.  
    I'm new to the USB device development, so I'm not really sure what else might be useful to others to troubleshoot.  It seems like I'm just one little step away from getting this going though.
    Zack

•    unknown device.PNG 39.0 K
•   USBFS_UART01.cywrk_.zip 3.7 MB