最近做一小项目,用到HOST,STM32F105还真不错,内部资源丰富.RAM足够我使用了.画原理图，layout PCB，打样焊接，一次性通过。将原例程中LCD显示修改成串口printf，很容易又方便的打印出了我的U盘内部数据.

  刚选这个方案的时候,还什么都不了解,甚至还问了很菜的问题,是否支持fat32?答案肯定是支持的!!

官方说明中有几点需要注意的

The current version of the STM32F105/7 USB host stack has the following known
limitations:
1. It supports only two USB standard class applications, i.e:
   a) Mass Storage Class (MSC) for accessing USB flash pendrives,
   b) Human Interface Device (HID) class for keyboard and mouse devices.
2. It supports only one interface and one configuration selection (default config).
3. It does not support mass storage devices with multiple logical units.
4. It comes with the EFSL FAT filesystem support:
   a) The page size is fixed to 512 bytes. Flash pendrives with higher page granularity
are not supported.
   b) Long filenames and Unicode are not supported.
5. Very short delay between device detach/attach may result in abnormal operation.
6. Compatibility issues have been encountered with some devices at the enumeration phase.
7. After connecting and disconnecting a non-supported class device and then attaching a supported class device, enumeration

   这个东东还在继续研究中... ...