1.配置usb host和sd卡
Device Drivers --->
SCSI device support --->
SCSI disk support
USB support --->
Support for Host-side USB
USB verbose debug messages
--- Miscellaneous USB options
[ ] USB device filesystem
[ ] Enforce USB bandwidth allocation (EXPERIMENTAL)
[ ] Dynamic USB minor allocation (EXPERIMENTAL)
--- USB Host Controller Drivers
EHCI HCD (USB 2.0) support
[ ] Full speed ISO transactions (EXPERIMENTAL)
[ ] Root Hub Transaction Translators (EXPERIMENTAL)
Intel ixp435/ixp465 on-chip EHCI HCD support
ISP116X HCD support
OHCI HCD support
UHCI HCD (most Intel and VIA) support
SL811HS HCD support
--- USB Device Class drivers
USB Modem (CDC ACM) support
USB Printer support
--- NOTE: USB_STORAGE enables SCSI, and 'SCSI disk support'
--- may also be needed; see USB_STORAGE Help for more information
USB Mass Storage support
USB Mass Storage verbose debug
MMC/SD Card support --->
MMC support
MMC debugging
MMC block device driver
2.配置usb和sd卡支持的文件系统(一般usb都以vfat格式，所以此处选择支持vfat)
File systems --->
DOS/FAT/NT Filesystems --->
MSDOS fs support
VFAT (Windows-95) fs support
(437) Default codepage for FAT
(iso8859-1) Default iocharset for FAT
NTFS file system support
[ ] NTFS debugging support
NTFS write support
3.配置文件系统支持的字符集
File systems --->
Native Language Support --->
(iso8859-1) Default NLS Option
Codepage 437 (United States, Canada)
Simplified Chinese charset (CP936, GB2312)
NLS ISO 8859-1 (Latin 1; Western European Languages)
NLS UTF8
4.进入文件系统后，在/dev下面建立两个设备节点:
mknod /dev/sdb1 b 8 17(usb)
mknod /dev/sda1 b 8 1 (sd)
在我的系统linux-2.6.16.rt.x里，u盘被识别为/dev/sdb1,sd卡被识别为/dev/sda1,他们的主设备号和次设备号必须要和上面的一样，否则，会有错误。
