usb2.0协议规范资料:rnd_chmfr_ECNFINAL.pdf,UnicodeECN.pdf,resistor_ecn.pdf,errata-092800-1207001.pdf,InterfaceAssociationDes criptor_ecn.pdf,Inter-Chip USB Supplement to the USB 2.0 Specification_1.0.pdf,OTG Supplement v1.2.pdf,ecn1-usb20-miniB-revd.pdf,usb_20.pdf