usb không virutvirus trên mạng internet

... THE USB SPECIFICATION 7 2.1 SUMMARY OF USB PROTOCOL 7 2.2 USB OBJECTIVES 7 2.3 USB Bus TOPOLOGY 8 2.4 USB DATA FLOW MODEL 9 2.5 USB PIPE CONCEPT (DEVICE ADDRESS AND ENDPOINT) 10 2.6 USB ... not suitable as a USB device 2.3 USB Bus Topology The USB Specification defines the interconnections and communications between two main elements of a USB system: USB host PC and USB devices Its ... 20Step 1: Understand the USB Specification2 Step 1: Understand the USB Specification The first step to design a USB device is to understand the USB Specification The USB Specification 1.0 has

Ngày tải lên: 18/01/2018, 12:52

... tin cá nhân) được lưu trên chip đều không thể truy cập và như vậy không thể dùng được vào việc gì khác Thẻ thông minh hay USB token? Một sự khác nhau giữa thẻ thông minh và USB token là hình dáng ... về USB token với cả chứng thực dựa trên chip và bộ nhớ flash để lưu trữ được các file và tài liệu… Hình 1: Hai ví dụ về các thiết bị chứng thực dựa trên chip Trang 6Cả thẻ thông minh và USB ... khẩu chỉ là một cơ chế chứng thực không đủ là bởi vì người dùng thường nhớ không tốt cũng như bảo vệ các mật khẩu không an toàn Có thể bạn cũng thấy rằng mật khẩu không được bảo vệ một cách thích

Ngày tải lên: 28/06/2014, 08:20

... What USB Can’t Do 7 USB versus Ethernet 10 USB versus IEEE-1394 11 'XQNWVKQPQHCP+PVGTHCEG   USB 1.0 11 USB 1.1 12 USB 2.0 12 USB 3.0 ... 148 Cypress EZ-USB 152 ARM 156 %QPVTQNNGTUVJCV+PVGTHCEGVQ%27U   ST-NXP Wireless ISP1582 157 PLX Technology NET2272 157 FTDI USB UART and USB FIFO 159 ...   USB 1.0 11 USB 1.1 12 USB 2.0 12 USB 3.0 13 USB On-The-Go 14 Wireless USB 14 Trang 5iv $WU%QORQPGPVU

Ngày tải lên: 04/07/2014, 07:20

... should use a USB interface? Find out whether your device should use USB or another interface If the choice is USB, you’ll learn how to decide which of USB’s four speeds—including USB 3.0’s SuperSpeed—and ... other USB devices? Find out how to develop a hostfor an embedded system or a USB On-The-Go device that can function as both a USB device and a limited-capability host that accesses other USB devices ... SuperSpeed—and which of USB’s four transfer types are appropriate for your application • What controller chip should my device use? Every USB device contains an intelligent controller to manage USB communications

Ngày tải lên: 04/07/2014, 07:20

... option with the release of USB 2.0, and USB 3.0 defined SuperSpeed 4GNKCDNG USB’s reliability is due to both the hardware and the protocols The hardware specifications for USB drivers, receivers, ... compares USB with other interfaces 'CU[VQ7UG Ease of use was a major design goal for USB, and the result is an interface that’s a pleasure to use for many reasons: One interface for many devices USB ... Wireless options USB originated as a wired interface, but technologies are now available for wireless communications with USB devices Hot pluggable Users can connect and disconnect a USB device whenever

Ngày tải lên: 04/07/2014, 07:20

... communicate with USB devices, a computer needs hardware and software that support the USB host function The hardware consists of a USB host con-troller and a root hub with one or more USB ports The ... A USB 3.0 hub contains both a USB 2.0 hub and a SuperSpeed hub and han-dles traffic at any speed SuperSpeed traffic uses the SuperSpeed hub’s circuits and wires, and other traffic uses the USB ... hubs between the host and device are USB 3.0 (Figure 1-2) Otherwise the device must use a slower speed For compatibility with USB 2.0 hosts and hubs, Figure 1-1 USB uses a tiered star topology Each

Ngày tải lên: 04/07/2014, 07:20

... %QORCVKDKNKV[ USB 3.0 is backwards compatible with USB 2.0 Will USB 1.x and USB 2.0 devices work with USB 3.0 hosts? Yes A USB 3.0 host has a USB 2.0 bus in parallel with a SuperSpeed bus Will USB 3.0 ... Can I use a USB 3.0 cable with a USB 2.0 host? Yes The USB 3.0 Standard-A plug fits the USB 2.0 Standard-A receptacle, so you can use a USB 3.0 cable to attach a USB 3.0 device to a USB 2.0 host ... communicate at a USB 2.0 speed Can I use USB 3.0 cable with a USB 2.0 device? No A USB 3.0 cable has a USB 3.0 Standard-B or USB 3.0 Micro-B plug, and these plugs don’t fit USB 2.0 receptacles

Ngày tải lên: 04/07/2014, 07:20

... care whether the device uses USB or another interface For example, the NET Framework includes Directory and File classes for accessing files on drives, which may use USB A vendor-supplied driver ... features and uses of each type Control transfers are the only type with functions defined by the USB specifica-tion Control transfers enable the host to read information about a device, set a device’s ... also contain class- and vendor-specific requests that send and receive data for any purpose All USB devices must support control transfers Trang 2Bulk transfers are intended for applications where

Ngày tải lên: 04/07/2014, 07:20

... Trang 1A USB 2.0 hub communicates with a USB 2.0 host at high speed unless a USB 1.x hub is between the host and hub When a low- or full-speed device is attached to a USB 2.0 hub, the ... components responsible flow-or perflow-orm- perform-ing split transactions are the USB 2.0 host controller and a USB 2.0 hub that has an upstream connection to a high-speed bus segment and a downstream ... 'PUWTKPI5WEEGUUHWN6TCPUHGTU USB 2.0 transfers use status and control codes and error-checking to help ensure that data gets to its destination as quickly as possible and without errors 5VCVWUCPF%QPVTQN The USB 2.0

Ngày tải lên: 04/07/2014, 07:20

... operation with any host For the hub class, USB 2.0 and USB 3.0 recommend average response times of under 5 ms &GVGEVKPICPF*CPFNKPI'TTQTU If a USB 2.0 device doesn’t return an expected handshake ... accept the data, a USB 2.0 device can take up to 5 seconds to accept all of the data and complete the Status stage (though once begun, the Status stage must complete within 50 ms) USB 3.0 devices ... USB requests and performing other infrequent configuration tasks This approach helps ensure that the transfers complete quickly by keeping the reserved bandwidth as open as possible But the USB

Ngày tải lên: 04/07/2014, 07:20

... only the information transferred in the data packet (USB 2.0) or Data Packet Payload (SuperSpeed), excluding PID and CRC bits USB 2.0 and USB 3.0 require interrupt endpoints in a default interface ... end-point(s) Every USB 2.0 or USB 3.0 device with isochronous endpoints must have an interface that requests no isochronous bandwidth so the host can configure the Figure 3-7 USB 2.0 isochronous ... recipient, SOF packets (USB 2.0), or Isochronous Timestamp Packets (SuperSpeed) For example, a microphone’s input may synchronize to the out-put of speakers The descriptor for a USB 2.0 or higher isochronous

Ngày tải lên: 04/07/2014, 07:20

... bandwidth To help ensure that devices will enu-merate without problems, default interfaces in USB 2.0 and USB 3.0 devices must request no isochronous bandwidth In other words, a default interface ... attempts to enumerate the device by issuing control transfers contain-ing standard USB requests to the device All USB devices must support control transfers, the standard requests, and endpoint ... the host in response to the next Get Port Status request A USB 1.x hub may instead detect the device’s speed just after a bus reset USB 2.0 requires speed detection before the reset so the hub

Ngày tải lên: 04/07/2014, 07:20

... bits are tenths, and the final four bits are hundredths USB 1.1 is 0110h (not 0101h) USB 2.0 is 0200h USB 3.0 is 0300h. A device with bcdUSB = 0210h or higher must support the BOS descriptor A ... standard USB descriptors The device must store the contents of its descriptors and respond to requests for the descriptors 6[RGU Table 4-1 lists the descriptors defined in the USB 2.0 and USB 3.0 ... peripheral (Wireless USB) FFh Vendor-specific (can instead be declared at the interface level) Trang 7idVendor is a Vendor ID assigned by the USB-IF to members of the USB-IFand others who pay

Ngày tải lên: 04/07/2014, 07:20

... the device speed and type of transfer For USB 2.0, bits 10 0 are the maximum packet size with a range of 0–1024 For USB 1.x, the range is 0–1023 In USB 2.0, bits 12 11 indicate how many additional ... way to provide this information, the Wireless USB specification introduced two new descriptor types The USB 2.0 Link Power Management Addendum and USB 3.0 specifi-cation also incorporate these ... value may range from 1–255 For isochronous end-points in USB 1.x devices, the value must be 1 For isochronous endend-points in full-speed USB 2.0 devices, values 1–16 are allowed, and the interval

Ngày tải lên: 04/07/2014, 07:20

... To update descriptors for a USB 1.x device to USB 2.0, all except some devices that have isochronous endpoints require just one change: in the device descrip-tor, bcdUSB must be 0200h or greater ... specific to a technology or another aspect of a device or its function. 02h = USB 2.0 EXTENSION 03h = SUPERSPEED_USB 04h = CONTAINER ID 00h, 05h–FFH (reserved) 3 Capability-Dependent varies Capability-specific ... 5VTWEVWTGF4GSWGUVUHQT %TKVKECN&CVC Of USB’s four transfer types, control transfers have the most complex structure They’re also the only transfer type with functions defined by the USB specifica-tion This

Ngày tải lên: 04/07/2014, 07:20

... function on a USB 3.0 bus, bit 0 = 1 if the function supports remote wakeup, and bit 1 = 1 if the host has enabled the func-tion for remote wakeup For requests directed to an interface on a USB 2.0 ... target interface or endpoint doesn’t exist Comments: For requests directed to devices operating at USB 2.0 speeds, two status bits are defined Bit zero is the Self-Powered field: 0 = bus-powered, ... cleared, the device responds with STALL Behavior is undefined if wLength > 0000h Comments: For USB 2.0, this request can clear the DEVICE_REMOTE_WAKEUP and ENDPOINT_HALT features The request

Ngày tải lên: 04/07/2014, 07:20

... high-speed USB boards with EZ-USB chips: the USBee EX2 Experimenter’s Board from CWAV, Inc and the QuickUSB Module from Bitwise Systems, Inc Both boards contain programmed Cypress EZ-USB FX2 controllers, ... that handles non-USB tasks and communicates with the USB controller as needed These chips are sometimes called USB interface chips to distinguish them from microcontrollers with USB capabilities ... ASICs that function as USB controllers +PUKFGC75$%QPVTQNNGT A typical USB 2.0 controller contains a USB transceiver, a serial interface engine, buffers to hold USB data, and registers

Ngày tải lên: 04/07/2014, 07:20

... can use four USB-specific instructions: USBInit initializes the USB port USBService monitors the bus status and manages low-level USB communi-cations A PICBASIC PRO program must call USBService ... CY7C64713 EZ-USB full CY7C6801x EZ-USB full/high Silicon Laboratories C8051F34x low/full Standard Microsystems Corporation (SMSC) USB2005, USB222x full, full/high Texas Instruments TUSB3210/3410 ... infor-mation for USB communications and interrupts Devices with simpler I/O needs can use the 20-pin PIC18(L)F1xK50 series Microchip provides USB Framework firmware and example applications for USB communications

Ngày tải lên: 04/07/2014, 07:20

... enables adding USB to just about any CPU circuit A disadvantage is the need to use two chips instead of having the CPU and USB controller on a single chip Also, example code for USB communications ... fit a defined USB class and need only bulk or isochronous transfers #TEJKVGEVWTG FTDI’s chips take a different approach to USB design The controllers handle enumeration and other USB communications ... available Some interface chips support a command set for USB-related communications, while others use a series of registers to store USB data and configuration, status, and control information

Ngày tải lên: 04/07/2014, 07:20

... Measurement No support Video Windows 98 Gold: USB camera minidriver library USBCAMD 1.0 (not supported under Windows 2000) Windows Me: USB camera minidriver library USBCAMD 2.0 Windows XP SP2: class driver ... use the usbser.sys driver. Composite CDC devices should use Windows XP SP3 or later, which have updated versions of the usbser.sys and usbccgp.sys drivers For mapping Remote NDIS to USB, Windows ... controller For USB/Ethernet bridges, Asix Electronics Corporation has the AX88172A, which converts between full- or highspeed USB and 10- or 100-Mbps Ether-net K-Micro has the KLKUSB220 with a

Ngày tải lên: 04/07/2014, 07:20