nec electronics inc. a12569eu1v0pb00 march 1997 preliminary cmos asic universal serial bus interface product brief nec's usb family support family full low full/low speed speed speed CMOS-8LH (0.5m gate array) CMOS-8LHd (0.5m gate array) cb-c8vm jun-97 jun-97 jun-97 (0.5m cell-based) cb-c9 under under under (0.35m cell-based) development development development applications today?s mainstream pentium-based multimedia pcs and most of the last generation 486-based pcs have many low-speed ?legacy? i/o functions. these functions are either attached to the 16-bit isa-bus (industry standard architecture) or have become isa-functions integrated into an i/o bridge. this i/o bridge is connected to a high- bandwidth local bus like the pci-bus or vesa-vlb. due to the hardware dependency of these functions, their migration to a virtual os like microsoft windows ? 95 or windows nt ? has been difficult. usb is an industry-standard created to solve legacy and connectivity problems, consolidate the i/o functions, and provide a means for ?computer telephony integration?. although usb was initially developed for the x86-based pc platform, the technology is not excluded from the other platforms like powerpc?, sparc?, mips?, alpha?, etc. in many ways, usb is helping to shape the multi- media pc of the coming decade. usb features ? two data transfer speeds: ? 12 mbits/s for full-speed ? 1.5 mbits/s for low-speed ? differential output driver ? 200mv differential receiver sensitivity ? special +/- full and low speed usb i/os ? dual speed i/os with full and low speed select multimedia pc with usb technology overview the universal serial bus (usb) is a serial interface that provides connectivity for peripheral devices such as the printer, mouse, and keyboards. two data transfer speeds are supported: full-speed at 12 mbits/s and low-speed at 1.5 mbits/s. the driver side is of differential output, with output enable and slew rate control. the receiver side has a differential signal sensitivity of 200mv and supports a single-end signal level. the macro features either an on-board pull-up resistor at the upstream side or a pull-down resistor at the down- stream side. external pull-up and pull-down resistors are therefore required. all non-nec trademarks are the property of their respective owners.
usb interface 2 for literature, call toll-free 7 a.m. to 6 p.m. pacific time: 1-800-366-9782 or fax your request to: 1-800-729-9288 no part of this document may be copied or reproduced in any form or by any means without the prior written consent of nec electronics inc. (necel). the information in this document is subject to change without notice. all devices sold by necel are covered by the provisions appearing in necel terms and conditions of sales only. including the limitation of liability, warranty, and patent provisions. necel makes no warranty, express, statutory, implied or by description, regarding information set forth herein or regarding the freedom of the described devices from patent infringement. necel assumes no responsibility for any errors that may appear in this document. necel makes no commitments to update or to keep current information contained in this document. the devices listed in this document are not suitable for use in applications such as, but not limited to, aircraft control systems, aerospace equipment, submarine cables, nuclear reactor control systems and life support systems. ?standard? quality grade devices are recommended for computers, office equipment, communication equipment, test and measurement equipment, machine tools, industrial robots, audio and visual equipment, and other consumer products. for automotive and transportation equipment, traffic control systems, anti-disaster and anti-crime systems, it is recommended that the customer contact the responsible necel salesperson to determine the reliabilty requirements for any such application and any cost adder. necel does not recommend or approve use of any of its products in life support devices or systems or in any application where failure could result in injury or death. if customers wish to use necel devices in applications not intended by necel, customer must contact the responsible necel sales people to determine necel?s willingness to support a given application. ?1997 nec electronics inc./printed in u.s.a. document no. a12569eu1v0pb00 nec electronics inc. corporate headquarters 2880 scott boulevard p.o. box 58062 santa clara, ca 95052 tel 408-588-6000 full-speed usb connection example
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