AM7968-125JC datasheet(54/127 Pages) AMD

54 / 127 page

Publication# 12330

Rev. E

Amendment /0

Issue Date: April 1994

TAXIchipTM Integrated Circuits

Technical Manual

1.0 INTRODUCTION

Modern electronic systems move data from point-to-point across physical layer bounda-

ries using either serial or parallel data links. Parallel data links provide fast data

transfers and are compatible with most computer architectures. However, conventional

parallel data links are burdened with cost/performance issues such as costly multi-con-

ductor cables, crosstalk, RFI, bit-to-bit skew and other concerns associated with multiple

wire interfaces. Serial data links, although simpler and less costly, have not provided

sufficient bandwidth to compete with the high data transfer rates of parallel links.

Recent technological advances have altered the cost performance trade-off between

serial and parallel data transfer techniques. A new chip set from Advanced Micro

Devices offers a high performance integrated alternative to traditional serial/parallel data

transfer techniques. The TAXlchip set (Transparent Asynchronous Xmitter-Receiver

Interface) provides the means to establish a transparent high speed serial link between

two high performance parallel buses. The TAXlchip set consists of a Transmitter, which

takes parallel data and transmits it serially at up to 175 MHz, and a Receiver, which

converts the serial data stream back to parallel form. TAXlchips provide a simple parallel

interface through a high speed serial link, while maintaining the data bandwidth required

by the system.

1.1 The Am7968 TAXI Transmitter

The TAXITM Transmitter consists of an input latch, an encoder, a parallel to serial shift

Data are input to the latch, encoded, and shifted out at the serial data rate. The encod-

ing used is the efficient 4B/5B scheme specified for the ANSI X3T9.5 Fiber Distributed

Data Interface (FDDI specification). This encoding divides an 8-bit byte into two, 4-bit

nibbles. Each nibble is encoded into a 5-bit symbol. The 10-bit encoded byte is format-

ted into an NRZI data stream for output to the media. This 4B/5B encoding is 80%

efficient, using a 125 Mbaud transmission rate to send 100 Mbps of data.

The Am7968 Transmitter has differential pseudo-ECL (referenced to +5 V) outputs

which can drive 50

Ω lines. This capability makes it easy to directly interface with

shielded twisted pair or coaxial cables.

The pseudo-ECL outputs are also compatible with the ECL interface of optical compo-

nents used to drive fiber optic cable. In addition to providing high bandwidth and low

attenuation, fiber optic data transmission also offers noise immunity, eliminates RFI and

provides data security. Declining optical components costs are bringing the advantages

of fiber optic data transmission to an ever wider range of applications, from process

control to avionics. The TAXlchip set is the ideal complement for fiber optic interfaces.

AM7968-125JC Datasheet(PDF) 54 Page - Advanced Micro Devices

AM7968-125JC Datasheet(HTML) 54 Page - Advanced Micro Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL