DP83266 datasheet(4/152 Pages) NSC

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20 General Features

The DP83266 MACSI device is a highly integrated FDDI

controller Together with the DP8325657 PLAYERa de-

vice it forms a full-featured high performance FDDI chip set

useful for designing end station attachments concentrators

bridges routers and other FDDI connections The MACSI

device provides all of the features and services of both the

DP83261 BMAC device and the DP83265 BSI-2 device with

enhanced performance and reliability

For system connection the MACSI device provides a simple

yet powerful bus interface and memory management

scheme to maximize system efficiency and it is capable of

interfacing to a variety of host busesenvironments The

MACSI device provides a 32-bit wide data interface which

can be configured to share a system bus to main memory or

to use external shared memory Also provided are 28-bit

addresses multiplexed on the data pins as well as demulti-

plexed on dedicated pins The system interface supports

virtual addressing using fixed-size pages

For network connection the MACSI device provides many

services which simplify network management and increase

system performance and reliability The MACSI device is

capable of batching confirmation and indication status fil-

tering MAC frames with the same Information field as well

as Void frames and performing network monitoring func-

tions

21 FDDI MAC SUPPORT

The MACSI device implements the ANSI X3T95 FDDI MAC

standard protocol for transmitting receiving repeating and

stripping frames The MACSI device provides all of the infor-

mation necessary to implement the service primitives de-

fined in the standard

22 MAC ADDRESSING SUPPORT

Both long (48-bit) and short (16-bit) addressing are support-

ed simultaneously for both Individual and Group addresses

23 MAC BRIDGING SUPPORT

Several features are provided to increase performance in

bridging applications

On the receive side external address matching logic can be

used to examine the PH

Indicate byte stream to decide

whether to copy a frame how to set the control indicators

and how to increment the counters

On the transmit side transparency options are provided on

the Source Address the most significant bit of the Source

Address and the Frame Check Sequence (FCS)

In addition support for an alternate stripping mechanism

(implemented using My

Void frames) provides maximum

flexibility in the generation of frames by allowing the use of

Source Address Transparency (SAT)

24 MAC SERVICE CLASS SUPPORT

All FDDI MAC service classes are supported by the MACSI

device including Synchronous Asynchronous Restricted

Asynchronous and Immediate service classes

For Synchronous transmission one or more frames are

transmitted in accordance with the station’s synchronous

bandwidth allocation

For Asynchronous transmission one programmable asyn-

chronous priority threshold is supported in addition to the

threshold at the Negotiated Target Token Rotation time

For Restricted Asynchronous transmission support is pro-

vided to begin continue and end restricted dialogues

For Immediate transmissions support is provided to send

frames from either the Data Beacon or Claim states and

either ignore or respond to the received byte stream After

an immediate transmission a token may optionally be is-

sued

25 DIAGNOSTIC COUNTERS

The MACSI device includes a number of diagnostic coun-

ters and timers that monitor ring and station performance

These counters allow measurement of the following

Number of frames transmitted and received by the

station

Number of frames copied as well as frames not copied

Frame error rate of an incoming physical connection to

the MAC

Load on the ring based on the number of tokens re-

ceived and the ring latency

Ring latency

Lost frames

The size of these counters has been selected to keep the

frequency of overflow small even under worst case operat-

ing conditions

26 MANAGEMENT SERVICES

The MACSI device provides management services to the

Host System via the Control Bus Interface This interface

allows access to internal registers to control and configure

the MACSI device

27 RING PARAMETER TUNING

The MACSI device includes settable parameters to allow

tuning of the network to increase performance over a large

range of network sizes

The MACSI device supports systems of two stations with

little cable between them to ring configurations much larger

than the 1000 physical attachments andor 200 kilometer

distance that are specified as the default values in the stan-

dard

The MACSI device also handles frames larger than the

4500 byte default maximum frame size as specified in the

standard

28 MULTI-FRAME STREAMING INTERFACE

The MACSI device provides an interface to support multi-

frame streaming Multiple frames can be transmitted after a

token is captured within the limits of the token timer thresh-

olds

29 BEACON CLAIM AND VOID FRAMES GENERATION

For purposes of transient token and ring recovery no proc-

essor intervention is required The MACSI device automati-

cally generates the appropriate MAC frames

210 SELF TESTING

Since the MACSI device has a full duplex architecture loop-

back testing is possible before entering the ring and during

normal ring operation

There are several possible loopback paths

Internal to the MACSI device

Through the PLAYERa device(s) using the PLAYERa

configuration switch

Through the PLAYERa Clock Recovery Module

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