5228-DS07-R datasheet(13/100 Pages) BOARDCOM

13 / 100 page

Data Sheet

BCM5228

7/12/04

Broa d c om Co rp o r a t i o n

Document

5228-DS09-405-R

Functional Description

Page 1

Secti on 1: Fu nction al Descri p ti on

OVERVIEW

The BCM5228 is a single-chip device containing eight independent Fast Ethernet transceivers. Each transceiver performs

all of the physical layer interface functions for 100BASE-TX full-duplex or half-duplex Ethernet on Category 5 unshielded

twisted-pair (UTP) cable, and 10BASE-T full-duplex or half-duplex Ethernet on Category 3, 4, or 5 UTP cable. Each port can

also be configured for 100BASE-FX full-duplex or half-duplex transmission over fiber-optic cabling when paired with an

external fiber-optic line driver and receiver.

The chip performs:

•

4B5B, MLT3, NRZI, and Manchester encoding and decoding

•

Clock and data recovery

•

Stream cipher scrambling/descrambling

•

Digital adaptive equalization

•

Line transmission

•

Carrier sense and link integrity monitor

•

Auto-negotiation

•

RMII, SMII, S3MII, and management functions

The BCM5228 can be connected to a MAC through the RMII or SMII on one side, and directly to the network media on the

other side through either:

•

Isolation transformers for UTP modes

•

Fiber-optic transmitter/receiver components for FX mode

The BCM5228 is compliant with the IEEE 802.3 standard.

ENCODER/DECODER

In 100BASE-TX and 100BASE-FX modes, the BCM5228 transmits and receives a continuous data stream on twisted-pair

or fiber-optic cable. When the RMII Transmit Enable pin is asserted, data from the transmit data pins is encoded into 5-bit

code groups and inserted into the transmit data stream. The 4B5B encoding is shown in Table 1 on page 4. The transmit

packet is encapsulated by replacing the first two nibbles of preamble with a start-of-stream delimiter (J/K codes) and

appending an end-of-stream delimiter (T/R codes) to the end of the packet. The transmitter repeatedly sends the idle code

group between packets.

In TX mode, the encoded data stream is scrambled by a stream cipher block and then serialized and encoded into MLT3

signal levels. A multimode transmit DAC is used to drive the MLT3 data onto the twisted-pair cable. In FX mode, the

scrambling function is bypassed and the data is NRZI encoded. The multimode transmit DAC drives differential positive ECL

(PECL) levels to an external fiber-optic transmitter.

5228-DS07-R 数据表(PDF) 13 Page - Broadcom Corporation.

5228-DS07-R 数据表(HTML) 13 Page - Broadcom Corporation.

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