5220-DS02-R datasheet(50/90 Pages) BOARDCOM

50 / 90 page

BCM5220

Preliminary Data Sheet

04/20/04

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

Page 38

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5220-DS04-405-R

Bypass NRZI Encoder/Decoder

The NRZI encoder and decoder can be bypassed by writing a 1 to bit 8 of MII register 10h, causing 3-level NRZ data to be

transmitted and received on the cable. Normal operation (3-level NRZI encoding and decoding) can be re-enabled by writing

a 0 to this bit.

Bypass Receive Symbol Alignment

Receive symbol alignment can be bypassed by writing a 1 to bit 7 of MII register 10h. When used in conjunction with the

bypass 4B5B encoder/decoder bit, unaligned 5B codes are placed directly on the RXER and RXD1, RXD0 pins.

Baseline Wander Correction Disable

The baseline wander correction circuit can be disabled by writing a 1 to bit 6 of MII register 10h. The BCM5220 corrects for

baseline wander on the receive data signal when this bit is cleared.

FEF Enable

Controls the far end fault mechanism associated with 100BASE-FX operation. A 1 enables the FEF function and a 0 disables

it.

Reserved Bits

The reserved bits of the 100BASE-X Auxiliary Control register must be written as 0 at all times. Ignore the BCM5220 outputs

when these bits are read.

5220-DS02-R Datasheet(PDF) 50 Page - Broadcom Corporation.