DP83255AVF datasheet(22/96 Pages) NSC

22 / 96 page

50 Registers (Continued)

MODE REGISTER (MR)

The Mode Register is used to initialize and configure the PLAYER device

In order to minimize interruptions on the network it is recommended that the PLAYER device first be put in STOP mode (ie set

the RUN bit to zero) before programming the Mode Register the Configuration Register or the Current Transmit State Register

ACCESS RULES

ADDRESS

READ

WRITE

00h

Always

RNRZ

TNRZ

TQL

EXLB

ILB

RUN

Bit

Symbol

Description

RUN

RUN STOP

0 Enables the STOP mode Refer to Section 42 STOP Mode of Operation for more

information

1 Normal Operation (ie RUN mode)

Note

The RUN bit is automatically set to 0 when the RST pin is asserted (ie set to ground)

ILB

INTERNAL LOOPBACK

0 Disables Internal Loopback mode (ie normal operation)

1 Enables Internal Loopback mode

Refer to Section 43 Loopback Mode of Operation for more information

EXLB

EXTERNAL LOOPBACK

0 Disables External Loopback mode (ie normal operation)

1 Enables External Loopback mode

Refer to Section 43 Loopback Mode of Operation for more information

CASCADE MODE

0 Disables synchronization of cascaded PLAYER devices

1 Enables the synchronization of cascaded PLAYER devices

Refer to Section 44 Cascade Mode of Operation for more information

TQL

TRANSMIT QUIET LEVEL

This bit is used to program the transmission level of the Quiet

symbols

0 Low level Quiet symbols are transmitted through the PMD Data Request pins

(ie TXDae low TXDbe high)

1 High level Quiet symbols are transmitted through the PMD Data Request pins

(ie TXDae high TXDbe low)

TRANSMIT ENABLE

The TE bit controls the action of FOTX Enable (TXE) pin independent

of the current transmit mode When TE is 0 the TXE output disables the optical transmitter

when TE is 1 the optical transmitter is disabled during the Off Transmit Mode (OTM) and

enabled otherwise The On and Off level of the TXE is dependent on the FOTX Enable Level

(TEL) pin to the PLAYER device The following rules summarizes the output of TXE

(1) If TE e 0 then TXE e Off

(2) If TE e 1 and OTM then TXE e 0ff

(3) If TE e 1 and not OTM then TXE e On

TNRZ

TRANSMIT NRZ DATA

0 Transmits data in Non-Return-To-Zero-Invert-On-Ones format

1 Transmits data in Non-Return-To-Zero format

RNRZ

RECEIVE NRZ DATA

0 Receives data in Non-Return-To-Zero-Invert-On-Ones format

1 Receives data in Non-Return-To-Zero format

DP83255AVF Datasheet(PDF) 22 Page - National Semiconductor (TI)

DP83255AVF Datasheet(HTML) 22 Page - National Semiconductor (TI)

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