TNETX3150 datasheet(41/113 Pages) TI1

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TNETX3150/TNETX3150A

ThunderSWITCH™ 15-PORT 10-/100-MBIT/S ETHERNET™ SWITCH

SPWS027F – FEBRUARY 1997 – REVISED SEPTEMBER 1997

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

port-N control register at 0x8*N + 0000 (N = port number in hex)

RESET

INITIAL VALUES AFTER RESET

CONDITIONS

BIT

DISABLE

ENABLE

STFORTX

STFORRX

ADRDIS

MWIDTH

TXPACE

FORCEHD

M00UPLINK = 1

M00UPLINK = 0

ports 01–14

M00UPLINK = 0

port 00

BIT

NAME

FUNCTION

DISABLE

Port disable. Writing a 1 to DISABLE disables the port. Frames are not forwarded from or to a disabled port. The

port, however, attempts to transmit any previously queued frames.

DISABLE is a latched bit. It is set by both hard and soft reset.

ENABLE

Port enable. Writing a 1 to ENABLE enables the port if the DISABLE bit is not set. Writing a 0 to ENABLE has no

effect. ENABLE is always read as 0.

STFORTX

Store and forward on transmission. Cut-through to this port is not allowed when STFORTX = 1.

STFORRX

Store and forward on receive. Cut-through from this port is disabled when STFORRX = 1.

ADRDIS

Address match disable. When ADRDIS = 1, the port does not take part in address-matching activity. Addresses

are not captured for this port and any stored address is invalidated. Frames are not forwarded to the port except

by EAM or BRUN functions. This permits selection between the ports that use external and internal address

mappings.

This

allows

the

external

address-match

engine

restricted

subset

TNETX3150/TNETX3150A ports using the internal single-address lookup. If all ADRDIS bits = 1, all ports rely on

the external address-match hardware. If a no-match code is received, the frame is discarded. If the uplink ADRDIS

bit is set and a frame address has not been matched, the frame is discarded. ADRDIS should be set for all ports

using external address hardware to discard frames using the EAM no-operation code.

MWIDTH

MII width selection. MWIDTH is valid only on 10-/100-Mbit/s capable ports (ports 00, 01, 02). When MWIDTH =

1 and the port is operated in 10-Mbit/s mode, the interface is operated in nibble-serial mode. When MWIDTH = 0,

the interface is operated in bit-serial mode.

TXPACE

Transmit pacing. When TXPACE = 1, the port uses transmission pacing to enhance performance. When

TXPACE = 0, transmit pacing is disabled.

FORCEHD

Force half duplex. When FORCEHD = 1, the DUPLEX terminal is pulled down (active pulldown on the input), forcing

the PHY to operate in half-duplex mode.

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