The NWK954 is a fully integrated, unmanaged, 4-port Fast

Ethernet Repeater conforming to the IEEE 802.3 100BASE-TX
Standard. The device integrates the 802.3 Repeater functions
with four 100BASE-TX PHY modules, enabling direct connection
to the isolation transformers with no additional PHY components.

It has built-in LED drivers for display of port activity and

network utilization. There is a local expansion port which allows
up to six NWK954s to be cascaded to form a 24-port repeater
with no additional components.

With the addition of simple backplane driver/receivers, up to

eight 24-port repeaters can be stacked.

The NWK954 is supplied in a 128-pin PQFP and interfaces

to the twisted pair media through 1:1 isolation transformers.

QUAD RJ45

QUAD

MAGNETICS

NWK954

QUAD

MAGNETICS

NWK954

QUAD

MAGNETICS

NWK954

QUAD

MAGNETICS

NWK954

QUAD

MAGNETICS

NWK954

QUAD

MAGNETICS

NWK954

CLOCK DRIVERS

OSCILLATOR

BACKPLANE BUFFERS

BACKPLANE CONTROLS

LOCAL EXPANSION BUS

Fig. 1 System block diagram

FEATURES

Compliant with IEEE 802.3 100BASE-TX Repeater
Unit Specification

Incorporates four IEEE 802.3 Compliant 100BASE-TX
Ports

Local Expansion Port for Cascading to 24 Ports

Stackable Backplane for Expansion up to 192 Ports

Link/Activity LED and Receive Error LED for each Port

Collision LED

Five LED Network Utilization Display

Base Line Wander Correction

Power Saving on Unused Ports

Driven from a Single 25MHz Clock

Single 5V supply

Low Power CMOS Technology

128-pin PQFP package

ORDERING INFORMATION

NWK954D/CG/GH1N

NWK954

QUAD FAST ETHERNET REPEATER

PRELIMINARY INFORMATION

Supersedes January 1998 version, DS4842 - 1.1

DS4842-2.1 April 1998

NWK954

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65

IRD3

IRD2

DIGGND2

DIGVDD2

P0_RXLED_N

P0_ERLED_N

P1_RXLED_N

P1_ERLED_N

P2_RXLED_N

P2_ERLED_N

P3_RXLED_N

P3_ERLED_N

ACTLED_N4

ACTLED_N3

ACTLED_N2

ACTLED_N1

ACTLED_N0

DIGGND3

DIGVDD3

COLLED_N

BPDOE_N

BPDIE_N

BPCOLOE_N

ACT

OUT_N

BPCOLIN_N

ACTIN_N1

ACTIN_N2

ACTIN_N3

DIGGND4

DIGVDD4

IRD1

IRD0

IRD4

LACTOUT_N

DIGVDD1

DIGGND1

RESET_N

LACTIN_N1
LACTIN_N2
LACTIN_N3
LACTIN_N4
LACTIN_N5

TDC

TDIO

TA4
TA3
TA2

SUBVDD1

P0_RXGND3

P0_RXVDD3
P0_RXVDD2

P0_RXGND2
P0_RXGND1

P0_RXVDD1

P0_RXIN

P0_RXIP

P0_TXVDD3

P0_TXGND3

P0_TXREF

P0_TXGND2

P0_TXVDD2

P0_TXON
P0_TXOP
P0_GND1

BPCLK
BPCOL_N
DIGGND5
DIGVDD5
BPACTIN_N4
BPACTIN_N5
BPACTIN_N6
BPACTIN_N7
PSEN0
PSEN1
TXCLKIN
DIGGND6
DIGVDD6
VREFGND
VREFVDD
SUBVDD2
P3_RXGND3
P3_RXVDD3
P3_RXVDD2
P3_RXGND2
P3_RXGND1
P3�RXVDD1
P3_RXIN
P3_RXIP
P3_TXVDD3
P3_TXGND3
P3_TXREF
P3_TXGND2
P3_TXVDD2
P3_TXON
P3_TXOP
P3_TXGND1

128

127

126

125

124

123

122

121

120

109

108

107

106

105

104

103

102

101

100

P1_TXGND1

P1_TXOP

P1_TXON

P1_TXVDD2

P1_TXGND2

P1_TXREF

P1_TXGND3

P1_TXVDD3

P1_RXIP

P1_RXIN

P1_RXVDD1

P1_RXGND1

P1_RXGND2

P1_RXVDD2

P1_RXVDD3

P1_RXGND3

P2_RXGND3

P2_RXVDD3

P2_RXVDD2

P2_RXGND2

P2_RXGND1

P2_RXVDD1

P2_RXIN

P2_RXIP

P2_TXVDD3

P2_TXGND3

P2_TXREF

P2_TXGND2

P2_TXVDD2

P2_TXON

P2_TXOP

P2_TXGND1

NWK954

Fig. 3 Pin connections � top view

FUNCTIONAL DESCRIPTION

Overvlew

The NWK954 is a mixed-signal CMOS device which

integrates all of the functions required for an unmanaged 4-
port 100BASE TX repeater as defined in the IEEE 802.3
Standard. The device incorporates all of the necessary
100BASE-TX PHY functions to allow direct interfacing to a
quad 1:1 magnetics module with a modest number of external
passive components. The built-in expansion port allows
cascading of up to 6 NWK954s to build a 24-port repeater
with no additional components and also allows stacking of
up to eight 24-port repeaters with the addition of simple
backplane driver/receiver components. The operating status
of the device is indicated on 14 outputs designed to directly
drive LEDs. This high level of integration combined with low
power consumption and low pin count offers an efficient and
low cost solution for Fast Ethernet unmanaged repeater design.

Compliance with Standards

The NWK954 is designed for compliance with the IEEE 802.3

Standard, Clause 24 (100BASE-X PCS and PMA), Clause 25
(100BASE-TX PMD) and Clause 27 (Repeater for 100Mb/s
Baseband Networks). Clause 25 references the FDDI twisted
pair PMD Standard, henceforth referred to as TP-PMD.

Compatibility With Other Devices

The NWK954 is designed to connect directly to 5 other

NWK954 devices using the expansion bus. The Expansion Port
is identical to that used on the NWK950 Repeater Controller.
The Expansion Port may be connected to a backplane through
external driver/receivers. The backplane specification is identical
to that used by the NWK950, so repeaters using the NWK950
may be stacked with repeaters using the NWK954.

GP128

NWK954

PORT 0

TRANSCEIVER

P0_TXOP

P0_TXON

P0_TXREF

P0_RXIP

P0_RXIN

PORT 1

TRANSCEIVER

P1_TXOP

P1_TXON

P1_TXREF

P1_RXIP

P1_RXIN

PORT 2

TRANSCEIVER

P2_TXOP

P2_TXON

P2_TXREF

P2_RXIP

P2_RXIN

PORT 3

TRANSCEIVER

P3_TXOP

P3_TXON

P3_TXREF

P3_RXIP

P3_RXIN

RESET_N

PSEN [1:0]

TXCLKIN

[4:2]

VOLTAGE

REFERENCE

REPEATER

CONTROLLER

POWER-ON

RESET

IRD [4:0]

LACTOUT_N

LACTIN_N

BPACTOUT_N

BPACTIN_ N [7:1]

BPDIE_N

BPDOE_N

BPCLK

BPCOL_N

BPCOLIN_N

BPCOLOE_N

EXPANSION

PORT

ACTLED_N [4:0]

COLLED_N

P0_RXLED_N

P0_ERLED_N

P1_RXLED_N

P1_ERLED_N

P2_RXLED_N

P2_ERLED_N

P3_RXLED_N

P3_ERLED_N

LED

DRIVERS

TRANSCEIVER

CONTROL

SCRAMBLER

DESCRAMBLER

LINE

MONITOR

SIPO AND

DECODER

CLOCK

RECOVERY

EQUALIZER

AND BLW

CORRECTION

PISO

AND

ENCODER

125MHz

SYNTHESIZER

RX SIGNAL

DETECT

TX DRIVER

Port [3:0] transceiver details

Fig. 4 NWK954 block diagram

NWK954

Basic Repeater Function

The Repeater Controller monitors activity on the 4 twisted

pair ports and on the Expansion Port. When a packet is received
on one of the twisted pair ports it is forwarded to the other 3
twisted pair ports and to the Expansion Port. When a packet is
received on the Expansion Port it is forwarded to all 4 twisted
pair ports. When receive activity is detected on 2 or more ports
the Repeater Controller will send the jam signal to all twisted
pair ports for the duration of all activity associated with the
collision event.

Jabber Protection

The Repeater Controller provides receive jabber protection

to ensure that the network is not disrupted by excessively long
data streams. If a received data stream exceeds 65,536 bit times
then the receiving port will be shutdown. In the shutdown state
data received on the faulty port is ignored and packets received
from other ports are not transmitted to the faulty port. A port will
recover from the shutdown state when the incoming data stream
ends or if the device is reset.

Auto-Partition Function

The auto-partition function prevents faulty behaviour on a

network segment from disrupting the entire network. The
Repeater Controller counts consecutive collisions on each port
and will partition a port that causes more than 60 consecutive
collisions. In the partitioned state, packets received on the faulty
port will be ignored but packets received from other ports will
continue to be transmitted to the faulty port. The port will recover
from the partitioned state when valid activity is detected on the
port or if the device is reset.

Carrier Integrity Monitor

The Repeater Controller detects false carrier events on all

ports. A false carrier is defined as receive activity that does not
commence with the correct start-of-packet sequence. When a
false carrier event is detected, the Repeater Controller will
transmit the jam signal on all ports for the duration of the false
carrier event provided it does not exceed 450-500 bit times.
After this time the port will be isolated and the jam signal will
cease. The NWK954 will also isolate a port that suffers 2
successive false carrier events. In the isolated state, packets
received from the faulty port are ignored and packets received
from other ports are not transmitted to the faulty port. A port will
recover from the isolated state when a valid inter-packet gap is
detected and is followed by either a valid packet exceeding 450-
500 bit times or by an idle sequence exceeding 33000 (

�

25%)

bit times.

Expansion Port

The Expansion Port allows up to 6 NWK954s to be cascaded.

This allows a 24-port hub to be built with no additional external
components. The Expansion Port includes a 5-bit parallel
bidirectional data bus (IRD) which carries unscrambled symbol data
and a 25MHz sampling clock (BPCLK). Each NWK954 indicates
receive activity on any of its 4 twisted pair ports by asserting the
local activity output (LACTOUT_N). The LACTOUT_N signals from
each NWK954 connect to the local activity inputs (LACTIN_N) of all
the other cascaded NWK954s.

When a collision occurs between 2 twisted pair ports on an

NWK954, the event is communicated to other cascaded NWK954s
by asserting the collision signal (BPCOL_N). This instructs all
cascaded NWK954s to transmit the jam signal for the duration of
the collision event. BPCOL_N is also asserted when a collision occurs
between 2 twisted pair ports on different NWK954s.
Backplane

The Expansion Port allows hubs to be stacked via a backplane

bus. This requires the addition of some simple external driver/
receivers. The functional requirement for these components is
illustrated in Fig. 6. Contact Mitel for full details of recommended
components.

BPACTIN_ N [7:1]

LACTIN_N [5:1]

LACTOUT_N

BPCOLIN_N

BPCOL_N

BPCLK

IRD [4:0]

TXCLKIN

BPACTIN_ N [7:1]

LACTIN_N [5:1]

LACTOUT_N

BPCOLIN_N

BPCOL_N

BPCLK

IRD [4:0]

TXCLKIN

BPACTIN_ N [7:1]

LACTIN_N [5:1]

LACTOUT_N

BPCOLIN_N

BPCOL_N

BPCLK

IRD [4:0]

TXCLKIN

BPACTIN_ N [7:1]

LACTIN_N [5:1]

LACTOUT_N

BPCOLIN_N

BPCOL_N

BPCLK

IRD [4:0]

TXCLKIN

BPACTIN_ N [7:1]

LACTIN_N [5:1]

LACTOUT_N

BPCOLIN_N

BPCOL_N

BPCLK

IRD [4:0]

TXCLKIN

BPACTIN_ N [7:1]

LACTIN_N [5:1]

LACTOUT_N

BPCOLIN_N

BPCOL_N

BPCLK

IRD [4:0]

TXCLKIN

CLOCK

DRIVER

25MHz

OSCILLATOR

Fig. 5 Cascaded NWK954s

Электронный компонент: NWK954CG