9883 datasheet(12/56 Pages) INTEL

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LXT9883/9863 — Advanced 10/100 Unmanaged Repeater

Datasheet

Document #: 249115

Revision #: 003

Rev. Date: 08/07/01

10 Mbps IRB Signals

IR10DAT

I/O

10 Mbps IRB Data. This bidirectional signal carries data on the 10 Mbps IRB. Data is

driven and sampled on the rising edge of the corresponding IRCLK. This signal must be

pulled High by a 330

Ω resistor. Buffer this signal between boards.

IR10CLK

I/O

Tri-state

Schmitt

10 Mbps IRB Clock. This bidirectional, non-continuous, 10 MHz clock is recovered

from received network traffic. During idle periods, the output is high-impedance. Schmitt

triggering is used to increase noise immunity.

IR10DEN

10 Mbps IRB Driver Enable. This output provides directional control for an external

bidirectional transceiver (74LVT245) used to buffer the IRBs in multi-board applications.

It must be pulled up by a 330

Ω resistor. When there are multiple devices on one board,

tie all IR10DEN outputs together. If IR10DEN is tied directly to the DIR pin on a

74LVT245, attach the on-board IR10DAT, IR10CLK and IR10ENA signals to the “B” side

of the 74LVT245, and connect the off-board signals to the “A” side of the 74LVT245.

IR10ENA

I/O

10 Mbps IRB Enable. This active Low output indicates carrier presence on the IRB. A

330

Ω pull-up resistor is required to pull the IR10ENA output High when the IRB is idle.

When there are multiple devices, tie all IR10ENA outputs together. Buffer these

signals between boards.

IR10COL

I/O

10 Mbps IRB Collision. This output is driven Low to indicate a collision occurred on the

10 Mbps segment. A 330

Ω resistor is required on each board to pull this signal High

when there is no collision. Do not connect between boards and do not buffer.

IR10COLBP

I/O

10 Mbps IRB Collision - Backplane. This active Low output has the same function as

IR10COL, but is used between boards. Attach this signal only from the device with FPS

= 0 to the backplane or connector, without buffering. The output must be pulled up by

one 330

Ω resistor per stack.

IR10CFS

A, I/O

10 Mbps IRB Collision Force Sense. This three-state analog signal indicates transmit

collision when driven Low. IR10CFS requires a 215

Ω, 1% pull-up resistor. Do not

connect this signal between boards and do not buffer.

IR10CFSBP

A I/O

Note: 10 Mbps IRB Collision Force Sense - Backplane. Functions the same as

IR10CFS, but connects between boards. Attach this signal only from the device

with FPS = 0 to the backplane or connector, without buffering. This signal

requires one 330

Ω, 1% pull-up resistor per stack. This signal can be set for 5V or

3.3V modes by the COMP_SEL pin.

MACACTIVE

Note: MAC Active. Active High input allows external ASICs to participate in 10 Mbps

IRB. Driving data onto the IRB requires the external ASIC assert MACACTIVE

High for one clock cycle, then assert IR10ENA Low. ASIC monitors IR10COL

(active Low) for collision. By using MACACTIVE, the repeater—not the MAC—

drives the three-level IR10CFS pin.

HOLDCOL

I/O

Note: Hold Collision for 10 Mbps mode. This active High signal is driven by the

device with FPS = 0 to extend a non-local transmit collision to other devices on

the same board. Do not attach the HOLDCOL signals from different boards

together.

Table 3.

Inter-Repeater Backplane Signal Descriptions (Continued)

Symbol

Type

1, 2

Description

1. I = Input, O = Output, I/O = Input/Output, D = Digital, AI = Analog Input, A I/O = Analog Input/Output, OD = Open Drain,

OS = Open Source, PD = Pull Down, PU = Pull Up. Even if the IRB is not used, required pull-up resistors must be installed as

listed above.

NC = No Clamp. Pad does not clamp input in the absence of power.

2. Pins are 5V tolerant, unless indicated.

3. IR100CFS is not 5V tolerant.

4. IR10CFS is not 5V tolerant.

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