PRELIMINARY
Am79C984A
enhanced Integrated Multiport Repeater (eIMR™)
DISTINCTIVE CHARACTERISTICS
s Repeater functions comply with IEEE 802.3
Repeater Unit specifications
s Full LED support for individual port status LEDs
and network utilization LEDs
s Four integral 10BASE-T transceivers with onchip filtering that eliminate the need for external
filter modules on the 10BASE-T transmit-data
(TXD) and receive-data (RXD) lines
s Programmable extended distance mode on the
RXD lines, allowing connection to cables longer
than 100 meters
s One Reversible Attachment Unit Interface
(RAUI™) port that can be used either as a
standard IEEE-compliant AUI port for
connection to a Medium Attachment Unit (MAU),
or as a reversed port for direct connection to a
Media Access Controller (MAC)
s Low cost suitable for non-managed multiport
repeater designs
s Expandable to increase number of repeater
ports with support for up to seven eIMR devices
without the need for an external arbiter
s Twisted Pair Link Test capability conforming to
the 10BASE-T standard. The Link Test function
and the transmission of Link Test pulses can be
optionally disabled through the control port to
allow devices that do not implement the Link Test
function to work with the eIMR device.
s Programmable option of automatic polarity
detection and correction permits automatic
recovery due to wiring errors
s Full amplitude and timing regeneration for
retransmitted waveforms
s CMOS device with a single +5-V supply
s All ports can be individually isolated
(partitioned) in response to excessive collision
conditions or fault conditions.
GENERAL DESCRIPTION
The enhanced Integrated Multiport Repeater (eIMR)
device is a VLSI integrated circuit that provides a system-level solution to designing non-managed multiport
repeaters. The device integrates the repeater functions
specified in Section 9 of the IEEE 802.3 standard and
Twisted Pair Transceiver functions complying with the
10BASE-T standard.
The eIMR device provides four Twisted Pair (TP) ports
and one RAUI port for direct connection to a MAC. The
total number of ports per repeater unit can be increased by connecting multiple eIMR devices through
their expansion ports, hence, minimizing the total cost
per repeater port.
The device is fabricated in CMOS technology and
requires a single +5-V supply.
This document contains information on a product under development at Advanced Micro Devices. The
information is intended to help you evaluate this product. AMD reserves the right to change or discontinue
work on this proposed product without notice.
Publication# 20650 Rev: B Amendment/0
Issue Date: January 1998
