PRELIMINARY
Am79C982
b
asic Integrated Multiport Repeater (
b
IMR)
DISTINCTIVE CHARACTERISTICS
s
Fully backward-compatible with existing
IMR/IMR+ device non-managed hub designs
— Pin/socket-compatible with the Am79C980
(IMR) and Am79C981 (IMR+) devices
s
Repeater functions comply with IEEE 802.3
Repeater Unit specifications
s
Four and eight 10BASE-T port options available
s
Low-cost, flexible solutions suitable for
non-managed repeater designs
s
Integral 10BASE-T transceivers utilize the
required predistortion transmission technique
s
Attachment unit interface (AUI) port allows
connectivity with 10BASE-5 (Ethernet) and
10BASE-2 (Cheapernet) networks, as well as
10BASE-F and/or Fiber Optic Inter-Repeater
Link (FOIRL) segments
s
Minimum mode facilitates LED implementation
and provides four LED display options for port
status
s
Built-in pulse stretching for carrier sense LED
display
s
On-board PLL, Manchester encoder/decoder,
LED display and FIFO
s
Expandable to increase number of repeater
ports
s
All ports can be separately isolated (partitioned)
in response to excessive collision conditions or
fault conditions
s
Network management and optional features are
accessible through a dedicated serial
management port
s
Twisted-pair Link Test capability conforming to
the 10BASE-T standard. The receive Link Test
function can be optionally disabled through the
management port to facilitate interoperability
with devices that do not implement the Link Test
function
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
Preamble loss effects eliminated by deep FIFO
s
CMOS device features high integration and low
power with a single +5 V supply
GENERAL DESCRIPTION
The
b
asic Integrated Multiport Repeater (
b
IMR™) chip
is a VLSI circuit that provides a system-level solution to
designing a compliant 802.3 repeater incorporating
10BASE-T transceivers. The device integrates the
Repeater functions specified by Section 9 of the
IEEE 802.3 standard and twisted-pair Transceiver
functions complying to the 10BASE-T standard. The
Am79C982-4 provides four and the Am79C982-8 pro-
vides eight integral twisted-pair medium attachment
units (MAUs), and an attachment unit interface (AUI)
port in an 84-pin plastic leaded chip carrier (PLCC).
A network based on the 10BASE-T standard uses un-
shielded twisted-pair cables, therefore providing an
economical solution to networking by allowing the use
of low-cost unshielded twisted-pair (UTP) cable or
existing telephone wiring.
The total number of ports per repeater unit can be in-
creased by connecting multiple
b
IMR devices through
their expansion ports, hence minimizing the total cost
per repeater port. Furthermore, a general-purpose
attachment unit interface (AUI) provides connection
capability to 10BASE-5 (Ethernet) and 10BASE-2
(Cheapernet) coaxial networks, as well as 10BASE-F
and/or Fiber Optic Inter-Repeater Link (FOIRL) fiber
segments. Network management and test functions
are provided through TTL-compatible I/O pins.
The device is fabricated in CMOS technology and
requires a single +5 V supply.
Publication#
19406
Rev:
B
Amendment/0
Issue Date:
January 1999
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.
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