PRELIMINARY
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# 21170 Rev:B Amendment/0
Issue Date: November 1996
Am79C871
Quad Fast Ethernet Transceiver for 100BASE-X Repeaters (QFEXrTM)
DISTINCTIVE CHARACTERISTICS
s
Compatible with IEEE 802.3u standard for
100BASE-TX and 100BASE-FX
s
Shared Media Independent Interface (MII) for
100BASE-X Repeater applications
s
Quad Integrated Digital CMOS 100 Mbps clock
recovery circuits
s
Individual False Carrier Indication signal for
repeater applications
s
Programmable loopback modes
s
Scramble and descramble feature supported for
100BASE-TX
s
Link Monitor and Far End Fault Indication (FEFI)
s
Programmable LED support
s
IEEE 1149.1-compatible JTAG support
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Carrier Integrity Monitor (CIM) support
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Direct interface to TX (MLT-3) or FX Physical
Medium Dependent (PMD) devices
s
CMOS device features high integration and low
power with a single +5 V supply in 100-pin PQFP
GENERAL DESCRIPTION
The Am79C871 Quad Fast Ethernet Transceiver for
Repeaters (QFEXr) is a CMOS device that implements
the Media Independent Interface (MII), Physical Coding
Sublayer (PCS), and Physical Medium Attachment
(PMA) for four 100BASE-TX/FX ports. The QFEXr de-
vice shares a single MII for the four ports.
In conjunction with external PMD devices, such as
MLT-3 or fiber optic transceivers, the QFEXr device
supports operation over two pairs of shielded twisted-
pair (STP) cable, two pairs of Category 5 unshielded
twisted-pair (UTP) cable, or two multi-mode fibers.
The functions performed by the device include encod-
ing the MII 4-bit data (4B/5B), decoding the received
code groups (5B/4B), generating carrier sense and
collision detect indications, serializing code groups for
transmission, de-serializing received serial data,
mapping transmit, receive, carrier sense, and collision
at the MII interface, and recovering clock from the
incoming data stream. The QFEXr device offers
stream cipher scrambling and descrambling capability
for 100BASE-TX applications.
When transmitting, the QFEXr device receives 4-bit
(nibble) wide data across the MII at 25 million nibbles
per second. It then encodes the data, optionally scram-
bles the data, serializes the data, and transmits an
NRZI data stream.
When receiving, the QFEXr device receives the NRZI
data stream from the network. It then recovers the
clock from the NRZI data stream, de-serializes the data
stream, optionally descrambles the data stream, and
decodes the code groups (5B/4B). The QFEXr device
communicates with the repeater device through the
MII. This interface has been optimized for repeater ap-
plications and is compatible with Clause 22 of the IEEE
802.3 standard specification.
Am79C871
3
P R E L I M I N A R Y
ORDERING INFORMATION
Standard Products
AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed
by a combination of the elements below.
Valid Combinations
Valid Combinations list configurations planned to be sup-
ported in volume for this device. Consult the local AMD sales
office to confirm availability of specific valid combinations and
to check on newly released combinations.
DEVICE NUMBER/DESCRIPTION
Am79C871
Quad Fast Ethernet Transceiver for 100BASE-X
Repeaters (QFEXr)
TEMPERATURE RANGE
C = Commercial (0°C to +70°C)
ALTERNATE PACKAGING OPTION
\W = Trimmed and formed in a tray
PACKAGE TYPE
K = 100-pin Plastic Quad Flat Pack (PQR100)
Am79C871
C
K
SPEED OPTION
Not Applicable
\W
Valid Combinations
Am79C871
KC\W
4
Am79C871
P R E L I M I N A R Y
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