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# 20651
Rev: B Amendment/0
Issue Date: January 1998
Am79C985
enhanced Integrated Multiport Repeater Plus (eIMR+TM)
DISTINCTIVE CHARACTERISTICS
s
Repeater functions compliant with IEEE 802.3
Repeater Unit specifications
s
Direct interface with the Am79C987 Hardware
Implemented Management Information Base
(HIMIBTM) device for building a basic managed
multiport repeater
s
Full software backwards compatibility with
existing hub designs using Integrated Multiport
Repeater Plus (IMR+TM)/HIMIB devices
s
Network management and optional feature
accessibility through a dedicated serial
management port
s
Four integral 10BASE-T transceivers with on-
chip filtering eliminating the need for external
filter modules on the 10BASE-T transmit-data
(TXD) and receive-data (RXD) lines
s
One Reversible Attachment Unit Interface
(RAUITM) port used either as a standard IEEE-
compliant AUI port for connection to a Medium
Attachment Unit (MAU) or a reversed port for
direct connection to a Media Access Controller
(MAC)
s
Low cost suitable for managed multiport
repeater designs
s
Number of repeater ports easily expandable
with support for up to seven eIMR+ devices
without the need for an external arbiter
s
All ports capable of being individually isolated
(partitioned) in response to excessive collision
conditions or fault conditions
s
Flexible LED support for individual port status
and network utilization LEDs
s
Programmable extended distance mode on RXD
lines allowing connection to cables longer than
100 meters
s
Link Test function and Link Test pulse
transmission capable of being disabled through
the management port allowing devices that do
not implement the Link Test function to work
with the eIMR+ device
s
Programmable automatic polarity detection and
correction option permitting automatic
recovery from wiring errors
s
Full amplitude and timing regeneration for
retransmitted waveforms
s
CMOS device with a single +5-V supply
GENERAL DESCRIPTION
The enhanced Integrated Multiport Repeater Plus
(eIMR+) device is a VLSI integrated circuit that pro-
vides a system-level solution to designing managed
multiport repeaters. The device integrates the repeater
functions specified in Section 9 of the IEEE 802.3
standard and Twisted Pair Transceiver functions com-
plying with the 10BASE-T standard.
The eIMR+ device provides four Twisted Pair (TP) ports
and one reversible AUI (RAUI) port for direct connec-
tion to a MAC. The total number of ports per repeater
unit can be increased by connecting multiple eIMR+
devices through their expansion ports, hence, minimiz-
ing the total cost per repeater port.
The eIMR+ device also provides a connection to the
Am79C987 HIMIB device. The HIMIB device monitors
all the necessary counters, attributes, actions, and
notifications specified by IEEE 802.3, Section 19
(Layer Management for 10 Megabit per second (Mbps)
Baseband Repeaters). When the eIMR+ and HIMIB
devices are used together as a chip set, they provide a
cost-effective solution to the problem of designing
10BASE-T basic managed multiport repeaters.
The device is fabricated in CMOS technology and
requires a single +5-V supply.
2
Am79C985
P R E L I M I N A R Y
BLOCK DIAGRAM
.
RX
MUX
Phase
Loc
k
Loop
FIFO
FIFO
CONTR
OL
Preamb
le
J
am Sequence
P
a
r
titioning
Link T
est
Timers
AU
I
Po
r
t
DI
CI
DO
TP
Po
r
t
0
RXD
TXD
RXD
TXD
Reset
Cloc
k
Gen
CLK
Expansion P
o
r
t
DA
T
JA
M
T
est
and
Management
Po
r
t
SI_D
SO
RST
SCLK
AMODE
RX
MUX
TX
MUX
eIMR+ Chip
Control
TP
Po
r
t
3
Manchester
Encoder
Manchester
Decoder
COL
ACK
SELI[
1:0
]
SELO
LED
Interf
ace
LD
A[4:0], LDB[4:0]
LDGA, LDGB
LDC[2:0]
A
CT[7:0]
STR
SI
CRS_I
CRS
20651B-1
Am79C985
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
Am79C985
enhanced Integrated Multiport Repeater Plus (eIMR+)
TEMPERATURE RANGE
C = Commercial (0C to +70C)
ALTERNATE PACKAGING OPTION
\W = Trimmed and formed in a tray
PACKAGE TYPE
J = 84-Pin Plastic Leaded Chip Carrier (PL 084)
K = 100-Pin Plastic Quad Flat Pack (PQR100)
Am79C985
C
J
SPEED OPTION
Not Applicable
\W
Valid Combinations
Am79C985
JC, KC\W
4
Am79C985
P R E L I M I N A R Y
RELATED PRODUCTS
.
Part No.
Description
Am7990
Local Area Network Controller for Ethernet (LANCE)
Am7992B
Serial Interface Adapter (SIA)
Am7996
IEEE 802.3/Ethernet/Cheapernet Transceiver
Am79C90
CMOS Local Area Network Controller for Ethernet (C-LANCE)
Am79C98
Twisted Pair Ethernet Transceiver (TPEX)
Am79C100
Twisted Pair Ethernet Transceiver Plus (TPEX+)
Am79C981
Integrated Multiport Repeater Plus (IMR+TM)
Am79C982
basic Integrated Multiport Repeater (bIMRTM)
Am79C983
Integrated Multiport Repeater 2 (IMR2TM)
Am79C984A
enhanced Integrated Multiport Repeater (eIMRTM)
Am79C987
Hardware Implemented Management Information Base
(HIMIBTM)
Am79C988
Quad Integrated Ethernet Transceiver (QuIETTM)
Am79C900
Integrated Local Area Communications Controller (ILACCTM)
Am79C940
Media Access Controller for Ethernet (MACETM)
Am79C960
PCnetTM-ISA Single-Chip Ethernet Controller (for ISA bus)
Am79C961
PCnetTM-ISA+ Single-Chip Ethernet Controller for ISA (with Microsoft Plug n' Play Support)
Am79C961A
PCnetTM-ISA II Full Duplex Single-Chip Ethernet Controller for ISA
Am79C965
PCnetTM-32 Single-Chip 32-Bit Ethernet Controller
Am79C970
PCnetTM-PCI Single-Chip Ethernet Controller (for PCI bus)
Am79C970A
PCnetTM-PCI II Full Duplex Single-Chip Ethernet Controller (for PCI bus)
Am79C974
PCnetTM-SCSI Combination Ethernet and SCSI Controller for PCI Systems
Am79C985
5
P R E L I M I N A R Y
TABLE OF CONTENTS
DISTINCTIVE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Standard Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
RELATED PRODUCTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
CONNECTION DIAGRAMS (PL 084) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
CONNECTION DIAGRAMS (PQR100) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
LOGIC SYMBOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
LOGIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
PIN DESIGNATIONS (PL084) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Listed by Pin Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
PIN DESIGNATIONS (PQR100) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Listed by Pin Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
AUI Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Twisted Pair Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Expansion Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Management Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
LED Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Miscellaneous Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
FUNCTIONAL DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Basic Repeater Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Repeater Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Signal Regeneration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Jabber Lockup Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Collision Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Fragment Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Auto Partitioning/Reconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Detailed Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
AUI Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
TP Port Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Twisted Pair Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Connection to Alternate Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Twisted Pair Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Link Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Polarity Reversal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Visual Status Monitoring (LED) Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Network Activity Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Expansion Bus Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Internal Arbitration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
IMR+ Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
eIMR+ /HIMIB Interconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Management Port Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Command/Response Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Port Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Management Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
SET (Write Commands) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Get (Read Commands) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
SYSTEMS APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
eIMR+ to TP Port Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Twisted Pair Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Twisted Pair Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
MAC Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
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