AM79C984AKCW AMD [Advanced Micro Devices], AM79C984AKCW Datasheet - Page 27

• Manufacturer Part Number: AM79C984AKCW
• Manufacturer: AMD [Advanced Micro Devices]

Link Test Status of TP ports
SI Data
SO Data
where n is a port number in the range 0–3.
The response to this command gives the Link Test sta-
tus of all the TP ports. A disabled port continues to report
Link Test status. Re-enabling the port causes the port
to be placed in the Link Test Fail state.
Receive Polarity Status of TP Ports
SI Data
SO Data
where n is a port number in the range 0–3.
The response to this command gives the Received Po-
larity status of all the TP ports. If the polarity is detected
as reversed for a TP port, then the eIMR device will set
the appropriate bit in this command’s result only if the
Polarity Reversal Function is enabled for that port.
MJLP Status
SI Data
SO Data
Each eIMR device contains an independent MAU Jab-
ber Lock Up Protection timer. The timer is designed to
inhibit the transmit function of the eIMR device if it has
been transmitting continuously for more than 65536 bit
times. This bit remains set and is only cleared when the
MJLP status is read using this command.
Version
SI Data
SO Data
The response to this command gives the version of the
eIMR device. 0011 was chosen to help distinguish the
eIMR device from the IMR (Am79C980) and the IMR+
(Am79C981) devices.
L n = 0
L n = 1
P n = 0
P n = 1
1101 0000
0000 L3..L0
TP Port n in Link Test Failed
TP port n in Link Test Passed
1110 0000
0000 P3......P0
TP Port n Polarity Correct
TP port n Polarity Reversed
1111 0000
M000 0000
1111 1111
0000 0011
P R E L I M I N A R Y
Am79C984A
SYSTEMS APPLICATIONS
eIMR to TP Port Connection
The eIMR device provides a system solution to designing
non-managed multiport repeaters. The eIMR device con-
nects directly to AC coupling modules for a 10BASE-T
hub. Figure 7 shows the simplified connection.
Twisted Pair Transmitters
TXD signals need to be properly terminated to meet the
electrical requirement for 10BASE-T transmitters. Prop-
er termination is shown in Figure 8 which consists of a
110- resistor and a 1:1 transformer. The load is a twisted-
pair cable that meets IEEE 802.3, Section 14.4 specifi-
cations. The cable is terminated at the opposite end by
100 .
Twisted Pair Receivers
RXD signals need to be properly terminated to meet the
electrical requirements for 10BASE-T receivers. Proper
termination is shown in Figure 9. Note that the receivers
do not require external filter modules.
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