am79c984a Advanced Micro Devices, am79c984a Datasheet - Page 25

• Manufacturer Part Number: am79c984a
• Description: Enhanced Integrated Multiport Repeater Eimr
• Manufacturer: Advanced Micro Devices

Disable Automatic Receiver Polarity Reversal (Per TP
Port)
SI Data
SO Data
This command disables the Automatic Receiver Polarity
Reversal function for the TP port designated by the two
least-significant bits in the command byte. If this func-
tion is disabled on a TP port receiving with reversed
polarity (due to a wiring error), the TP port will fail the
Link Test due to the incorrect polarity of the received
Link pulses.
The state of Automatic Polarity Reversal function is set
by SI on reset. If SI is HIGH at the rising edge of RST,
the eIMR device disables Automatic Polarity Reversal.
If SI is LOW at the rising edge of RST, the eIMR device
enables Automatic Polarity Reversal.
Enable Automatic Receiver Polarity Reversal (Per TP
Port)
SI Data
SO Data
This command enables the Automatic Receiver Polarity
Reversal function for the TP port designated by the two
least-significant bits in the command byte. If enabled in
a TP port, the eIMR chip will automatically invert the
polarity of that port’s receiver circuitry if the TP port is
detected as having reversed polarity (due to wiring er-
ror). After reversing the receiver polarity, the TP port
could then receive subsequent (reverse polarity)
packets correctly.
Disable Receiver Extended Distance Mode (Per TP
Port)
SI Data
SO Data
This command disables the Receiver Extended
Distance Mode and restores the RXD circuit of the trans-
ceiver to normal squelch levels for the TP port driver
designated by the two least-significant bits of the com-
mand data.
Enable Receiver Extended Distance Mode (Per TP Port)
SI Data
SO Data
This command modifies the RXD circuit of the trans-
ceiver for the TP port driver designated by the two least-
significant bits of the command data. The RXD squelch-
threshold value is lowered to accommodate signal at-
tenuation associated with lines longer than 100 meters.
At reset, Receiver Extended Distance Mode is disabled
and the RXD circuit defaults to normal squelch-thresh-
old values.
0110 00##
None
0111 00##
None
0110 10##
None
0111 10##
None
P R E L I M I N A R Y
Am79C984A
Disable Software Override of LEDs
(Per Port - AUI and TP, Global)
SI Data
SO Data
This command disables Software Override of the Port
LEDs.
Individual LEDs and combinations of LEDs can be
selected via the lower four bits of the command byte as
follows:
Following command execution, the attributes displayed
on the LEDs will be determined by LDC
Override of LEDs is disabled after reset.
Enable Software Override of Bank A LEDs (Per Port -
AUI and TP, Global)
SI Data
SO Data
This command forces the LEDs in Bank A to blink. In-
dividual LEDs and combinations of LEDs can be select-
ed via the lower four bits of the command byte as follows:
The designated LED driver(s) will switch between LOW
and ‘off’ at the rate set by the Software Override Blink
Rate command. Enable Software Override of Bank A
LEDs references the blink rate last issued and overrides
any other attribute specified by LDC
ride of LEDs is disabled after reset.
####
0000-0011 TP0 - TP3
0100-0111 Reserved
1000
1001
1010
1011
1100
1101
1110
1111
####
0000-0011 TP0 - TP3
0100-0111 Reserved
1000
1001
1010
1011
1100
1101
1110
1111
1001 ####
None
Port(s) affected
AUI port
Reserved
Reserved
All TP ports
All ports
Global
Reserved
Reserved
1011 ####
None
Port(s) affected
AUI port
Reserved
Reserved
All TP ports
All ports
Global
Reserved
Reserved
0-2
. Software Over-
0-2
. Software
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