AM79C978A AMD [Advanced Micro Devices], AM79C978A Datasheet - Page 150

• Manufacturer Part Number: AM79C978A
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: AMD [Advanced Micro Devices]

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LEDPOL
LEDDIS
this bit indicates that the OR of
the enabled signals is true.
The logical value of the LEDOUT
status signal is determined by the
settings of the individual Status
Enable bits of the LED register
(bits 8 and 6-0).
This bit is read accessible al-
ways. This bit is read only; writes
have no effect. LEDOUT is unaf-
fected by H_RESET, S_RESET,
or STOP.
LED Polarity. When this bit has
the value 0, then the LED pin will
be driven to a LOW level when-
ever the OR of the enabled sig-
nals is true, and the LED pin will
be disabled and allowed to float
high whenever the OR of the en-
abled signals is false (i.e., the
LED output will be an Open
Drain output and the output val-
ue will be the inverse of the LED-
OUT status bit).
When this bit has the value 1,
then the LED pin will be driven to
a HIGH level whenever the OR of
the enabled signals is true, and
the LED pin will be driven to a
LOW level whenever the OR of
the enabled signals is false (i.e.,
the LED output will be a Totem
Pole output and the output value
will be the same polarity as the
LEDOUT status bit).
The setting of this bit will not ef-
fect the polarity of the LEDOUT
bit for this register.
This bit is always read/write ac-
cessible. LEDPOL is cleared by
H_RESET and is not affected
by S_RESET or setting the
STOP bit.
LED Disable. This bit is used to
disable the LED output. When
LEDDIS has the value 1, then the
LED output will always be dis-
abled. When LEDDIS has the val-
ue 0, then the LED output value
will be governed by the LEDOUT
and LEDPOL values.
Am79C978A
12
11-10 RES
9
8
7
100E
MPSE
FDLSE
PSE
Reserved locations. Written and
Full-Duplex Link Status Enable.
This bit is always read/write ac-
cessible. LEDDIS is cleared by
H_RESET and is not affected
by S_RESET or setting the
STOP bit.
100 Mbps Enable. When this bit
is set to 1, a value of 1 is passed
to the LEDOUT bit in this register
when the Am79C978A controller
is operating at 100 Mbps mode.
This bit is always read/write ac-
cessible. 100E is cleared by
H_RESET and is not affected
by S_RESET or setting the
STOP bit.
read as zeros.
Magic Packet Status Enable.
When this bit is set to 1, a value of
1 is passed to the LEDOUT bit in
this register when Magic Packet
frame mode is enabled and a
Magic Packet frame is detected
on the network.
This bit is always read/write ac-
cessible. MPSE is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP bit.
Indicates the Full-Duplex Link
Test Status. When this bit is set,
a value of 1 is passed to the LED-
OUT
Am79C978A controller is func-
tioning in a Link Pass state and
full-duplex operation is enabled.
When the Am79C978A controller
is not functioning in a Link Pass
state with full-duplex operation
being enabled, a value of 0 is
passed to the LEDOUT signal.
This bit is always read/write ac-
cessible. FDLSE is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP bit.
Pulse Stretcher Enable. When
this bit is set, the LED illumination
time is extended for each new oc-
currence of the enabled function
for this LED output. A value of 0
disables the pulse stretcher.
signal
when
the