AM79C976 Advanced Micro Devices, AM79C976 Datasheet - Page 200

• Manufacturer Part Number: AM79C976
• Description: PCnet-PRO 10/100 Mbps PCI Ethernet Controller
• Manufacturer: Advanced Micro Devices

When LEDPE is cleared to 0, programming of the
LED0 register is disabled. Writes to this register will be
ignored.
Note: Bits 15-0 in this register are programmable
through the EEPROM.
Bit
31-16
15
14
200
Name
RES
LEDOUT
LEDPOL
zeros and read as undefined.
(non-stretched) value of the LED
output pin. A value of 1 in 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 only; writes have
no effect. LEDOUT is unaffected
by H_RESET, S_RESET, or
STOP.
the value 0, then the LED pin will
be driven to a LOW level whenev-
er the OR of the enabled signals
is true, and the LED pin will be
disabled and allowed to float high
whenever the OR of the enabled
signals is false (i.e., the LED out-
put will be an Open Drain output
and the output value will be the
inverse of the LEDOUT 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.
Reserved locations. Written as
This bit indicates the current
LED Polarity. When this bit has
Description
P R E L I M I N A R Y
Am79C976
13
12
11-10 RES
9
8
LEDDIS
100E
MPSE
FDLSE
Read/Write accessible. LEDPOL
is cleared by H_RESET and is
not affected by S_RESET or set-
ting the STOP bit.
Read/Write accessible. LEDDIS
is cleared by H_RESET and is
not affected by S_RESET or set-
ting the STOP bit.
Read/Write accessible. 100E is
cleared by H_RESET and is not
affected by S_RESET or setting
the STOP bit.
Read/Write accessible. MPSE is
cleared by H_RESET and is not
affected by S_RESET or setting
the STOP bit.
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.
is set to 1, a value of 1 is passed
to the LEDOUT bit in this register
when the Am79C976 controller is
operating at 100 Mbps mode.
read as zeros.
When this bit is set to 1, a value
of 1 is passed to the LEDOUT bit
in this register when Magic Pack-
et frame mode is enabled and a
Magic Packet frame is detected
on the network.
Full-Duplex Link Status Enable.
Indicates the Full-Duplex Link
Test Status. When this bit is set,
a value of 1 is passed to the LED-
OUT signal when the Am79C976
controller is functioning in a Link
Pass state and full-duplex opera-
tion
Am79C976 controller is not func-
tioning in a Link Pass state with
full-duplex operation being en-
abled, a value of 0 is passed to
the LEDOUT signal.
LED Disable. This bit is used to
100 Mbps Enable. When this bit
Reserved locations. Written and
Magic Packet Status Enable.
is
enabled.
When
8/01/00
the