AM79C976KI AMD (ADVANCED MICRO DEVICES), AM79C976KI Datasheet - Page 160

• Manufacturer Part Number: AM79C976KI
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM79C976KI

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 2.97V
• Operating Supply Voltage (max): 3.63V
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 208
• Lead Free Status / RoHS Status: Not Compliant

LED0 Control Register
Offset 0E0h
This register controls the function(s) that the LED0 pin
displays. Multiple functions can be simultaneously en-
abled on this LED pin. The LED display will indicate the
logical OR of the enabled functions. This register de-
160
11-10
Bit
15
14
13
12
9
8
7
6
LEDOUT
LEDPOL
LEDDIS
FDLSE
LNKSE
MPSE
Name
100E
RES
PSE
This bit indicates the current (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).
LED Polarity. When this bit has the value 0, then the LED pin will be driven to a LOW level
whenever 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 output 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 effect the polarity of the LEDOUT bit for this register.
The default value of this bit is 0.
LED Disable. This bit is used to disable the LED output. When LEDDIS has the value 1, then the
LED output will always be disabled. When LEDDIS has the value 0, then the LED output value will
be governed by the LEDOUT and LEDPOL values.
The default value of this bit is 0.
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 Am79C976 controller is operating in 100 Mbps mode.
The default value of this bit is 0.
Reserved locations. Written and read as undefined.
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.
The default value of this bit is 0.
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 LEDOUT signal when the Am79C976 controller is functioning in a Link
Pass state and full-duplex operation is enabled. When the Am79C976 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.
The default value of this bit is 0.
Pulse Stretcher Enable. When this bit is set, the LED illumination time is extended for each new
occurrence of the enabled function for this LED output. A value of 0 disables the pulse stretcher.
The default value of this bit is 1.
Link Status Enable. When this bit is set, a value of 1 will be passed to the LEDOUT bit in this
register when in Link Pass state.
The default value of this bit is 1.
Table 63.
P R E L I M I N A R Y
Am79C976
LED0 Control Register
faults to Link Status (LNKST) with pulse stretcher en-
abled (PSE = 1) and is fully programmable.
All bits in this register are restored to their default val-
ues when the RST pin is asserted, before the serial
EEPROM is read, and after a serial EEPROM read er-
ror.
This register is an alias of BCR4.
Description
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