Micrel, Inc.
Pin Number
24
25
26
Pin Name
VDDIO
INT#/
PHYAD0
LED0/
TEST
Type
(1)
P
Ipu/O
Ipu/O
Pin Function
KS8721BL/SL
Digital IO 2.5/3.3V tolerant power supply. 3.3V power input of voltage regulator.
See “Circuit Design Ref. for Power Supply” section for details.
Management Interface (MII) Interrupt Out. Interrupt level set by Register 1f, bit 9.
During reset, latched as PHYAD[0]. See “Strapping Options” section for details.
Link/Activity LED Output. The external pull-down enable test mode and only used for
the factory test. Active low.
Link/Act
No Link
Link
Act
Pin State
H
L
–
LED Definition PHYAD0
“Off”
“On”
“Toggle”
27
LED1/
SPD100/
nFEF
Ipu/O
Speed LED Output. Latched as SPEED (Register 0, bit 13) during power-up/ reset. See
“Strapping Options” section for details. Active low.
Speed
10BT
100BT
Pin State
H
L
LED Definition
“Off”
“On”
28
LED2
Ipu/O
Full-duplex LED Output. Latched as DUPLEX (register 0h, bit 8) during power-up/ reset.
See “Strapping DUPLEX Options” section for details. Active low.
Duplex
Half
Full
Pin State
H
L
LED Definition
“Off”
“On”
29
LED3/
NWAYEN
Ipu/O
Collision LED Output. Latched as ANEG_EN (register 0h, bit 12) during power-up/
reset. See “Strapping Options” section for details.
Collision
No Collision
Collision
Pin State
H
L
LED Definition
“Off”
“On”
30
31
32
33
34
35
36
37
38
39
40
41
42
43
PD#
VDDRX
RX-
RX+
FXSD/
FXEN
GND
GND
REXT
VDDRCV
GND
TX-
TX+
VDDTX
GND
Ipu
P
I
I
Ipd/O
Gnd
Gnd
I
P
Gnd
O
O
P
Gnd
Power Down. 1 = Normal operation, 0 = Power-down. Active low.
Analog 2.5V power supply. See “Circuit Design Ref. for Power Supply” section for
details.
Receive Input. Differential receive input pins for 100FX, 100BASE-TX, or 10BASE-T.
Receive Input: Differential receive input pin for 100FX, 100BASE-TX, or 10BASE-T.
Fiber Mode Enable / Signal Detect in Fiber Mode. If FXEN = 0, FX mode is disable. The
default is “0”. See “100BT FX Mode” section for more details.
Ground.
Ground.
External resistor (6.49kW ) connects to REXT and GND.
Analog 2.5V power supply. 2.5V power output of voltage regulator. See “Circuit Design
Ref. for Power Supply” section for details.
Ground.
Transmit Outputs: Differential transmit output for 100FX, 100BASE-TX, or 10BASE-T.
Transmit Outputs: Differential transmit output for 100FX, 100BASE-TX, or 10BASE-T.
Transmitter 2.5V power supply. See “Circuit Design Ref. for Power Supply” section for
details.
Ground.
June 2009
8
M9999-062509-1.3
MICROCHIP [ MICROCHIP TECHNOLOGY ]
