Micrel, Inc.
Pin Number
Pin Name
20
DVDDL
21
TXD0
22
TXD1
23
TXD2
24
TXD3
25
DVDDL
26
TXD4
27
TXD5
28
TXD6
29
TXD7
30
DVDDH
31
TX_ER
32
GTX_CLK
Type(1) Pin Function
Single LED Mode
Activity
No Activity
Activity (RX, TX)
Pin State
H
Toggle
LED Definition
OFF
Blinking
KSZ9021GN
Tri-color Dual LED Mode
Link / Activity
Link off
1000 Link / No Activity
1000 Link / Activity (RX, TX)
100 Link / No Activity
100 Link / Activity (RX, TX)
10 Link / No Activity
10 Link / Activity (RX, TX)
Pin State
LED2 LED1
H
H
L
H
Toggle H
H
L
H
Toggle
L
L
Toggle Toggle
LED Definition
LED2 LED1
OFF
OFF
ON
OFF
Blinking OFF
OFF
ON
OFF
Blinking
ON
ON
Blinking Blinking
For Tri-color Dual LED Mode, LED1 works in conjunction with LED2 (pin 17 to
indicate 10 Mbps Link and Activity.
P
1.2V digital VDD
I
GMII Mode:
GMII TXD0 (Transmit Data 0) Input
MII Mode:
MII TXD0 (Transmit Data 0) Input
I
GMII Mode:
GMII TXD1 (Transmit Data 1) Input
MII Mode:
MII TXD1 (Transmit Data 1) Input
I
GMII Mode:
GMII TXD2 (Transmit Data 2) Input
MII Mode:
MII TXD2 (Transmit Data 2) Input
I
GMII Mode:
GMII TXD3 (Transmit Data 3) Input
MII Mode:
MII TXD3 (Transmit Data 3) Input
P
1.2V digital VDD
I
GMII Mode:
GMII TXD4 (Transmit Data 4) Input
MII Mode:
This pin is not used and can be driven high or low.
I
GMII Mode:
GMII TXD5 (Transmit Data 5) Input
MII Mode:
This pin is not used and can be driven high or low.
I
GMII Mode:
GMII TXD6 (Transmit Data 6) Input
MII Mode:
This pin is not used and can be driven high or low.
I
GMII Mode:
GMII TXD7 (Transmit Data 7) Input
MII Mode:
This pin is not used and can be driven high or low.
P
3.3V or 2.5V digital VDD
I
GMII Mode:
GMII TX_ER (Transmit Error) Input
MII Mode:
MII TX_ER (Transmit Error) Input
If GMII / MII MAC does not provide the TX_ER output signal, this pin should be
tied low.
I
GMII Mode:
GMII GTX_CLK (Transmit Reference Clock) Input
September 2010
11
M9999-091010-1.1