KSZ8081MNX / KSZ8091MNX 10Base-T/100Base-TX Evaluation Board User’s Guide
Micrel, Inc.
August 15, 2012
Rev.
1.0
9/13
4.2 Jumper Setting & Definition
At power-up, the KSZ8081MNX / KSZ8091MNX is configured using the chip’s internal pull-up and
pull-down resistors with its default strapping pin values. Jumpers are provided to override the
default settings, allowing for quick configuration and re-configuration of the board. To override the
default settings, simply select and close the desired jumper setting(s) and toggle the on-board
manual reset button (S1) for the new setting(s) to take effect. The KSZ8081MNX-EVAL /
KSZ8091MNX-EVAL strapping jumper settings are defined in Table 2 below.
Jumper
Definition
Open (default)
Close
J3 PHYAD0
1
0
J4 PHYAD1
0
1
J5 PHYAD2
0
1
J6 CONFIG0
CONFIG[2:0]
Mode
[open, open, open]
MII (default)
[close, close, open]
MII Back-to-Back
All other CONFIG[2:0] settings not listed are
reserved (not used).
J7 CONFIG1
J8 CONFIG2
J9 Isolate
Mode
Disable
Enable
J10 Nway
Auto-Negotiation
Enable
Disable
J11
Forced Speed (KSZ8081 only)
100Base-TX
10Base-T
J12 Forced
Duplex
Half
Full
J25
Broadcast Off – for PHY Address 0
Broadcast PHY address
Unique PHY address
J26
PME_N Pin Enable (KSZ8091 only)
Disable
Enable
Table 2. KSZ8081MNX-EVAL / KSZ8091MNX-EVAL Strapping Jumper Definition
The KSZ8081MNX-EVAL / KSZ8091MNX-EVAL has another set of jumpers that may be used to
loopback the MII interface. To loopback, all six jumpers must be installed. The individual jumpers
are defined in Table 3.
Jumper MII Signals
Normal Operation
MII Loopback Mode
J13 RXDV
/
TXEN
Open
Close
J14 RXC
/
TXC
Open
Close
J16
RXD2 / TXD2
Open Close
J17
RXD1 / TXD1
Open Close
J18
RXD0 / TXD0
Open Close
J19
RXD3 / TXD3
Open Close
Table 3. KSZ8081MNX-EVAL / KSZ8091MNX-EVAL Loopback Jumper Definition
