KSZ8041NLJ_10 MICREL [Micrel Semiconductor], KSZ8041NLJ_10 Datasheet - Page 18

• Manufacturer Part Number: KSZ8041NLJ_10
• Description: 10/100 Ethernet Transceiver with Extended Temperature Support
• Manufacturer: MICREL [Micrel Semiconductor]

Micrel, Inc.
Collision Detection
The MAC regenerates the COL signal of the MII from TX_EN and CRS_DV.
HP Auto MDI/MDI-X
HP Auto MDI/MDI-X configuration eliminates the confusion of whether to use a straight cable or a crossover cable
between the KSZ8041NLJ and its link partner. This feature allows the KSZ8041NLJ to use either type of cable to connect
with a link partner that is in either MDI or MDI-X mode. The auto-sense function detects transmit and receive pairs from
the link partner, and then assigns transmit and receive pairs of the KSZ8041NLJ accordingly.
HP Auto MDI/MDI-X is enabled by default. It is disabled by writing a one to register 1F bit 13. MDI and MDI-X mode is
selected by register 1F bit 14 if HP Auto MDI/MDI-X is disabled.
An isolation transformer with symmetrical transmit and receive data paths is recommended to support auto MDI/MDI-X.
The IEEE 802.3u standard defines MDI and MDI-X as follow:
Straight Cable
A straight cable connects a MDI device to a MDI-X device, or a MDI-X device to a MDI device. The following diagram
depicts a typical straight cable connection between a NIC card (MDI) and a switch, or hub (MDI-X).
April 2010
RJ-45 Pin
Media Dependent Interface
Transmit Pair
Receive Pair
Modular Connector
1
2
3
6
10/100 Ethernet
(RJ-45)
Figure 2. Typical Straight Cable Connection
NIC
MDI
Table 4. MDI/MDI-X Pin Definition
1
2
3
4
5
6
7
8
Signal
RD+
TD+
RD-
TD-
Straight
Cable
18
RJ-45 Pin
1
2
3
6
Media Dependent Interface
(Repeater or Switch)
Modular Connector
1
2
3
4
5
6
7
8
10/100 Ethernet
MDI-X
(RJ-45)
HUB
Transmit Pair
Receive Pair
Signal
RD+
TD+
RD-
TD-
M9999-040110-1.0
KSZ8041NLJ