KSZ8842-16MBL-EVAL MICREL [Micrel Semiconductor], KSZ8842-16MBL-EVAL Datasheet - Page 29

• Manufacturer Part Number: KSZ8842-16MBL-EVAL
• Description: 2-Port Ethernet Switch with Non-PCI Interface
• Manufacturer: MICREL [Micrel Semiconductor]

Power Management
The KSZ8842M features per port power-down mode. To save power, the user can power-down the port that is not in use
by setting bit 11 in either P1CR4 or P1MBCR register for port 1 and setting bit 11 in either P2CR4 or P2MBCR register for
port 2. To bring the port back up, reset bit 11 in these registers.
In addition, there is a full switch power-down mode. This mode shuts the entire switch down, when the PWRDN (pin 36) is
pulled down to low.
MDI/MDI-X Auto Crossover
To eliminate the need for crossover cables between similar devices, the KSZ8842M supports HP-Auto MDI/MDI-X and
IEEE 802.3u standard MDI/MDI-X auto crossover. HP-Auto MDI/MDI-X is the default.
The auto-sense function detects remote transmit and receive pairs and correctly assigns the transmit and receive pairs for
the KSZ8842M device. This feature is extremely useful when end users are unaware of cable types in addition to saving
on an additional uplink configuration connection. The auto-crossover feature can be disabled through the port control
registers.
The IEEE 802.3u standard MDI and MDI-X definitions are:
Straight Cable
A straight cable connects an MDI device to an MDI-X device or an MDI-X device to an MDI device. The following diagram
shows a typical straight cable connection between a network interface card (NIC) (MDI) and a switch, or hub (MDI-X).
Micrel, Inc.
October 2007
RJ45 Pins
Figure 7. Typical Straight Cable Connection
1
2
3
6
Table 1. MDI/MDI-X Pin Definitions
MDI
Signals
TD+
RD+
RD-
TD-
29
RJ45 Pins
1
2
3
6
MDI-X
Signals
RD+
TD+
RD-
TD-
KSZ8842-16/32 MQL/MVL/MVLI/MBL
M9999-102207-1.9