KSZ8091RNA Datasheet, PDF (22/67 Pages) Micrel Semiconductor – 10Base-T/100Base-TX Physical Layer Transceiver

Micrel, Inc.
KSZ8091RNA/KSZ8091RND
Crossover Cable
A crossover cable connects an MDI device to another MDI device, or an MDI-X device to another MDI-X device. Figure 6
shows a typical crossover cable connection between two switches or hubs (two MDI-X devices).
Figure 6. Typical Crossover Cable Connection
Loopback Mode
The KSZ8091RNA/RND supports the following loopback operations to verify analog and/or digital data paths.
• Local (digital) loopback
• Remote (analog) loopback
Local (Digital) Loopback
This loopback mode checks the RMII transmit and receive data paths between the KSZ8091RNA/RND and the external
MAC, and is supported for both speeds (10/100Mbps) at full-duplex.
The loopback data path is shown in Figure 7.
1. The RMII MAC transmits frames to the KSZ8091RNA/RND.
2. Frames are wrapped around inside the KSZ8091RNA/RND.
3. The KSZ8091RNA/RND transmits frames back to the RMII MAC.
4. Except the frames back to the RMII MAC, the transmit frames also go out from the copper port.
August 31, 2015
22
Revision 1.2