KSZ8873 - MII, RMII, MAC MII, and PHY MII

There are two versions of KSZ8873: RLL and MLL (also FLL, but that is MLL with fiber ports). RLL uses reduced media-independent interface (RMI) and MLL uses a media-independent interface (MII) in port 3. MII has two modes: MAC and PHY.

The PHY mode needs to be matched between the switch and MAC controller. Normally, the MAC controller is connected to the switch, so PHY MII mode is the default. When the switch is connected directly to another switch, then one of them has to be in MAC MII mode. The default 0xA6 register setting of 0x13 just means port 3 is running in RMII mode and the other PHY ports are using copper (or a regular Ethernet jack). The MAC/PHY MII setting does not apply to RMII.

For more information, visit the KSZ8873 product page.

© 2018 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.