3.4.1 Ethernet 10/100 Port (GMAC)

The KSZ8081 is a single-supply 10Base-T/100Base-TX Ethernet physical-layer transceiver for transmission and reception of data over standard CAT-5 unshielded twisted pair (UTP) cable. The KSZ8081 is a highly-integrated PHY solution. It reduces board cost and simplifies board layout by using on-chip termination resistors for the differential pairs and by integrating a low-noise regulator to supply the 1.2V core, and by offering 1.8/2.5/3.3V digital I/O interface support.

The KSZ8081RNA is connected over the Reduced Media Independent Interface (RMII) directly to the RMII-compliant MAC inside the SAM9X60D1G MPU. As the power-up default, the KSZ8081RNA uses a 25 MHz MEMS oscillator to generate all required clocks, including the 50-MHz RMII reference clock output for the MAC. For more information about the KSZ8081RNx, refer to the product web page.

An individual unique 48-bit MAC address (Ethernet hardware address) is allocated to this product and is stored in the Microchip 24AA025E48 TWI serial EEPROM described in Serial EEPROM with Unique MAC Address.

Additionally, for monitoring and control purposes, an LED functionality is carried on the RJ45 connectors to indicate activity, link, and speed status.