3.4.1 10/100/1000 RGMII SODIMM Ethernet Interface

The board exposes all the necessary RGMII signals provided by the embedded Ethernet GMAC1 controller. The RGMII slot is a one-piece (J15) 260-pin SODIMM connector. This allows connectivity to multiple inexpensive add-on boards equipped with RGMII compatible PHYs and switches.

The list of Ethernet device daughter boards can be seen below and is subject to future additions.

• EV12N54A - LAN8840 Gigabit Ethernet PHY

The board supplies 5V power to the daughter board and provides additional 3.3V and 2.5V power from the dedicated auxiliary power supply.

An optional on-board 25-MHz oscillator provides the 25-MHz input clock for the PHY or switch embedded in the daughter board. If not needed, it can be manually disabled by removing the jumper placed on header J37.

Separate MDIO interfaces at the connector allow the MPU to manage the daughter board device.

An individual unique 48-bit MAC address (Ethernet hardware address) is allocated to this product and is stored in the Microchip SST26VF064BEUI-104I/SM QSPI Flash memory and in the Microchip 24AA025E48 TWI EEPROM.

This interface also features SPI connectivity which will serve to connect to Ethernet switches that require SPI communication.