Product Description

The Arduino Ethernet Shield allows an Arduino board to connect to the internet. It is based on the Wiznet W5100ethernet chip (datasheet). The Wiznet W5100 provides a network (IP) stack capable of both TCP and UDP. It supports up to four simultaneous socket connections. Use the Ethernet library to write sketches which connect to the internet using the shield. The ethernet shield connects to an Arduino board using long wire-wrap headers which extend through the shield. This keeps the pin layout intact and allows another shield to be stacked on top.

The Ethernet Shield has a standard RJ-45 connection, with an integrated line transformer.

There is an onboard micro-SD card slot, which can be used to store files for serving over the network. It is compatible with the Arduino Uno and Mega (using the Ethernet library). The onboard microSD card reader is accessible through the SD Library. When working with this library, SS is on Pin 4. The original revision of the shield contained a full-size SD card slot; this is not supported.

The shield provides a standard RJ45 ethernet jack. The reset button on the shield resets both the W5100 and the Arduino board.

The shield contains a number of informational LEDs:

PWR: indicates that the board and shield are powered

• LINK: indicates the presence of a network link and flashes when the shield transmits or receives data
• FULLD: indicates that the network connection is full duplex
• 100M: indicates the presence of a 100 Mb/s network connection (as opposed to 10 Mb/s)
• RX: flashes when the shield receives data
• TX: flashes when the shield sends data
• COLL: flashes when network collisions are detected

The solder jumper marked “INT” can be connected to allow the Arduino board to receive interrupt-driven notification of events from the W5100, but this is not supported by the Ethernet library. The jumper connects the INT pin of the W5100 to digital pin 2 of the Arduino.