Arduino Ethernet Shield
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Technical Information
The Ethernet Shield uses the Wiznet W5100 Ethernet chip, providing an IP stack capable of both TCP and UDP with four simultaneous socket connections. The shield connects using the Ethernet Library.
Arduinos communicate with the W5100 and SD card using the SDI bus through the ICSP header. On the Duemilanove this is digital pins 11, 12, and 13, and pins 50, 10, and 52 on the Mega. Both boards use pin 10 to select the W5100 and pin 4 for the SD card. This pins cannot be used for general I/O. The hardware SS pin (pin 53) on the Mega much be kept as an output or the SPI interface will not function correctly.
The W5100 and SD card share the same bus, and therefor cannot be active at the same time. If one of the features is not being used in a program, it must be explicitly deselected. With the SD card, set digital pin 4 as an output and write it to HIGH. For the W5100, set digital pin 10 as HIGH.
The reset button resets both the W5100 and the Arduino.
The shield contains the following 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 "INT" can be connected to allow the Arduino to receive interrupt-driving event notification from the W5100. The jumper connects the INT pin of the W5100 to digital pin 2 of the Arduino. This is not supported by the Ethernet library.
Version differences
The V5 Ethernet Shield also contains an micro-SD card slot. The original shield does not contain this slot, but does have the appropriate board connections for adding this functionality with full-size SD cards. However, the libraries must be rewritten since this uses pin 2, or pin 2 must not be used in projects. There is no official SD card library for the shield, however, the sdfatlib library works well. See the Adafruit Tutorial.
The V5 also includes a reset controller to ensure the device is reset on power-up.Code
Availability
This page is a Component on bildr. Components are pages about specific parts, and include connection details and code when available.