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Topic: ethernet modules (Read 1 time) previous topic - next topic

tom_eaton

I know there is an Ethernet shield available but is there anything around that can be used instead? I'm looking for some sort of chip/module that you can communicate with using serial or a library of some description.

Thanks :)

PaulS

Well, you can communicate directly with the Arduino, using serial. No ethernet shield required.

You're welcome.

Want to try again explaining what you want to do?

Ran Talbott

The Adafruit Ethernet shield is pretty much just a pinout adapter (with optional 3.3V power supply) for the Wiznet (SPI-based) and XPort (async-serial-based) modules.  Each module has a relatively small number of pins connected to the Arduino,  so you could wire one up without using a shield if you wanted to.

westfw

There are about three varieties of ethernet shield "devices" out there:

1) Official Arduino Ethernet Shield with Wiznet chip.  The Wiznet chip is a "smart" network device that implements IP, TCP, and UDP on top of ethernet.  The arduino talks to to the Wiznet chip via SPI (a high-speed synchronous serial protocol) and sends commands like "open a connection", "send this data" and such.  The Wiznet supports four simultaneous connections.  Wiznet also sell "modules" containing the same chip, and there are shields available that allow such modules to be used with Arduino...

2) Microchip ENC28J60 "bare ethernet" shields.  The ENC28J60 is a single chip ethernet controller that can talk to the Arduino over SPI.  Unlike the Wiznet chip, it is not "smart" and only knows how to send bare ethernet packets.  Any higher level protocols (IP, TCP, etc) have to be implemented on the Arduino CPU.  Even with 32K/2K on an atmega328, it can be quite a challenge to implement such software and still have room for code that does anything else.  OTOH, such a device is theoretically most flexible, and somewhat cheaper than the Wiznet.

3) Lantronix XPORT module based shields (Adafruit sells a shield that accepts either a Wiznet Module or an XPORT module.)  These are "smarter" than even the wiznet chip (some include SSH with encryption, for example.)  The Arduino talks to these over async-serial using normal Serial.print() and similar functions (it sounds like this is what you're looking for.)  They're a sort of one-port network terminal server or tcp/ip "modem."  On the downside, they're more expensive and only support a single connection.  There are several other vendors that offer similar network/serial devices, but I don't think any of them have been incorporated at all onto arduino compatible boards.

tom_eaton

thank you westfw, that has given me a great starting point for research into the module i need, now for some serious googling!

hari

#5
Apr 04, 2010, 05:04 am Last Edit: Apr 04, 2010, 05:09 am by hwiguna Reason: 1
westfw,
Thank you for the detailed and concise description of the different devices.
Is there a wiki page listing the different ways to network an Arduino?
What's the policy for creating a new wiki page at arduino.cc?

It would be nice to have one page where everyone can go to see the pros and cons of different Arduino networking options.  For instance, has anyone worked with a SitePlayer before?

[edit]I don't have any Ethernet devices for my Arduino yet, so I've been trying to learn about them also.  Here are two product reviews I've found to be informative:
http://www.youtube.com/watch?v=HZBWBosU8Es
http://www.youtube.com/watch?v=EunS2cdTyKo
[/edit]

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