Arduino-like Uzebox

[scuzz]

I'm pretty sure you only need to use the clock pin, the MOSI, and the MISO and you would use SPI which would be more stable than the UART. The address and data pins are only needed if you're interfacing to the module using an external memory interface (like pretending that the chip is RAM to a chip with a memory controller). At least I'm pretty sure this is the case, as would seem to be implied by page 10 of the datasheet:

WIZ811MJ provides following interfaces of W5100.
-. Direct/Indirect mode bus access
-. SPI access

And because it says interfaces instead of interface, I would assume you could use either one. That being said I've never used a wiznet module so I have no idea

[uze6666]

Yes, we would only need a few pins for the SPI interface plus a CS pin, already defined in the pins allocation thread (PB2).

-Uze

[scuzz]

I would think that if you were trying to cut down on pins used (which I don't actually know if that's significant or necessary) you can just tie the not-CS pin low. Since there aren't any other devices on the SPI chain you don't ever have to worry about deactivating the SPI peripheral. The only thing is whether or not the Wiznet module can operate in a non-framed mode, and if you can prevent hiccups on the clock line.

[uze6666]

I would think that if you were trying to cut down on pins used (which I don't actually know if that's significant or necessary) you can just tie the not-CS pin low. Since there aren't any other devices on the SPI chain you don't ever have to worry about deactivating the SPI peripheral. The only thing is whether or not the Wiznet module can operate in a non-framed mode, and if you can prevent hiccups on the clock line.

For the Uzebox design, the SD card interface uses the SPI mode. So the module's CS pin must be controllable.

-Uze