Breadboarding the WIZnet module
The SPI adapter from NKC Electronics makes breadboarding the WIZnet 810MJ module
as easy as plugging in the pins. After feeling more than a little overwhelmed by
the thought of creating a circuit board for the module it was anti-climactic to
plug the thing on and have it work.
I build a standard 3-terminal power supply circuit using the 78L33 regulator. This
regulater is in a TO-92 case, so it makes for a compact circuit. I have both a 5-volt
and a 3.3-volt power supply on my breadboard now, and the two together take up only
3 or 4 square inches.
The first thing I did was hook the WIZnet module up to the power and ground and
turn on the board. I plugged in an ethernet cable and watched the link LED light
up. I was surprised and gratified that it worked the first time. Nothing ever does
for me.
Next I needed to hook up the WIZnet module to a Picaxe 18X. Again, this was as simple
as running wires from the Picaxe pins to the WIZnet module; the W5100 runs at 3.3
volts but it is tolerant of 5 volts on its input pins. Because of this there is
no need to create interface circuits, greatly simplifying the hookup. I suppose
there wouldn't be any harm in using interface circuits, but I didn't find them necessary.
With the module up and running and an 18X connected, it was time to start working
on the software that will make them work together. Read on, dear reader, read on.