lost (again), IC's and wires

[haarts]

Hi all,

I am having a hard time figuring all this electronic stuff out. Have patience with me. :)
I got a couple of I2C capable thermometer IC's as they should be 'trivial', not so for me. So I'd like to take the ultimate step back. 2 wires, one resistor and 1 LED. I would love to make it turn on on my command. Driven from my shiny (to be written) CLI program. Can anyone help me connecting this ridiculously simple thing to the IOW24? Think _really_ simple; what wire goes where? I know pin 9 is GND and pin 14 the +5V supply but how do I connect these? There seem to be no clear connection points. But in this scheme I only get a LED to simple give light. How do I take control over it? Does Px.x also output +5V if I send a '1' to them? Or should I use a transistor(I'm told a BC547 is the basic transistor for just about everything).
And is 'interface 1' in the documentation the first IO port? E.g. P0.x?

Thanks all for your patients!
Harm

[Guido Körber]

The IO-Warrior has "open drain outputs" with internal pull up resistors. That means it can not "source" a lot of current since when a pin is high the current comes from an internal resistor of about 7k? connected to +5V.

But when the pin is driven low it can "sink" quite a bit of current, the exact amount can be found in the DC electrical specs in the data sheet. So what you would want to do is connect your LEDs anode to +5V and the cathode with the resistor in series (does not matter if the resistor is before or behind the LED) to a pin on the IO-Warrior. The LED will light up when you write a zero to the pin.

Interface 0 and interface 1 are logical devices inside the IO-Warrior. Interface 0 controls the pins directly and interface 1 does the more complex stuff like IIC, LCD, etc.

[haarts]

Aha! Thanks a bunch, that was really helpful. I'll give that a try later this week.