Current max for GPIO pins should be more visible

[synic]

A lot of BBB users are likely coming from Arduino, where the maximum current per IO pin is 40mA, and they don't have to worry about it so much.

The BBB is 4mA to 6mA, depending on the pin, but nowhere in the hosted documentation does it mention this. It takes a bit of time to find out even if you look for it on google.

One of the hosted demos is an "external LED", and in that demo, it mentions using a resistor. The value of the resistor is not mentioned, though the one pictured is 220ohm. Depending on the forward voltage drop of the LED, you're most likely already exceeding the max current right out of the box. The user should be warned not to exceed the maximum current per IO pin.

[jadonk]

Do you have a suggestion on where to put this information as well?

BTW, thanks for the note. This will make sure it goes into the on-board and beagleboard.org documentation.

[synic]

I think it could go in a few places - maybe a new section in the left navigation bar under Hardware called "Limitations" or "Technical Specs" or something like that. Also, it'd be nice if it was visible on the "Cape Expansion Headers" page - maybe in addition to listing what every pin is, it could also list what the limitations of each pin are.

The page I really think it needs to be on is the http://192.168.7.2/Support/BoneScript/demo_blinkled_external/ page, where using the setup pictured could put you over the current limit. I think the value of the resistor should be changed to 330ohms (or even 560ohms) and that the value of the resistor should be clearly stated, with information on why that value was chosen. As it is now, it almost implies that the value of the resistor isn't important, but going over the limit could damage the processor.