I recently bought a breakout-gs board to do some simple hardware
interfacing with. I've never done anything hardware related so I
figured I'd start out by wiring a simple switch and led to the GPIO
lines. So far everything has worked great but I'm not sure that I
am really going at this the right way.
I ran a wire from GPIO 59 (lcd pads) and another from a ground
pad. In between I added a momentary NO pushbutton switch.
If I set the GPIO to output and set I could see when I pressed the
button that the setting went to clear. So that was fine, but it
didn't really make sense to me to drive the GPIO as output when a
button press seemed more like an input?? Then I played around
with the sample char driver in the wiki and some other interrupt driver
code I found in the mailing list. In both of those it appears
that the GPIOs are set as inputs so I thought I would give that a
try. Using either of those drivers I saw the interrupt being
triggered all the time unless I pressed my switch, then it
stopped. I was able to edit that code and get it to work with the
GPIO set as output and then the interrupt was triggered when I pressed
the button. Am I missing something here? Is setting the GPIO as
output to trigger interrups like I am doing the wrong way to do this?
That brings me to my led. I got it from digikey because it said
it was 3.4v and I knew the GPIOs could output 3.3v. It is rated
at 20 milli amps. If I hook this up to a GPIO and ground and
drive the GPIO on output set I see the led come on, and when I clear
the line it goes out. Great! Seems like it works to me, but
I just wanted to make sure I wasn't doing something that was bad
Guess you can tell I'm really new at this. The mailing list and
wiki have been a great resource in getting to where I am now, so thanks
to all of you gumstix folks out there!
Thanks for the help. Chris