@Lazar-Demin Thanks! I'm not that far along with my project, so it's definitely not too late for me.
Posts made by Brian Piersel
RE: Pull down resistors for GPIO
I'd recommend using a pull-up resistor and connecting the switch to ground. A capacitor across the switch will add some analog debounce as well. Using a pull-down instead will probably work, but the logic transition levels typically work better with a pull-up, perhaps .1 uF or 1 uF.
As for Kit's question, I think that means that the GPIOs have a 200k pull-up and pull-down resistance, and you need something smaller for a pull-up or pull-down to prevent the input from floating.
RE: I2C in python
Take a look at the ctypes library for Python. It allows you to call C library functions. It seems like it will work, but I'm waiting for some hardware before I can actually write and test any code. Once I get something working, I'll post it on Github.
RE: Where should we store programs on the Onion? Can we make users?
I've been storing programs in /root. It's not read-only (at least not on mine).
RE: Electrical Specs
I found a datasheet for the AR9331. The specs on the GPIO are lacking detail, but I did find the following:
VOH = 2.44 V
VOL = 0.1 V
VIH = 0.7 V
VIL = 0.3 V
(These are min/max values as appropriate.)
I'm not finding a maximum voltage for the GPIO pins. The datasheet I found is a preliminary from December 2010. I'm hoping a newer datasheet is available that has more complete electrical info.
RE: GPIO and Python?
@chris-mccaslin Thanks for the suggestion. I wasn't able to install that library, but that may be because I'm not familiar enough with Linux to understand what it needs. ;-) I did figure out how to access the ports through the filesystem (/sys/class/gpio). If nothing else gets posted before I get my code packaged nicely, I'll post it for others.