David,

not sure if you've found http://www.gumstix.org/tikiwiki/ but that has a number of tutorials and tips which should get you up and running with a "Hello world" type program.  As for twiddling GPIOs, it'll depend on the speed you want to do it at.  If doing it slowly (ie where timing isn't critical) is OK, then you can use the /proc/gpio interface, which is just opening a file in C then writing "set" or "clear" to it every time you want to twiddle the bit.  If you need to do it faster, then probably you'll want to write a kernel driver to do it, in which case the source code for the proc_gpio driver in the kernel tree will show you all you need to know -- that code is in buildroot/build_arm*/linux-*/drivers/gpio/ once you've built the buildroot.

Not sure what you mean by "lines which assert a power-on reset" -- if you mean a line through which you can reset the gumstix, then you can use the NRESET line on the 60-pin connector, which will hard-reset the CPU.  There are also a number of software mechanisms for doing soft resets, including a hardware watchdog counter.

C

On Sep 20, 2005, at 10:52 AM, David Bernat wrote:

Before you ask, I did a search, but something seems wrong with sf.net right now.

Are there any tutorials which include a little c/c++ code that shows how one can manipulate the GPIO and i2c bus on the GumStix Connex board? Also, any tutorial on how one can update system drivers, programs, linux kernel, and the ethernet device's MAC address from within linux itself. Any links would be helpful.

Also, would manipulating a couple of GPIO lines be suitable for pushing data into a serial-in, parallel-out register? Is there a better way that someone could suggest?
 
Are there any lines on the gumstix which assert a power-on reset? Any simple circuits that assert a power-on reset aside from any on the gumstix that you guys can suggest.

--dbernat32