Re: [Gumstix-users] Very General Newbie I/O Questions

[Dave H. <dhy...@gm...>]

HI Joe,

On 10/14/06, Joe Thielen <jo...@jo...> wrote:
> Dave, thanks so much for your response!  Clearly I will have to dig in
> and do some serious learning here.  The LED source code blew my mind
> ;).  All those numbers are freaking me out!

You'll probably want to take a look at the PXA Developer's guide. Most
of those numbers are register addresses. See section 4.1 of the PXA
Developer's Manual
http://www.intel.com/design/pca/applicationsprocessors/manuals/278693.htm

> I've another question... at first I was very confused as to why the LCD
> GPIOs were labeled as... LCD.  Then I took a look at the Intel PDF for
> the CPU, now it makes more sense :).  My question is, I've only tested
> the first couple of I/Os on the LCD portion of the breakout-gs.  But in
> the Intel PDF, it has different functions for the LCD pins 8-15.
>
> - Will I still be able to use those as simple inputs/outputs?  For
> example, it says LDD_[11-14] refer to clocks.  If I set these as outputs
> in GPIO mode, will they be solid outputs, or clocks?  And the same for
> if I switch it to an input?

If they're configured as GPIO pins then they're simple input/output
pins. If they're configured as the appropate AFx then they're behave
like that signal.

> - Is that what the "mode" is for (GPIO, AF1, AF2, etc...)?

Yep, think of like a switch to select which functionality is available
for a given pin.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/