On 5/12/07, Marc Nicholas <geekything@gmail.com> wrote:
Garth,

I'll agree that the Breakout-GS does tend to confuse...but rest assured: virtually all the pins on it (AFAIK) can be used as regular GPIO. The PXA255 configures most of its pins as either hardware-assisted functions (LCD, NSSP, I2C, UARTs) or can reconfigure as GPIOs....you do this from the software side of things.

You can even bit-bang those GPIOs from a shell script -- albeit not too fast.

Ah, great.  Thanks for your quick reply!  A related question;  would I want the console expansion board anyway to get access to the gumstix board or would the wifi board be enough?  My guess is that I would probably want need serial access if I wanted to upgrade the kernel or other lower level things.  However for just get getting started and downloading/running code, is a serial connection necessary?

Hope that helps,

-marc

P.S: One small gotcha -- what voltage level do you need for your interfaces?

I need 5v though I think it can be as low as 3.3v.  Do the GPIOs output weird levels?

Thanks!

Garth

On 5/12/07, Garth Webb < garth.webb@gmail.com> wrote:
Hi, I have a question about the expansion boards available for the gumstix.  I originally sent this directly to gumstix support since I don't actually own a gumstix board yet and I'm looking for purchasing advice, but they replied I should ask here.  That seems a little odd to me but...

I'm looking at purchasing the Connex 400xm along with the ethernet expansion board, and possibly one additional board.  I've combed through all the wiki pages on the expansion boards, and I'm still not sure what will best meet my needs. I need to interface with some custom digital circuits so what I really want is access to the GPIO lines on the 60 pin connector.  I need these pins to send out serial data with a clock and a latching signal.  It will communicate with a few devices so I need a few sets of these 3 digital outputs (or a few sets of two if I share the clock).

I thought that the breakout-gs board would be what I want, but from the wiki page (< http://docwiki.gumstix.org/Expansions#breakout-gs>) it seems that all the outputs are too specialized (20 LCD pads, PWM pads, etc) and there aren't any GPIO pins exposed.  The console board (<http://docwiki.gumstix.org/Expansions#console-hw >) seems to be more what I want with 20 GPIO pads, but it seems backward to get the console board to use it for the GPIO pads.

Maybe I want to interface with the hirose connector directly?  What is your recommendation?  Also, are there any resources for programming with the the GPIO lines?

Thanks for your help!

Garth Webb