Re: [Gumstix-users] Confused newbie looking for hardware recommendations

[<dhy...@al...>]

Hi Joe,

> Where I am confused is the third board that I need.  I was originally 
> looking at the breakout-gs, but then it looks like I'd need external 
> circuitry for the RS232 serial ports.  So now I'm thinking the 
> waysmall-stuart.  It looks like it has two RS232 serial ports onboard.	
> The SPEX thing says it has "I/O" pads.  But looking at the picture of 
> the circuit board, I don't see anywhere for I/O lines.	

Here's a photo of the back of a Waysmall HWUART board (the STUART looks
similar):
<http://davehylands.com/gumstix-wiki/WaySmall-STUART/WaySmall-Back.jpg>

> The breakout-gs 
> looks like it has holes for 16 GPIO lines.  But in the docs, these are 
> referred to as "LCD".  I don't want to use an LCD, I want a bunch of I/O 
> lines that I can set up individually to be used as either inputs (dry) 
> or outputs to control relays.  

Pretty much all of the pins on the connectors can be reconfigured as GPIO
pins. So for the LCD, if you don't want to connect up an LCD, you've now got
a bunch of pins that can be configured as GPIO (input or output).

> But at the same time, I'd like one or 
> more "real" serial ports (real meaning the circuitry is already on-board 
> and all I need is the cable).

Of the 20 pins on the back of the Waysmall boards:
<http://pubs.gumstix.com/boards/HWUART/B00002-R12.GPIO.png>
I think about 15 of them can be configured as GPIO.

One of the two serial ports on the waysmall (FFUART) is used as the console.
When you use any of the connex boards, the HWUART isn't usable. The other
serial port on the Waysmall STUART is the STUART port, and it should be
usable. Make sure that you also get the null-modem cable if you want to plug
your waysmall into the back of your PC.

You'll probably also want the other cable to make your gumstix look like a
PC (so some device that you would otherwise plug into your PC can be plugged
in directly to the gumstix), although from the photo of the cables, both
have female connectors on them, so a gender bender will probably need to be
used along with the straigh through cable to make it complete.

Dave Hylands