Matrix Orbital Corp

Howdy Yall, yet a nother question for ya. As far as hooking up an LED to my RX and TX on my board to show activity to and from the lcd. You will have to excuse my electrical stupidity. so one side goes to my GPO and the other to the RX pn?

() <---LED
|| <--TAILS
||_____
| |
| |
| RX
GPO1

is this the right way to do it?[/b]

I'm not sure what you meant by your diagram, but if you want to use an LED to show communication via the Rx and Tx lines you will need a little cct. set up first. You need current limiting resistors and a diode for the LED's first of all and you must have two LED's. One for Rx and one for Tx. You also have to tie them to ground in order for it to work. However this is not an easy process and I have never tried it before. Pins 1 and 44 off the processor are the pins that you need. Try a 1K resisor and work your way down to 500 ohms. If you want your LED's to be brighter you will need to implement a transistor in your cct. To me, it sounds like a lot of work for blinking communication lines. As for our USB modules, the Rx and Tx LED's are dedicated lines from the USB chip to perform this activity.

Ok... well that sounds a little more complicated then I wanted. So I'll hook up a 1 GPO for email and maybe one for power on or off. Do I use a GPO for an On and Off light. Or would that be some how worked into the 4br power input rig? Argh.. Sorry again for my electrical retardedness!

You really wouldn't need to use a GPO for a power on light, because like you say, wiring it straight to the PSU wold be equivalent.

Are you running LCDC? There's a lot of cool events that could map to GPOs turning on/off, like temp thresholds, CPU usage thresholds, all kinds of madness. How about a green LED if the CPU temp is below 45 degrees, yellow for 45-55, and red for above 55? (Or whatever numbers you like instead)

I could only have the two LED's though right? I have the GLK 123322-25WBL that only has 2 GPO's.

Right, sorry I missed that detail. Green and red then.

Actually you could use both GPOs to drive a tricolor LED: one GPO lit = green, other GPO lit = red, both lit = amber. That would be pretty tricky.

(Sorry if that confuses you, I know you said you were an electronics n00b.)

I maybe a newbie, but I've never been one to start with small projects. Thanks for the help

linear wrote:Actually you could use both GPOs to drive a tricolor LED: one GPO lit = green, other GPO lit = red, both lit = amber. That would be pretty tricky.

(Sorry if that confuses you, I know you said you were an electronics n00b.)

I like that...

I was looking at the events just now, and I can't immediately see how you would get the amber combination since there's no logical AND. My head hurts from thinking about it though.

Okay, I guess it would really be just two overlapping windows:

The green side would be on above some floor (say 0) and off above 55. the red would turn on above 45. So from 45-55 you have amber. Tight.

/me rummages for some tricolor LEDs...

hehe... don't worry bout it too much... I've not started on it yet

Oh yeah.. So I could hook that LED to the power supply? thats 12 volts isn't it? The LED is only rated for 2.1 I beleive. So I would have to add a resistor?
Luke

IF you want to hook an LED to your power supply, you have 5V (red) and 12V (yellow) available. Both require a resistor to limit the current to your LED.

To size that resistor, you need to know the diode's rated forward voltage and current, and plug them in here: http://www.bit-tech.net/article/68

diode?

LED == Light Emitting Diode.