Question about Motherboard electronics :o)

[jaimegmr]

Are pins where the hard drive and Power-On LEDs connect to +V and Ground? Or do the two pins power the LED by a voltage difference.

I need to know this in order to know if I can run 2 wires instead of 4 in a circuit board I am designing. This circuit board will have the 2 LEDs (hard drive and power) and I can use Ground from the rest of my circuit board. I would only have to run 2 wires from the motherboard to my circuit board, 1 for each of the +V pins for the LEDs, like this:

2 Wires Used:
From Motherboard
+V HDD >------------------(LED)-----------,
                                                             |--Ground
+V PWR >------------------(LED)-----------'

Otherwise I would have to do this and use more wires:

4 Wires:
From Motherboard:
+V HDD >---------------------------,--,
                                                 (LED)
Gnd      >---------------------------'--'

+V PWR >---------------------------,--,
                                                  (LED)
Gnd      >---------------------------'--'

Signature X__________________________ <-- Sign here please.

 

[ChipDeath]

I'm reasonably certain that it's a common ground. That would certainly be the easiest solution from the point of view of the mobo manu's anyway.

Test it - Try connecting the -ve from one of the two to the -ve of the other one, and see if it still lights up. 😱

---
Epox 8RDA+ V1.1 w/ Custom NB HS
Summer's here! so ease off the overclock...
XP1700+ @166x12 (~2Ghz), 1.45 Vcore
2x256Mb Corsair PC3200LL 2-2-2-4
Sapphire 9800Pro 400/730

 

[TheRod]

It's a commmon ground. The reason why they all have individual ground on the PCB, it'S because you often connect PC speakers, HDD led, power led, etc... To the front of a PC tower, that is often made of plastic. Also, these led, connection are often not close to each other, so it's easier tu run a ground wire for each one of them.

So, yes, you can use 1 common ground for all LED connector, etc...

By the way, what do you want to do with your custom PCB?

--
It's tricky to use words like <b><font color=green>AMD</font color=green></b> or <b><font color=blue>Intel</font color=blue></b> in a signature some users could think your are biased.

 

[jaimegmr]

I am going to make a circuit so that I can operate a Hitachi controller-based Character LCD Display through the serial port, instead of parallel port. I am also integrating the LEDs and power and reset buttons to this circuit since this will be connected to a car computer that I made. My circuit board will be connected to the LCD display in the front of the car, in the dashboard. The computer will be in the back of the car. That is why I want to run the least amount of cables 😱)

Signature X__________________________ <-- Sign here please.

 

[TheRod]

Wow! Veryinteresting project you have! You are probably making an MP3 player for your CAR based on an "old PC". HE HE HE!!! You will have a lot of headaches and fun making it!

--
It's tricky to use words like <b><font color=green>AMD</font color=green></b> or <b><font color=blue>Intel</font color=blue></b> in a signature some users could think your are biased.

 

[jaimegmr]

You guessed correctly 😱)

Im using a mini-Atx (about 9"x10") motherboard with an AMD K6-2 500mhz underclocked at 250mhz to lower the heat generated by the processor. It is running at 100Mhz front side bus and it has 128MB PC100 memory. The parts I am using are too much since I am using a DOS MP3 player program called MPXPlay and its system requirements are a 486DX-4/100 processor and 8MB of memory 😱)

Im including an serial port Infrared receiver so i can use any universal remote to control the MP3 player 😱)

Want to see the circuit board? It is about 3.3cm x 8.5cm once printed out at 300 DPI
Here it is:
<A HREF="http://www.jaimegmr.com/stuff/carputer_LCD_circuit.gif" target="_new">http://www.jaimegmr.com/stuff/carputer_LCD_circuit.gif</A> (my host is having major technical difficulties, so if you dont see it try again later)
I have never done something this small before, so I hope I dont mess up when soldering it.

Signature X__________________________ <-- Sign here please.

 

[TheRod]

Is this DOS player already support control via RS-232 or something like that?

--
It's tricky to use words like <b><font color=green>AMD</font color=green></b> or <b><font color=blue>Intel</font color=blue></b> in a signature some users could think your are biased.

 

[jaimegmr]

No, another program has to be loaded before MPXPlay. It is a TSR program, meaning its always in memory even when you run another program.

The program does support LCDs though by itself (both parallel and serial, although I had to modify the source code to get it to work correclty with my Serial LCD backpack chip (from Seetron.com))

For the Serial Remote circuit, you can use the circuit from <A HREF="http://lirc.org/receivers.html" target="_new">http://lirc.org/receivers.html</A>

Signature X__________________________ <-- Sign here please.<P ID="edit"><FONT SIZE=-1><EM>Edited by jaimegmr on 07/12/04 01:06 PM.</EM></FONT></P>

 

[Ned_Flanders]

you're a brainy man, I must admit.

<font color=blue>My dick is so big, that my dick has a dick. And my dicks' dick is bigger than yours.</font color=blue>