HD LED Cathode 1 o o 2 PS LED cathodeHD LED Cathode 1 o o 2 PS LED cathodeHD LED Cathode

  • Thread starter Thread starter Jethro
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J

Jethro

I have a MOBO Asus P4SD made for Hewlett Packard that has a header
mapped out as follows:

HD LED Cathode 1 o o 2 PS LED cathode
HD LED Anode 3 o o 4 PS LED anode
GND 5 o o 6 PWR Btn
M Reset 7 o o 8 GND
+5 VDC 9 o o 10 NC
NC 11 o o 12 GND
GRD 13 o
Chassis ID2 15 o o 16 +5 VDC
Chassis ID0 17 o o 18 Chassis ID1

I am not seen the terms cathode and anode applied in this scenario
before. Is cathode - + and anode = -?

No idea what M Reset, NC, ID2, ID1, ID0 are.

How careful should I be connecting these pins to connectors from my
case?
Is the PWR button and the opposite GND what I am used to as the POWER
SWITCH?

Any help here is appreciated.

Thanks

Jethro
 
Jethro said:
Sorry for prior post
Click to expand...

The mechanism I use to remember cathodes and anodes, is the letter
A for Anode, fits in the triangle on the diode symbol. To be forward
biased and light up, the Anode must be more positive than the Cathode.

(+) |\ | (-)
Anode | \| Cathode
---------| |------
| /|
|/ |

There is a more technical definition here, suitable for settling bets
while you're drinking :-)

http://www.av8n.com/physics/anode-cathode.htm

Having tried to look up some info on HP's scheme within the last
day, it looks like the plugs could go something like this.

HD LED ___/ 1 o o 2 \___ Power LED
\ 3 o o 4 /
Reset ___/ 5 o o 6 \___ Power
Switch \ 7 o o 8 / Switch

As far as damaging it, by putting the plugs on the
wrong pins, I would think those 8 pins are pretty
immune to mistakes. The LED path should have current limiting
resistors. The logic signals on the reset and power switches have
pullup resistors, that will limit the current. When I look at
your header diagram, the part that scares me most, is seeing
signals that look like raw "+5VDC" on the header. Unless those
are protected by 1 amp Polyfuses, there is room for some mischief
there if you aren't careful. But pins 1 thru 8 look pretty safe.

It is anyone's guess, what function pins 9 thru 18 are intended for.

Paul
 
I have a MOBO Asus P4SD made for Hewlett Packard that has a header
mapped out as follows:

HD LED Cathode 1 o o 2 PS LED cathode
HD LED Anode 3 o o 4 PS LED anode
GND 5 o o 6 PWR Btn
M Reset 7 o o 8 GND
+5 VDC 9 o o 10 NC
NC 11 o o 12 GND
GRD 13 o
Chassis ID2 15 o o 16 +5 VDC
Chassis ID0 17 o o 18 Chassis ID1

I am not seen the terms cathode and anode applied in this scenario
before. Is cathode - + and anode = -?
Click to expand...

Anode and cathode are terms describing the parts inside the
LED. Anode is positive, cathode negative. If you look
carefully at an LED (one that is clear so you can see
inside), the cathode is the lead with the dish shaped
termination on it. See picture;
http://www.lumasense.com/_images/_technology/diagram-led.gif

No idea what M Reset, NC, ID2, ID1, ID0 are.
Click to expand...

I'd guess it's just the reset switch (7-8), (N)o
(C)onnection, and the others aren't applicable, maybe one
pair was for a case intrusion switch.

How careful should I be connecting these pins to connectors from my
case?
Click to expand...

Medium? It wasn't an answerable question.
It won't kill anyone if wrong, but you don't want to be
hooking up anything to the 5V, nor doing anything except
hooking it up as it's expected to be, until you have a
reason to deviate from that and know what/why/etc.

If you hooked up power switch reversed, it still works (it
isn't polarized). Same with reset. LEDs if reversed just
won't light up, but wouldn't be damanged. Don't hook
anything up to the other unknown or 5V pins without reason.

Is the PWR button and the opposite GND what I am used to as the POWER
SWITCH?
Click to expand...

yes that'll work, or any other gnd if not the one directly
across from it.
 
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