Control the LPT voltage

[rreiss1@hotmail.com]

Hello,
I just completed the LabView 7.0 Basic Cours I..
I'm "playing" in LabView to get to know more functions and I want to control the LPT voltage is that possible to do with LabView?

Thank you,
Reiss Rotem

[Dennis_Knutson]

Read this application note and the links in there for some example programs. By "voltage", I'm assuming that you mean the on/off state.

[rreiss1@hotmail.com]

Hi again,
Thank you about the link I'll read it right away.. but I don't think I explained my self very good I'll write to you exacly what I Want..
I saw a guide on the internet "who to bulid a LEDs organ" And what it do is turn the LEDs on and off when there is music, by the rate.. I don't know how to build it but I want to know how to do the first part at least - To build an LPT cable that in is one side there is the computer and on the other side led on each pin.. If its not the way it has to be done please tell me what is my mestaiks because I know I have lot of them..

Thanks again,
Reiss Rotem

[Dennis_Knutson]

The link shows the pinout of a parallel port so I'd say that all you have to do is wire the LED's between the GND pin and the data lines. You'll need a series resistor in there as well.

[rreiss1@hotmail.com]

Hi,
Yes, I know.. This is 1 more thing that I want to talk about.. what is the LPT port voltage? 5v or 12v? I think that 5v but I'm not sure..

10q very much..

[craigherdman]

Reiss Rotem,

LPT port voltage is between +2.4v to +5.0v for a TTL high and between +0v and +0.8v for a TTL low. Hope that helps!

Craig H.
National Instruments

[rreiss1@hotmail.com]

Hi,
I'm feeling very stupid because I've alreasy forgot what is TTL.. 😕 I looked in my book of the "basic course I" and I didn't find nothing about it but I read the part on the LPT connection.. All I remember is that TTL realated to a squre signal or something like that.. please remind my.. 😞 But from what I understand from you I need to use high TTL and I can adjust it to send 1.7v to the pin that I need?? (1.7v because this is the LEDs voltage.....)

Thank you,
Reiss Rotem

[craigherdman]

Reiss,

Here is a super brief definition of TTL:

"Brief Definition of TTL".

For a more involved definition try this link:

"Definition of a TTL Compatible Signal".

Please post back with any other questions.

Craig H.
National Instruments