Parallel port input

[sonaiko]

Guys i have tried to input data through the parallel port.. weird results those i got!!

with the port is open circuit, it give an OUTPUT 1.8v eventhough i have the C5 pin high [to make it input]!!! thats wierd isnt it supposed to be zero?

another thing, when i connect a LED to the INPUT parallel port, it LIGHTS!!! ofcourse thats normal since there is a 1.8v going on there!!

I want the input lines NOT to give voltage when connected to nothing, and only if 5v or so connected to them my VB programme [or c++] should give me it is 1!!

what is going on?

 

[learner1]

There are few registers in parallel port such as control register, status register, data register. Some register are open collector or inverted level.
So you may see some voltage level there.

I ever visit some websites about parallel port & application that it may useful to you,

www.beyondlogic.org or www.geocities.com/bagtool/parallel_basic.html

 

[Dialtone]

Check the setting of the port in BIOS. Change it to EPP but NOT ECP/ That should allow you to manipilate the control register bit 5 for input. EPP setting works just fine as a Bi-Directional port that can be controlled by the control register.
Dialtone

 

[instruite]

All the parallel ports are not by default Bidirectional so you have to do certain settings as mentioned by Dialtone
I normally use to keep the output and input ports seperate
**broken link removed**
refer the above link it shows configuration on both bidirectional and seperate input and putput also
well it depends on your application what you want to use

 

[sonaiko]

Thanx guys i will try what u all said.

Are the ports 2-->9 output and input at the same time?
Can i make smthng like port 3 is output but port 4 is input at the same time? how can i do this?

thanx.