I am trying to acquire pulse signal (TTL 0 ,+5v) using parallel port (SPP 25 pins) on pin 12

[digital]

The state register adress is 379h. When I run continuously this VI, the value diplays 78 and 58 periodycally.


I think that 0 correponds to 58 and +5v correponds 78. Is this correct ?


So my questions are:


1) How can I do to read only pin 12.


2) How can I do to display graph of a pulse signal (TTL 0 +5v) from value.


I attached the I am using.


Thank you in advance

[Christian_L]

If you get an accurate representation in LabVIEW of the two different states, simply mask (logical AND) the number for the bit corresponding to the pin you are interested in. Doing a logical shift of the masked value will give you a 0 or 1 which you can plot on the graph or chart.