Toggling a bit on a parallel port at 1 MHz??

[nxb]

Hi

Objective: Trying to toggle a bit on a parallel port, specifically pin 3 which corresponds to D1 of a data register at a Frequency rate of 1Mhz.

Problem: Attached is the code that I am using. For my Register Address I am using 378 (hex) and for my Numeric I am using 1 & 2 to toggle between low and high on pin 3 of DB25 (parallel port).

             With the code that I have I am able to toggle the bit at a maximum frequency rate of about 1.5 KHz.

Measurement: Measurement of a frequency was taken by a oscilloscope by putting the probe in pin 3 of DB25 connector and ground lead to pin 19 of a DB25.

Question: Is there a way for LabVIEW to toggle this bit that I have described above, at a rate of 1MHz and maybe higher ?? Is there maybe another way of recoding my VI that will give me this result of 1MHz frequency rate ?

Thank you

[Omar_II]

You will not be able to do it with Windows running.

You only have a 1ms time resultion with Window, but every now and then Windows will interrupt things and you will skip clock tick.

You need to do the timing at the hardware level in a Real Time System, a FPGA board or a counter timer device.

But you will not get the results you are looking for using a printer port on a Windows machine.