Hi,
You should have no problem reading in a pulse/s into a digital input. If your pulse is wide enough (>5ms) you can use a software loop and continually monitor the digital port. If you see a high signal on the line you can decide if you want to output a digital pulse on one of the other lines.
If your pulse will be much smaller than 5ms then you might need to feed it into a counter. This counter should be set to do the single triggered pulse generation application and have the pulse output greater than 5ms. This way, you can feed the generated pulse into your digital input so that you can read it correctly (using method in the above paragraph).
The reason I am specifying 5ms is because, the software loop is determined by the operating system. I've
seen traditionally, this software loop can operate anywhere from 1ms to 10ms depending on how fast your computer is.
You can find links to example programs by searching ni.com/support and clicking on Example Code. You should search for digital input and output with 8255 (82C55) chip and the 8253 counter chip for single triggered pulse generation. I'm not sure what software you were using otherwise I could have done a quick search myself. Anyway, I hope that helps.
Ron