Pulse generation on PC parallel port and its maximum frequency

Question

Can i generate pulse pattern on any one out of 8 lines of IEEE1284 using Labview? if yes what is minimum period and duty cycle?
Yours sincerely

Answer 1

I doubt you will get up to 2 MBps and whatever you get you will not have any real control about the timing. If you use VISA LabVIEW sends the data to the COMM port driver and that driver outputs it with whatever handshake speed the remote side answers. Also in order to use anything but the old unidirectional printer mode you need to have a device that is intelligent enough to startup in Nibble mode to negotiate the maximum mode it supports. Without any remote device that does the negotiation and handshaking there won't be any EPP, ECP or whatever other bidirectional mode.
In unidirectional mode you can expect a few kBps at most and again the speed will be whatever the CPU is able to hammer through the parallel port. If you want to have any control of the speed you need to program the parallel port directly on register level. However that will maxout at 1 or 2 kBps at most and you should not expect any fine grained and steady speed control at that level. Windows is not realtime and trying to control anything reliably in software that is less than several 10ths of milliseconds is simply impossible without going into kernel mode and writing the timing critical parts in a kernel driver.
Also direct access to the paralell port registers is out of question for 64 bit Windows.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions