parallel port communication error with new addresses

[Superfly Snuka]

I found this vi that works on one of my PCI-card-based parallel ports:

http://zone.ni.com/devzone/cda/epd/p/id/1735

It refers to the ports by their VISA aliases instead of their hex base address.  This seems to be key.  One of my ports is not responding, but I will try to make sure the drivers and settings on it are identical to the one that's working and see if that makes 'er go.

[Superfly Snuka]

Both my ports now respond to the parallel.vi that I downloaded from the user-generated content--the hardware connection was messed up between my 2 cards (plug and socket not correctly aligned) and that was causing the problems with my second port.

Still, the fact that the examples for the parallel port included with LabView (Parallel Port Read and Write Loop.vi; Parallel Port Additional Data Register Inputs.vi) DO NOT function with parallel ports at addresses like the ones I have is very frustrating to a new LabView user.

I think if I had to start all over again, I might just buy the NI-USB 6501...it's only $99, but I should be able to get the same functionality from my dual parallel port, which I got for less than $10.  And in theory, it should be just as simple to control one as the other.

[K C]

Hi,

The addresses you mentioned are located at the PCI bus. I don't think you can access to these addresses the way you access the (good old) addresses of LPT1:.

The addresses of LPT1:, COM1: etc. are located in the IO address space of the old ISA bus. These are real I/O's which can be accesses with a processor In and Out instruction. Like we did with MsDos.  (Yes I know I am old   ) 

The addresses you see for a PCI device are the addresses for the PCI controller on a board. So you have to know how the board works and how to access the devices on this board through the PCI controller on this board.

With the VISA solution you don't have to worry about all this stuff. You can just access a device name where ever it is located.