Does the inport/outport VI inLabVIEW 7.1 used to communicate with EPP

[SUDEEP]

I have to create an interface to communicate with a device using the Parallel Port in the Enhanced mode (EPP).I have wriiten a few programs for reading/writnig to the Standard Parallel Port(SPP)and they work properly.I want to know whether the Inport/Outport VIs in LabVIEW 7.1 capable of handling the EPP protocol.When I try to use the same programs in EPP mode (address hex 378 + 4), the programs don't seem to work.I am attaching a sample program that I am using.Somebody please help me out.

[rolfk]

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@SUDEEP wrote:
I have to create an interface to communicate with a device using the Parallel Port in the Enhanced mode (EPP).I have wriiten a few programs for reading/writnig to the Standard Parallel Port(SPP)and they work properly.I want to know whether the Inport/Outport VIs in LabVIEW 7.1 capable of handling the EPP protocol.When I try to use the same programs in EPP mode (address hex 378 + 4), the programs don't seem to work.I am attaching a sample program that I am using.Somebody please help me out.

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I'm not familiar with the EPP protocol but you might have some timing issues. inport and outport from an application (user level) on Windows NT based systems (NT4, 2000, XP, 2003) is not extremely fast so it might be that your signals are not fast enough on the parallel port. Another issue might be that while 0x378 is typically used for the parallel port on PC systems this is not an absolute requirement. Some computers, especially notebooks, do have different base adresses for COM and LPT ports.

Rolf Kalbermatter

[SUDEEP]

Dear rolfk,
Thanks for your reply.I am using Windows 2000. I have tested the program when the PP was configured in the SPP mode and also verified the address using another utility.The base address for SPP is hex378.And i read in some documents that for EPP the base address would be hex(378 + 4).EPP has its own handshaking protocol.It seems that the Inport/Outport VIs cannot handle the EPP mode.Is there a way that I can still use LabVIEW ?

[Brett_B.]

What does your program do when you have it set to EPP mode? Do you get an error or does the program hang? What kind of device are you communicating with?

-Brett

[SUDEEP]

Dear Brett,
When I configure the PP to EPP and use the register address 37C to write to it, the program runs without giving any errors.But irrespective of the value you choose to write to EPP it always makes all the data pins high and returns FF on a susequent read.

I have just hooked up a scope to the parallel port.I actually aim to interface an IC to it, with which I have to communicate.
Thanks again for your concern.I hope that this would help you to find an answer for my problem.

Sudeep

[Emilie S.]

Hi SUDEEP:

I found some documentation and previous discussion forum posts that may help you with this. Please look through the following links.

Discussion Forum Thread: Parallel Port

Discussion Forum Thread: EPP in LabVIEW with Code Posted

I hope this helps you out.

Regards,

Emilie S.
Applications Engineer
National Instruments