parallel port communication error with new addresses

[MengHuiHanTang]

MD2 motors controlled by LabVIEW. I am trying to communicate with the motors through a parallel port. I plug in a PCI card which can provide another two parallel ports. I check their addresses which are 1110-1117 and 1120-1127. Then I replaced the old addresses (378), but could not communicate any more, neither writing nor reading. The parallel port setting in BIOS is bi-directional, since both writing and reading are necessary. Does this matter?

I really have no clue why or how this could happen. Any help appreciated.

[K C]

Hi,

Maybe it is a obvious question; are all addresses you mentioned in Hex ?

[JK1]

Hai,

Inorder to determine whether the parallel port is functioning porperly to the given commands, change the parallel port mode to SPP mode in BIOS.  Use the parallel port read and write loop.vi (found in example vi's) to confirm whether the port actually responds in its base address (in this case 378H). 

Check out the device manager to find if there are any conflicts to the port(Device Manager>>Ports(LPT&COM)>>Printer Port >>properties(In right click)>>resources.

Then process with the required mode of communication.

with regards,

JK

[Superfly Snuka]

I have a similar problem with a dual parallel port installed in a PCI slot.

You can't set the mode via BIOS, since BIOS does not see them as parallel ports, only as a communication device in a certain PCI slot.

The manufacturer of the card says the port will automatically configure to the correct setting (PPT, EPP, ECP) based on the handshake from the hardware, but this is no help when I'm just trying to see if I can get LabView to send a signal out to a breadboard.

All I need is the ability to send 5.5 or 0 V on the 8 data bits out of 2 parallel ports simultaneously, but I'm beginning to believe it may not be possible.

Any suggestions would be helpful.

[Hillary_C_E]

Hi Superfly,

Have you looked to see if you can see your ports in Measurement and Automation Explorer? Have you installed the VISA drivers? You may want to refer to this KnowledgeBase: Why Don't My Ports Appear Under VISA Resources in MAX? The related links at the bottom of the page might also prove to be helpful. Let us know if you have more questions?

[Superfly Snuka]

The ports show up as LPT2 and LPT3 in MAX, so I believe VISA is installed correctly.  They just don't respond to the Parallel Port Read and Write vi.  I've used Device Manager to see that they have hex addresses CCC8-CCCF and CCD8-CCDF (the motherboard parallel port is at 0378).  I put those addresses into the vi and it doesn't operate.

I'm going to try to tie some pins together to simulate having a printer connected to the port so that it will think to operate in the SPP configuration.

I'll tie pin 1 to pin 10.
Pins 11,12, and 17 will be grounded.
I'll tie pins 13 and 15, but let them float.  I've read this will help.

The other config I've read is to tie 12, 15, and 17 high, while tying pins 11 and 12 low.

I'll see if any of this works.

[Superfly Snuka]

Tying the pins didn't help.  When I enter the hex addresses into the vi, I don't have the ability to switch the voltage in the pins hi/lo like I do on port 0378.

[Superfly Snuka]

If this page is up-to-date, I may be screwed:

http://digital.ni.com/public.nsf/websearch/953A4AB52663089D85256427004778C4?OpenDocument 

It says the LPTs are found at addresses 378, 278, and 3BC.  Mine are at 378, CCC8, and CCD8, and I have no means to change that.

[JK1]

Hai,

I have installed a additional parallel port card (in pci slot) in my pc.  Then i installed the device driver that came along with the parallel port card.  I

checked out the base address it was 278H (but i dint look the address before installing the device driver).   In general centronics interface ( parallel port) are placed at their respective addresses strictly.  Try reinstalling the device driver that came along with the external parallel port card or try latest updates from the manufacturer if available.

of the card.

With best regards,
JK1

[Superfly Snuka]

I've tried multiple versions of the driver (included on CD, default Windows, updated from manufacturer's website) and none put the ports at a different address.