Register communication with an ISA device

[Din-o]

How does one do register communication with an ISA device; do the VISA IO calls work for ISA register access like they do for PCI/PXI ?

[MissyS]

Hi Din-o,

To communicate with a PCI/PXI device with VISA, you have to run the VISA Driver Development Wizard to generate a .inf file for the device. This allows Windows to recognize the device as a VISA device and let the VISA driver communicate with it. Here is a tutorial on this wizard. The available buses (as of VISA 4.0) for this wizard is PXI/PCI, USB, and Firewire.

That said, since the architecture is different for ISA versus PCI, it is not likely that this wizard will work for ISA. Maybe someone in the community has had experience with this?

If this ISA device has a driver that you can install, you can use Call Library Function Nodes in LabVIEW to call the device's driver application programming interface (API).

I hope this helps!

Regards,

[Din-o]

Hi Missy,

 Thanks for the response. Yea, I've been throught the whole VISA PCI driver development wizard process in my last project, which was to write a device driver for the DG-101, for use with the LV realtime OS. It worked out well and I was hoping there might be a way to do the same for ISA but I don't think there is. But thats OK, because it's my understandinmg that( if I'm corrrect ) the registers on an ISA device are just treated as memory offsets from the device's base address, which is set by DIP swirtches on the card; i.e. just write or read the calculated address directly from memory. While talking to Brandon( another NI eng ) on the phone yesterday, about an unrelated probelm, I posed the question to him, and he agreed that direct memory access with the CVI direct physical memory access functions should do the job. I'm not sure  how this would be done with native LV fcuntions , but I saw a Knowledge Base post that claimed the LV in port and out port fcunctions do the same in  LV. I'm not sure how this would work, since I/O and memory access are different beasts. But in any event, I like CVI so I have no problem using the CVI direct memory access fcuntions, if required, to get the job done. Next week I'll have acces to the lab where the machine and the card are located; so I'll be able to start playing around with them then, I'll let you know what I come up with. FYI, the card I need to access is an Agilent 10889B servo axis board, it's used to read the position data from an Agilent laser interferometer, and it's only available as an ISA card.

Thanks, -Dean

[ricardoheleno]

Hi!
I'm also trying to build a driver for one old ISA card, with register based access and with no interrupts. I have successfully tried to access the card registers by hardware address with INP and OUTP functions in LabView. About the CVI direct memory access fcuntions, is it possible to access isa registers  this way? And will it be faster? And one other thing.. im thinking to adpat the isa card (DT2815)  trought pci-isa adapter.. will i be able to access the  isa registers the same way before, if not will VISA driver work this way?

[Steak McDAX]

Hi Ricardoheleno,

Hope you had a good weekend!  I've been researching your post this afternoon and have a few answers for you.  As far as accessing the ISA registers, you can use the inp, outp, as well as the Physical Memory functions under the Utility library in CVI to access the registers.  They won't necessarily be faster than LabVIEW, but there is a possibility.

For your question about the adapter, if the adapter is a pass through box, then it might work.  There is usually lots of problems associated with converting to PCI (like PCMCIA to PCI)  because there is some conversion that is done at the board level that we won't really be able to support.

I hope this helps!