How to Support Multiple AT-GPIB Controllers On a VXIpc with VxWorks Installed
Hardware: VXI/VME/MXI>>VXI Controllers>>VXIpc-770
Problem: How do I modify the software provided for my VXIpc controller running VxWorks to support multiple AT-GPIB controllers?
Solution: Although the GPIB drivers included with the "NI software for VXIpc with VxWorks" do support up to four GPIB boards, the standard libraries do not have support for
AT GPIB boards other than the built-in GPIB port on your older model VXIpc (newer model VXIpc's have a
PCI GPIB built-in). Adding support for other boards requires a change in the library source code. If you require support for an AT GPIB plug-in board, or for some reason wish to change the interrupt line or base address for the built-in AT GPIB port, you must use one of the user configuration options. National Instruments provides several ways to change the configuration:
- The simplest method, which would be appropriate for a temporary change or a test configuration, involves the "gpib_setup" function in the "gpib_set.o" object file. To use this, load the "gpib_set.o" image. The "gpib_setup" function takes eight arguments -- four base-address/interrupt-line pairs. Each pair configures the corresponding GPIB interface (the first pair is gpib0). Use the "INVALID" value, -1, for a PCI GPIB (the default).
- The second option is to compile the file "gpib_cfg.c" with your new base address and interrupt line information. Load the resulting "gpib_cfg.o" file; then, load the user-configurable libraries, "nigpib2.o" and "espgpib2.o", so that you can use the information in "gpib_cfg.o".
- For a more permanent solution, generate "gpib_cfg.o" as described above and use the "ld386" (or "ldpentium", for Tornado 2.2) linker that is included with Tornado to permanently link "gpib_cfg.o" and the user-configurable library. For example, you could do the following:
C:\TEST> ld386 -r -o mynigpib.o nigpib2.o gpib_cfg.o
Then you can replace the default "nigpib.o" library with the "mynigpib.o" file generated by "ld386".
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Report Date: 01/31/2003
Last Updated: 01/31/2003
Document ID: 2TUDTCON
