Chapter 3
Developing Your Application
3-10
ni.com
VXImemAlloc()
returns 32-bit aligned, page-locked, contiguous buffers,
which work efficiently with
VXImove()
, but only if the function returns
MEM_OK (0)
. A status of
MEM_OK_USE_MEMCOPY (1)
means this buffer
cannot be used directly with
VXImove()
.
VXImove()
can also move blocks of data to and from a single VXI address.
This is commonly referred to as
FIFO mode
. For more information, refer
to the NI-VXI online help.
Local Resource Access Functions
VXImemAlloc()
does not allocate onboard RAM on the VXI-8340
series; it only allocates system RAM on the motherboard. If you want
to access onboard RAM on the VXI-8340 series, access it as if it were
VXI memory—that is, by using high-level or low-level VXIbus access
functions. You can use
GetDevInfo()
on the VXI-8340 series device to
determine the VXI address space and VXI address of this onboard RAM.
Debugging
NI Spy and VISAIC are useful utilities that can aid in identifying the causes
of problems in your application.
NI Spy tracks the calls your application makes to National Instruments
T&M drivers including NI-VXI, NI-VISA, and NI-488.2. NI-488.2 users
may notice that NI Spy is very similar to GPIB Spy. It highlights functions
that return errors, so you can quickly spot which functions failed during
your development. NI Spy can log the calls your program makes to these
drivers so you can check them for errors at your convenience.
You can also control your instruments interactively using VISAIC. You
can use VISAIC to control and communicate with your instruments with
NI-VISA without having to write a program. This utility is an excellent
platform for quickly testing instruments and learning how to communicate
with them.
Refer to the online help for instructions on how to use VISAIC and to learn
about their features. In VISAIC, you can right-click to reach
What’s This
help and function help.