Appendix B
PC Card Questions and Answers
©
National Instruments Corporation
B-3
DAQMeter DAQCard-4050 User Manual
2.
How do I determine all of the memory that Card Services can
use?
One way to find out which memory addresses Card Services can
use is to run a utility such as
MSD.EXE
that scans the system and
tells you how the system memory is being used. For example, if you
run such a memory utility and it tells you that physical addresses
C0000 to C9FFF are being used for ROM access, then you know
that C8000–D3FFF is an invalid range for Card Services and should
be changed to CA000–D5FFF.
3.
How can I find usable I/O addresses?
Identify usable I/O addresses by trial and error. Of the three
resources used—memory, I/O, interrupts—I/O conflicts will be
low. You can use the NI-DAQ Configuration Utility in Windows to
diagnose I/O space conflicts. When you have configured the
NI-DAQ Configuration Utility for a particular I/O space, save the
configuration. If there is a conflict, the configuration utility will
attempt to report an error describing the conflict.
4.
How do I find usable interrupt levels?
Some utilities, such as
MSD.EXE
, will scan the system and display
information about what is using hardware interrupts. If you have
such a utility, you can run it to determine what interrupts Card
Services can use. Card Services needs an interrupt for itself as
well as one interrupt for each PCMCIA socket in the system. For
example, in a system with two PCMCIA sockets, at least three
interrupts should be allocated for use by Card Services.
Keep in mind that utilities such as
MSD.EXE
will sometimes report
that an interrupt is in use when it really is not. For example, if the
computer has one serial port, COM1, and one parallel port, LPT1,
you know that IRQs 4 and 7 are probably in use. In general, IRQ5
is used for LPT2, but if the computer does not have two parallel
ports, IRQ5 should be usable. IRQ3 is used for COM2, but if the
computer has only has one serial port, IRQ3 should be usable.