Crashing while runing appl to test PCI6602

Question

I am testing PCI6602 with P4+Win2K+SP4, after installed driver V6.9.3, no resource conflict. everyting is OK.
However, when I run my simple application(just setup I/O and initializion for counters.), it crashed everytime!
say "Stop ... Address ... DRIVER_IRQL_NOT_LESS_OR_EQUAL... nidaq32k.sys"
But if I run the application line by line use breakpoints, it is fine.
It looks like something relateed to the sriver's speed.
So I updated the driver to V7.1, it looks better, but still crashs ocassionally when I continuously re-run application quickly. the driver's name changed to "swmidi.sys" in the Blue Screen. If I wait some time to re-run my application, it looks OK.
Does anybody know why this crash happens and how to preve
nt/solve the problem?
Our machine is medical equipment, if something like that crashed, it would be disaster!
Youe help will be greatly appreciated!
James

Answer 1

Hey James,
Normally, crashes like this are related to your default settings in your application. You didn't mention what programming language you are using, but if you are using LabVIEW, make sure all of your shift registers have default values wired into the left side. In addition, if you are programming in text-base I would suggest setting every parameter with a default value. Don't ever rely on the default of any value to be zero.
Once a program has executed it will still reside in memory for a short period of time, or until the OS over writes that location. If the program is executed again while all the values still reside in memory, then the new default values will be the last value that was written to that integer, float, pointer or shift register.
If your program was assuming the value would be zero you can run into some serious problems.
You can run one of our shipping examples designed for the 6602 to verify the driver is working correctly and it is not a driver problem.
I hope this helps out.
Joshua P.
Application Engineering
National Instruments