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Question asked by VRFuser on May 6, 1996
send q VEE_DOS ww vrf

from: Greg Goebel / HP-MXD / 970-679-3030 / FAX 970-679-5971
to:   ? Dankowski
date: Tuesday, 07 May 1996 1133 MDT

> Hello everybody,
> We have the following problem with HP Vee 3.12 running with Windows 95 :
> we want to drive a stepping motor unit under HP-VEE.  There is no
> problem running the control program for the motor in a DOS-Window.  But
> if the program is executed as a "I/O - Execute Program (PC)" within
> HP-VEE we have problems with the timing : The motor is not running
> continously anymore.
> The DOS Program is written in Power-Basic 3.0 and uses Assembler
> routines.  In detail, the time-delay between two micr osteps (100
> microseconds) is implemented using IRQ 15 Subroutine 86h of system BIOS.
> It seems like HP-VEE is disturbing the system timing.  Is there a
> posibility to run the program exclusively without any further background
> operation of HP-VEE?
> Thanks for your help.

Hmm ... Windows is not anything resembling a real-time operating system and I
would suspect you would have the same or similar problems if you operated the
two programs in parallel.

Note that under Win95 you are operating under a "virtual" DOS environment and
no longer have the same level of access to hardware.  To achieve reliable
interrupt response, you will need (according to our lab people) a low-level
Windows VxD (virtual device driver) ... which is somewhat beyond what we can
provide much help on.

If you have more questions, let us know.

[<>] regards -- gvg