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vrf New User - talking to DAC

Question asked by VRFuser on Nov 18, 2001
On my side, I have blown a serial port a couple of times.  It hapenned after
occurences of glitches on the AC line.  As a temporary solution, we try to
electrically isolate the peripheral from the AC line or from the serial
port.  If you can, connect everything (AC line) on the same surge suppressor
(or even a UPS, wich is even better).

For parallel port applications, we prefer using an I/O card that offers more
bits than the parallel port.

For Bill's question:
With an ISA card, you can program the port directly with a peek/poke dll.
To do fast transfers, you can do "blockpoke", wich writes a complete block
of data directly to a specific I/O address on the card.  You end up with the
speed limit of the I/O card itself.  For PCI cards, it is more complicated
to do peek/poke, because the PCI interface is a lot more complex.  There are
dll's that can help interfacing with such cards.  Keithley I/O cards come
with DriverLINX, wich can be accessed thru ActiveX or dll.  There is a
sample dll that could easily be modified to do what you want.  I have
modified mine to do a 16 bits "blockpoke" of predefined hardware
instructions to configure my hardware.  It is pretty fast (more than I
expected initially).

If speed is not that important, but simplicity is, there is another way that
doesn't require any special hardware in your PC or any dll.  In one of our
test stations, we have an Agilent GPIB switcher (model 3488A) that is
basically a digital input/output device.  You can add as much as 5 digital
I/O cards with 16 bits each (model 44474A).  The bits can be addressed
individually or grouped by 8 or 16 bits.  I haven't explored other
manufacturers to see what they have to offer in that area.  Obviously this
type of interface is more expensive, but you may save some programming or
debugging time...

-----Message d'origine-----
De: Drago, William @ NARDAEAST []
Date: 19 novembre 2001 07:41

Yes, I agree. I wrote a PLL control program that uses the parallel port and
once this software was in general use in our factory, printer ports started
blowing left and right. Instead of replacing the mother boards I just
installed a cheap ($29) parallel port as a replacement for the original

As far as using the serial port goes, I've never blown any up. Typically I'm
using them as intended (talking to a UARTs.)

I'm doing a project now that requires the use of an I/O board. How do you
talk to them from VEE, and how fast can you transfer data?

Bill Drago
Test Engineer
L3 Communications - Narda Microwave East

> -----Original Message-----
> From: Kathy Kiessling []
> Sent: Friday, November 16, 2001 8:21 PM
> My two cents.  I've avoided using the serial port and
> parallel when talking to DAC, ADC, and PLL's.  ComputerBoards
> makes a nice complement of digital I/O boards at a very
> reasonable cost, provides a VEE interface, and DLL's, and the
> code has required no re-engineering as we've migrated OS's
> over the years. 
> There is a side benefit for this as well.  We are a hardware
> manufacturer, and ever so occasionally we are engineering or
> troubleshooting a unit, and we do sometimes blow up the
> controlling the board though these communication lines.
> Since we are using an $89 card, it is easy to stock a few
> spares and the owner can replace it.  If we had been using
> the serial or parallel port, repair or replacement is much
> more complicated and costly, it involves IT, and on the newer
> computers where these are built in, you're buying a new
> motherboard.
> Kathy Kiessling
> Senior Test Engineer
> Endwave Corporation
>  -----Original Message-----
> From:      Beliveau, Bruno []
> Sent:     Friday, November 16, 2001 5:34 AM
>  << File: Win95 >> << File: WinNT >>
> If you interface with serial or paralel ports, you don't need
> the peek/poke dll (unless you want to directly instruct the
> hardware interface).  But if you want it, here are the dll's
> (Win95 and WinNT) that came from the Agilent web site
> (unsupported downloads).  There are also third party peek/poke
> dll's.
> -----Message d'origine-----
> De: Diane Donnelly []
> Date: 15 novembre 2001 22:09
> Thank you for all the replies to my inquires, they've been helpful.
> As far as my question three.  I am using VEE to generate
> specific waveforms.
> What I want to do is output those waveforms to either a
> serial or parallel
> port (which ever one VEE supports easily).
> What I plan on connecting to that port is a digital to analog
> converter,
> that I have to build, so I can view the waveforms on an
> external device such
> as an oscilloscope.  I don't know if anyone out there has
> done anything like
> this and was looking for ideas on how to accomplish the job.
> I've had some
> replies that mention peek/poke dll but I don't know where to
> get that file
> or if I'll need it.  Appreciate all the help!
> -----Message d'origine-----
> De: Beliveau, Bruno []
> Date: 15 novembre 2001 11:56
> I have two comments to add with the peek/poke dll:
> (1) there is a Win 95/98 version and a WinNT version
> (2) it is easy to work with if you interface with a ISA/EISA
> card and things
> get complicated if you interface with a PCI card - in the later case a
> configurable driver, such as DriverLINX, could be handy
> -----Message d'origine-----
> De: Drago, William @ NARDAEAST []
> Date: 15 novembre 2001 09:42
> The VEE files already are in ASCII format. You can view them and make
> changes with any text editor - if you understand what you're
> looking at.
> A VXE file is the VEE executable format. This is not the same
> as a dos or
> windows executable in that in order to run a VXE you have the
> VEE runtime or
> development environment installed. The VXE files are smaller than the
> original and are good to use when you don't want someone to
> see or modify
> your original code. To make a VXE click File->Create RunTime Version.
> There's plenty of info in the VEE help, search for runtime.
> As far as interfacing your own boards to VEE, that could be
> tricky. There's
> a DLL floating around that will allow VEE to peek/poke any
> I/O address. You
> will probably have to make use of it. I did a project here
> where we designed
> a custom board with a microprocessor and a UART. I talk to this board
> through a serial port which VEE has built in support for - very easy.
> Bill Drago
> L3 Communications - Narda Microwave East
> -----Message d'origine-----
> De: Richard Kleinhenz []
> Date: 15 novembre 2001 09:36
> 1. .vee files are ascii, you can view (and modify, if you're
> careful
> using an ascii editor
> 2. .vxe files are for the runtime environment.  You can
> freely distribute
> Vee runtime, and .vxe files, without any royalty issues.  To
> generate, use
> file - create runtime version.  Documentation in the books,
> of course, and
> under help (content) - installing and distributing Vee runtime
> 3. Don't understand the question
> Richard Kleinhenz
> > -----Original Message-----
> > From: Lancelotduloc []
> > Sent: Thursday, November 15, 2001 8:57 AM
> >
> > I am relatively new to the VEE environment and have a few questions.
> >
> > 1.Can I save my VEE files in an ASCII format?  (I'm using
> VEE Pro 6.0)
> >
> > 2.Can anyone tell me what a .vxe file is and how to go about
> > generating one, or where to find more information about it?
> >
> > 3.Rather than using the boards available for VEE, I will be
> > doing a digital to analog conversion of my own design to output
> > to a device, any suggestions?
> >
> > Diane Donnelly
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