RE: First release of Port IO library for Windows 9x/ME/NT/2000/XP/2003

[Rolf K. <rol...@ci...>]

Jim Kring [mailto:ji...@ji...] wrote:

> I downloaded and tested on my WinXP laptop, but I couldn't=20
> get it to work.
> My laptop doesn't have a parallel port, which might be the problem (no
> hardware at 0x378).  When I run the test VI, regardless of=20
> what I set the
> "write value" to, the "written value" (read value) is always 255.

Well 255 is the inactive state of the databus as it is terminated
with pullup resistors in all modern systems. Not really sure what
other addresses would be save. I completely crashed my system the
first time I wrote into the first few address at 0x0 by accident ;-)

One possibility might be to test the port at 0x42 which should be
the counter for the beeper. I included a beeper example which might
be useful as test/example utility for people to see that the
routines actually work at all ;-)

But I'm sure there are soon computers out there which do not have
this speaker anymore! The hardware will probably remain as it is
nowadays all integrated in the chipsets but the speaker may have
to go to save another 5 cent in production costs in some computers.

> I'll see if I can get some other folks to do some further testing.
> It might be nice to do some speed benchmarks in a real-world=20
> application.  I know someone with a Parallel Port I2C/SPI driver
> board. The device driver for the board currently uses NI's PortIO
> driver. A speed boost would be really useful for this person's
> application since chip test folks always want to do things *faster* =
:-) =20

Well, I was thinking that with a little change I may squezze out
another few ns ;-). No honestly this is about as fast as it gets
and it is a real hack as it effectively circumvents all the protection
the Windows NT kernel puts up to prevent an application from trashing
the system or even possibiliy gaining access to resources usually
protected by passwords and such.
But hey there are people who want this and I'm not going to prevent
other people from shooting in their own foot ;-)=20
On Linux there is also a similar possible hack I have investigated,
but to be honest I am reluctant to try to do that there. It just
goes around any and all protection built into the kernel by requiring
a user to have root privileges to do certain stuff.

> Also, I'll volunteer to create an MNU file for this package=20
> so that we can integrate it into the palettes.

Well thanks I just looked at teh OpenG installer you sent me. Nice.

Rolf Kalbermatter
CIT Engineering Nederland BV    tel: +31 (070) 415 9190
Treubstraat 7H                  fax: +31 (070) 415 9191
2288 EG Rijswijk	http://www.citengineering.com
Netherlands		mailto:rol...@ci...
=20