Wade Carpenter wrote:

> > > Here's where I noticed that I'm not able to get it to work properly.  I
> > > tried to connect the port to a 74LS05 (Inverter) and the output and
> inputs
> > > to this chip are something like 1.3V. Total garbage.  Regardless of the
> > > port's state.  I do believe that the software I'm using to toggle all of
> > the
> > > outputs on the port is correct.


Hi Wade, I often use the parallel port
for quick and nasty PC interfacing. :o)

Have you connected the 0v (gnd) of your
logic chip to the main ground pins in the par
port? Did you connect all the ground pins
in the par port together? Make sure you do
both of these.

The par port should be outputting standard
type logic levels, about 0.6v for low and
3.5v to 4.2v for high.

If you connect to the INPUTS in the par port,
these normally have a fairly strong pullup
resistor attached and you will need a very
low series resistor, any values over 180 ohms
will fail to pull the par port inputs low
enough, 120 ohms is a good value.

For the par port OUTPUTS just use a 1k or 2k2
resistor between the par port output and your
logic chip input.

Also check your PC bios settings, even old
286/386 usually have EPP capability, just they
are normally set to "standard" in the bios.

Hope that helps. Maybe you should show your
circuit??
:o)
-Roman

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