parallel port input

[Brandon Cernicky]

Leh,

By default, E-Prime is directed to work best when a
parallel port is in standard mode (also known as AT or
Output only).  This allows for 8 output bits on the
DATA register (pins 2-9) and 5 input bits on the
STATUS register (pins 10-13, 15).

First, make sure that the external device is
connecting to one of the ground pins (18-25) and that
the device is using a true TTL signal to set the 1/0
states.

It is possible that on the machines where you are
having trouble, the parallel port mode is configured
for the newer Bi-Directional, ECP, or EPP modes where
the pins control different behaviors.  You can
determine what the parallel port mode is and configure
it through the system BIOS.

Although the parallel port hardware key is designed to
be a pass-through device, you may find difficulty in
getting communications to work when connecting devices
to the hardware key.  I would encourage you to
temporarily not use the parallel key while debugging
to ensure proper communications.  PST does offer a USB
version of the hardware key.

If you continue to have troubles, you may want to
contact PST web support and ask them for a set of
script routines they have that can configure the
parallel port to work in Bi-Directional mode, which
would allow you to read and write to the DATA register
and have all eight bits of input and output (but not
at the exact same time of course).  Going through the
DATA register also allows for no bits being inverted.
The pre-canned script does all of the technical work
and all that is needed in the experiment is an InLine
with "ConfigurePortForRead" call to setup the port.

-Brandon

~~~~~~~~~~~~~~~~~~~~~~~~
Brandon S. Cernicky
Senior Software Engineer
Psychology Software Tools

> Hi all,
>
> I'm trying to collect input from an external device
connected through the
> parallel port via pins 15, 13, 12 and 10.
>
> I have defined my port device as below:
> address: 889
> size: 8
> invert: No
> mask: -1
>
> This worked on some computers but on some computers,
I can only read from
> pins 15 and 10 which gave me the hexadecimal outputs
of 4 and 7, respectively.
>
> Strangely enough, on those computers that can only
read from pins 15 and
> 10, when the parallel port device is connected
through the EPrime parallel
> key (for single licenses), pin 12 worked as well,
but I still can't read
> from pin 13.
>
> I hope someone could provide me with some insights
as to what is happening.
>
> Thanks much!
>
> Regards,
> Leh Woon



		
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