Parallel port control register problem

[zack]

Hi,
I need some advice and help. I have successfully done a parallel port
interface circuit that consists of diodes and resistors. The LEDs
represent the bits of CONTROL and DATA registers. everything else works
fine except when i put values to the CONTROL registers. when i put `0'
or `1' to any of the CONTROL register pins, all DATA LEDs will be on
(but dimmer). checking back the DATA register value, it retains the
previous value; didn't change to 255. I had to restart the program to
reset the LEDs.
i'm currently using Windows 2000, Visual C++ 6.0 on a Xeon platform. I
don't think this is software issue, because I have tested the software
and the circuit on a Pentium 3 platform. Does anyone have any opinion?
Thank you very much.

 

[Si Ballenger]

Hi,
I need some advice and help. I have successfully done a parallel port
interface circuit that consists of diodes and resistors. The LEDs
represent the bits of CONTROL and DATA registers. everything else works
fine except when i put values to the CONTROL registers. when i put `0'
or `1' to any of the CONTROL register pins, all DATA LEDs will be on
(but dimmer). checking back the DATA register value, it retains the
previous value; didn't change to 255. I had to restart the program to
reset the LEDs.
i'm currently using Windows 2000, Visual C++ 6.0 on a Xeon platform. I
don't think this is software issue, because I have tested the software
and the circuit on a Pentium 3 platform. Does anyone have any opinion?
Thank you very much.

Sounds like a software problem, as it fixes itself when you
restart the program. Hardware usually "works the way it's wired"
and doesn't change on its own.

 

[Donald]

Sounds like a software problem, as it fixes itself when you
restart the program. Hardware usually "works the way it's wired"
and doesn't change on its own.

That is correct, hardware will work the way its wired.

Zack, check your wiring and post a schematic of the actual board.

donald

 

[The Real Andy]

That is correct, hardware will work the way its wired.

Zack, check your wiring and post a schematic of the actual board.

donald

IF you are using win2000 i dont think you can write directly to the
hardware. How are you doing this? Are you using DeviceIOControl() to
write to the port?

 

[zack]

finally i managed to get it done. it was not because of wiring or
hardware issues. i went to -> right click `My Computer' -> click
`Properties' -> `Hardware' tab -> click `Device Manager'. from there i
clicked `Ports' -> double click `Printer Ports'
there'll be a new window displaying the printer's properties. On `Ports
Settings' tab i enabled `Enabled legacy Plug N Play detection' and the
problem solved.
I'm using Inpout32.dll library for Windows 2000