Using lpt1 in Windows
dsc at swcp.com
Wed Oct 18 18:10:07 CDT 2006
On Oct 18, 2006, at 1:00 AM, Paul Williams wrote:
> I am developing some educational software that uses a sensor that
> into the parallel port. I need to be able to read and set the state
> of the i/o
> pins on that port. I have tried using read/write to file lpt1
> without any
> success, can anyone point in the right direction with a snippet of
If the sensor needs arbitrary wiggling or reading of the handshake
lines, then you will need a special driver. There are a few out
there, but most would need an external wrapper. Long ago I saw a
driver that converted LPT bit twiddling and sensing to something that
was virtually a serial driver. That should work great. Look for
parallel port drivers online.
If you just need the 8 output I/O lines and the sensor provides the
handshake (or at least ties busy and paper error to the ground) you
should be able to open that and at minimum write to it. I'm pretty
sure I have in the distant past. I forgot the name to use. Try
"lpt:", "lpt1:", "\\.\lpt", and "\\.\lpt1" and the like. You might
have to use the BIOS to set the mode for the device. Sometimes you
have to set the mode to classic and that will limit you to output only.
If that does not work try something like shell("type fileWithMyByte >
lpt") for output only.
If you bought the sensor, the manufacturer might have much better
info or hobby groups might.
You will want to get parallel port monitor software or a parallel
port utility to confirm what you are doing and to check out the
sensor directly. Look for those online, too.
You might want to get some hardware to monitor the lines. The serial
line gadgets will probably not work.
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