[fpc-pascal] Parallel Port Access with Free Pascal - windows

James Richters james at productionautomation.net
Fri Jul 22 19:49:36 CEST 2016

I like the looks of that Velleman K8055,  that would do the job for me if I
can get it to work.   I would actually prefer a linux port of my program
however I keep hitting a roadblock when I try to use the graph unit.  My
program used the turbo pascal graph unit exclusively for it's user interface
and I'm trying to avoid re-writing the entire thing.  It works fine in
windows, but when I try to run it on linux I can't get it to compile, it
can't find the graph unit.  I may have some directories set wrong or
something, I'm not sure, but that's what's holding me up on a linux port.

-----Original Message-----
From: fpc-pascal-bounces at lists.freepascal.org
[mailto:fpc-pascal-bounces at lists.freepascal.org] On Behalf Of Mark Morgan
Sent: Friday, July 22, 2016 10:19 AM
To: fpc-pascal at lists.freepascal.org
Subject: Re: [fpc-pascal] Parallel Port Access with Free Pascal - windows

James Richters wrote:
> What I need to do is be able to read some 5v TTL Inputs in and write 
> some 5v TTL outputs out.  The parallel port always worked when my 
> program was a DOS program.. it was so simple, just do Port[$378]:= data to
set the bits on the
> port  or data:=port[$378] to read some bits from the port.   I'm not
> to some hardware other than a parallel port if it will be able to
> with freepascal easily, if anyone can make a recommendation.   Serial
> won't work because they are not made to just read and write bits like 
> the parallel port and they are not TTL voltage levels.

Something like a Velleman K8055, which I've talked to using libusb on Linux.
Or an Arduino with appropriate firmware. Or go the whole hog and port the
program onto a Raspberry Pi: Bo's doing something like you're asking.

Any of those have the advantage that the electronics can be positioned to
minimise the signal run carrying TTL. Long printer cables are generally bad

Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]
fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org

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