Newsgroups: comp.robotics
From: ANDREW@labman.demon.co.uk (ANDREW WHITWELL)
Path: brunix!sgiblab!swrinde!pipex!demon!labman.demon.co.uk!ANDREW
Subject: C and the printer port?
Organization: Labman Automation Ltd, Stokesley, TS9 5JY. UK.
Reply-To: ANDREW@labman.demon.co.uk
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Date: Thu, 21 Jul 1994 12:08:39 +0000
Message-ID: <774792519snz@labman.demon.co.uk>
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If you want to control stepper(s) motors from the parallel port then I can
tell you now that it is very easy - we have built an 'interface' card
that goes between the port and the stepper motors and has 16 outputs and 
16 inputs (soon to be 64 of each !).

The question of running the motors at a useful speed (usually fast) seems
to make everyone start diving into C and assembly language - WHY ?

The software for our stepper controller was written in POWERBASIC 3.0 and
whilst being very easy to write (you can't get much simpler than BASIC) 
it was also very fast. After converting the same code into C and PASCAL
there was no massive difference in speed - even on a slowish 286 running
four stepper motors we had to slow the program down - not try to get it to
go faster !. The average fast running speed is about 4000 steps/second !

Some people may think this is a load of rubbish or think that I am talking
a load of rubbish and if this is the case then can anyone show me a routine
written in C or assembly language that is EASY to use and understand. I am
no software engineer but using C or assembly language to try and develop
software for the first time (especially for a beginner) is very time
consuming.

The card we use now has not been used to it's full potential, at the moment
we are using it to control a 4-axis robot - it's other uses are wide and
varied when it comes to using stepper motors to move things about.



-- 
MARK
LABMAN AUTOMATION LTD.
