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From: Alasdair MacLean <alasdair@aifh.ed.ac.uk>
Subject: Re: bidirectional parallel port
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Date: Wed, 15 Mar 1995 14:13:30 GMT
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Xref: glinda.oz.cs.cmu.edu sci.electronics:123793 comp.robotics:18917

 
>  
>   
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>      Subject: Re: bidirectional parallel port 
>         Date: Tue, 14 Mar 1995 15:27:18 GMT 
>         From: marjakan@efa.cc.lut.fi (Erkka Marjakangas) 
> Organization: Lappeenranta University of Technology, Finland 
>   Newsgroups: sci.electronics, comp.robotics 
>   References: 1 
>  
>       
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>  
> jmh@vttoulu.tko.vtt.fi (Jorg-Michael Hasemann) writes: 
>  
> >Hello, 
> >I would like to get some information about the (bidirectional) 
> >parallel port. I know that the standard printer port is uni- 
> >directional only. However, newer printer port more and more 
> >often support bidirectional modes, i.e. writing *and* reading 
> >from pins D(0)-D(7). 
> Hmm, I never knew that. All the printer ports I've bumped to   
have been 
> bidirectional. 
>  
> >My question is now, how to test whether my printer card   
supports 
> >a bidirectional printer port (e.g. PS/2 mode printer port) and 
> >how to actually read data from the printer port. 
> If you don't have specs or tech.ref. manuals there's no way to   
test. 
> Bidirectional ports quite surely have a register to indicate   
the direction 
> of each data pin. If you don't know the registers address, it's   
no use 
> testing more. Well, you could reassemble the device driver, and   
check how 
> it is implemented, it might come up with something, but it's   
probably 
> waste of time 
>  
> >I also would love to get information about the electrical   
charac- 
> >teristics of the bidirectional printer port. 
> Check for MC68230. It is described in almost all of the books   
about 
> Motorola 68000 chip that I have seen. 
> If you or your friend owns Amiga HArdware Reference manual, it   
describes 
> very thoroughly the bidirectional transfer between computer and   
peripheral. 
>  
> -- 
> Erkka Marjakangas, Mustolankatu 42, 53420 LPR, FINLAND  | If   
impossible was 
> Amiga2000+A3001+4MB+80MB   <-  PARNET  ->  A1200+120MB  |   
impossible, you 
> marjakan@cc.lut.fi  [* PGP key available at request *]  | would   
not be 
> WWW:  <A HREF="http://www.lut.fi/~marjakan">HomePage</A>|   
reading this! 
>  
>   
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>  
 
It IS possible to test your parallel port. Grab the file   
para13.zip from one of Simtel mirrors in the io_util subdirectory   
and that will tell you what you want to know. 
--  
 
						-Alasdair 
		 
[ The opinions expressed are my own and are therefore undeniably   
correct beyond a shadow of a doubt. ] 
		 
Alasdair MacLean, University of Edinburgh, Dept. of Artificial 
Intelligence, 5 Forrest Hill, Edinburgh, EH1 2QL 
tel. (+44) 0131 650 4497	fax. 0131-650-6899 
email alasdair@aifh.ed.ac.uk 
<URL:http://www.dai.ed.ac.uk/staff/personal_pages/alasdair/index.  
html> 


