🚀 go-pugleaf

In article <billq.661025394@s.ms.uky.edu> billq@ms.uky.edu (fill in blank) writes:


 I am trying to use my PC(XT)'s paralle port to read the
   8-bits information from the chip.  I have had some luck reading in from the
   OUTPUT lines on the parallel port (i.e. I am breaking some rules ... I guess

Maybe you are braking some rules but I have not noticed that this causes any
damage to hardware. Parallel port (in most PC machines) can withstand
those short circuits.

  But this is not working perfectly yet.  I am using transisitors to drive the
   port (letting the A/D drive the transistors as switches, then use these to

I have used 74LS245 chip to drive those OUTPUT lines succesfully. It has
has worked without any problems. 

   drive the tri-state parallel port).  Its acting like when it see more then 4
   or 5 0 bits, well ... it starts messing up, like maybe its drawing too much
   current or somthing?

There is some kind of current limiting system in the parallel port. I have
measured that the parallel port in my AT can supply about 40mA when short 
circuited tp ground.

   Any body beed doen this road before?
  Any body got a better way of designing
   an A/D ==> pc system?

I have designed an A/D system to PC using ADC0809 A/D converter. It 
uses the parallel port output lines as input for 8 bit data. My system
can make about 22 000 conversions / second, because I have boosted 
ADC0809 by using clock frequency of over 2 MHz. I have used this
circuit for about 1/2 years for sampling audio signals.

I have my information in computer format: text and GIF pictures.
Unfortunately it is not available in any ftp site. It has only been
downloadable in some BBSs here in Finland.
Please e-mail if interrested in getting more information.


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	 d39060t@puukko.hut.fi            Helsinki University of Technology