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Author Topic: Pins 2-9 as Inputs  (Read 4197 times)

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Pins 2-9 as Inputs
« on: November 20, 2007, 10:29:24 AM »
Just curious as to why one cannot change pins 2-9 to INPUTS on Port 1.

Am I correct.........
     Port 1=                                         5 inputs
     Port 2 = 5 inputs + 2-9 as inputs = 13 inputs
                                  Total              28   
Thanks       



Offline Chaoticone

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Re: Pins 2-9 as Inputs
« Reply #1 on: November 21, 2007, 06:37:56 AM »
You are correct, or at least very close. I don't have Mach on this machine so I can't double check it right now. My guess to the question is this. Why would you need inputs if you had no outputs?

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!

Offline jimpinder

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Re: Pins 2-9 as Inputs
« Reply #2 on: November 21, 2007, 10:46:55 AM »
The LPT1 port on a PC (the printer port)  is actually three addresses on the computer. Two of these are outputs ONLY and one address is an input ONLY. They cannot be changed.

If you add a second port it is actually just  another connection to the computer at a differebt address. It all depends on the way the port has been built. If it is built like the original printer ports, it will also have two addresses as outputs and one  address as inputs. If it is built as a general purpose port, then you will be able to input or output on all the lines.

Check the spec before you buy !!!

Jim
Not me driving the engine - I'm better looking.
Re: Pins 2-9 as Inputs
« Reply #3 on: November 21, 2007, 03:42:01 PM »
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=260176038135&ssPageName=STRK:MEWA:IT&ih=016

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=290179106057&ssPageName=STRK:MEWA:IT&ih=019

Brett......GOOD Point.

Hello Jim,
   Above are 2 that will fit but I am not sure of the specs.
Would you mind to take a peek at them and let me know if you think either or both would work for me.
I would be much appreciative,
Thanks   :-\

PS: I checked with Rogers Machine, he does not have the low profile cards. But thanks for the link.
« Last Edit: November 21, 2007, 04:08:52 PM by Overloaded »

Offline klmark

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Re: Pins 2-9 as Inputs
« Reply #4 on: November 21, 2007, 04:14:43 PM »
Hi Overloaded
If I am right you are looking for a 2 port card Have a look at that web site  http://www.candcnc.com/QuickPicker2.htm this is where I got my from and they work really good for $20.00 a peace or gave them a call                      klmark














Re: Pins 2-9 as Inputs
« Reply #5 on: November 21, 2007, 04:49:34 PM »
klmark,
I did not see what I need in the product list so I sent them an inquiry.
Thanks for the link.

Offline jimpinder

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Re: Pins 2-9 as Inputs
« Reply #6 on: November 29, 2007, 11:34:55 AM »
The second card seemed to be the better one, and came with drivers - but I think you are doing the best thing !!!  If you know what you want enquire from the manufacturer and see if they will do what you want.

Jim
Not me driving the engine - I'm better looking.
Re: Pins 2-9 as Inputs
« Reply #7 on: November 29, 2007, 12:13:45 PM »
Thanks Jim,
I ended up buying a low profile card with a std. bracket.
After a little "hacking" on the bracket, it seems to be working just fine.
I may change PC's soon anyway. This one has only 1 PCI slot. No modem now.
It does have 8 USB ports though.

Thanks again.

Offline TonyP

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Re: Pins 2-9 as Inputs
« Reply #8 on: November 29, 2007, 03:25:54 PM »
Just a cautionary note. Some older ports may not be fully capable of switching to inputs. I have been designing a new breakout board, which will use LPT2 as mainly inputs, and found that the built-in port (which had been LPT1) could be made to take inputs, but the output drivers were not disabled. This caused a current of about 40ma to flow through any switch attached to the input. Not a problem for switches but a problem for the port itself. It was also not really practical to drive them with logic. In the end I've had to specify that it must be used with  a modern ECP/EPP card.
There is some good info on the web on parallel ports which describes the different cicuits used and problems associated with them. Can't point to it at the moment, but I think I just did a search for parallel port interfacing.

Tony
Re: Pins 2-9 as Inputs
« Reply #9 on: November 29, 2007, 04:17:25 PM »
Hey.. thanks Tony,
  I'll read up a bit on the subject. I NEED to. Most of what I read on the package comes across as "unintelligible hieroglyphics" to me.  ::)
But it DOES say...... SPP/EPP/ECP Mode