Parallel port electronics

[Simon Lemieux]

Hi there,
I'm a newbie in electronics and I would like to learn by making a
logic transistor board from the parallel port output so that by giving
a different output, I could read a specific input, or send a specific
impulse. Anyway...

I was wondering if anybody had a more detailed tuturial on using the
parallel port with electronics (not speaking about the internal stuff
in the computer, really just the electronic part).

I already found this one:
http://www.tldp.org/HOWTO/IO-Port-Programming-6.html

Which gives some information but not too much, maybe there is another
document somewhere I could read.

Thanks for any info,
Simon

 

[Ed]

"Simon Lemieux" <xilopublic1@ca.inter.net> wrote in message
news:eb4b2c87.0407131932.5858cdb4@posting.google.com...

Hi there,
I'm a newbie in electronics and I would like to learn by making a
logic transistor board from the parallel port output so that by giving
a different output, I could read a specific input, or send a specific
impulse. Anyway...

I was wondering if anybody had a more detailed tuturial on using the
parallel port with electronics (not speaking about the internal stuff
in the computer, really just the electronic part).

I already found this one:
http://www.tldp.org/HOWTO/IO-Port-Programming-6.html

Which gives some information but not too much, maybe there is another
document somewhere I could read.

Thanks for any info,
Simon

Hi Simon,

I once connected an IDE harddrive to the parallel port of a PC. To do it I
just used 74HC374 latches. Do a search in google for +"parallel port"
+74hc374 and your get plenty of results. If you want to program it from
Windows NT or Win2K then your need a special DLL to access the parallel
port. I used WinIO, but plenty are available.

Hope that helps,

 

[Simon Lemieux]

I once connected an IDE harddrive to the parallel port of a PC. To do it I
just used 74HC374 latches. Do a search in google for +"parallel port"
+74hc374 and your get plenty of results. If you want to program it from
Windows NT or Win2K then your need a special DLL to access the parallel
port. I used WinIO, but plenty are available.

Wow, well, I certainly wouldn't want to connect any electrics to an
IDE cable, I just wonder how I would access it later. But I did check
google and found more information than I needed, thank you very much!

BTW, the nice thing about the parallel port and electronics is that
you get 12 output signals and 5 input signals, and with a USB/parallel
adapter, you can have up to (well, on my own computer) 3 parallel
ports! Which is more than needed!

Thanks a lot,
Simon

 

[Bart T.]

BTW, the nice thing about the parallel port and electronics is that
you get 12 output signals and 5 input signals, and with a USB/parallel
adapter, you can have up to (well, on my own computer) 3 parallel
ports! Which is more than needed!

I thought all modern parallel ports (> 1995) are bi-directional thus
making the 8 data pins also usable as inputs. Or is it not that
simple? Maybe this explains the problems I've been having with reading
74HC outputs from one of the data pins while using the other data pins
to write data to the chips?

 

[Chris]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Bart T. wrote:

I thought all modern parallel ports (> 1995) are bi-directional thus
making the 8 data pins also usable as inputs. Or is it not that
simple? Maybe this explains the problems I've been having with
reading 74HC outputs from one of the data pins while using the other
data pins to write data to the chips?

Hi,
Ouch, that's a bad idea (writing to some pins and reading back on
others). The parallel port *is* bidirectional, but it's either *all
output* or *all input* ("all" meaning the 8 data lines plus the
strobe line). The computer software must control which direction the
port operates in (it usually stays in output mode unless explicitly
changed). You certainly won't be able to use some pins as outputs and
some as inputs at the same time! I hate to think what would have
happened if your parallel port didn't have the current limiting
device it obviously does (connect two output pins together...).

If you want a bit of input with mostly output, use the appropriate
input pins (the control pins) and keep the main part of the port in
output mode. If you need 8-bit transmission in both directions but
only one at a time, using some kind of protocol, use bidirectional
(but check your protocol carefully to make sure you *won't* be
connecting two outputs together at any time!). You may end up wanting
to use a microcontroller for handshaking if you need bidirectional
operation.

Chris
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (GNU/Linux)

iD8DBQFA/tzknwjA8LryK2IRAjA8AKDGijP8Yt7ewG87pxT0k+2KWmXpwgCgrnjj
1OpK6PilSTPgvfNv3An23Yw=
=j0aH
-----END PGP SIGNATURE-----

 

[Bart T.]

Chris <chris2k01@hotmail.com> wrote in message news:<%0BLc.81655$Rf.29231@edtnps84>...

If you want a bit of input with mostly output, use the appropriate
input pins (the control pins) and keep the main part of the port in
output mode.

I've since switched to using a status pin for input and it sort of
works, but there's still an electrical issue I can't solve. For some
reason, making a direct connection between an output pin (on the
74HC165) and the parallel port causes some problems with the 74HC165
internally (data is corrupted -- only consecutive strings of 1's are
properly read.)

I made a post to sci.electronics detailing this problem, here's a
Google link:

http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&threadm=AoLLc.48056%24qK.18571%40amsnews02.chello.com&prev=/groups%3Fq%3Dsci.electronics%26ie%3DUTF-8%26hl%3Den%26btnG%3DGoogle%2BSearch

Thanks for the help.