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How prevalent is open collector outputs (with no internal pull-up
resistors) on the data pins?
resistors) on the data pins?
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How prevalent is open collector outputs (with no internal pull-up
resistors) on the data pins?
Have not seen it anywhere on the port connector pins..
"Normally the Printer Card will have internal pull-up resistors, butHave not seen it anywhere on the port connector pins..
The Centronics Printer Port and the IEEE-1284 interface that replacedHow prevalent is open collector outputs (with no internal pull-up
resistors) on the data pins?
dunno. I thought most had 10K or so pull up.How prevalent is open collector outputs (with no internal pull-up
resistors) on the data pins?
Yes, I read that too. Long story short.....If you were designing aThe Centronics Printer Port and the IEEE-1284 interface that
replaced it both used open collector ICs at the source
Most do hence the dilemma. Should one go to the extra expense (andI thought most had 10K or so pull up
It's more than just a common value being used. This is the equation toThe Centronics Printer Port and the IEEE-1284 interface that
replaced it both used open collector ICs at the source
Yes, I read that too. Long story short.....If you were designing a
device that had to interface with the PP, would you go to the extra
expense of including pull-up resistors on each data line, bearing in
mind that only very few OC variants exist these days? And if you do,
what pull-up value would you choose, bearing in mind that it would be
in parallel with the value chosen in most PPs out there today and it
would be on its own with OC variants? 10K? 4.7K?
The best I've seen in terms of advice is not to go below 4.7K but if
4.7K **or lower** is already being used in the device....Hmmmm. You
see what I'm getting at....Leaving well enough alone with no extra
pull-ups added and not catering to the few OC variants may be the
better waty to go.
BTW, just about every PP link can be found on this page (look for PP
section);
http://www.epanorama.net/links/pc_interface.html#parallel
On Dec 12, 11:57 pm, "www.interfacebus.com"
Interfacebus.Engin...@gmail.com> wrote:- Hide quoted text -
- Show quoted text -
You don't know what is used in the PP circuit. You will be usingIt's more than just a common value being used. This is the equation
to calculate pull-up values.
risk? use a part with internal pullupI thought most had 10K or so pull up
Most do hence the dilemma. Should one go to the extra expense (and
possible risk) catering to the few that don't.
True, that was a poorly designed standard [or no standard]. So I wouldIt's more than just a common value being used. This is the equation
to calculate pull-up values.
You don't know what is used in the PP circuit. You will be using
external pull-up resistors in most cases where they are not even
required.
On Dec 13, 3:23 pm, "www.interfacebus.com"
Interfacebus.Engin...@gmail.com> wrote:- Hide quoted text -
- Show quoted text -