Re: Need help with parallel port input design-follow up question

Jeff,
Not a 14069, the 4069. One of these :
http://www.fairchildsemi.com/ds/CD/CD4069UBC.pdf
Those are the very chips I make by day.

PC 5 volt supply is probably more than enough to get this to fly.

I would avoid caps on the output of the 4069, but it is common and
safe to put caps across VCC and ground (or VDD and VSS). 0.1u
is usually enough, if you got 1u it's lots more safety. Still
talking pennies for these parts.

-d

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "washcomp" <jeff@w...> wrote:
> Lloyd:
>
> I'm nearly clueless on this stuff. Am I right in assuming that a
> Motorola MC14069UB is the same as the 4069 you refered to? (It's
> what Google found). If so, am I right in assuming that VDD should
be
> set at 5 volts and VSS as ground? Can I use the PC 5 volt supply?
> (otherwise, I've got to figure out how to use the Vregulator,
> probably no big deal though). Does the 10K resistor pack go to
> ground? And if so, from the input side or the output side? The
> diagram on the spec sheet also shows a capacitor on the output side
> to ground. Is this required (and if so, what's a good value)?
Sorry
> to sound so lame, but haven't done this before.
>
> Regards,
> Jeff
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Lloyd Leung" <lloyd@l...>
> wrote:
> > Jeff,
> >
> > I think an opto-isolator is overkill. I would suggest using a
7404
> or 4069
> > hex inverter, to accomplish the same thing. Both are very cheap.
> Download
> > the PDF (google, "7404 pdf" or "4069 pdf") and see what pins are
> what.
> > You'll figure it out.
> >
> > Use a 7805 voltage regulator to get the power from the 12V source
> down to 5V
> > as well. And to clean up the power, place a 10uF cap across the
> output and
> > ground after the 7805.
> >
> > A resistor network of 10k ohm will help pull up the current to 5V
> as well.
> >
> > Depending on how quickly you want this board, I would recommend
Dean
> > Coullard's break out board. It's well made and clean, and simple.
> > http://members.shaw.ca/axxus/db1v20.htm . I asked him last week,
> he was out
> > of stock, but will be getting some in soon.
> >
> >
> > I bought one, and am very happy with it. It made things a lot
> easier to
> > wire up.
> >
> >
> > Cheers.
> > Lloyd,
> > Toronto
> >
> >
> >
> > -----Original Message-----
> > From: washcomp [mailto:jeff@w...]
> > Sent: September 15, 2003 4:50 PM
> > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > Subject: Need help with parallel port input design
> >
> > I'd like to provide opto-isolation to the 5(?) input pins on a
> > parallel port used to monitor limit switches. I understand that
> I'll
> > also have to provide some resistors? What's the easiest way to do
> > this? I looked at the Digikey catalog and they offer about 4
> million
> > opto-isolators of all types, but I'm kinda clueless about which to
> > use or an actual circuit to make use of the right one. Any help
> > would be appreciated. I've bought an 8 port parallel relay board
> and
> > figure I can retrofit this to the input pins (they are currently
> not
> > connected on the relay board, but it has a 12v DC supply built on)
.
> >
> > Thanks and regards,
> > Jeff