Flip Flop madness

G

Glenn Ashmore

Guest
Maybe I am working under a misconception but I have tried everything and
can't seem to get this to work.

The problem I am having is with the 4013. I can get it to work in the basic
bi-stable mode by pulsing CLK and it latches fine until the next pulse but I
want to use SET to bring Q high on stay latched until a RESET from the
counter turns it off. Nothing I try will work. I am delivering a clean
square 200ms pulse and Q stays high only as long as the pulse lasts. Do
set and reset not latch the way CLK does? I have all the inputs on the
second flip flop and CLK and DATA tied to low.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com
 
"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote in message
news:6AyOd.43$BT1.7016@news.uswest.net...

I seem to recall that the 4013 has active high set and
reset inputs. The behavior you describe is what is
supposed to occur when both are driven active at
the same time. Are you sure you have the other
forcing input inactive?

For what its worth, I've seen the 4013 used in a
number of different circuits and it does what the
datasheet claims. So, if my above guess is not
enough to do the trick, perhaps you could post
more details of how you are driving it.
Click to expand...
Figured it out. When all else fails, replace the chip.

Glenn
 
"Glenn Ashmore" <gashmore@cox.net> wrote in message
news:zlxOd.35469$EG1.6296@lakeread04...
Maybe I am working under a misconception but I have tried everything and
can't seem to get this to work.

The problem I am having is with the 4013. I can get it to work in the basic
bi-stable mode by pulsing CLK and it latches fine until the next pulse but I
want to use SET to bring Q high on stay latched until a RESET from the
counter turns it off. Nothing I try will work. I am delivering a clean
square 200ms pulse and Q stays high only as long as the pulse lasts. Do
set and reset not latch the way CLK does? I have all the inputs on the
second flip flop and CLK and DATA tied to low.
Click to expand...
I seem to recall that the 4013 has active high set and
reset inputs. The behavior you describe is what is
supposed to occur when both are driven active at
the same time. Are you sure you have the other
forcing input inactive?

For what its worth, I've seen the 4013 used in a
number of different circuits and it does what the
datasheet claims. So, if my above guess is not
enough to do the trick, perhaps you could post
more details of how you are driving it.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
 
Glenn Ashmore wrote:
Maybe I am working under a misconception but I have tried everything and
can't seem to get this to work.

The problem I am having is with the 4013. I can get it to work in the basic
bi-stable mode by pulsing CLK and it latches fine until the next pulse but I
want to use SET to bring Q high on stay latched until a RESET from the
counter turns it off. Nothing I try will work. I am delivering a clean
square 200ms pulse and Q stays high only as long as the pulse lasts. Do
set and reset not latch the way CLK does? I have all the inputs on the
second flip flop and CLK and DATA tied to low.
Click to expand...
Check the power pins. If the power pin isn't connected, it'll look like
the thing is working because it'll get powered by the pulse. When the
pulse goes away, it'll drop back to ground.

Can you make it flip (or is that flop?) by triggering it manually?

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.
 
On Wed, 9 Feb 2005 18:51:02 -0500, "Glenn Ashmore" <gashmore@cox.net>
wrote:

Maybe I am working under a misconception but I have tried everything and
can't seem to get this to work.

The problem I am having is with the 4013. I can get it to work in the basic
bi-stable mode by pulsing CLK and it latches fine until the next pulse but I
want to use SET to bring Q high on stay latched until a RESET from the
counter turns it off. Nothing I try will work. I am delivering a clean
square 200ms pulse and Q stays high only as long as the pulse lasts. Do
set and reset not latch the way CLK does? I have all the inputs on the
second flip flop and CLK and DATA tied to low.
Click to expand...
I see you've figured it out already. But for what it's worth,
I recall many times where 4013s wouldn't clock properly
on a protoboard, even though the same circuit worked
fine on a PC board. The common "fix" around the lab
was to put a 10K resistor in series with the chip clock
or data line. Nobody could ever determine exactly
what was going on (think we only had 20 MHz scopes
back then), but the assumption was that the protoboard
inter-hole capacitance was causing mischief somewhere.
The typical circuits were not at high clock rates, probably
all under 100 kHz, and the problems existed even when
we slowed the clock way down. 4013s with 10K resistors
got to be a joke around the lab. Never seemed to have
these problems with anything else.

Best regards,




Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
 
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