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'Newbie Counter Question *non pic related*'
1998\03\18@195910 by IDJ Sparkz

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Hi..

*I have a non PIC related question. *

For class project.. I had to build a simple modified binary up/down counter
from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds
simple huh? Well I'm new to digital) Now being so fascinated by how that
works.. and for extra credit, I have to come up with with a way to make the
counter count from 0 to 10, then from 10 back to 0 and keep cycling and I have
only the following to use:

74193 binary counter
and/or/nand/nor gates
j-k flip flops

If someone could kindly steer me in the right direction, I'd really appreciate
it.


- tony

1998\03\18@222644 by TONY NIXON 54964

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picon face
I'm sure there are lots of people on this list, including myself, who
are willing to help with your problem, but I often wonder, who
deserves the 'extra credit' ;-)

Anyway. I haven't tested this but it may help you out.

To detect a zero count, connect 2 OR gates to 193 Qa, Qb, Qc, Qd. The
outputs from these gates is connected to a NOR gate. This then gives
a logic 1 when a count of 0 is reached.

To detect a 10 count, connect an AND gate to 193 Qb and Qd. When a count
of 10 is reached a logic 1 is produced.

The output from the NOR gate and the AND gate are connected to
another OR gate and the output from this gate is connected to the
Clk input to a JK Flip Flop. The J input is tied Hi, and the K input
is tied low to toggle the FF output on positive clock pulses.

The FF Q output is connected to The Up pin on the 193.
The FF Q bar output is connected to the Dn pin on the 193.

Thus when a count of 0 or a count of 10 is reached the JK FF will
toggle and change the count state on the 193.

I just thought of this off the top of my head, so you may need to
experiment a bit. The JK FF has some extra inputs for you to connect,
but these are explained in the data sheet, and don't forget about
leaving unused gate inputs floating. Thats a no no, although TTL will
pull high if left disconnected.

Tony

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1998\03\18@222644 by TONY NIXON 54964

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picon face
I'm sure there are lots of people on this list, including myself, who
are willing to help with your problem, but I often wonder, who
deserves the 'extra credit' ;-)

Anyway. I haven't tested this but it may help you out.

To detect a zero count, connect 2 OR gates to 193 Qa, Qb, Qc, Qd. The
outputs from these gates is connected to a NOR gate. This then gives
a logic 1 when a count of 0 is reached.

To detect a 10 count, connect an AND gate to 193 Qb and Qd. When a count
of 10 is reached a logic 1 is produced.

The output from the NOR gate and the AND gate are connected to
another OR gate and the output from this gate is connected to the
Clk input to a JK Flip Flop. The J input is tied Hi, and the K input
is tied low to toggle the FF output on positive clock pulses.

The FF Q output is connected to The Up pin on the 193.
The FF Q bar output is connected to the Dn pin on the 193.

Thus when a count of 0 or a count of 10 is reached the JK FF will
toggle and change the count state on the 193.

I just thought of this off the top of my head, so you may need to
experiment a bit. The JK FF has some extra inputs for you to connect,
but these are explained in the data sheet, and don't forget about
leaving unused gate inputs floating. Thats a no no, although TTL will
pull high if left disconnected.

Tony

PicNPoke Multimedia 16F84 Beginners PIC Tools.

PicNPoke - PicNPlay - PicNPlan - PicNPrep - PicNPost
PicNPort - Plus DT type saver.
New addition - PicNQuiz.

http://www.dontronics.com/picnpoke.html

1998\03\19@070509 by Morgan Olsson

picon face
At 18:57 1998-03-18 EST, you wrote:
>Hi..
>
>*I have a non PIC related question. *
>
>For class project.. I had to build a simple modified binary up/down counter
>from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds
>simple huh? Well I'm new to digital) Now being so fascinated by how that
>works.. and for extra credit, I have to come up with with a way to make the
>counter count from 0 to 10, then from 10 back to 0 and keep cycling and I
have
>only the following to use:
>
>74193 binary counter
>and/or/nand/nor gates
>j-k flip flops
>
>If someone could kindly steer me in the right direction, I'd really
appreciate
>it.
>
>
>- tony

Use a PIC and write "74193" on top of it!    ;)

Wel:, dont cheat, work on further with open mind.

/Morgan
/  Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \
\  spam_OUTmrtTakeThisOuTspaminame.com, ph: +46 (0)414 70741; fax +46 (0)414 70331    /

1998\03\19@070509 by Morgan Olsson

picon face
At 18:57 1998-03-18 EST, you wrote:
>Hi..
>
>*I have a non PIC related question. *
>
>For class project.. I had to build a simple modified binary up/down counter
>from a 74193 IC that counts from 0 to 10 and repeats. (Yea I know it sounds
>simple huh? Well I'm new to digital) Now being so fascinated by how that
>works.. and for extra credit, I have to come up with with a way to make the
>counter count from 0 to 10, then from 10 back to 0 and keep cycling and I
have
>only the following to use:
>
>74193 binary counter
>and/or/nand/nor gates
>j-k flip flops
>
>If someone could kindly steer me in the right direction, I'd really
appreciate
>it.
>
>
>- tony

Use a PIC and write "74193" on top of it!    ;)

Wel:, dont cheat, work on further with open mind.

/Morgan
/  Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \
\  .....mrtKILLspamspam@spam@iname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331    /

1998\03\19@110305 by Jorge Ferreira

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face
       Well Tony


       I didn't understand one thing, do you want it to count 0,1,...,10,0,1 or
up and down 0,1,...,9,10,9,8,...1,0,1,2,... and so on. Or do you nedd both.

       If you want to count up continues ...9,10,0,1,.. you just have to detect
10 and them (using AND gates again) direct 1 clock pulse to the MR pin
instead of the clock up.
       The switching of the clock bettwen clock up and MR can be obtained just
combining logic gates, you dont even need a F/F. But if you want it to be
synchronus (less sensitive to noise and to propagation delays) you can set
up a F/F with the J/K inputs activated by the detection logic and clocked
in the oposite fase of the counter clock.

       In the other option, you have to do is to detect when it as reached 10.
In
that situation you switch the clock pulse to de oposite direction (the chip
as separate up and down clocks), them when it reaches 0 you switch again.
       The switching is obtained using two AND gates to control the clock and o
ne
F/F to select the state UP or DOWN. You conect the J to 0 detection circuit
and the K to 10 detection circuit and clock in opposite fase to the counter.

       The clocking of the F/Fs in oposite fase is to make sure that they switc
h
state in bettwen counting clocks. As the counter clock are positive logic
(rising edge) you make sure the F/Fs have negative logic clocks or else
feed them with an inverted clock.


       Hope theis helps.

       Best of luck

       Jorge F

PS: I'm not in favour of doing someone elses school works, because that
someone else becomes the looser of the tale. But I don't mind giving some
directions and warning for possible pitfals.


At 08:47 98.03.19 +0100, you wrote:
{Quote hidden}

===============================================================
cumprimentos / best regards
     Jorge Ferreira          //.....jorgegfKILLspamspam.....mail.telepac.pt
------ Make sure brain is in gear before engaging mouth -------
===============================================================

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