All About Circuits Forum Convert a D flip flop into JK
 User Name Remember Me? Password
 Register Blogs FAQ Members List Today's Posts Search Today's Posts Mark Forums Read

 Homework Help Stuck on a textbook question or coursework? Cramming for a test and need help understanding something? Post your questions and attempts here and let others help.

#1
11-19-2010, 05:28 AM
 wind_blast942 Junior Member Join Date: Sep 2010 Posts: 22
Convert a D flip flop into JK

I am confused on how to systematically convert a D flip flop into a JK flip flop
J K Q Q+ D
0 0 0 0
0 0 1 1
0 1 0 0
0 1 1 0
1 0 0 1
1 0 1 1
1 1 0 1
1 1 1 0

I am able to merge the characteristic and excitation table together, but since there are some values where Q to Q+ changes from 1 to 0, and there is no excitation
possible for a d flip flop to effect this change.

In this case what should i do?
#2
11-19-2010, 08:27 AM
 Georacer Super Moderator Join Date: Nov 2009 Location: Athens, Greece (GMT +2) Posts: 4,875

A FF is always excited by its input. As long as the clock is pulsing it will change its state according to the J K and Q (or D and Q) data.

What you need to do is extract the Boolean function Q+=F(J,K,Q) and drive its output in the D input of your FF. Since a D FF will drive its next state where its D input is, you will be able to control the FF by changing that input.
__________________
.
I am a prisoner of high standards and low social skills
____________________________________

I wish I was the best at what I would do, and what I would do wouldn't be pretty.
#3
11-19-2010, 08:53 AM
 wind_blast942 Junior Member Join Date: Sep 2010 Posts: 22

By solving Q+ = f(J,K,Q), i get J AND (NOT Q); so does it mean i connect this expression into the D ff?

But in this case wouldn't K not affect the flip flop at all?

#4
11-19-2010, 11:36 AM
 Georacer Super Moderator Join Date: Nov 2009 Location: Athens, Greece (GMT +2) Posts: 4,875

Maybe you need to check again your Karnaugh map solution. Try it once more.
__________________
.
I am a prisoner of high standards and low social skills
____________________________________

I wish I was the best at what I would do, and what I would do wouldn't be pretty.
#5
11-19-2010, 11:49 AM
 wind_blast942 Junior Member Join Date: Sep 2010 Posts: 22

My mistake it should be Q+ = (J . |Q) + (|K . Q)

So to confirm will the circuit look like this? With Q as the output and J,K as the input?

#6
11-19-2010, 12:27 PM
 Georacer Super Moderator Join Date: Nov 2009 Location: Athens, Greece (GMT +2) Posts: 4,875

Still no...

Are you sure you 're making this K-map?

I suggest a revision on your K-maps.
Attached Images
 K-Map.png (17.0 KB, 62 views)
__________________
.
I am a prisoner of high standards and low social skills
____________________________________

I wish I was the best at what I would do, and what I would do wouldn't be pretty.
#7
11-19-2010, 01:12 PM
 wind_blast942 Junior Member Join Date: Sep 2010 Posts: 22

But doesn't this K-Map give: (J . |Q) + (|K . Q) ?
#8
11-19-2010, 03:38 PM
 Georacer Super Moderator Join Date: Nov 2009 Location: Athens, Greece (GMT +2) Posts: 4,875

Yes, it does. My bad.
F=JQ'+K'Q is the correct answer.
__________________
.
I am a prisoner of high standards and low social skills
____________________________________

I wish I was the best at what I would do, and what I would do wouldn't be pretty.

 Tags convert, flip, flop

 Related Site Pages Section Title Video Lecture JK Flip-Flop - Digital Worksheet Counters Worksheet Flip-flop circuits Video Lecture Counters - Digital Textbook Serial-in/serial-out shift register : Shift Registers Textbook Finite State Machines : Sequential Circuits Counters Textbook Asynchronous counters : Sequential Circuits Counters Textbook Synchronous counters : Sequential Circuits Counters Textbook Asynchronous flip-flop inputs : Multivibrators Textbook The J-K flip-flop : Multivibrators

 Similar Threads Thread Thread Starter Forum Replies Last Post Georacer Feedback and Suggestions 17 10-31-2010 04:07 AM jegues Homework Help 11 10-22-2010 03:14 PM th1alb General Electronics Chat 2 12-01-2009 08:00 PM

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Electronics Forums     General Electronics Chat     The Projects Forum     Homework Help     Electronics Resources Software, Microcomputing, and Communications Forums     Programmer's Corner     Embedded Systems and Microcontrollers     Computing and Networks     Radio and Communications Circuits and Projects     The Completed Projects Collection Abstract Forums     Math     Physics     General Science All About Circuits Commmunity Forums     Off-Topic     The Flea Market     Feedback and Suggestions

All times are GMT. The time now is 03:19 PM.