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=Electronics Hardware Questions=

   
   

 
 

Q:How to convert D-latch into JK-latch and JK-latch into D-latch?
 
 
 
 


 
 
 

A: from H.T.
 

Compare the truth tables of D-latch and JK-latch accordingly:

clk	D	Q
==================
+	0	0
+	1	1




clk	J	K	Q
=========================
+	0	0	hold
+	0	1	0
+	1	0	1
+	1	1	switch to opposite



Using these truth tables it is easy to convert JK-latch into D-latch.
		 _______
     D		|	|   Q
     ___________|J	|----
       |  	|	|
     __|__     > clk	|   _
     \   / 	|	|   Q
      \ /    ___|K	|----
       v    |	|_______|
       o    |
       |____|       				 
                        


To convert D-latch into JK-latch some extra logic is required.
The following table shows the relation between J,K and D

J	K	D
=================
0	0	Q
0	1	0
1	0	1
1	1	!Q


             _______________________________
	    |                               |
       	 ___|___		 _______    |
	|	|		|	|   |
    _J__|       |_______________|D    Q |---'
	| A	|		|	|
	|	|		|	|
     K	|	|		|clk  _	|
    ----|   	|	      --|     Q |--.
	|_______|		|_______|  |
	   |			     	   |
	   |_______________________________|
	   
	   
Looking at the drawing and the table it is not too hard to implement block A.
Probably the easiest way is to use a MUX.
J and K are the control signals and 1,0,Q,!Q are the data inputs.	   	



 
 
 
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