How to reverse the binary counter of jk flip-flop by using switch?

from 1>3>5>7 to 7>5>3>1

 

http://forum.allaboutcircuits.com/showthread.php?t=3002

 

can any1 help me?

 

Try looking at the internal logic of an up/down counter. Why the requirement of the counter only outputting odd numbers?

 

just an example. thanks alot. i try to search for it

 

looked through it but still cant think of it how to reverse it.

 

Have you looked at http://www.allaboutcircuits.com/vol_4/chpt_11/index.html ??

Consider that if "output" runs:

0000
0001
0010
0011
:
:
1111
then "not-output" -- the output inverted -- runs:

1111
1110
1101
1100
:
:
0000

--Rich

 

but how to control it by using switch?

 

The switch controls a multiplexer that selects either the true (Q) outputs, or the complement(Q-bar) outputs.

 

i was thinking the same thing but.
for the sequence 1>3>5>7
wont the not o/p be 6>4>2>0 and not 7>5>3>1
m i missing something?

 

rich is right, the "Q not" outputs will count down. to get only odd outputs an lsb ff will not be used and the lsb output can just be tied high, and tied low for only even outputs.

 

got it, thanks.
(i m learning too )