Specific Counter on Breadboard

I would really appreciate some help with the following...I'm trying to wire a counter on a breadboard that counts in a specific sequence ( 2,6,7,5,1,8,0 ). I figured out the Logic Form and the JK Logic Programming part, but still fuzzy on K-Maps and how to wire the logic gates. If someone could help me with the wiring schematic, I would be very grateful. Thank You.

I'm working with the following...

555 Timer ( Working )
Man72 Seven Segment Display wired to a 7447 ( Counts 0,1 )
2 JK Flip Flop Chips ( 4 JK Flip Flops Total )
1 Quad AND Gate Chip ( Can use others if need be )
1 Quad OR Gate Chip ( Can use others if need be )
Multisim v. 13

Thanks again,

Renick Marsh

What issues do you have with K-maps? If you've know the logic you need to make this work then the wiring up should be simple enough.

Personally I would use a decade counter with the 7th output connected to reset and outputs 1-7 connected to the relevant 7447 inputs through a series diode and 10k pull down resistor.
For example:
on count 1, output 1 of the 4017 is high, this is connected to input B (via series diode) of the 7447 giving a '2'
on count 2, output 2 of the 4017 is high, this is connected to input C & B (via series diode) of the 7447 giving a '6'
....
on count 7, output 7 of the 4017 is high, this is connected to reset of the 4017 and thus all 7447 inputs are low giving a '0'
The pattern then repeats.


Or do you have to use logic gates and flip flops for some reason?

Thanks for the reply.

I've found a 7490 chip in my toolbox...will that work??? Also, I've already made a 0-9 decade counter using logic gates and flip flops, but I had a wiring schematic to follow. Could that be altered to count specific numbers? I can upload the schematic if need be. Trying to figure this out without a schematic is confusing. Thanks again for the help.

You could use a 7490 but it wouldn't work in the way I described above, it would need additional logic.
Your 0-9 decade counter should work fine if connected up in the way i described above.
Please do upload a schematic, I'd do one myself but i'm really busy until next week so wont have time I'm afraid.

I've included schematics of two counters I have already completed and the work I've done so far on the specific counter...Not sure were to go from here. Thanks again

With a little help from my Instructor, I finally figured out the K-Maps and Boolean Expressions. From there I was all good. It took 4 JK Flip Flops and 6 AND gates. I've included a schematic of the drawing I did in Multisim. Thanks again.