newbie who needs help

[crws]

as the subject suggests im kind a new to circuits. I am trying to implement a design which will run through a sequence of 1-2-0-2-3-0-2-5 which will be hopefully generated by jk flip flops set up as counters, with a basic clock triggering all jk's. The circuit will display one bit at a time to a 7 segment display, which will be powered by a bcd to 7 segment decoder. The problem i am having is that so far my sequence runs 1-2-5 and that is it. I dont know what is going wrong or what i should do andy suggestions would be much appreciated.. Many thanks

 

[Optikon]

as the subject suggests im kind a new to circuits. I am trying to implement a design which will run through a sequence of 1-2-0-2-3-0-2-5 which will be hopefully generated by jk flip flops set up as counters, with a basic clock triggering all jk's. The circuit will display one bit at a time to a 7 segment display, which will be powered by a bcd to 7 segment decoder. The problem i am having is that so far my sequence runs 1-2-5 and that is it. I dont know what is going wrong or what i should do andy suggestions would be much appreciated.. Many thanks

The best thing you can do to get good help from users here, is to post your schematic here. To diagnose your circuit, it is best if we can see how it is wired up. Otherwise, we will all be speculating and probably wasting your time.

 

[crws]

this is the schematic im working on, which is not working.

 

[Roff]

I don't see how you can do this with a 3 bit state machine. States 0 and 2 are dependent on the previous two states, i.e., 0 is preceded by 1-2 and 2-3, and 2 is preceded by 2-0, 3-0, and (assuming wraparound) 5-1. This means you need memory for the 2 previous states instead of just one.
If you can use a simple 3 bit binary counter and a decoder, it would seem to be simpler.

 

[ljcox]

Ron is right. You can't design a counter that follows the sequence you indicated. But, you can obtain that sequence by decoding.

The total number of states is 8. So use a 3 bit Modulo 8 counter that counts from 0 to 7 in the normal manner and use decoding to generate the sequence you require ie. 1-2-0-2-3-0-2-5. For example
When the counter is in state 0 the output of the decoder is 1.
When the counter is in state 1 the output of the decoder is 2.
When the counter is in state 2 the output of the decoder is 0.
When the counter is in state 3 the output of the decoder is 2.
etc

You may wish to look at this post https://www.electro-tech-online.com...t-areas-for-double-side-pcbs.8396/#post-40672

It outlines the process of how to design sequential circuits using JK Flip Flops.

Len