Help with 4 bit register with JK flip-flops

[Canvas]

Hey guys, im new here so if i do anything wrong please let me know, k first off im trying to make a 4 bit register for my electronics class using 4 J-K flip flops, now i can get parallel load to work, but ive also been asked to add more then just parallel load, so first off here is my circuit a the moment

View attachment 64379

You can switch each one on, then once parallel load is enabled the data will be thrown in and stored, and then can be cleared with parallel load again but just with no data on, but what im stuck on at the moment is im trying to implement serial shift left, but ive tried many different ways and i still cant get it to work, this is one circuit but it doesnt clear correctly

View attachment 64380

only works for register 2 shift left to register 1,

could someone show me how i can implement serial shift left to my circuit?

Thank you

Canvas

Just created a new Design for the 4bit register
View attachment 64381

 

[Ratchit]

Canvas,

...but what im stuck on at the moment is im trying to implement serial shift left, but ive tried many different ways and i still cant get it to work,

could someone show me how i can implement serial shift left to my circuit?

Any good logic book should show you how to make a shift register. How can you expect to succeed if you don't connect the output of the J-Ks to the input of the following or previous J-Ks?

Is there anything wrong with the shift key of your keyboard?

Ratch

 

[Dean Huster]

As Ratch mentioned, you have a problem with the outputs -- they don't go anywhere. The outputs of the previous JKs have to go to the JK inputs of the next one in line. It's simple enough. Without that connection, you can't expect to shift the data. What makes things complicated, whether parallel loading, synchronous clearing or especially changing the thing from right shift to left shift, is that fact that you end up using four times more external gates than you do flip flops to get the job done. All that is why you use MSI shift registers. It is a good exercise in design to "roll your own" just to see how it's done and understand the logic, even if it is impractical to use in a circuit. Same goes with a synchrohous counter circuit.