VLSI DESIGN: 4-bit Asynchronous up counter using JK-FF (Structural model)
Design steps of 4-bit (MOD-16) synchronous up counter using J-K flip-flop
4 bit synchronous up counter using JK flip flops
How to design a synchronous counter 4 bit using JK flip flop that can count up even numbers from 0 to 14, and count down odd numbers from 15 to 0 in 1 system - Quora
Asynchronous Counter: Definition, Working, Truth Table & Design