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
flipflop - Why use JK Flip Flops in syncronous/asyncronous binary counters rather than D flip flops? - Electrical Engineering Stack Exchange
digital logic - In a JK Binary Counter from 0 to 9, why is the NAND gate connected to the second and fourth J-K flip flop and not the first and fourth? -
JK Flip Flop - Basic Online Digital Electronics Course