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
VHDL and Verilog Codes: SYNCHRONOUS COUNTER USING D FLIPFLOP
How to make a 3 bit D flip-flop up/down counter - Quora
Digital Synchronous Counter - Types, Working & Applications