verilog - Asynchronous Down Counter using D Flip Flops - Electrical Engineering Stack Exchange
Digital Asynchronous Counter (Ripple Counter) - Types & Application
Digital Asynchronous Counter (Ripple Counter) - Types & Application
DeldSim - 3-Bit Down Counter
Down Counters and Up-Down Counters in Digital Electronics
Counters | CircuitVerse
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