AE&I: LESSON 20. Counters-Asynchronous and synchronous counter-decade counter-up down counter- ring and Johnson counter.
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
![4-bit Mod-12 Synchronous Counter using D flip-flop || Sequential Logic Circuit | Digital Electronics - YouTube 4-bit Mod-12 Synchronous Counter using D flip-flop || Sequential Logic Circuit | Digital Electronics - YouTube](https://i.ytimg.com/vi/0jxvgMORUCE/hqdefault.jpg)