2. Counters Chapter 17 Subject: Digital System Year: 2009

3. 3 Overview Asynchronous and synchronous binary counters 2 bit asynchronous binary counter 2 bit synchronous binary counter

4. Asynchronous and synchronous The term asynchronous refers to events that do not have a fixed time relationship with each other and, generally, do not occur at the same time. An asynchronous counter is one in which the flip-flops (FF) within the counter do not change states at exactly the same time because they do not have a common clock pulse. The term synchronous refers to events that have a fixed time relationship with each other. A synchronous counter is one in which all the flip-flops in the counter are clocked at the same time by a common clock pulse. Bina Nusantara University 4

5. 2 bit asynchronous binary counter Bina Nusantara University 5

6. 3 bit asynchronous binary counter Bina Nusantara University 6

7. 4 bit asynchronous binary counter Bina Nusantara University 7

8. asynchronous decade counter Bina Nusantara University 8

9. 2 bit Synchronous binary counter Bina Nusantara University 9

10. 3 bit Synchronous binary counter Bina Nusantara University 10

11. 4 bit Synchronous binary counter Bina Nusantara University 11