1. Synchronous Counters

2. Lecture Overview Classifications of Counters Definitions
Synchronous Counter…
Modulus 8 with Discrete Gates (SSI)
Modulus 16 with Discrete Gates (SSI)
74LS163 Synchronous 4 Bit Counter
Understanding Device
Truncated Count

3. Classifications of Counters
Asynchronous Counters
Only the first flip-flop is clocked by an external clock. All subsequent flip-flops are clocked by the output of the preceding flip-flop.
Asynchronous counters are slower than synchronous counters because of the delay in the transmission of the pulses from flip-flop to flip-flop.
Asynchronous counters are also called ripple-counters because of the way the clock pulse ripples it way through the flip-flops.
Synchronous Counters
All flip-flops are simultaneously clocked by an external clock.
Synchronous counters are faster than asynchronous counters because of the simultaneous clocking.
Synchronous counters are an example of a state machines design.

4. Modulus-8 Synch Counter AnalysesQ2 Q1 Q0
Q0 : Toggles Every Time… J0 & K0 = 1
Q1 : Toggles When Q0=1… J1 & K1 = Q0
Q2 : Toggles When Q0=1 & Q1=1… J2 & K2 = Q1 x Q0

5. Modulus-8 Synch Counter Design

6. Modulus-16 Synch Counter AnalysesQ3 Q2 Q1 Q0
Q0 : Toggles Every Time… J0 & K0 = 1
Q1 : Toggles When Q0=1… J1 & K1 = Q0
Q2 : Toggles When Q0=1 & Q1=1… J2 & K2 = Q1 x Q0
Q3 : Toggles When Q0=1 & Q1=1 & Q2=1… J3 & K3 = Q2xQ1xQ0

7. Modulus-16 Synch Counter Design

8. 74LS163 Synchronous 4 Bit Counter
Clear
Terminal Count
Data In
Data Out
Enables
Load Data

11. 74LS163 : How It Works

12. 74LS163 : 6 (0110) to 15 (1111) CNT

13. 74LS163 : 6 (0110) to 12 (1100) CNT

14. Understanding Circuit Maker Labels
DATA SHEET
CIRCUIT MAKER