Synchronous Counters
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
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.
Modulus-8 Synch Counter Analyses 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
Modulus-8 Synch Counter Design
Modulus-16 Synch Counter Analyses Q3 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
Modulus-16 Synch Counter Design
74LS163 Synchronous 4 Bit Counter Clear Terminal Count Data In Data Out Enables Load Data
74LS163 : How It Works
74LS163 : 6 (0110) to 15 (1111) CNT
74LS163 : 6 (0110) to 12 (1100) CNT
Understanding Circuit Maker Labels DATA SHEET CIRCUIT MAKER