Flip-flops Chapter4 Simple counter
Flip-flops Chapter4 Simple counter
a Counting is a fundamental function of digital circuits aa digital counter consists of a collection of flip-flops that change states(set or reset) in a prescribed sequence
◼ Counting is a fundamental function of digital circuits. ◼ A digital counter consists of a collection of flip-flops that change states (set or reset) in a prescribed sequence
Divide by 2, 4 and 8 Counters a Asynchronous counter The output of one flip-flop provides the clock for the next flip -flops a When all of the flip-flop outputs are available, these are called modulo-n counters where n represent the terminal counter
◼ Asynchronous counter ◼ The output of one flip-flop provides the clock for the next flip-flops. ◼ When all of the flip-flop outputs are available, these are called modulo-n counters where n represent the terminal counter. •Divide by 2,4 and 8 Counters
Cc Q1 1Q2 CLK JcK Q1 CK Q2 CLK Q101901101 Q20 0 0 0
KJ Q1’ Q1 C CLK KJ Q2’ Q2 C 1 1 VCC CLK Q1 Q2 00 10 01 11 00 10
Johnson Counter(synchronous) Q2 Q3D Q4 Q4 4>c Q1 CDC @2roc Q3 C CLK The output of one flip-flop directly connects to the input of another
•Johnson Counter (synchronous) ◼ The output of one flip-flop directly connects to the input of another. D Q1’ Q1 C D Q2’ Q2 C D Q3’ Q3 C D Q4’ Q4 C CLK