L10-sequential-2009 - Sequential Logic Circuits Trac D....

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Sequential Logic Circuits Sequential Logic Circuits Trac D. Tran ECE Department The Johns Hopkins University Baltimore, MD 21218 Outline Outline ± Sequential logic and memory elements ² Set-Reset flip-flop ² Toggle flip-flop or edge-triggered flip-flop ² Sequential circuits as finite state machine ± Applications ² Car Alarm ² Modulo-N binary counter ² Random access memory (RAM)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Sequential Logic Sequential Logic ± Combinatorial logic circuits: current input values determine the output value ± Sequential logic circuits: output value also depends on past input values. Sequential logic circuits have memory ± Common memory elements ² Set-Reset Flip-Flop (SR-FF, RS Latch): basic computer memory cell ² Toggle Flip-Flop (T-FF): basic computer counting cell Set Set -Reset Flip Reset Flip -Flop Flop Q Q S R 1 1 1 1 0 1 0 1 1 0 1 0 Q Q 0 0 Q Q R S Comment hold reset set strange state Timing Diagram S R Q Q
Background image of page 2
3 SR SR -FF Analysis FF Analysis Q Q S R S R Q Q 0 1 1 0 0 1 0 1 0 1 0 0 Q Q S 0 1 1 0 0 1 0 1 0 1 0 0 Q R Q initial state set transition reset transition ± Q remembers which input, S or R, was 1 last ± If S then Q=1 ± If R then Q=0 Set Set -Reset Flip Reset Flip -Flop: On Hold Flop: On Hold Timing Diagram S R Q Q Q Q S R ± Initial state:
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/02/2010 for the course ENGINEERIN 520.101 taught by Professor Tracdtran during the Winter '06 term at Johns Hopkins.

Page1 / 10

L10-sequential-2009 - Sequential Logic Circuits Trac D....

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online