1 / 16

Sequential Logic

Sequential Logic. Flip-Flop Circuits By Dylan Smeder. What Is A Sequential Circuit?. Circuit that has memory Sequence of inputs creates memory At the simplest a Flip-Flop circuit “Sequential Circuits along with combinational circuits are the building blocks of computers”. Simple memory.

sage
Télécharger la présentation

Sequential Logic

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Sequential Logic Flip-Flop Circuits By Dylan Smeder

  2. What Is A Sequential Circuit? • Circuit that has memory • Sequence of inputs creates memory • At the simplest a Flip-Flop circuit • “Sequential Circuits along with combinational circuits are the building blocks of computers”

  3. Simple memory • Flip-Flop circuits have the ability to store 1 bit integers which is represented by either 1 or 0 • The output of an operation is used as input for the next operation • The truth table is affected by memory instead of having one set of output for a set of input there are two different sets of output

  4. SR Flip-Flop • Simple Flip-Flop circuit • Two inputs “S” and “R” • S = Set • R= Reset • Two outputs which are the complements of each other Q and Q’ • Truth table has strange output

  5. How does a SR Flip-Flop work? • If S==1 and R==1 Q=0 and Q’=1 then Case A Q is 0 NOR 0 which equals 1 • Cases A B C are similar to A • Case D and E are different. Each depends on the previous output. If in the previous output Q==0 and Q’==1 then Q=1 and Q’=0 • If Q==1 and Q’==0 then Q=0 and Q’=1

  6. Clocked D Flip-Flop • Variation of a SR Circuit • Can be set with a single input • Pulse input CK • D input

  7. How does Clocked D Flip-Flop Circuit Work? • When CP is equal to 0 the input from D is ignored • When CP equals 1 D and its complement are inputted in to the SR circuit

  8. Clocked JK Flip-Flop • Variation of a Clocked D Flip-Flop Circuit • When CP equals 0 input from K and J are Ignored • When CP equals 1 if K=J=1 it sets if in reset it resets if in set

  9. Edge Detection • With a single input there can be various signal levels but the only level needed is when it switches from 1 to 0 or 0 to 1 • Edge detection only records theses changes • Effectively levels out oscillations • If it records a positive edge it is called a positive edge triggered • If it records a negative edge it is called a negative edge triggered

  10. T Flip-Flop • Positive edge triggered JK Flip-Flop • J and K inputs are tied together • Used as counters

  11. Random-Access Memory • Can read and write at any point in memory • Implemented using D Flip-Flops • Each row contains 16 Flip-Flops • A Decoder

  12. Binary Counter • Holds each pulse in memory • Each pulse add another number • Binary format

  13. Register • Used to hold one item of information • CPU’s have many registers • AX is an example in Assembly

  14. Clocks and Sequencers • To perform operations a CPU often requires a specific sequence of sub operations • A sequencer is used to make sure operations happen in correct order • A clock is a circuit that outputs 0’s and 1’s at specific frequencies

  15. Real World Application • The RAM discussed is a model for a chip that can actually be found in a computer • The binary counter can be bought at http://www.web-tronics.com/webtronics/74hc161n.html for 45 cents each • The Flip-Flop circuits are models of usable chips

  16. Sources • http://www.wearcam.org/ece385/lectureflipflops/flipflops/ • http://www.web-tronics.com/webtronics/74hc161n.html • Assembly language and computer architecture using C++ and JAVA, Anthony J Dos Reis, 2004

More Related