TY - JOUR AU - Haikal, Aizat PY - 2022/08/09 Y2 - 2024/03/29 TI - Learn Digital Design of Microcomputer Systems with Deeds JF - Proceedings of the Informatics Conference JA - Informatics VL - 8 IS - 17 SE - DO - UR - https://ojs.journals.unisel.edu.my/index.php/icf/article/view/240 SP - AB - <p><strong>Classification of Sequential Logic</strong></p><p>As standard logic gates are the building blocks of combinational circuits, bistable latches and flip-flops are the basic building blocks of sequential logic circuits. Sequential logic circuits can be constructed to produce either simple edge-triggered flip-flops or more complex sequential circuits such as storage registers, shift registers, memory devices or counters. Either way sequential logic circuits can be divided into the following three main categories:</p><ul><li class="show">1.&nbsp;Event Driven–&nbsp;asynchronous circuits that change state immediately when enabled.</li><li class="show">2.&nbsp;Clock Driven–&nbsp;synchronous circuits that are synchronised to a specific clock signal.</li><li class="show">3.&nbsp;Pulse Driven–&nbsp;which is a combination of the two that responds to triggering pulses.<p>&nbsp;</p><p><strong>SR Flip-Flop</strong></p><p>The&nbsp;<strong>SR flip-flop</strong>, also known as a&nbsp;<em>SR Latch</em>, can be considered as one of the most basic sequential logic circuit possible. This simple flip-flop is basically a one-bit memory bistable device that has two inputs, one which will “SET” the device (meaning the output = “1”), and is labelled&nbsp;<strong>S</strong>&nbsp;and one which will “RESET” the device (meaning the output = “0”), labelled&nbsp;<strong>R</strong>.</p><p>Then the&nbsp;SR&nbsp;description stands for “Set-Reset”. The reset input resets the flip-flop back to its original state with an output&nbsp;Q&nbsp;that will be either at a logic level “1” or logic “0” depending upon this set/reset condition.</p><p>A basic&nbsp;NAND&nbsp;gate SR flip-flop circuit provides feedback from both of its outputs back to its opposing inputs and is commonly used in memory circuits to store a single data bit. Then the SR flip-flop actually has three inputs,&nbsp;Set,&nbsp;Reset&nbsp;and its current output&nbsp;Q&nbsp;relating to it’s current state or history.</p><p>The term “Flip-flop” relates to the actual operation of the device, as it can be “flipped” into one logic Set state or “flopped” back into the opposing logic Reset state.</p></li></ul> ER -