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Date: Wed, 08 Jan 1997 21:42:19 GMTServer: NCSA/1.4.2Content-type: text/html<html><head><title>CSE467 Laboratory Assignment #5</title></head><body bgcolor="#dddddd" text="#000000" link="#0000ee" vlink="501080" alink="ff0000"><h1>CSE467: Advanced Logic Design</h1><h3>Ted Kehl Fall1996 </h3><hr><h3>Lab 5</h3><p><h3>Using the Oscilloscope and Logic Analyzer</h3><p><b>Distributed: Nov 11<br> Due: TA option<br></b><hr><H3>Objectives</H3>After completing this lab you will know how to use the oscilloscopeand logic analyzer to test and debug sequential circuits.<p>You should divide into groups of two to complete this lab assignment.<H3>I. Digital Oscilloscope and Switch Debouncing</H3>The digital oscilloscope lets you examine the detailedbehavior of signals as a function of time. You will examinethe output of the clock generator provided in yourDesignKit. You will also observe switch bounce and learnhow to measure propagation delay.<H4>The Oscilloscope</H4>Oscilloscopes display voltage waveforms as a function oftime in much the same way that a simulatordisplays signal waveforms. The scopes that you will beusing are part of the Tektronix 1230 logic analyzers. Thesescopes can sample two signals and display their waveformseither separately or simultaneously. Each signal is sampledat some rate up to 100 MHz (every 10ns.) and this sampledsignal is displayed according to commands that you enterinto the logic analyzer. Oscilloscopes sample the voltageof the signal and display its value at each sample time.Logic analyzers work similarly except that they only sample0 and 1 values. The hard part of operating the scope isindicating (1) how you want the signal sampled and (2) howyou want it displayed. This lab assignment will try to showyou how to do both.<H4>The Tek 1230 Logic Analyzer / Digital Oscilloscope</H4>The Tektronix 1230 logic analyzer console has a videomonitor on the left side of the console. Buttons and ribboncable connectors are on the right side. Because the 1230uses menus on the monitor to control operation, few controlsare needed on the console. However, the menus and commandscan be confusing.<P>The logic analyzers with digital scope boards have BNCconnectors on the rear panel for scope and trigger input.Probes are attached to the BNC connectors to makemeasurements. These probes provide extra impedance to thecircuit to minimize disturbance to the circuit.<P>After the logic analyzer is powered up using the switchlocated on the rear panel, it will eventually display anopening screen. Press the <MENU> key to start operation.The figure at the top of the next page is a road map forusing the oscilloscope that shows what commands areavailable in the different modes. You will find it helpfulto refer to this figure as you read the rest of the labassignment.<P>The main menu is divided into three sections: SETUP, DATA,and UTILITIES. Only two of these menus are used to accessthe scope capabilities of the system. The menu selectionmarked "Digital Scope" in the "DATA" section is used todisplay waveforms (<A>). The menu selection marked "DigitalScope" in the "SETUP" section is used to change setupparameters of the oscilloscope (<5>) that determine how thesignals are sampled.<hr><p><img src=roadmap.jpeg><p><hr>Notice the menu bar on the bottom of the screen. The menubar simply provides a reminder of the commands available.Commands are always issued by pressing a key and not throughthe menu. A command does not need to be visible in themenu bar for you to perform that command using the keypad.The menu bar assists you in remembering which functions areavailable from which menus and modes. If there are toomany commands, then pressing the <F> key will rotate throughmultiple menu bars.<P>The <NOTES> key is used to display on line help about theavailable commands and options. A screen of referencematerial will be displayed on the screen when you press the<NOTES> key.<P>The arrow keys are used to move the cursors around thescreen. In some cases, the cursor is a highlightedselection that can be moved from one item to another. Thevalue of a highlighted selection is changed either by usingthe <0> and <2> to rotate through the available alternativesor by entering the proper value using the keypad.<H4>Using the Oscilloscope to Examine Your Clock Generator</H4>Find the BNC connector marked "SCOPE INPUT CH1" on the rearof the console and connect an oscilloscope probe to it.Connect the tip of the probe to the output of your clockgenerator. Remember that your clock generator output is opencollector so you will need a pull-up resistor. Connect theblack grounding wire to the ground of your Protoboard.<H5>The DATA / DIGITAL SCOPE screen</H5>Before you start, make sure you are starting with thedefault setup by pressing <NOTES> and <ENTER>simultaneously. Now press <MENU> to obtain the logicanalyzer's main menu. Press <A> on the logic analyzerkeypad to go to the Digital Scope Display screen. You'llsee a window which displays signal waveforms and a list ofparameters on the left side of the screen.<P>This screen functions in two modes. One mode brings up areverse video cursor which allows you to change some of thesetup parameters listed on the left side of the screen. Inthe other mode, the reverse video cursor is not present, butyou can change other parameters by commands accessed viakeypad.<H4>Selecting Channel</H4>The "CHANNEL" field indicates which channel is beingdisplayed. To change this setting press the <0> and <2>keys. Set the oscilloscope to display channel 1. Youshould see the clock waveform on the screen.<H5>Changing the Setup</H5>Enter the "change setup" mode by pressing the <DON'T CARE /X> key. A reverse video cursor will appear. Use the cursorkeys to move the cursor. You'll see that you can change theATTENUATOR, POSITION, and TIMEBASE fields. Use the arrowkeys to move the cursor and the <0> and <2> keys to changethe values.<H4>Attenuator</H4>The "ATTENUATOR" field is used to set the vertical scale ofthe display. That is you select the number volts per gridsquare so that your waveform fits in the display. Set theattenuator to 2v per square.<H4>Position</H4>The "POSITION" field indicates the vertical displacementused in displaying the waveform. By adjusting thisparameter, you can shift the waveform up or down. Using theattenuator and position together, you can view any part ofthe waveform in any detail.<H4>Timebase</H4>"TIMEBASE" is used to set the horizontal scale of thedisplay, that is, how often your signal is sampled. Thisparameter is usually set so that enough of the signal iscaptured. For example, by changing this parameter, you canchoose how many periods of a periodic waveform are displayedon the screen.<P>Change these three parameters until you get an easy to readtrace of your clock signal. Change the frequency of yourclock signal. Observe how this changes your trace.<P>To retain your changes, you must press the <ENTER> key afteryou have finished adjusting parameters. If you press the<DON'T CARE / X> key to leave the "change setup" mode, yourchanges will be discarded.<H5>Controlling the Display</H5>Now that you have determined how you want to sample thesignal, there are several commands that change how it isdisplayed.<H4>Zoom in/out</H4>Note the bar graph display above the scope display. Thisgraph indicates what part of the waveform is being displayedon the screen. You can press the <4> and <5> keys to changethe resolution of the display. In effect, the horizontalscale of the trace expands or contracts. Decreasing thenumber of samples displayed on the screen allows you toexamine a waveform in more detail.<H4>Scanning the Trace and taking Measurements</H4>Note the cursor in the trace display. You can move thiscursor left and right using the arrow keys. As youmove the cursor, the cursor position is displayed so thatyou can measure the time from one point on the trace toanother. This measurement is made even easier by theability to place a reference cursor using the <ENTER> key.This establishes that location as a reference point; thereference point will be marked with a dashed line. Thenmove the cursor to the second point. The delta values willbe displayed on the screen display.<P>The cursor can be changed to a horizontal cursor using the<E> key. This is useful for measuring the voltages.<H4>Taking Measurements with a Grid</H4>You can take approximate measurements from this screen bysuperimposing a grid on the screen. Press <3> to toggle thegrid on and off. Although this allows you to read valuesdirectly from the screen, these measurements are necessarilyquite approximate. Precise measurements are better takenusing the cursors.<H5>Using the SETUP / DIGITAL SCOPE screen</H5>Not all of the scope sampling settings are accessible fromthe Change Setup part of the DATA / DIGITAL SCOPE screen.Press <MENU> and then <5> to obtain the SETUP / DIGITALSCOPE screen and examine the other scope settings. Use thearrow keys to move the reverse video cursor around thescreen. You can change the values of the parameters bypressing the <0> and <2> keys. Some of the settings on thisscreen are also accessible from the Change Setup screen.<H4>Coupling</H4>"Coupling" toggles between AC and DC. The DC stands fordirect coupling. DC is used to display all frequencycomponents of a signal. If you want to use the scope as asimple voltmeter, be sure the input is DC coupled. ACfilters the direct component of the signal, so that only thealternating component of the signal is displayed. Thissetting can be used to examine a small alternating signal⌨️ 快捷键说明
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