Massachusetts Institute of TechnologyDepartment of Electrical Engineering and Computer Science6.111 - Introductory Digital Systems LaboratoryBrief Introduction to the HP Logic AnalyzerThere are two principal instruments used by digital engineers to test and debug digitalsystems. The oscilloscope is used in order to make accurate timing measurements and toinvestigate voltage vs. time characteristics of signals. Oscilloscopes generally have a limitednumber of channels. Logic analyzers have many more channels, have limited timing resolu-tion, and display only binary signals. In the 6.111 lab we have instruments which combinelogic analyzers and digital oscilloscopes. The Model 1663AS has 32 logic analyzer channels,the Model 1662AS has 64 channels. Both have two ‘scope channels. These logic analyzerscan be configured as timing analyzers which give a waveform display similar to that of anoscilloscope or as state analyzers which display signals in terms of binary or hex numbers,or both at the same time.The logic analyzer is a fairly complex instrument. There are numerous documents pro-vided by HP to explain its use. At the instrument room desk you may sign out a Training Kit,containing a signal source card and a Guide with a series of tutorial lessons on how to usethe instrument. At several places in the laboratory there is a three-ring notebook containingthe full-fledged Reference Manual. All of this documentation, including this document, arebest read in the laboratory while you are seated in front of the logic analyzer so that youcan try out various operations as they are described.The logic analyzers are set up and controlled by interacting with menus. It will be mucheasier for you to learn the operation of the analyzer by trying out menu selection as you goalong. Indeed, you can learn a considerable amount about the logic analyzer without evenhooking up any signals to the logic analyzer. Turn on the logic analyzer and wait for it tocomplete its internal diagnostics and load the initial configuration. The logic analyzer hasa disk drive that can be used to store configuration files. You will find it desirable to haveyour own 3.5” DSDD (1.0 MB) disk, which is available at the instrument room.Front Panel ControlsThe front panel consists of a display, disc drive, menu buttons, key pad, and cursor knob.There is also a mouse which can be used for most control operations. The cursor knob isused for scrolling through ranges of fields or for adjusting time per point, delay, etc. Themouse, with its buttons, can be used (largely interchangeably) with the “Menu,” directionalarrow buttons, “Select” and “Done” buttons to select operations.Preparing Your Own DiscFrom the power-on state, click on “Analyzer” and select “System,” then click on “RS-232/HP-IB” and select “Disk.” Click on “Load” and select “Format Disk.” To proceed toformatting a disk, insert a BLANK disk in the drive, click on “Execute” and “Continue.”6.111 — Brief Introduction to the HP Logic Analyzer 2Now you can “Store” any configuration you want to save to your disk and at some latertime “Load” it back into the analyzer.There does not seem to be any simple way to initialize the logic analyzer to its power-onstate. However, if you store this state into a file on your disc, then you can get back tothe power-on state at any time by loading the stored file. Go to the I/O menu and selectdisc operations. Select the left-hand field and then select the store operation. Now enter aname, such as INITIAL LD, as the destination file name and execute this operation. Now youcan reset the logic analyzer to the initial condition by loading the file INITIAL LD from disc.Selecting MenusThe system configuration screen is one of several menus. The others are easily selectableby the mouse. To get back to the system configuration file from one of the other menus,select the upper one-in-from-left field of one of these menus and then select the desired menu.Actually the format, trigger, and display menus consist of a menu for each enabled analyzer.In the system menu the initial condition is that analyzer 1 is selected to be a timing analyzerand analyzer 2 is off. Change Analyzer 2 to be a state analyzer. Now select the configura-tion menu, and you can get either state format specification for machine 2 or timing formatspecification for machine 1. You can move between these easily using the mouse.System MenuTwo separate analyzers can be configured. Each can be either off, a timing analyzer, or astate analyzer. The system menu is also used to assign pods to analyzer 1 or analyzer 2.Each pod has its own cable to a connector on the back of the analyzer and provides sixteenchannels plus a clock. Each channel is indicated by a dash or an up-down arrow. The up-down arrow indicates that transitions on that signal are occurring.Format MenuThe primary use of the format menu is to enter labels and assign individual signal(s) to thoselabels. You can turn a label on or off or modify it, which means that you can enter newtext for that label. In this menu you can also select a threshold which is used to determinewhether the pod signal is 1 or 0. Almost all of the time you will keep the default thresholdset for TTL. When in the state format menu you can also select the clock which will beused to sample the pod signals for each state. There is one clock signal for each pod. Theyare labeled J, K, L, and M for pods 1 through 4 respectively. You can enable the samplingof data on the falling, rising , or both edges of the clock, or when it is low or high. If youselect multiple clocks, then the state will be sampled when either of the selected conditionsis satisfied. You can even select clocks which are wired to pods which are not assigned tothis state analyzer. If you have both analyzers as state analyzers you can use one clock toclock the lower eight bits and another to clock the upper eight bits. Details are given inChapter 11 of the Reference Manual.6.111 — Brief Introduction to the HP Logic Analyzer 3Trigger MenuAs with the format menu, there are two types: the timing trigger specification and the statetrigger specification. The basic function of both of these menus is to decide what informationto store and when to stop storing information and switch to the display menu. Both of thesemenus can be set to capture a single set of data or to repetitively capture and display data.The term “to arm” means that
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