Lab Introduction
Contents
1. A lab report in pdf format is to be emailed to the grader after each lab project Please send See Lab Report Guidelines for instructions on the content The report is due prior to the beginning of the next lab project on the following week Only a single report is necessary from each team not one from each individual The report should be professional in writing style content and appearance If figures are hand drawn they must be neat Scan any hand drawn figures and paste them into your document It is acceptable to attach long figures and program listings to the end of the report be sure to label them with a figure number and caption Grading will be based on the rubric attached to each lab assignment In general grading is a combination of 1 Technical soundness e g does the circuit or program work correctly and is it designed properly 2 How well the report describes the work e g does it show an in depth understanding 3 Neatness organization spelling grammar etc EENG 383 Microcomputer Architecture and Interfacing 2 Equipment Each bench has a PC oscilloscope digital multimeter DMM and function generator In addition the lab also contains e A laser printer e Copper wire of different colors e Cabinets with drawers containing additional discrete parts resistors capacitors ICs Each bench has one of two types of oscilloscopes Agilent MSO6012A or Tektronix TBS1102 Their capabilities are similar each2. 16 digital channels simultaneously The digital probes for this are different from the analog probes and can be found in the little compartment on top of the oscilloscope This can be very helpful for looking at busses that carry multiple digital logic signals It is not required to use the logic analyzer in the labs in this course but it would be useful skill for you in the future EENG 383 Microcomputer Architecture and Interfacing 5 Tektronix TBS1102 Oscilloscope The Tektronix TBS1102 oscilloscope is shown in Figure 6 The user s manual is available online at http www testequipmentdepot com tektronix pdf tbs 1000_manual pdf The right side of the front panel has buttons for vertical control horizontal control and triggering The left side has the screen display and to the right of the display a set of five softkeys These are buttons whose behavior changes depending on the display i d Softkeys p 0 et Trigger controls Horizontal controls Figure 6 The Tektronix TBS1102 oscilloscope Turn on the oscilloscope the button at the top left side Two oscilloscope probes should be attached to the scope Plug the two probes into the BNC connectors marked 1 and 2 on the bottom of the front panel Note that each probe Figure 7 has a retractable tip for measuring a signal as well as a ground clip You should always connect the ground clip to a ground in your circ
3. has 100 MHz bandwidth 2 digital channels and storage capability However since the user interface is a little different on each it would be better to stick with one or the other for the duration of the semester to avoid learning a second system 3 Oscilloscope Basics An oscilloscope is basically a graph displaying device it draws a graph of an electrical signal Typically the vertical Y axis represents voltage and the horizontal X axis represents time Our scopes have two channels meaning that they can display two signals simultaneously There are lots of tutorials and resources online about using oscilloscopes Here are some basic video tutorials e http www youtube com watch v CzY2abWCVTY this one starts from a very basic level but appears to be quite thorough e http www youtube com watch v 7nwIIPN9QEY this one is much shorter but uses a Tektronix scope similar to ours A webpage with lots of links to tutorials is at http www tek com learning oscilloscope tutorial If you know of other good resources please let me know When using an oscilloscope you need to adjust three basic settings to accommodate an incoming signal e Vertical Controls the vertical position of the traces as well as which traces are shown and their scale Note that only the currently selected trace will be affected by the controls in this group e Horizontal The time base Controls the time scale and position Note that all traces are a
4. EENG 383 Microcomputer Architecture and Interfacing Lab Introduction This is an introduction to the lab for EENG 383 It goes over how the lab is run and provides a description of the equipment in the lab In addition since we will be using the oscilloscopes extensively in this course it also provides a tutorial on the use of the oscilloscopes and links to further resources No lab report is required for this lab however make sure you know how to do the tasks in this lab 1 Lab Mechanics We will meet weekly in room BB305 in Brown Hall Although the assignments are intended to be done during the regularly scheduled lab period you may come into the lab at other times to finish assignments or work on class related projects You can come during the lab instructor s normally scheduled hours or arrange a separate time Students will work in teams of up to two people Each team will check out a kit from the technician in room BB313 containing the parts that will be used throughout the semester You can take the kits home to work on assignments or leave them in the lab We will have a series of lab projects usually one per week All handouts data sheets and other material are on the course website Before coming to lab read the handout and do any preparation that is called for in the handout Bring the kit and a notebook for taking notes and data It will also be helpful to bring a USB flash drive for capturing oscilloscope displays
5. Type dge Rising Mode Coupling CHT 2000y CH KE Ke rT ee 19 Aug 13 22 11 1 00000kHz Figure 8 Trigger Menu Select mode Auto using the fourth softkey There are two modes Normal and Auto Normal mode displays a waveform when the trigger conditions are met otherwise the oscilloscope does not trigger and the display is not updated Auto mode is the same as Normal mode except it forces the oscilloscope to trigger if the trigger conditions are not met We will use edge triggering Press the Type softkey topmost softkey in the trigger controls group This will cycle through the various triggering modes Edge Video and Pulse The second softkey selects which channel 1 or 2 is used as the source of the trigger The softkey labeled slope allows you to change what type of edge you want to trigger on rising falling or either See what happens if you change this from rising to falling Also try changing the trigger level 1 e the voltage at which the trigger will occur with the knob labeled Level To use cursors press the Cursors button on the front panel The display shows two active softkeys Pressing the top softkey cycles through Off Amplitude and Time cursor modes Select the Time mode Select the appropriate cursor by selecting either the fourth cursor 1 or fifth softkey cursor 2 Use the Entry knob ligh
6. ffected simultaneously by these controls e Trigger Controls the triggering Often when looking at signals with an oscilloscope you are looking at a repeating signal Triggering allows you to horizontally align repetitions of this signal When the oscilloscope sees a trigger event it puts a trace onto the screen A trigger event happens when the voltage goes past the Trigger Level This allows a repeating wave to be overlaid on top of itself in such a way that it reinforces previous traces and makes the trace brighter EENG 383 Microcomputer Architecture and Interfacing Normally the acquire mode of the oscilloscope is set to free running meaning that it continuously tries to capture data and display it on the screen Sometimes you would like to look at a signal that doesn t happen often so you would like to capture the event when it does happen and then be able to view the waveform on the screen There is a mode that allows you to capture just a single sequence of data on the screen Another useful feature of the oscilloscope is the cursor A cursor is simply a line that you can move across the display Two horizontal cursor lines can be moved up and down to bracket a waveform s amplitude for voltage measurements and two vertical lines move right and left for time measurements A text readout shows the voltage or time at the cursor positions Determine which type of oscilloscope you have at your bench and then go to the appro
7. he BNC adapter found in your kit see Figure 10 to the function generator s TTL output 11 EENG 383 Microcomputer Architecture and Interfacing Figure 10 BNC to post adapter Connect the oscilloscope probe directly to the adapter or if it is easier attach wires to the adapter and connect the probe to the wires Display the square wave on the oscilloscope and determine its frequency Adjust the frequency on the function generator to 38 KHz Place the cursors so that you measure the period and amplitude of the waveform and capture an image of the oscilloscope screen on a USB flash drive ask the instructor to borrow one if you didn t bring one Make sure you are able to paste the image into a Word document since you will need to do that in future labs 12
8. he ground symbol Connect your two probe tips to the square wave tab and the two ground clips to the ground tab Press the Auto Scale button You should see the waveforms shown in Figure 1 Experiment with the horizontal controls You can change the time scale of the displayed signals i e number of seconds per division and also shift the entire waveform left or right The time per division is shown at the top of the screen Experiment with the vertical controls You can change the vertical scale of a signal i e number of volts per division and also shift the entire signal up or down Note the position of the little arrow at the left of the trace which indicates the position of ground The volts per division is shown at the top of the screen Note that only the selected signal is affected by the vertical controls To change the selected signal press the 1 or 2 buttons Now let s experiment with the trigger controls Press the mode coupling key in the trigger area This should bring up the Trigger Mode and Coupling Menu on the display Figure 3 EENG 383 Microcomputer Architecture and Interfacing lt Holdoff i 60 000ns Be Figure 3 Trigger Mode and Coupling Menu Select mode Auto on the leftmost softkey There are two modes Normal and Auto Normal mode displays a waveform when the trigger conditions are met otherwise the oscilloscope does not trigger and the display is no
9. ng it Now the display automatically displays the positions of X1 and X2 as well as DX You can also adjust the positions of the horizontal cursors Y1 and Y2 See if you can adjust the cursors to measure the period and amplitude of the waveform on channel 1 as shown in Figure 5 EENG 383 Microcomputer Architecture and Interfacing 830 000000us X Mode Source Normal Figure 5 Adjusting the cursors Finally you can capture the image on the display to a file on a USB flash drive This is useful to in creating lab reports To do this plug a USB drive into the port on the front panel Then press the Save Recall button This will bring up the Save Recall menu on the display Press the softkey labeled Save this will save the image to a file on the USB drive Some tips The Auto Scale button is helpful when you press it the oscilloscope looks at the incoming signals and makes its best guess as to the settings for voltage scale and time scale to give a reasonable display It is a good starting point but you should be able to adjust things yourself to give you exactly the display you need The Quick Measure button is also helpful the oscilloscope will display the amplitude and frequency of the waveform being displayed You can change the type of measurement to be displayed using the Entry knob Note the Agilent oscilloscopes also have a logic analyzer capability that lets you view
10. priate section below i e Section 4 or Section 5 and follow through the tutorial for that specific oscilloscope Then practice your skills in Section 6 4 Agilent MSO6012A Oscilloscope The Agilent MSO6012A oscilloscope is shown in Figure 1 The user s manual is available online at http cp literature agilent com litweb pdf 54684 97011 pdf The right side of front panel has buttons for vertical control horizontal control and triggering The left side has the screen display and underneath the display a set of six softkeys These are buttons whose behavior changes depending on the display Fe 7 __ a Trigger controls N Figure 1 The Agilent MSO6012A oscilloscope EENG 383 Microcomputer Architecture and Interfacing Turn on the oscilloscope the button at the lower left Open the lid on the top of the oscilloscope and get out the two oscilloscope probes Plug the two probes into the BNC connectors marked 1 and 2 on the bottom of the front panel Note that each probe Figure 2 has a retractable tip for measuring a signal as well as a ground clip You should always connect the ground clip to a ground in your circuit Figure 2 Oscilloscope probe The oscilloscope generates a square wave for testing purposes This signal is available on the metal tab marked with a square wave symbol on the bottom of the front panel in the area marked Probe Comp Next to it is another metal tab marked with t
11. t updated Auto mode is the same as Normal mode except it forces the oscilloscope to trigger if the trigger conditions are not met We will use edge triggering Press the edge button on the front panel in the trigger controls group This should bring up the Edge Trigger Menu on the display Figure 4 Using the leftmost softkey you can select which channel 1 or 2 is used as the source of the trigger The softkey labeled slope allows you to change what type of edge you want to trigger on rising falling or either See what happens if you change this from rising to falling Also try changing the trigger level i e the voltage at which the trigger will occur with the knob labeled Level EENG 383 Microcomputer Architecture and Interfacing Edge Trigger Menu a ooUrce gt Figure 4 Edge trigger menu To use cursors press the Cursors button on the front panel This should bring up the menu shown in Figure 5 On the leftmost softkey select mode Normal to indicate you want decimal numbers to be displayed instead of binary or hexadecimal To change where the two vertical cursors are displayed select X on the 3 softkey from the left Select X1 using the 4 softkey and then use the Entry knob see Figure 1 to adjust the position of the first vertical cursor Similarly you can adjust the position of the second vertical cursor by selecting X2 and adjusti
12. ted LED to adjust the position of the selected cursor See if you can adjust the cursors to measure the period and amplitude of the waveform on channel 1 as shown in Figure 9 10 EENG 383 Microcomputer Architecture and Interfacing MM Pos DODDS 0 00 Cursor 2 0 00s 4 724 CH1 Z 2 564 CH1 2 00 i M 500 us Hi i 19 Aug 13 22 23 Figure 9 Adjusting the cursors Finally you can capture the image on the display to a file on a USB flash drive This is useful to in creating lab reports To do this plug a USB drive into the port on the front panel Then press the Save Recall button This will bring up the Save Recall menu on the display Press the softkey labeled Save this will save the image to a file on the USB drive Some tips The Auto Scale button is helpful when you press it the oscilloscope looks at the incoming signals and makes its best guess as to the settings for voltage scale and time scale to give a reasonable display It is a good starting point but you should be able to adjust things yourself to give you exactly the display you need The Measure button is also helpful the oscilloscope will display the amplitude and frequency of the waveform being displayed You can change the type of measurement to be displayed using the Entry knob 6 Skills Practice In this section you will use the oscilloscope to measure the frequency of the function generator Attach t
13. uit EENG 383 Microcomputer Architecture and Interfacing Figure 7 Oscilloscope probe The oscilloscope generates a square wave for testing purposes This signal is available on the metal tab marked with a square wave symbol on the bottom of the front panel in the area marked Probe Comp Next to it is another metal tab marked with the ground symbol Connect your two probe tips to the square wave tab and the two ground clips to the ground tab Press the Auto Scale button You should see the waveforms shown in Figure 6 Experiment with the horizontal controls You can change the time scale of the displayed signals i e number of seconds per division and also shift the entire waveform left or right The time per division is shown at the top of the screen Experiment with the vertical controls You can change the vertical scale of a signal 1 e number of volts per division and also shift the entire signal up or down Note the position of the little arrow at the left of the trace which indicates the position of ground The volts per division is shown at the bottom of the screen There is independent control of each waveform Use channel 1 knob for waveform 1 and similarly for waveform 2 Now let s experiment with the trigger controls Press the Trig Menu key in the trigger area This should bring up the Trigger on the display Figure 8 EENG 383 Microcomputer Architecture and Interfacing M Pos 0 000s TRIGGER
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