E3VB Education Engagement Electrical Validation Board Experiment Description Sep 2013 Intel Contacts: Dennis Griffith, Mike Anderson, Tony Muilenburg Page 1 of 49 Contents Overview ...................................................................................................................................................... 4 Schematic Overview .................................................................................................................................. 4 Layout Overview ......................................................................................................................................... 5 Routing Examples ...................................................................................................................................... 6 Clocks .......................................................................................................................................................... 7 Experimental Setup.................................................................................................................................... 8 Experiments ................................................................................................................................................ 8 Blocks ....................................................................................................................................................... 8 Crosstalk Circuit 1 .................................................................................................................................. 9 Crosstalk Circuit 2 ................................................................................................................................ 12 Decoupling Circuit ................................................................................................................................ 16 Corners and Vias.................................................................................................................................. 18 Mystery Traces ..................................................................................................................................... 20 Simultaneous Switching Outputs ....................................................................................................... 24 LCR Transmission Line ....................................................................................................................... 26 Driver Circuit ......................................................................................................................................... 28 Package Differences............................................................................................................................ 31 Intersymbol Interference ..................................................................................................................... 33 Appendix .................................................................................................................................................... 36 1.1: Clock Design ................................................................................................................................. 36 1.2: Board Layers ................................................................................................................................. 36 1.3: Clock Drivers ................................................................................................................................. 40 Driver U9:........................................................................................................................................... 40 Driver U14: ........................................................................................................................................ 41 1.4: Mystery Traces ............................................................................................................................. 42 Routing ............................................................................................................................................... 42 Probe Points...................................................................................................................................... 44 1.5: Integrated Circuits ........................................................................................................................ 44 Page 2 of 49 1.6: Schematic Contents ..................................................................................................................... 44 1.7: Experiment Headers .................................................................................................................... 45 Page 3 of 49 Overview The Education Engagement Electrical Validation Board was created as part of an initiative called Intel Learning Company 2.0 to engage with university and help teach students electrical validation concepts. The board is made up of several circuits designed for hands-on experiments that can be conducted using a low bandwidth oscilloscope. These experiments demonstrate the importance of adhering to good design practices when laying out and routing signals on a board. The board is configurable using sockets and jumpers so that the student can see the difference in signal integrity when following or violating good design practices. The physical board is shown in Figure 1. Figure 1: E3VB board Schematic Overview The schematic is available in PDF format, with the experiments grouped in one or two pages. Ten main experiments are listed, though many more signal integrity concepts can be demonstrated. Figure 2 shows an example schematic circuit diagram. See appendix 1.8 for the schematic contents. Page 4 of 49 Figure 2: Schematic diagram example from the “corners and vias” experiment Layout Overview The board file can be opened using Allegro free physical viewer. The tool can be used to search for components, signals, integrated circuits, etc. A snapshot of the top layer is shown in Figure 3 with signal routing visibility disabled. A snapshot of each of the layers is available in appendix 1.2. Page 5 of 49 Figure 3: Top layer of the EV board Routing Examples Figure 4 and Figure 5 show examples of routing on the board. Many of the signal traces are very long, routed too close to others, or violate routing practices. These characteristics are ideal for demonstrating common signal integrity issues. Page 6 of 49 Figure 4: Layer "Signal 1" Figure 5: Layer "Signal 2" Clocks Two sets of clocks are used to feed the ten experiments. The clock frequency for the first five experiments and experiment 7 are driven from the first set. This clock is selected and enabled by populating one jumper on each of two header pin sets. The first set is labeled J54, and is shown in Figure 6 with 1 MHz selected. The second set is labeled J71, and provides the clock signal for the remaining experiments. Four frequencies are available including: 1 MHz, 2 MHz, 4 MHz, and 8 MHz. See Appendix 1.1 for more information about how the clocks are generated. Figure 6: The 1 MHz clock is selected using a jumper Page 7 of 49 Experimental Setup Power for the board is provided using mini USB. The cable can be plugged into a wall adapter, or laptop computer. Signals are measured using an oscilloscope with a recommended bandwidth of 500 MHz or more. Signals are probed using normal oscilloscope probes, or a BNC to BNC cable for two of the experiments. Figure 7 shows the BNC to BNC connector attached to the board. Header pins are provided for oscilloscope probing, as demonstrated in Figure 8. Figure 8: Probe connections Figure 7: BNC Connection to the board Experiments In this section, we will walk through the ten experiments, describing how to configure the board and connect probes to outputs in order to measure the signals. Blocks The experiments are broken into blocks as much as possible, and outlined in white on the board. Figure 9 shows the location of each of the experiments overlaid on the board. The BNC connectors are oriented up. Page 8 of 49 Figure 9: Experiment Blocks Crosstalk Circuit 1 The first experiment was designed to show the effects of crosstalk. A signal is driven down a long trace that has two traces routed closely to it on either side. The trace in the middle is called the victim trace, and the traces next to it are called aggressors. Figure 10 shows the victim trace routing. Figure 11 and Figure 12 show the aggressors. Page 9 of 49 Figure 10: Victim trace Figure 11: Aggressor 1 trace Figure 12: Aggressor 2 trace Each of the three traces can be configured independently to behave in one of three ways: toggle, stay high, or stay low. When in toggle mode, the clock is routed to the signal. The effect Page 10 of 49 the aggressor traces have on the victim can be viewed and measured using an oscilloscope. Figure 13 shows the schematic diagram for the victim trace. The aggressors schematic blocks look the same. The signal comes into a header that is designed to provide three selectable inputs: High, Low, and Toggle. For the victim trace, the header is labeled J30. The board also has a label “V” next to this header. The aggressors can be configured similarly using headers J24 and J28 (also labeled A1 and A2). Figure 13: Victim schematic diagram Figure 14 shows where the experiment is located on the board (circled in white). Figure 14: Crosstalk circuit 1 location The inverting buffer chips labeled U6 and U3 are socketed so different chips can be tried and compared for this experiment. Both sockets should be stuffed as shown in Figure 15. Page 11 of 49 Figure 15: Inverting buffer integrated circuit stuffed in socket U6 If a clock frequency has not yet been enabled, this should be done by stuffing one of the header pins labeled 1MHz, 2MHz, 4MHz and 8MHz in the center of the board with a jumper. This header is labeled J54. Victim Output Exercise Connect the oscilloscope to the victim output labeled J43. Capture the output for the victim signal when the victim and both aggressors are toggling at 1MHz. Zoom in on the rising and falling edges. How does the signal change when the aggressors are disabled vs enabled? The quality of the victim signal when the aggressors are switching is dependent on the quality of the chip used. Repeat the exercise for two different chip types, and compare the results. Two possible chips could be: sn74ac04n 74f04N While the inverting buffer between the transmission line and output cleans up much of the distortion on this transmission line. There is still significant distortion on the output. Crosstalk Circuit 2 This experiment is similar to crosstalk circuit 1, but the victim signal is differential, and the chips are soldered down rather than socketed. The victim portion of the schematic is shown in Figure 16. The aggressor traces are routed the same as the aggressor (and victim) traces from the first crosstalk circuit. Page 12 of 49 Figure 16: Differential victim circuit design Routing for the victim and aggressor are long and close together as shown in Figure 17 and Figure 18. Figure 17: Differential victim trace (green dashed line) Page 13 of 49 Figure 18: Aggressors surrounding the victim signal (green dashed line) The location of the circuit for this experiment is shown in Figure 19 circled in white. Figure 19: Crosstalk circuit 2 location Similar to the first experiment, pattern selection headers are provided to set the signals high, low, or to toggle. When in toggle mode, the clock is routed to the trace. The jumpers used to select the pattern are as follows: Aggressor 1: J45 Aggressor 2: J44 Page 14 of 49 Victim: J46 To set the signal low, leave the jumper unpopulated. Populating the jumper on pins 1 and 2 will set the signal high, and stuffing 2 and 3 will set the signal to toggle up and down. Outputs can be measured at the following pins: Victim Output: J32 Aggressor 1 Output: J37 Aggressor 2 Output: J67 Exercise Unlike the previous experiment where the victim signal was referenced to ground, the positive victim signal will be referenced to the negative victim signal in this exercise. Figure 20 shows how the differential signal is built. The top signal is the positive leg of the signal, probed from J64 to ground. The signal in the center is the negative signal probed from J65 to ground. The bottom signal is the combined differential signal probing from J65 to J64. Note: all three of these signals were probed at the start of the transmission line. Figure 20: Differential signal made up of the combined positive and negative signals Page 15 of 49 To see the effects of crosstalk on the signal, enable the aggressor traces and set them to toggle. To enable the aggressor traces, populate jumpers J63 and J42. Next, the aggressors should be set to toggle, which will create noise on the differential signal. Aggressor 1 can be set at header J45, and aggressor 2 can be set at header J44. How does the victim channel look when: Neither of the aggressors are enabled? Aggressor 1 is enabled and toggling? Both aggressors are enabled and toggling? Only aggressor 2 is enabled and toggling? Repeat the above set of experiment for the case where the victim is toggling, and the case where the victim lane is not toggling. What is the amplitude of the distortion for each case? Decoupling Circuit It is important for high speed signal design to prevent undesired coupling between circuits. One way to reduce coupling is to add capacitance. Good grounding is another important aspect. Exercise 3 explores both of these. Figure 21 and Figure 22 show how the chips for this exercise are fed. The amount of capacitance for the voltage feeding the chips can be changed by adding a jumper to J78 labeled VCCIN. The grounding can be changed by adding a jumper to J69 labeled SGND. Figure 21: Input capacitance Figure 22: Ground jumper Page 16 of 49 The decoupling circuit can be found on the middle left side of the experiment board (circled in white in Figure 23). Figure 23: Decoupling circuit Decoupling Exercise The output for this experiment can be measured at the header block labeled: Lo T T T T Hi (J48 – J53). The outputs labeled T look similar to each other. Capture waveforms at the output for the case where VCCIN is populated, and compare the output to the case where the jumper is not populated. What is the difference in circuit behavior? Grounding Exercise The ground provided for the inverting buffer goes through a long high impedance trace when jumper J69 is removed. Figure 41 shows the routing for this trace. Figure 24: High Z Trace to Ground Page 17 of 49 Measure the impedance for this trace with the jumper removed. Adding the jumper J69 connects the point directly to ground. How does the signal compare when the header labeled SGND is populated with a jumper vs unpopulated? Zoom in on the rising and falling edges of the signal. Corners and Vias When routing a circuit board, it is important to be careful not to make corners too tight, and to minimize the number of vias. This exercise will explore what the signal looks like with poor routing. Figure 25, Figure 26, and Figure 27 show routing for three different traces labeled VTP, CTP, and TLTP. The TLTP trace is the optimally routed, while VTP has lots of vias, and CTP has lots of corners. Figure 25: TLTP Trace Figure 26: VTP Trace Page 18 of 49 Figure 27: CTP Trace (over two layers) The circuit is pretty simple. The clock signal comes in, goes through an inverting buffer, down a trace, and through another inverting buffer. The general circuit topology is shown in Figure 28. There are test points at the beginning of the trace, the end, and at the output. Figure 28: General circuit topology Figure 29 shows where the location of the experiment on the board. Page 19 of 49 Figure 29: Corners and vias experiment location The test points include: VTP start: J58 CTP start: J59 TLTP start: J57 VTP end: J56 CTP end: J47 TLTP end: JJ61 Vout: J60 Cout: J47 TLout: J62 Exercise Compare the rising and falling clock edges for the three signals. How do the edges compare when probing at the start of the trace, and the end of the trace. Note: The difference may be small enough that it is hard to measure. Mystery Traces For this exercise, the oscilloscope will be used to find trace length and impedance using a technique called Time-domain reflectometry (TDR). A signal is sent down the trace, and signal corruption due to reflections will be measured to determine trace characteristics. Trace length is determined, by measuring time, and impedance is determined by measuring voltage level. Exercise Page 20 of 49 Figure 30 shows the location of the circuit components and trace selector on the top of the board. Figure 30: Mystery traces exercise location Adding a jumper to Header J14 will enable the clock on one of eight traces, each of which is routed differently. Figure 31 shows an example of the rising edge of the corrupted signal, and how the trace length can be determined by the duration the signal stays at one level. In this example, there are three different segments each with different impedance. The impedance can be determined by the voltage level, and the trace width can be calculated from this. The routing is shown in Figure 32 . Figure 31: Mystery trace example Page 21 of 49 Figure 32: Trace 5 routing To measure the signal, a BNC connector is attached from the scope to the U1 connector on the board. The shape of the rising edge of the signal is captured from which information about the signal can be determined. In addition, probe points were placed between each of the trace sections to help demonstrate how each leg of the trace contributes to the shape of the signal. Figure 33 shows the circuit diagram. Page 22 of 49 Figure 33: Circuit Diagram The layer, size, and time for each of the traces are captured in the following table: Experiment Layer 1 S1 2 S2 3 S1 4 S2 5 S1 6 S3 7 S1 8 S2 Trace 1 Size (mil) 40 6 20 10 20 6 40 40 Time (nS) 2 3 2 3 2 4 2 2 Layer S2 S3 S4 Trace 2 Size (mil) 20 20 8 Time (nS) 2 2 4 Layer S3 Trace 3 Size (mil) 6 Time (nS) 2 S4 6 2 S2 40 2 S4 S3 6 6 2 3 S2 12 2 Additional probe points are available and outlines in the appendix under the mystery traces section. Page 23 of 49 Simultaneous Switching Outputs When multiple outputs switch simultaneously, it is difficult for power distribution to keep up. The ground potential for the device briefly raises compared with the system ground. This effect is known as simultaneous switching noise, or ground bounce. Induction in the board, traces, and components keep power from being delivered instantaneously. This exercise is designed using counters that feed a driver so that many edges line up only some of the time. The location of the exercise on the board is shown in Figure 34. Figure 34: Simultaneous switching exercise location The circuit for this exercise is made up of eight signals that feed a driver. Two counters provide seven square waves that feed seven of the signals. The eighth signal is DC voltage with the level controlled by a potentiometer labeled CW LOWER (designator U20). The threshold can be changed by turning the screw on the potentiometer, and measured at header J88. Exercise To begin this exercise, enable the counters by populating header J87 (next to the potentiometer) with a jumper. The output of each of the seven signals is made available at header J102. Each output is a square wave with twice the period of the preceding as shown in Figure 35. The clock was captured along with the signals for comparison (J93). Page 24 of 49 Figure 35: Driver outputs, and clock in When the 1 MHz signal is selected for the clock, the frequency of each output is as follows: Output 0 1 2 3 4 5 6 Frequency (kHz) 250 125 62.5 31.3 15.6 7.8 3.9 When the 8 MHz signal is selected, each clock frequency increases by a factor of 8. Every 128 clock cycles all seven of the counter signals switch at the same time. This creates a spike on the output signal. The same thing can happen even when only a few of the signals switch, though the amplitude of the distortion will be smaller. Measure the output, hit run and stop on the oscilloscope many times to view different noise profiles, or set the trigger level high to view spikes created by switching. Compare the signal with the clocks enabled and disabled. Page 25 of 49 Enable persistence on the oscilloscope to see what the output looks like over many superimposed cycles. LCR Transmission Line For this experiment, a clock signal is sent down a transmission line that can be lengthened using jumpers, or outfitted with resistors, inductors and capacitors to mimic trace characteristics for high speed signals. Clock 7 first goes through an inverting buffer, then has a connection for a BNC connector to make measurements. From there, the trace extends across the board with jumper headers that can be populated with the elements. The inverting buffer block is labeled U5, and the BNC connector U2. The schematic for this circuit is shown in Figure 36, and the location on the board is shown in Figure 37. Figure 36: LCR Transmission Line Circuit Figure 37: Location of the LRC Transmission Line Exercise Page 26 of 49 Figure 38 shows the routing for the transmission line. Figure 38: Transmission line routing Exercise To begin, take a look at how the signal changes due to lengthening the trace. The transmission line is made as short as possible by removing the four jumpers that extend the transmission line: TL1, TL2, TL3, and TL4 with designators: J26, J110, J2, and J111. Compare what the signal looks like when each of the next stages are enabled. Many configurations can be explored by adding resistors and capacitors to the legs rather than just extending them with jumpers. Figure 39 shows three examples. The ISI exercise has another example of a possible block in the circuit (an inductor and capacitor). Page 27 of 49 Figure 39: Three possible configurations Driver Circuit This circuit provides an environment to compare driver technology. Relatively inexpensive drivers exist that cannot switch as quickly as the more expensive ones. Some drivers can switch the rising edge quickly, but not the falling edge, etc. Sockets are provided on the board so that the driver chips can be swapped out. Here is a recommended list of chips to try: Chip 74C04 74HC04 74F04 74AC04 Description Inexpensive weak driver Medium Speed Fast rising edge, slow falling edge Fast on both edges The circuit is similar to that used in the crosstalk exercise, and is shown in Figure 40. The trace labeled SGTP (slotted ground test point) is routed over a slot in the ground plane, making it more susceptible to noise. Figure 41 and Figure 42 show the routing. Test points are available at the beginning of the trace, the end, and at the output after going through the inverting buffer. The sockets provided for the inverting buffers are labeled U18 and U17. Figure 40: Driver Circuit Page 28 of 49 Figure 41: Routing for Signal SGTP (in blue) Figure 42: Routing for signal TP (in blue) Figure 43 shows the section of the SGTP trace that is routed over a slot in the ground plane. Page 29 of 49 Figure 43: SGTP signal routed over a slot in the ground plane Exercise To begin this exercise, compare the 74AC04 chip to the 74F04 chip when used as a circuit driver. Measurements can be taken at the end of the transmission line for both the TP trace and the SGTP trace. Figure 78 shows the location of the circuit for this exercise on the board. Figure 44: Driver Circuit Location The first measurement can be taken for signal TP at header J72. Page 30 of 49 Package Differences This exercise was designed to show differences in signal quality due to package type used. The chips are all soldered down to the board, so four circuits are provided which are the same. Figure 82 shows one of these four circuits. The input signal (the clock) goes through the chip, then down a long transmission line. The traces of interest are labeled “Near” and “Far” and are routed differently. Measurement points are provided at the start and end of the transmission line. The measurement points close to the start of the traces for the four circuits are as follows: Probe points at the start of the Transmission line Signal “Near” Signal “Far” 9_1 D1 9_1 D2 9_2 D1 9_2 D2 9_3 D1 9_3 D2 9_4 D1 9_4 D2 Measurement points at the end of the traces are: Probe points at the end of the Transmission line Signal “Near” Signal “Far” 9_1 S1 9_1 S2 9_2 S1 9_2 S2 9_3 S1 9_3 S2 9_4 S1 9_4 S2 Figure 45: Package Difference Circuit Topology Page 31 of 49 The package type and size used in this exercise are as follows: The circuit for this experiment is located on the bottom of the board, circled in Figure 46 in white. Figure 46: Package Difference Circuit Location Routing for the SOIC chip is shown in Figure 47 for the “far” signal, and Figure 48 for the “near” signal. Page 32 of 49 Figure 48: SOIC “Near” Trace Figure 47: SOIC “Far” Trace Exercise For this exercise, signals are driven with four chips each of which has a different package. The signal can be compared for each package type. Intersymbol Interference Intersymbol interference signal distortion is a result of previous symbols interfering with the current symbol. As an example, this could affect the duty cycle. Page 33 of 49 To create this effect, this exercise uses a counter which feeds into shift registers. The output is then driven down a circuit similar to the driver circuit, but with an inductor and capacitor, as shown in Figure 49. These elements help simulate what the circuit response would look like if a high speed interface was used. Figure 49: ISI Circuit Design Switches are provided which the shift registers use to create the signal See Figure 50. Figure 50: DIP Switches Experiment The circuit for this exercise is located in the center bottom portion of the board, and is circled in white. See Figure 51. Page 34 of 49 Figure 51: ISI Circuit Location Three probe points are provided for this experiment: In: J89 Out: J86 TLine: J82 Exercise Configure the dip switches to create different patterns, and observe the effect the patterns have on future signals. Duty cycle is one area of interest when observing signal integrity impacts. As an example of what to expect from toggling the switches, an example configuration is shown in Figure 52, along with the signal in Figure 53. Figure 52: Jumper configuration for the ISI exercise Page 35 of 49 To trigger with the oscilloscope, it is useful to use output 2 of header J102 (from the simultaneous switching exercise). This output allows for triggering on a 62.5 kHz signal when the clock is at 1MHz, and a 500 kHz signal when the clock is set to 8 MHz. This is ideal to capture waveforms for this exercise. Figure 53: In vs Tline vs Out using the 1 MHz clock Compare the input to output signal, and to the transmission line. Does the input always follow the ouput? Appendix 1.1: Clock Design The clock was designed using a binary counter. Each of the four outputs is equivalent to a clock with a different frequency. Figure A1 shows an example. Figure A1: Binary counter outputs 1.2: Board Layers Each of the layers with signals routed can be seen in the following figures Page 36 of 49 Figure A2: Top Routing Page 37 of 49 Figure A3: Bottom routing Page 38 of 49 Figure A4: Signal 1 routing Page 39 of 49 Figure A5: Signal 2 Routing 1.3: Clock Drivers Driver U9: 1_1: Crosstalk circuit 1 1_2: Crosstalk circuit 2 2_1: Crosstalk circuit 2 2_2: Corners and Vias 3: Mystery Traces Page 40 of 49 4: Simultaneous Switching 5: Crosstalk circuit 1 7: Decoupling Driver U14: 6: Driver Circuit 8: LCR T-line 9_1: Package Differences 9_2: Package Differences 9_3: Package Differences 9_4: Package Differences 10: Intersymbol interference (one pin is a no-connect) Page 41 of 49 1.4: Mystery Traces Routing Page 42 of 49 Page 43 of 49 Probe Points Trace 1 2 3 4 5 6 7 8 Probe Point 1 2 J117 J5 J11 J7 J9 J8 J91 J6 J114 J107 J116 J13 J16 J115 3 J12 J27 J4 1.5: Integrated Circuits TPS79601DCQG4: ULTRALOW-NOISE LINEAR REGULATOR SN74HC191D: POSITIVE EDGE TRIGGERED 4-BIT BIDIRECTIONAL BINARY COUNTER CD74AC04M: HEX Inverter, AC-CMOS, 14 Pin, Plastic, SOP SN65LVDS1DR: High-Speed Differential Line Driver/Receiver SN74AC11240DW: SOIC SO24 package, Octal Buffer/Line Driver with 3−State Outputs, inverted output SN74AC240PW: TSSOP Package, Octal Buffer/Line Driver with 3−State Outputs, inverted output MC74AC240DW: SOIC SO20 Package, Octal Buffer/Line Driver with 3−State Outputs, inverted output SN74AC240N: DIP Package Octal Buffer/Line Driver with 3−State Outputs, inverted output SN74LV165ARGYRG4: Counter Shift Registers Parallel-Load 8-Bit Shift Register MC74HC04ADR2G: Hex inverter 1.6: Schematic Contents 1. Education Engagement EV Board 2. Power Supply and Regulator 3. Clock Generation 4. Crosstalk Circuit #1 5. Crosstalk Circuit #1 - Spares 6. Crosstalk Circuit #2 7. Crosstalk Circuit #2 - Spares 8. Decoupling Circuit 9. Corners and Vias Page 44 of 49 10. Corners and Vias - Spares 11. Mystery Traces 12. Simultaneous Switching Outputs 13. LCR T-Line 14. Driver Circuit 15. Driver Circuit - Spares 16. Package Differences - SOIC / TSSOP 17. Package Differences - DIP / 74AC11240 18. Intersymbol Interference 19. Intersymbol Interface - Output & Spares 20. Mounting holes - TDR Test Point 1.7: Experiment Headers Experiment 1: Crosstalk 1 J17: Aggressor 1 transmission line test point (beginning) J18: Aggressor 1 output test point J19: Victim transmission line enable J20: Victim transmission line test point (beginning) J21: Aggressor 2 transmission line test point (beginning) J22: Aggressor 2 output test point J24: Aggressor 1 pattern select J28: Victim pattern select J29: Aggressor 1 transmission line enable J30: Aggressor 2 pattern select J31: Aggressor 1 transmission line test point (end) J35: Victim transmission line test point (end) J38: Aggressor 2 transmission line test point (end) J41: Aggressor 2 transmission line enable J43: Victim output test point Page 45 of 49 Experiment 2: Crosstalk 2 J66: Aggressor 1 transmission line start test point J37: Aggressor 1 output test point J64: Victim transmission line start test point (positive) J65: Victim transmission line start test point (negative) J40: Aggressor 2 transmission line start test point J67: Aggressor 2 output test point J44: Aggressor 2 pattern select J45: Aggressor 1 pattern select J46: Victim pattern select J63: Aggressor 1 transmission line enable J33: Aggressor 1 transmission line end test point J36: Victim transmission line end test point (positive) J39: Victim transmission line end test point (negative) J68: Aggressor 2 transmission line end test point J42: Aggressor 2 transmission line enable J32: Victim output test point Experiment 3: Decoupling J78: VCCIN decoupling enable J70: Clock in test point J69: SGND: Direct ground J48: Test point Low J49: Test point toggle 1 J50: Test point toggle 2 J51: Test point toggle 3 J52 Test point toggle 4 J53: Test point high Experiment 4: Corners and vias Page 46 of 49 J73: Clock in test point J57: TL transmission line test point (beginning) J61: TL transmission line test point (end) J62: TL out test point J58: V transmission line test point (beginning) J56: V transmission line test point (end) J60: V out test point J59: C transmission line test point (beginning) J47: C transmission line test point (end) J55: C out test point Experiment 5: Mystery Traces U1: BNC connector test point J14: Trace selector Experiment 6: Simultaneous switching J93: Clock in test point J87: Counter enable J90: Count up/down select J95: RCO: ripple carry over J100: Min/Max J88: Input threshold test point J102: Output test points 0 through 6, and out Experiment 7: LCR transmission line U2: BNC connector test point J26: Stage 1 upper J25: Stage 1 lower J110: Stage 2 upper J109: Stage 2 lower J2: stage 3 upper Page 47 of 49 J3: stage 3 lower J111: stage 4 upper J112: stage 4 lower Experiment 8: Driver comparison and slotted ground J81: slotted ground transmission line test point (beginning) J75: slotted ground transmission line test point (end) J76: slotted ground output test point J77: transmission line test point (beginning) J72: transmission line test point (end) J74: output test point Experiment 9: Package differences J105: 9_1_S1 - test point (beginning) J106: 9_1_S2 - test point (beginning) J98: 9_1_D1 - test point (end) J99: 9_1_D2 - test point (end) J104: 9_2_S1 - test point (beginning) J103: 9_2_S2 - test point (beginning) J97: 9_2_D1 - test point (end) J96: 9_2_D2 - test point (end) J101: 9_3_S1 - test point (beginning) J94: 9_3_S2 - test point (beginning) J80: 9_3_D1 - test point (end) J79: 9_3_D2 - test point (end) J83: 9_4_S1 - test point (beginning) J84: 9_4_S2 - test point (beginning) J108: 9_4_D1 - test point (end) J113: 9_4_D2 - test point (end) Page 48 of 49 Experiment 10: Intersymbol interference S1: Dip switches S2: Dip switches J89: In test point J82: Transmission line test point (beginning) J86: Output test point Other Clock frequency selectors J54: Block 1 J71: Block 2 Page 49 of 49