EGR 240 Lab 1. May 3-4, 2006. Rev. A

EXPERIMENT: D/A Converter – Soldering, Use of Multimeter and Oscilloscope

References

  1. Lecture slides D2.2: Digital to Analog (D/A) Converter.
  2. Tektronix TDS 210 Oscilloscope User Manual (available on class website)
  3. Keithley multimeter user manuals, 175A, 179A (available on class website)
  4. http://www.dannyg.com/examples/res2/resistor.htm

LAB

Part A. Soldering.

1. Solder the 2R-R resistor network shown in Figure 1 on the board provided to you in the lab. You will keep this circuit to use in future Labs.

Figure 1. 2R-R Resistor Network Layout and Schematic


Part B. Multimeter.

1. Connect the inputs [B3:B0] to the four toggle switches, S7, through header J7. When a toggle switch is set to H the corresponding output on J7 will be 5V. When a toggle switch is set to L the corresponding output on J7 will be ground or 0V.

Figure 2. PLDT-3 Board Connections.

2. Measure the voltage V using a multimeter as you change the toggle switches from 0000 to 1111. Record your results in Table 1.

Table 1

Switches / Decimal Value / Voltage V
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111

Part C. Oscilloscope.

1. The Xilinx 95108 CPLD is programmed to produce four square waves on pins 31, 32, 33, and 34 on headers HD3 and HD4. Measure these square waves on an oscilloscope and record the voltage and frequency of each signal in Table 2.

Table 2

Signal / Max. voltage, V / Frequency, KHz / Period, ms
Pin 31
Pin 32
Pin 33
Pin 34

2. Connect the inputs [B3:B0] in Fig. 1 to pins 31, 32, 33, and 34 in header HD3 and HD4. Measure the voltage, V, in Fig. 1 on the oscilloscope. Set the time scale to display one complete cycle of the waveform. Sketch the waveform on the screen layout below. Indicate the time scale and the voltage scale.

Volts/Division (vertical)

______

Time/Division (horizontal)

______

Oscilloscope Screen Layout

Have your lab instructor sign your results.


Answer questions 1 – 4 on the class website for next week:

1. What is the resistor color code for each of the following resistor values?

a. 10 W

b. 2.2 KW

c. 390 W

d. 5.6 MW

e. 47 KW

f. 820 KW

2. What is the resistor value for each of the following color codes?

a. orange-white-red

b. black-brown-orange

c. yellow-violet-yellow

d. green-blue-green

e. blue-gray-black

f. red-red-brown

3. Use Excel to plot the voltage V as a function of the decimal values of the switches from Table 1. Explain the result.

4. Plot the four waveforms from Pins 31, 32, 33, and 34 on the same page using the same scale. Include 8 periods of the Pin 34 waveform. Explain how these four waveforms produce the 16 binary values shown in Table 1. Show a plot of V measured in Part C and explain the result.

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