Lab 1: Using the Lab Hardware and Reading Datasheets 1.9 2004/07/23 12:17:39 GMT-5 2005/08/24 16:51:29 GMT-5 Adrian Valenzuela adrianv@rice.edu Adrian Valenzuela adrianv@rice.edu Patrick Frantz jpfrantz@rice.edu ELEC226 Function Generator Oscilloscope In this lab we will learn how to use tools such as the function generator and the oscilloscope. We will also learn the basics to reading datsheets and schematics. Reproduce each of the following figures as closely as possible, and include a screenshot in your write up. Don't forget to include the measurements and cursors. Some of the input signals have introduced an offset. If you are using the Tektronix TDS 3012B and it has an ethernet connection, you can easily take screenshots of the display. Simply type the IP address of the oscilloscope into your computer's web browser, and it will connect to the scope's web interface. If you don't know the IP address of your scope, restart it. The 3012B will display its current address during it's start up sequence. Once you're connected to the scope from your web browser, you may save the image of the current display or control it through the web interface. By default, the oscilloscope acquires the signal with a very rough sampling process. If you wish to improve the quality of your display you may change the Acquisition Mode. You may do this by going to Quick Menu-> Acquire Mode then changing the mode. Averaging several samples will give you a much smoother looking result.

Figure 1: Sine Wave Sine wave with measurements and cursors

Figure 2: Square Wave Square wave with measurements and cursors

Figure 3: FFT of Sine Wave Sine wave and it's FFT. FFT options may be found under the Math section.

Now we will measure a couple signals directly on the ELEC226 board and learn how to read a schematic. Download lab1_2_lite.hzx. Open CrossStudio Release 1.3, and set your target as the MSP430 USB CrossConnect. You can do this by clicking on View-> Targets. The Targets window should open up on the right panel. Right click on MSP430 USB CrossConnect and select Connect. You may download the project file to the MSP by selecting Download File-> Download CrossWorks Executable File and navigating to the desired file. Now locate the two high frequency crystal oscillators. They are small silver cylinders. Directly probe the two oscillators, and measure their respective frequencies. Next, using the schematic locate the pin that outputs SMCLK or MCLK. (Use the pin on Port 5.) This is currently configured to output one of the oscillators. Probe this pin and compare with the results that you obtained probing the oscillators directly. Next, using the schematic locate the output pins for DAC0. Measure the peak-to-peak amplitude, and frequency of the signal and include a screenshot. Next, we will run a couple signals from the function generator through the board's Analog to Digital Converters (ADC) and measure it a couple different places. Download lab1_3_lite.hzx. Download the file like you did in Problem 2. Set your function generator to produce a signal less than 2 kHz. Connect it to the input of A1, analog input 1, and measure the signal at the output of DAC0. Try to recreate the following figure.

Sine wave through ADC and DAC

What happens are you increase the frequency or amplitude of the input signal? At what frequency does the signal very become skewed?