DORDT COLLEGE ENGINEERING DEPARTMENT
EMBEDDED MICROCOMPUTER SYSTEMS--EGR 304
(Spring 2017)

PROBLEM SETS

(Last update: 5/01/2017 8:34 pm)
PS
#   		Assigned Due Returned Assignment
10

4/20 4/27 5/01   Topics: A/D and D/A conversion
  Read: Slides from class.
  Scan through Chapters 2 and 3 of The Data
  Conversion Handbook, 2005 ed. Walt Kester.
 
  Work the following problems;
  1.) A cell-phone quality voice signal was
  converted from analog to digital with a sampling
  rate of 8 kHz and 8 bits-sample. Unfortunately
  the anti-aliasing filter used was improperly
  designed. It actually had a cutoff frequency of
  of 8 kHz. Using graphs, show what happens if a
  5 kHz sinusoid is passed through this poorly
  designed digital to analog converter. (Ref: class
  slides from 4/13 and Ch. 2 of handbook, pages
  2.27-31 or pages 29-33 in some PDF readers.
  Especially note Figure 2.30 in the handbook.)
 
  2.) An 8-bit dual-slope analog to digital is
  desired to operate at 1000 samples per second.
  Specify the necessary minimum clock rate for the
  used in this converter. Explain your answer.
  (Ref: Ch 3 of handbook, pages 3.96, 3.97 or
  pages 98 and 99 in some PDF readers.)
 
  3.) Design a R-2R D/A converter with an 8-bit
  unsigned binary input to produce an output that
  spans from 0 volts to 2.55 volts maximum.
  Provide a complete schematic in the style of the
  slide from class on 4/18. Show resistor values.
  Assume a precision 3.3 volt reference supply is
  available but that it can supply no more than
  50 mA. Assume the operational amplifier has
  adequate power supplies and is ideal. Assume
  that resistor values above 200 kΩ are too
  large (dimensionally) to be practical.
9

3/21 4/04 4/10   Read Freescale's tutorials on motors.
  DC Motors
  Brushless DC Motors
  Stepper Motors
  Switched Reluctance Motors
  Brushless AC Motors
  (Now hosted by NXP, which bought out Freescale.)
  A few caveats about the above tutorials. . .
  In the illustration of the "Switched Reluctance"
  motor, the rotor will assume an induced
  magnetic field to oppose the applied magnetic
  field. This is not illustrated, probably
  because it might imply that the rotor is
  permanently magnetized, which it is not. It is
  just iron (or a steel alloy).
  In the illustration of the "AC Induction Motor"
  the coloration of the induced magnetic field
  in the rotor is backwards. According to Lens'
  Law, the induced field will oppose the applied
  magnetic field from the stator. Thus the red
  (north) pole of the stator will face a green
  (south) pole on the rotor, just as in any other
  motor.
 
  Also read this motor tutorial and
  also read Jones on Stepping Motors and
  optionally this control tutorial from
  "Process Automation Control." Much of what is
  described in the control tutorial is done via
  microcontrollers and relays, etc.
 
  Do these problems on motors
  Helpful link: Lin model 211-13-01 and note
  the "Torque Curves" tab.
 
  On 3/23 the due date on this assignment was delayed
  from 3/28 to 4/03.
8

2/28 3/21 4/10   Topic: Interrupts
  Read this overview on interrupts
  and this on Arduino interrupt programming
  and this on Raspberry Pi interrupt handling
  and this on WireingPiFunctions
 
  Do these problems on interrupts
  Errata: On problem 3.17 part (d) note that the
  only way for Tpi to be an average and a maximum
  at the same time is that the ISR is requested
  exactly every Tpi. This was the author's intent.
  (As opposed to allowing actual request
  intervals to sometimes exceed Tpi.)
 
  (On 3/02 the due date was extended from 3/14 to 3/21)
7

2/21 2/28 4/28   Browse the USB Standard version 2.0 on reserve
  in the library (Ask a librarian for it by
  name, "Universal Serial Bus Revision
  2.0 Specification." Also available from USB.org.
  If you download it from USB.org be sure to
  read the 2.0 version. (The 2.0 version
  superceeds the 1.0 version which is now
  withdrawn. However the 3.0 version is an
  addendum to the 2.0 version. It cannot stand
  on its own.)
 
  Do answer some essay questions on USB.
  To turn in your work, edit this file of essay
  questions to insert your answers, save it to
  your local hard disk (or other media) and then
  upload it to Canvas from your local storage.
 
  Optional Reading: USB article in Wikipedia
6

2/14 2/21 4/28   Study for the Test on Thursday, 2/16. Then. . .
  Read this Ethernet Tutorial.
 
  Take this twenty-question quiz on Ethernet.
  E-mail your quiz grade to Prof. De Boer.
  You are encouraged to repeat the quiz until
  you get a perfect grade. Turn in only your
  best grade.
 
  Optional: Example Python sockets using TCP/IP
  Optional: Books in Dordt's Library
  Optional: Wikipedia article Ethernet
5

2/07 2/14 4/10   Read A Guide to Debouncing
  Read RS-232 in Wikipedia
 
  Do this problem:
  Plot voltage vs. time of the Tx line in RS-232
  for sending this text: "Z#" (without the
  quotation marks, with a capital "Z"). Assume
  ±12 V signal voltages, 53 kbaud, eight data
  bits, and one stop bit. Be sure to label your
  axes properly. An ASCII table can be found in
  many places, e.g. http://www.asciitable.com
  Note that the illustration in the Wikipedia
  reading does not have properly labeled axes.
  Specifically the the independent axis lacks
  scale and units.
 
  Optional: The entire RS-232 standard is
  available from Dordt's library. Interface
  Between Data Terminal Equipment And Data
  Circuit-Terminating Equipment Employing Serial
  Binary Data Interchange TK7887.5 .I57 1997
 
  Optional: Read about teleprinters.
 
  Very Optional: Listen to a Teletype machine.
  And see a Teletype machine connected to a
  Digital Equipment Corporation (DEC, a brand)
  model PDP-8/e computer. This computer could be
  booted "manually" via a bank of switches that
  allows the direct entry of machine code word-by
  word, executing each instruction as fast as the
  operator can enter the code. Wow, that's fast!
 
  Optional: Example of RS-232 products. Many in
  this brochure support RS-232 for remote control.
4

1/31 2/07 2/14   Topics: Parallel interfacing, I/O Drivers
  Read about multiplexing LED's and also
  multiplexing a keypad. Also read about
  Debouncing a switch or keyboard (don't miss p2)
 
  Draw a schematic showing how to connect a two-
  digit common cathode 7-segment LED display
  and a 4x4 keypad to up to 12 bits of general
  I/O. Specify how each bit is used (Input,
  output, or bidirectional) There are many
  many valid correct methods. You may be able
  to share rows or columns between the 7-seg.
  display and the keypad. You may ignore the
  matter of key bounce. You may search the
  Web for additional help on this assignment.
 
  Optional: "epic" guide to keyboard internals.
3

1/24 1/31 2/14   Read this handout on transmission lines.
  (This copy might print better on your printer.)
 
  Scan over these application notes from Texas
  Instruments on transmission lines. Read
  The section in AN-807 on the "tabular method."
  AN-806, and AN-807, and AN-808.
 
  Do 2.1 and 2.6 in the first handout linked above.
 
  Optional: A transmission line theory tutorial
  Optional: Animation of VSWR on a T-line
  If the above java app will not run, look here.
  Optional note: The application notes linked above were
  origianlly developed by National Semiconductor.
  There is more on National Semi in Wikipedia.
  Optional: TI has purchased National Semi
 
2

1/17 1/24 2/14

Since this was an elec- tronic sub- miss- ion, no physical item to return 		  We will collaboratively document some of Git.
 
  On your own computer or on your "G: drive"
  create an empty folder called "PS-2". Do not
  inialize this folder as a repository in Git.
  Using Git Bash's "cd" command, change the
  working directory to your new empty "PS-2"
  folder. From Git Bash, clone Prof. De Boer's
  public respository named "PS-2" into your new
  "PS-2" folder. The URL to Prof. De Boer's
  public repository is
  https://github.com/dfdeboer/PS-2.git.
  The specific git command you need to do the
  clone operation is:
 
  git clone https://github.com/dfdeboer/PS-2.git .
 
  Notice the space and dot (period) on the end
  of the command. That causes the clone to be
  created in Git's current working directory.
  After cloning the remote repo to your filespace
  open your local copy of "Git_Commands. . ." and
  continue to follow instructions from there.
1

1/10 1/12 1/17

Since this was an elec- tronic sub- miss- ion, no physical item to return 		  Read "Embedded system" from Wikipeadia
  Read "System on a Chip from Wikipedia"
  Briefly browse the Raspberry Pi web site.
  Do the introductory problems
  Note the SoC chip on the R-Pi is the Broadcom
  part number "BCM2837R1FBG"
 
  Turn this problem set in electronically.
  Save your answers as doc or docx format.
  Enter this page via Canvas and click here,
  then follow instructions from Canvas to turn
  the assignment in.

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