Quiz < Embedded_Systems

<p align="center"><font face="Liberation Sans, sans-serif"><font size="6"> *Mid - Semester Quiz* </font></font></p> <h2 align="center">Embedded Systems course</h2> <h2 align="left">General remarks:</h2> <p align="left">In the following quiz more than one answer may be correct or all of the answers may be wrong.</p> <h2 align="left">Linux commands</h2>
   1 <p align="left">You have downloaded the file yesterday.txt into your Downloads directory, which is a sub-directory of your home directory, as is the directory exercises.<br /> You want to copy this file into the exercises/solutions/exercise_2<br /> First you do:<br /><br /> <font face="Courier New, monospace">cd </font><font face="Courier New, monospace">~/</font><font face="Courier New, monospace">exercises/solutions/exercise_3<br /><br /> </font><font face="Liberation Serif, serif" size="3"> *Which of the following commands will copy the file as desired?* </font></p>
   * <p align="left"><font face="Courier New, monospace"><font size="3">%BLUE%cp ~/Downloads/yesterday.txt%ENDCOLOR% .</font></font></p>
   * <p align="left">%BLUE%<font face="Courier New, monospace"><font size="3">cp $HOME/Downloads/yesterday.txt .</font></font>%ENDCOLOR%</p>
   * <p align="left"><font face="Courier New, monospace"><font size="3">cp $HOME/Downloads/yesterday.txt ..</font></font></p>
   * <p align="left"><font face="Courier New, monospace"><font size="3">cp ~/Downloads/yesterday.txt exercises/solutions/exercise_2</font></font></p>
   * <p align="left">%BLUE%<font face="Courier New, monospace"><font size="3">cp ~/Downloads/yesterday.txt $HOME/exercises/solutions/exercise_2</font></font>%ENDCOLOR%</p>
   * <p align="left">%BLUE%<font face="Courier New, monospace"><font size="3">cp ~/Downloads/yesterday.txt ~/exercises/solutions/exercise_2</font></font>%ENDCOLOR%</p>
<ol start="2"> <li> <p align="left"><font face="Liberation Serif, serif"><font size="3"> *You are the super user and you do:* </font></font></p> <p align="left"><font size="3"><font face="Courier New, monospace">cd /<br /> rm -rf <b><br /></b></font><font face="Liberation Serif, serif"><br />This will: </font></font></p> </li> </ol>
   * <p align="left"><font face="Liberation Serif, serif"><font size="3">print “permission denied” and do nothing</font></font></p>
   * <p align="left"><font face="Liberation Serif, serif"><font size="3">remove a file named ‘*’</font></font></p>
   * <p align="left">%BLUE%<font face="Liberation Serif, serif"><font size="3">wipe your complete operating system off the disk including all user files</font></font>%ENDCOLOR%</p>
   * <p align="left"><font face="Liberation Serif, serif"><font size="3">delete all files in the / directory except of directory files and their contents</font></font></p>
<p align="left"> </p> <ol start="3"> <li> <p align="left"><font face="Liberation Serif, serif"><font size="3"> *You type:* </font></font></p> <p align="left"><font face="Courier New, monospace"><font size="3">ls ~/Downloads &gt; downloads.txt<br /><br /> <font face="Liberation Serif, serif"> *What will it print?* </font></font></font></p> </li> </ol>
   * <p align="left"><font face="Liberation Serif, serif"><font size="3">All the file names in your Download directory</font></font></p>
   * <p align="left"><font face="Liberation Serif, serif"><font size="3">nothing, but it will create an empty file named downloads.txt</font></font></p>
   * <p align="left">%BLUE%<font face="Liberation Serif, serif"><font size="3">nothing, but it will create a file named downloads.txt with all the names of the files in ~/Downloads in it</font></font>%ENDCOLOR%</p>
   * <p align="left"><font face="Liberation Serif, serif"><font size="3">it will count the number of files you have in your Downloads directory</font></font></p>
---++ C programming

   1 <p><b>What does this function do?<br /><br /><img alt="sine.png" height="172" src="%ATTACHURL%/sine.png" title="sine.png" width="439" /><br /></b></p>
   * <p>%BLUE%It calculates and returns the value of the sin function of an angle, which must be given in degrees (the angle parameter must be a double value in degrees)%ENDCOLOR%</p>
   * <p>It calculates and returns the value of the sin function of an angle, which must be given radians (the angle parameter must be a double value in radians)</p>
   * <p>It returns an error message</p>
   * <p>It is simply plain wrong and does not compile</p>

<ol start="2"> <li> *Here is an add function and its calling main program in a single file . The file is named “add.c”. What does this program do?*

<b><br /></b><img alt="add.png" height="226" src="%ATTACHURL%/add.png" title="add.png" width="380" />
</li> </ol>
   * <p>It fails because the main program does not call the add function</p>
   * <p>It fails because the main program should call the add function with the right variable names num1 and num2 and not val1 and val2</p>
   * <p>%BLUE%It prints 6.0000 + 7.0000 = 13.0000%ENDCOLOR%</p>
   * <p>If does not compile because the add function must be in a different file</p>
   * <p>It does not compile because there is no add.h include file<br /><br /></p>

<ol start="3"> <li><b>Pointers<br /></b>You declare a pointer in this way:<br /><br /><font face="Courier New, monospace">char *helloWorld=”Hello World!”;<br /> </font><font face="Courier New, monospace"><font size="3">char *helloPtr = helloWorld;<br /><br /></font></font><font face="Liberation Serif, serif"><font size="3"><b>What is the value of the helloPtr</b></font><font face="Liberation Serif, serif"><b>?</b></font> </font></li> </ol>
   * <p>%BLUE%<font face="Liberation Serif, serif"><font size="3">The address of the character ‘H’</font></font>%ENDCOLOR%</p>
   * <p><font face="Liberation Serif, serif"><font size="3">The character H, which has the hex value of 0x48</font></font></p>
   * <p><font face="Liberation Serif, serif"><font size="3">It contains all the characters of the string “Hello World!”</font></font></p>
   * <p>%BLUE%<font face="Liberation Serif, serif"><font size="3">The same value as helloWorld</font></font>%ENDCOLOR%</p>
   * <p><font face="Liberation Serif, serif"><font size="3">none of the above</font></font></p>

---++ The Raspberry Pi
   1 <p> *What is gpio?* </p>
   * <p>%BLUE%a <b>G</b>eneral <b>P</b>urpose<b> I</b>nput<b> O</b>utput pin%ENDCOLOR%</p>
   * <p>%BLUE%the name of a command defined in the wiringPi library%ENDCOLOR%</p>
   * <p>a <b>G</b>eneralized <b>P</b>eripheral <b>I</b>nterface <b>O</b>ption</p>
   * <p>The Raspberry Pi does not have such a thing</p>

<ol start="2"> <li> *What is the I2C bus?* </li> </ol>
   * <p>A university shuttle bus taking Uli to the I2C hostel</p>
   * <p>An industry standard serial bus with only 3 connections:</p>
      * <p>Vcc</p>
      * <p>ground</p>
      * <p>a signal pin</p>
   * <p>%BLUE%An industry standard bus with 4 connections:%ENDCOLOR%</p>
      * <p>Vcc</p>
      * <p>ground</p>
      * <p>a data line (SDA)</p>
      * <p>a clock line (SCL)</p>
   * <p>The parallel bus connecting the CPU to memory and/or peripherals</p>
   * <p>none of the above</p>

---++ Understanding data sheets

Please read the [[http://www4.vmi.edu/faculty/squirejc/Research/IC_Datasheets/digital_cmos/Write%20Only%20Memory.pdf][attached data sheet]] and find out what the device does
   * <p>%BLUE%It is an April’s joke of a Sygnetics engineer and it is complete nonsense%ENDCOLOR%</p>
   * <p>It is a device that is used to store non-volatile information in a micro-controller chip such as the ARM processor we use on the Raspberry Pi</p>
   * <p>It is a memory type specially designed for embedded systems</p>
   * <p>It is a memory type used within sensors</p>
<p align="center"><font face="Liberation Sans, sans-serif"><font size="6"> *Good luck!* </font></font></p> <h2 align="left">Solutions:</h2>

The correct answers are highlighted in %BLUE%blue.%ENDCOLOR%

-- %USERSIG{UliRaich - 2017-11-15}%

---++ Comments

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I	Attachment	History	Action	Size	Date	Who	Comment
png	add.png	r1	manage	20.1 K	2017-11-15 - 16:14	UnknownUser
png	sine.png	r1	manage	14.2 K	2017-11-15 - 16:16	UnknownUser
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Topic revision: r3 - 2017-11-16 - uli