PA 8001 2014 Practical 2 - Revision history

Ceres: Undo revision 5560 by Ceres (talk)

2015-09-28T04:18:19Z

Undo revision 5560 by Ceres (talk)

Ceres at 04:16, 28 September 2015

2015-09-28T04:16:11Z

Ceres at 02:47, 29 September 2014

2014-09-29T02:47:26Z

Ceres at 02:44, 29 September 2014

2014-09-29T02:44:52Z

Ceres at 02:43, 29 September 2014

2014-09-29T02:43:46Z

Ceres at 00:44, 29 September 2014

2014-09-29T00:44:39Z

Ceres at 00:43, 29 September 2014

2014-09-29T00:43:49Z

Ceres at 07:22, 28 September 2014

2014-09-28T07:22:15Z

Ceres at 00:13, 28 September 2014

2014-09-28T00:13:57Z

Ceres at 00:13, 28 September 2014

2014-09-28T00:13:15Z

@@ Line 39: / Line 39: @@
 Now you can restart the Raspberry Pi and work on the PiFace!
- pressing right, releasing and then pressing left and releasing will result in showing the following sequence of strings on PiFace Screen: away, approaching, on-bridge, away.
+You use the navigation switch to move between these three states back and forth, by moving the switch to right and left, respectively.
 === Part 2: Train Controller ===
-You use the navigation switch to have a customer arrived at ticket machine 1.
+[[File:two_trains_2014.png|300px|thumb|super|Part 3: Train Controller.]]
-Ticket machine 2 has customers arriving at a fixed period (3 seconds).
-Each ticket machine has a delay of 1 second between reading the last ticket from both machines and issuing the next one.
-The current tickets of ticket machines 1 and 2 are displayed on the left- and the right-hand-sides of the LCD display of PiFace, respectively.
-The initial state of both ticket machines indicates number 0.
+The status of Train1 and Train2 are to be displayed on the PiFace Screen on the left-most and right-most side of the LCD Screen, respectively.
-Hence, by pressing right, releasing before 3 seconds, a customer arrives at ticket machine 1 and
+Train1 is controlled by the navigation switch as specified in Part 2.
-second later will receive ticket number 1 displayed on the left-most corner of the LCD.
+Train2 is controlled by a timer that moves the train from one state to other within 5 seconds, unless blocked by the unavailability of the bridge.
-Exactly after 3 seconds from the start of the system, a customer will arrive at ticket machine 2 and one second later will get the next available ticket
+The access to bridge has to be protected by a mutual exclusion mechanism.
-displayed on the left-most corner.
 Use the POSIX Thread (pthread) library to implement concurrency. More information about pthread with some examples can be found [http://www.cs.cmu.edu/afs/cs/academic/class/15492-f07/www/pthreads.html here].
 == [[PA 8001 Ed 2013|Back to Embedded Systems Programming]] ==

@@ Line 39: / Line 39: @@
 Now you can restart the Raspberry Pi and work on the PiFace!
-You use the navigation switch to move between these three states back and forth, by moving the switch to right and left, respectively.
+ pressing right, releasing and then pressing left and releasing will result in showing the following sequence of strings on PiFace Screen: away, approaching, on-bridge, away.
-The current status of the switch is displayed on the LCD display of PiFace.
-The initial state of the train is away. Hence, pressing right, releasing, pressing right, releasing and then pressing left and releasing will result in showing the following sequence of strings on PiFace Screen: away, approaching, on-bridge, away.
 === Part 2: Train Controller ===
-[[File:two_trains_2014.png|300px|thumb|super|Part 3: Train Controller.]]
+You use the navigation switch to have a customer arrived at ticket machine 1.
+The current tickets of ticket machines 1 and 2 are displayed on the left- and the right-hand-sides of the LCD display of PiFace, respectively.
-The status of Train1 and Train2 are to be displayed on the PiFace Screen on the left-most and right-most side of the LCD Screen, respectively.
+The initial state of both ticket machines indicates number 0.
-Train1 is controlled by the navigation switch as specified in Part 2.
+Hence, by pressing right, releasing before 3 seconds, a customer arrives at ticket machine 1 and
-Train2 is controlled by a timer that moves the train from one state to other within 5 seconds, unless blocked by the unavailability of the bridge.
+second later will receive ticket number 1 displayed on the left-most corner of the LCD.
-The access to bridge has to be protected by a mutual exclusion mechanism.
+Exactly after 3 seconds from the start of the system, a customer will arrive at ticket machine 2 and one second later will get the next available ticket
 Use the POSIX Thread (pthread) library to implement concurrency. More information about pthread with some examples can be found [http://www.cs.cmu.edu/afs/cs/academic/class/15492-f07/www/pthreads.html here].
 == [[PA 8001 Ed 2013|Back to Embedded Systems Programming]] ==

← Older revision		Revision as of 02:47, 29 September 2014
Line 62:		Line 62:
	The access to bridge has to be protected by a mutual exclusion mechanism.		The access to bridge has to be protected by a mutual exclusion mechanism.

		+	Use the POSIX Thread (pthread) library to implement concurrency. More information about pthread with some examples can be found [http://www.cs.cmu.edu/afs/cs/academic/class/15492-f07/www/pthreads.html here].

	== [[PA 8001 Ed 2013\|Back to Embedded Systems Programming]] ==		== [[PA 8001 Ed 2013\|Back to Embedded Systems Programming]] ==

@@ Line 37: / Line 37: @@
 -press Esc and type :wq
-Now you can restart the pi work on the piface!
+Now you can restart the Raspberry Pi and work on the PiFace!
 The exercise is about a train that is moving on different tracks, until it reaches a bridge.

@@ Line 2: / Line 2: @@
 There are three main objectives for this practical:
 * Implement the mutual exclusion primitives,
-* Use them in implementing a simple access control protocol
+* Use a concurrency library,
 == Instructions ==
@@ Line 15: / Line 17: @@
 For each function in the code, you need to write a piece of comment, describing its pre- and post-condition and a few test-cases.
-=== Part 1: Yield ===
+=== Part 1: I/O on PiFace ===
-−
-Restore Raspbian on Raspberry Pi.
-−
-Download the [[media:tiny_threads.zip|tiny threads library]] and run the sample program test1 using GCC on Linux.
-Notice that only one thread in the sample program gets to execute.
-This is so because there is no way of switching context: there is no invocation to yield() in the program and
-furthermore, there is no implementation for yield().
-In this exercise you will implement the function
-−
- yield()
-−
-in tinythreads.c.  The function should
-−
-−
-* enqueue the current thread in the ready queue (as you can see in the source file tinythreads.c there are functions already implemented for enqueuing and dequeuing).
-−
-* pick the first element in the queue, dequeue it and dispatch it! It is dispatch that makes the context-switch trick! (check the definition of dispatch).
-−
-=== Part 2: I/O on PiFace ===
 In this exercise, we familiarize ourselves with the [http://www.piface.org.uk/products/piface_control_and_display/ PiFace Control and Display] hardware and its [https://github.com/piface software library]: you need both libmcp23s17 and libpifacecad.
@@ Line 66: / Line 49: @@
-=== Part 3: Train Controller ===
+=== Part 2: Train Controller ===
 The final part of the assignment consists of implementing a sample of a train controller with two trains and a bridge, depicted below.

@@ Line 43: / Line 43: @@
 $ cd libmcp23s17/ && make && cd -
 $ cd libpifacecad/ && make
 Enable the SPI interface
 $ sudo vi /etc/modprobe.d/raspi-blacklist.conf
 -press insert, then add a # add before blacklist spi-bcm2708
-then press Esc and type :wq
 Now you can restart the pi work on the piface!

← Older revision		Revision as of 07:22, 28 September 2014
Line 54:		Line 54:


−	[[File:two_trains_2014.png\|~~600px~~\|thumb\|super\|Part 3: Train Controller.]]	+	[[File:two_trains_2014.png\|300px\|thumb\|super\|Part 3: Train Controller.]]

← Older revision		Revision as of 00:13, 28 September 2014
Line 54:		Line 54:


−	[[File:two_trains_2014.png\|~~400px~~\|thumb\|super\|Part 3: Train Controller.]]	+	[[File:two_trains_2014.png\|600px\|thumb\|super\|Part 3: Train Controller.]]