Wiki source code of LEGO Mindstorms with leJOS and SCCharts

Version 44.1 by Soeren Domroes on 2019/05/06 15:26

version	line-number	content
3.1	1	= Program LEGO Mindstorms with leJOS and SCCharts =
	2
	3
	4
	5	{{toc minLevel="2"/}}
	6
	7	----
	8
	9	== Overview ==
	10
21.1	11	Mindstorms is a product family from Lego, with sensors, motors and a programmable brick. The newest iteration of the product family is the EV3 programmable brick. Its predecessors are NXT and RCX. In the following we will see how to develop applications for the NXT brick.
1.1	12
7.1	13	Several open-source, third-party replacements for the offical Lego firmware have been developed. These support many well known programming languages, such as Java, C/C++, Python, Lua, etc. In the following we will use KIELER SCCharts to program Mindstorms running the Lego Java Operating System ([[leJOS>>url:http://www.lejos.org/\|\|shape="rect"]]). Therefore we will first install leJOS NXJ and flash its firmware. Afterwards we will create a simple SCCharts project in KIELER that we will compile and deploy to the NXT brick.
5.1	14
35.1	15	If you want to learn the SCCharts langugage first, you can follow these links:
	16
42.1	17	* [[Introduction to SCCharts>>doc:SCCharts (pre 1\.0)]]
44.1	18	* [[The Textual SCCharts Language SCT>>doc:Textual SCCharts Language SCT]]
35.1	19	* [[SCCharts Examples>>doc:Examples]]
	20
3.1	21	----
	22
	23	== Download and install leJOS ==
	24
22.1	25	Download and extract the newest archives for your Operating System from [[Sourceforce>>url:http://sourceforge.net/projects/nxt.lejos.p/files/\|\|shape="rect"]] (Linux/Mac) or use the Setup.exe (Windows).
3.1	26
7.1	27	The further installation is explained in detail at [[http:~~/~~/www.lejos.org/nxt/nxj/tutorial/Preliminaries/GettingStarted.htm>>url:http://www.lejos.org/nxt/nxj/tutorial/Preliminaries/GettingStarted.htm\|\|shape="rect"]].
3.1	28
31.1	29	Do not forget to flash the download leJOS firmware to the Mindstorms brick as explained in the tutorial!
	30
7.1	31	=== Known issues ===
3.1	32
27.1	33	==== Linux ====
17.1	34
7.1	35	On Linux there is an issue when uploading the firmware because of a kernel module ([[http:~~/~~/ubuntuforums.org/showthread.php?t=1123633>>url:http://ubuntuforums.org/showthread.php?t=1123633\|\|shape="rect"]]). If you can't upload the firmware with your Linux OS, add blacklist cdc_acm{{code language="none"}}{{/code}} at the very end of the file {{code language="none"}}/etc/modprobe.d/blacklist.conf{{/code}}. Afterwards execute {{code language="none"}}sudo rmmod cdc_acm{{/code}}. This will remove the cdc_acm module from the kernel and prevent its restart. Now try to flash the firmware again.
3.1	36
17.1	37	Another issue is that the development package of libusb has to be installed. On Ubuntu you can do this by using {{code language="none"}}sudo apt-get install libusb-dev{{/code}}.
	38
30.1	39	Furthermore, to use USB connection, a java library has to be compiled via ant. To do this perform cd /path/to/leJOS/build and start ant. If the ant build tool is not installed on your system, you can do so via sudo apt-get install ant.
17.1	40
27.1	41	==== Windows ====
	42
	43	The setup.exe of the current LEGO Fantom driver for Windows (1.2.0) has an awkward issue. If you get an error message (Developer Error) because an .msi file could not be found, don't panic. The file is part of the downladed archive (in the Products folder) but you have to start it manually.
	44
30.1	45	==== Mac OS X ====
	46
	47	The leJOS NXJ tools require a 32 Bit version of Java. However, newer 32 Bit versions of Java are not longer available for Mac. Thus to use leJOS the installation of Java 1.6 is required, which is the last one that supports a 32 Bit mode. You can download the installer for Java 1.6 from [[https:~~/~~/support.apple.com/kb/dl1572?locale=en_US>>url:https://support.apple.com/kb/dl1572?locale=en_US\|\|shape="rect"]]. It will install Java 1.6 to ///System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home// so that the environment variable //LEJOS_NXT_JAVA_HOME//, which is set in the installation instructions, points to the correct path.
	48
33.1	49	The environment variable LEJOS_NXT_JAVA_HOME is set in the installation tutorial by editing ~~/.profile. However, on a Mac the environment variables defined in this file are not visible for GUI Applications, only for apps started from terminal. Thus to use leJOS together with KIELER, one either has to start KIELER from terminal or set the environment variable so that all GUI applications can access it. However, this does not seem to be trivial on Mac (see also [[http:~~/~~/stackoverflow.com/questions/135688/setting-environment-variables-in-os-x>>url:http://stackoverflow.com/questions/135688/setting-environment-variables-in-os-x\|\|shape="rect"]]).
30.1	50
3.1	51	----
	52
7.1	53	== Test the Mindstorm ==
3.1	54
7.1	55	A simple Hello World application for the Mindstorms is developed as part of the leJOS tutorial [[http:~~/~~/www.lejos.org/nxt/nxj/tutorial/Preliminaries/FirstProgram.htm>>url:http://www.lejos.org/nxt/nxj/tutorial/Preliminaries/FirstProgram.htm\|\|shape="rect"]]
3.1	56
27.1	57	If this works with your device, you are able to start using KIELER to develop applications for the NXT brick.
3.1	58
	59	----
	60
28.1	61	== Download and Configure KIELER
	62	==
27.1	63
	64	Download and unpack the nightly build of KIELER for your OS. It is available at the [[doc:Downloads]] page.\\
	65
33.1	66	Note: Java 1.8 is needed on all operating systems. With Java 1.7 not all plugins of KIELER will be loaded. Furthermore on Windows, you will need to download the 32 Bit version of KIELER – even if you have a 64 bit operating system! Otherwise flashing the brick and uploading to the brick will fail.
27.1	67
28.1	68	=== The Eclipse plugin for leJOS ===
27.1	69
24.1	70	There is an Eclipse plugin for leJOS which adds a project creation wizard and launch configuration to the platform.
3.1	71
24.1	72	1. You have to install it via the Eclipse Marketplace (//Help > Eclipse Marketplace...//).
	73	OR
25.1	74	1. Install the plugin manually (Help > Install new Software...). Use the following update site\\
	75	11. for NXT: [[http:~~/~~/www.lejos.org/tools/eclipse/plugin/nxj/>>url:http://www.lejos.org/tools/eclipse/plugin/nxj/\|\|shape="rect"]]
	76	11. for EV3: [[http:~~/~~/www.lejos.org/tools/eclipse/plugin/ev3/>>url:http://www.lejos.org/tools/eclipse/plugin/ev3/\|\|shape="rect"]]
24.1	77
25.1	78	If you have an NXT brick, install the leJOS NXJ Plug-in. If you have an EV3 brick, install the leJOS EV3 plugin.
	79
40.1	80	[[image:attach:Screenshot_20171016_130805.png]]
	81
37.1	82	Tip: To speed up the installation, uncheck the option "Contact all update sites during install to find required software". This will reduce the installation time from drastically (around 30 seconds instead 10 minutes).
	83
40.1	84	\\
8.1	85
28.1	86	After the installation, the plugin requires a little configuration. Go to //Window > Preferences > leJOS NXJ// (//Window > Preferences > leJOS EV3 //respectively) and enter the base directory of your leJOS installation in the NXJ_HOME field.
19.1	87
33.1	88	For EV3, the plugin requires the IP address to connect to the brick (it may work without, but its safer to directly set the name. Reduces headache ). Check Connect to named brick and enter the IP adress of the brick (displayed on the brick at startup).
3.1	89
	90	----
	91
14.1	92	== Creating an Example Project ==
	93
33.1	94	The following shows how to create a project, which will turn on a light if a button is pressed.
14.1	95
15.1	96	=== Create a new project: ===
14.1	97
18.1	98	1. Choose //File > New > Project > KIELER SCCharts > SCCharts Project//
21.1	99	1. In the project creation wizard that opens, select //Mindstorms NXJ// or// Mindstorms EV3// (depending on your brick) as environment and hit //finish//
14.1	100	1. The project wizard from the leJOS plugin opens. Set the project name to //Flashlight// and click //finish//.
	101	1. The project is created and the model file is opened in an editor (This might take a few seconds).
	102
40.1	103	=== Edit the Model: ===
14.1	104
	105	Change the contents of the model file to the following code and save it.
	106
32.1	107	{{code language="sct" theme="Eclipse" title="Floodlight.sct"}}
14.1	108	scchart Flashlight {
	109
	110	@Wrapper TouchSensor, S4
	111	input bool button;
	112
	113	@Wrapper Floodlight, S1
	114	output bool light;
	115
	116	initial state lightOff
	117	--> lightOn with button / light = true;
	118
	119	state lightOn
	120	--> lightOff with !button / light = false;
	121	}
	122	{{/code}}
	123
	124	This model will start in the state lightOff. If the button is pressed, it will turn on the light and change to the corresponding state, where the light is turned off, as soon as the button is not pressed anymore.
	125
21.1	126	The annotations on the input and output variable are used to define which wrapper code is used to set / read them. @Wrapper TouchSensor, S4 will set the input variable to true iff the touch sensor on the port S4 is pressed. @Wrapper Floodlight, S1 on the output variable will turn on the red led of the light sensor that is attatched to port S1 iff the variable is true.
	127
40.1	128	The available wrapper code snippets are defined in the directory //assets/snippets// in ftl files (FreeMarker template files). The table below gives an overview of the available wrapper code snippets.
21.1	129
26.1	130	Note: The Floodlight of the EV3 has a pretty high latency when switching between on and off.
	131
39.1	132	Note: To view ftl files with highlighting, you may want to install the //FreeMarker IDE// feature from the JBoss Tools. However, this is not necessary to work with KIELER. JBoss Tools is available in the Eclipse Market Place and via update site. The update site for stable releases is [[http:~~/~~/download.jboss.org/jbosstools/neon/stable/updates/ >>url:http://download.jboss.org/jbosstools/neon/stable/updates/\|\|shape="rect"]]. Note that only the //FreeMarker IDE// feature is required (Abridged JBoss Tools > FreeMarker IDE).**
14.1	133	**
	134
40.1	135	=== Build the Project: ===
14.1	136
40.1	137	The model is now ready to be compiled. Compilation is done in the background when the project is built. There are two ways to build a project: manually using //Project > Build Project//, or automatically via //Project > Build Automatically//. If the automatic build is enabled, resources are built when they are saved.
14.1	138
40.1	139	Building the project will create a new folder //kieler-gen// in which all results are saved. This includes the compiled code from the model, an executable simulation for the model and wrapper code that is ready to be deployed to the Mindstorms Brick.
18.1	140
40.1	141	The simulation is saved as JAR file in //kieler-gen/sim/bin// and can be started via //Right Click > Run as > KIELER Simulation//. Models and variables of a running simulation are displayed in the Data Pool View.
19.1	142
40.1	143	[[image:attach:Screenshot_20171016_110005.png]]
	144
	145	Besides the simulation, the finished wrapper code that can be uploaded to the Mindstorms brick is created as part of the project build. It is saved in //kieler-gen/model//. To upload it to the Mindstorms brick, use //Right Click > Run as > leJOS NXT Program//.
	146
	147	[[image:attach:Screenshot_20171016_120554.png]]
	148
	149	==== Excluding the Simulation from the NXT Build ====
	150
	151	It is necessary to exclude the simulation directory and org.json directory inside kieler-gen from the NXT project specific build via //Right Click > Build Path > Exclude//. Afterwards the project has to be build again to remove all error markers in these directories.
	152
	153	[[image:attach:Screenshot_20171016_105821.png]]
	154
	155	Normally the NXT project attempts to compile all Java files in the kieler-gen directory for the platform. However, the simulation that is generated is not targeted at the Mindstorms brick and has compilation errors. It is compiled separately by KIELER.
	156
33.1	157	=== Available Wrapper Code Snippets ===
	158
40.1	159	There are several wrapper code snippets that can be used as annotations on input and output variables in the model file. These snippets are inserted in the main file template as part of the project build. The available snippets are listed below.
33.1	160
	161	For sensors, the port has to be on of S1, S2, S3, S4.
	162
34.1	163	For motors / actuators the port has to be one of A, B, C, D.
33.1	164
35.1	165	(% class="wrapped" %)
33.1	166	\|=(((
	167	Snippet Name and Parameters
	168	)))\|=(((
	169	Description
	170	)))\|=(((
	171	Use on
	172	)))\|=(% colspan="1" %)(% colspan="1" %)
	173	(((
	174	Variable type
	175	)))\|=(((
	176	Remark
34.1	177	)))\|=(% colspan="1" %)(% colspan="1" %)
	178	(((
	179	Defined in File
33.1	180	)))
	181	\|(% colspan="1" %)(% colspan="1" %)
	182	(((
	183	Clock, milliseconds
	184	)))\|(% colspan="1" %)(% colspan="1" %)
	185	(((
36.1	186	Sets a variable to true for one tick if the time in milliseconds passed since the last time it was set to true.
33.1	187	)))\|(% colspan="1" %)(% colspan="1" %)
	188	(((
	189	input
	190	)))\|(% colspan="1" %)(% colspan="1" %)
	191	(((
	192	bool
	193	)))\|(% colspan="1" %)(% colspan="1" %)
	194	(((
	195	See also ResetClock.
34.1	196	)))\|(% colspan="1" %)(% colspan="1" %)
	197	(((
	198	timing.ftl
33.1	199	)))
	200	\|(% colspan="1" %)(% colspan="1" %)
	201	(((
	202	ResetClock, clockVariableName, autoFalse
	203	)))\|(% colspan="1" %)(% colspan="1" %)
	204	(((
	205	Resets a clock, such that the full time intervall of the clock has to elapse, before the clock will be set to true again.
	206
	207	If autoFalse is true, the reset variable will be set to false automatically.
	208	)))\|(% colspan="1" %)(% colspan="1" %)
	209	(((
	210	output
	211	)))\|(% colspan="1" %)(% colspan="1" %)
	212	(((
	213	bool
	214	)))\|(% colspan="1" %)(% colspan="1" %)
	215	(((
	216	autoFalse is true per default.
34.1	217	)))\|(% colspan="1" %)(% colspan="1" %)
	218	(((
	219	timing.ftl
33.1	220	)))
	221	\|(% colspan="1" %)(% colspan="1" %)
	222	(((
	223	Time
	224	)))\|(% colspan="1" %)(% colspan="1" %)
	225	(((
41.1	226	Reads the elapsed time since program start (milliseconds)
33.1	227	)))\|(% colspan="1" %)(% colspan="1" %)
	228	(((
	229	input
	230	)))\|(% colspan="1" %)(% colspan="1" %)
	231	(((
	232	int
	233	)))\|(% colspan="1" %)(% colspan="1" %)
	234	(((
39.1	235	\\
34.1	236	)))\|(% colspan="1" %)(% colspan="1" %)
	237	(((
	238	timing.ftl
33.1	239	)))
	240	\|(% colspan="1" %)(% colspan="1" %)
	241	(((
38.1	242	TickLoopDuration, targetInMilliseconds
33.1	243	)))\|(% colspan="1" %)(% colspan="1" %)
	244	(((
	245	Delays the execution until the tick loop takes at least as long as the given target duration.
	246
	247	The input variable is set to the actual tick loop duration.
	248	)))\|(% colspan="1" %)(% colspan="1" %)
	249	(((
	250	input
	251	)))\|(% colspan="1" %)(% colspan="1" %)
	252	(((
	253	int
	254	)))\|(% colspan="1" %)(% colspan="1" %)
	255	(((
	256	Should be used on the very first input variable in the model, such that waiting is the last action in the tick loop.
41.1	257
	258	In case the actual tick loop duration is longer than the target duration, the modeler can provide some error handling.
34.1	259	)))\|(% colspan="1" %)(% colspan="1" %)
	260	(((
	261	timing.ftl
33.1	262	)))
	263	\|(% colspan="1" %)(% colspan="1" %)
	264	(((
38.1	265	TickWakeUp
	266	)))\|(% colspan="1" %)(% colspan="1" %)
	267	(((
41.1	268	(% class="content-wrapper" %)
	269	(((
	270	Sets the input variable to the current system time (milliseconds). The model can add to this variable to get a new value. This is the next system time the tick function will be called.
38.1	271
41.1	272	In other words, the next tick function call is delayed until the wake up time has been reached.
	273
	274	For instance the statement nextTickWakeUp += 500 could be used to call the tick function again in 500 milliseconds, if nextTickWakeUp is an input with the corresponding annotation.
	275	)))
38.1	276	)))\|(% colspan="1" %)(% colspan="1" %)
	277	(((
	278	input
	279	)))\|(% colspan="1" %)(% colspan="1" %)
	280	(((
	281	int
	282	)))\|(% colspan="1" %)(% colspan="1" %)
	283	(((
	284	Should be used on the very last input variable in the model, such that waiting and settings the system time is the last action done, before the tick function call.
	285	)))\|(% colspan="1" %)(% colspan="1" %)
	286	(((
	287	timing.ftl
	288	)))
	289	\|(% colspan="1" %)(% colspan="1" %)
	290	(((
42.1	291	TickCount
	292	)))\|(% colspan="1" %)(% colspan="1" %)
	293	(((
	294	Counts the ticks. First tick is 0, the following are 1, 2, 3, ...
	295	)))\|(% colspan="1" %)(% colspan="1" %)
	296	(((
	297	input
	298	)))\|(% colspan="1" %)(% colspan="1" %)
	299	(((
	300	int
	301	)))\|(% colspan="1" %)(% colspan="1" %)
	302	(((
	303	\\
	304	)))\|(% colspan="1" %)(% colspan="1" %)
	305	(((
	306	timing.ftl
	307	)))
	308	\|(% colspan="1" %)(% colspan="1" %)
	309	(((
33.1	310	Sleep
	311	)))\|(% colspan="1" %)(% colspan="1" %)
	312	(((
	313	Lets the current thread sleep the time in milliseconds of the variable value.
	314	)))\|(% colspan="1" %)(% colspan="1" %)
	315	(((
	316	output
	317	)))\|(% colspan="1" %)(% colspan="1" %)
	318	(((
	319	int
	320	)))\|(% colspan="1" %)(% colspan="1" %)
	321	(((
39.1	322	\\
34.1	323	)))\|(% colspan="1" %)(% colspan="1" %)
	324	(((
	325	timing.ftl
33.1	326	)))
	327	\|(% colspan="1" %)(% colspan="1" %)
	328	(((
	329	Print, autoReset
	330	)))\|(% colspan="1" %)(% colspan="1" %)
	331	(((
	332	Prints a string variable if the string is not empty. If autoReset is true then the string variable is set to the empty string after it has been printed
	333	)))\|(% colspan="1" %)(% colspan="1" %)
	334	(((
	335	output
	336	)))\|(% colspan="1" %)(% colspan="1" %)
	337	(((
	338	string
	339	)))\|(% colspan="1" %)(% colspan="1" %)
	340	(((
	341	autoReset is true per default.
34.1	342	)))\|(% colspan="1" %)(% colspan="1" %)
	343	(((
	344	print.ftl
33.1	345	)))
	346	\|(% colspan="1" %)(% colspan="1" %)
	347	(((
	348	DrawString, x, y
	349	)))\|(% colspan="1" %)(% colspan="1" %)
	350	(((
	351	Prints a string to the given x and y coordinate on the LCD.
	352	)))\|(% colspan="1" %)(% colspan="1" %)
	353	(((
	354	output
	355	)))\|(% colspan="1" %)(% colspan="1" %)
	356	(((
	357	string
	358	)))\|(% colspan="1" %)(% colspan="1" %)
	359	(((
39.1	360	\\
34.1	361	)))\|(% colspan="1" %)(% colspan="1" %)
	362	(((
	363	print.ftl
33.1	364	)))
	365	\|(% colspan="1" %)(% colspan="1" %)
	366	(((
	367	Button, buttonId
	368	)))\|(% colspan="1" %)(% colspan="1" %)
	369	(((
	370	Sets a variable to true iff the button on the Mindstorms device is pressed.
	371	)))\|(% colspan="1" %)(% colspan="1" %)
	372	(((
	373	input
	374	)))\|(% colspan="1" %)(% colspan="1" %)
	375	(((
	376	bool
	377	)))\|(% colspan="1" %)(% colspan="1" %)
	378	(((
	379	The buttonId has to be one of ENTER, LEFT, RIGHT
34.1	380	)))\|(% colspan="1" %)(% colspan="1" %)
	381	(((
	382	touch_and_buttons.ftl
33.1	383	)))
	384	\|(% colspan="1" %)(% colspan="1" %)
	385	(((
	386	TouchSensor, port
	387	)))\|(% colspan="1" %)(% colspan="1" %)
	388	(((
	389	Sets a variable to true iff the touch sensor on the given port is pressed.
	390	)))\|(% colspan="1" %)(% colspan="1" %)
	391	(((
	392	input
	393	)))\|(% colspan="1" %)(% colspan="1" %)
	394	(((
	395	bool
	396	)))\|(% colspan="1" %)(% colspan="1" %)
	397	(((
39.1	398	\\
34.1	399	)))\|(% colspan="1" %)(% colspan="1" %)
	400	(((
	401	touch_and_buttons.ftl
33.1	402	)))
	403	\|(% colspan="1" %)(% colspan="1" %)
	404	(((
	405	LightSensor, port, percentValue
	406	)))\|(% colspan="1" %)(% colspan="1" %)
	407	(((
	408	Reads the value of a light sensor.
	409
	410	If percentValue is true, the a percent value is retured, based on the light sensor calibration.
	411	)))\|(% colspan="1" %)(% colspan="1" %)
	412	(((
	413	input
	414	)))\|(% colspan="1" %)(% colspan="1" %)
	415	(((
	416	int
	417	)))\|(% colspan="1" %)(% colspan="1" %)
	418	(((
	419	percentValue is not available on EV3
34.1	420	)))\|(% colspan="1" %)(% colspan="1" %)
	421	(((
	422	light.ftl
33.1	423	)))
	424	\|(% colspan="1" %)(% colspan="1" %)
	425	(((
	426	CalibrateLightSensor, port, signal
	427	)))\|(% colspan="1" %)(% colspan="1" %)
	428	(((
	429	Calibrates a light sensors high or low values. This means if the variable is true, the current value of the light sensor is taken as its reference high / low value.
	430	)))\|(% colspan="1" %)(% colspan="1" %)
	431	(((
	432	output
	433	)))\|(% colspan="1" %)(% colspan="1" %)
	434	(((
	435	bool
	436	)))\|(% colspan="1" %)(% colspan="1" %)
	437	(((
	438	signal has to be one of High, Low
34.1	439	)))\|(% colspan="1" %)(% colspan="1" %)
	440	(((
	441	light.ftl
33.1	442	)))
	443	\|(% colspan="1" %)(% colspan="1" %)
	444	(((
	445	Floodlight, port
	446	)))\|(% colspan="1" %)(% colspan="1" %)
	447	(((
	448	Reads / Sets the state of the red lamp of the light sensor.
	449	)))\|(% colspan="1" %)(% colspan="1" %)
	450	(((
	451	input
	452
	453	output
	454	)))\|(% colspan="1" %)(% colspan="1" %)
	455	(((
	456	bool
	457	)))\|(% colspan="1" %)(% colspan="1" %)
	458	(((
39.1	459	\\
34.1	460	)))\|(% colspan="1" %)(% colspan="1" %)
	461	(((
	462	light.ftl
33.1	463	)))
	464	\|(% colspan="1" %)(% colspan="1" %)
	465	(((
	466	RCXLamp, port
	467	)))\|(% colspan="1" %)(% colspan="1" %)
	468	(((
	469	Turns an RCX lamp on (variable is true) or off (variable is false)
	470	)))\|(% colspan="1" %)(% colspan="1" %)
	471	(((
	472	output
	473	)))\|(% colspan="1" %)(% colspan="1" %)
	474	(((
	475	bool
	476	)))\|(% colspan="1" %)(% colspan="1" %)
	477	(((
39.1	478	\\
34.1	479	)))\|(% colspan="1" %)(% colspan="1" %)
	480	(((
	481	light.ftl
33.1	482	)))
	483	\|(% colspan="1" %)(% colspan="1" %)
	484	(((
	485	MotorSpeed, port, brake
	486	)))\|(% colspan="1" %)(% colspan="1" %)
	487	(((
	488	Reads / Sets the speed of the motor in degrees per minute. If the speed value is negative, the motor will drive backwards. If the speed is zero, the motor will actively brake until it stops (brake is true) or remove all power and rollout (brake is false).
	489	)))\|(% colspan="1" %)(% colspan="1" %)
	490	(((
	491	input
	492
	493	output
	494	)))\|(% colspan="1" %)(% colspan="1" %)
	495	(((
	496	int
	497	)))\|(% colspan="1" %)(% colspan="1" %)
	498	(((
	499	brake is true per default.
34.1	500	)))\|(% colspan="1" %)(% colspan="1" %)
	501	(((
	502	motor.ftl
33.1	503	)))
	504	\|(% colspan="1" %)(% colspan="1" %)
	505	(((
	506	MotorIsMoving, port
	507	)))\|(% colspan="1" %)(% colspan="1" %)
	508	(((
	509	Sets a variable to true iff the motor on the given port is moving.
	510	)))\|(% colspan="1" %)(% colspan="1" %)
	511	(((
	512	input
	513	)))\|(% colspan="1" %)(% colspan="1" %)
	514	(((
	515	bool
	516	)))\|(% colspan="1" %)(% colspan="1" %)
	517	(((
39.1	518	\\
34.1	519	)))\|(% colspan="1" %)(% colspan="1" %)
	520	(((
	521	motor.ftl
33.1	522	)))
	523	\|(% colspan="1" %)(% colspan="1" %)
	524	(((
	525	MotorRotation, port
	526	)))\|(% colspan="1" %)(% colspan="1" %)
	527	(((
	528	Lets a motor rotate the variable value in degrees. This is only done if the value is unequal zero. If the value is negative, the motor rotates backwards. The variable is set to zero afterwards, such that setting the variable once to a value //X//, will let the motor rotate //X// degrees.
	529	)))\|(% colspan="1" %)(% colspan="1" %)
	530	(((
	531	output
	532	)))\|(% colspan="1" %)(% colspan="1" %)
	533	(((
	534	int
	535	)))\|(% colspan="1" %)(% colspan="1" %)
	536	(((
39.1	537	\\
34.1	538	)))\|(% colspan="1" %)(% colspan="1" %)
	539	(((
	540	motor.ftl
33.1	541	)))
	542	\|(% colspan="1" %)(% colspan="1" %)
	543	(((
	544	Beep, volume
	545	)))\|(% colspan="1" %)(% colspan="1" %)
	546	(((
	547	Plays a beep sound as long as the variable is true.
	548	)))\|(% colspan="1" %)(% colspan="1" %)
	549	(((
	550	output
	551	)))\|(% colspan="1" %)(% colspan="1" %)
	552	(((
	553	bool
	554	)))\|(% colspan="1" %)(% colspan="1" %)
	555	(((
	556	default volume is 10
34.1	557	)))\|(% colspan="1" %)(% colspan="1" %)
	558	(((
	559	sound.ftl
33.1	560	)))
	561	\|(% colspan="1" %)(% colspan="1" %)
	562	(((
	563	Buzz, volume
	564	)))\|(% colspan="1" %)(% colspan="1" %)
	565	(((
	566	Plays a buzz sound as long as the variable is true.
	567	)))\|(% colspan="1" %)(% colspan="1" %)
	568	(((
	569	output
	570	)))\|(% colspan="1" %)(% colspan="1" %)
	571	(((
	572	bool
	573	)))\|(% colspan="1" %)(% colspan="1" %)
	574	(((
	575	default volume is 10
34.1	576	)))\|(% colspan="1" %)(% colspan="1" %)
	577	(((
	578	sound.ftl
33.1	579	)))
	580	\|(% colspan="1" %)(% colspan="1" %)
	581	(((
	582	BeepSequence, direction, volume
	583	)))\|(% colspan="1" %)(% colspan="1" %)
	584	(((
	585	Plays a sequence of tones in either ascending or descending tone frequency if the variable is true.
	586
	587	The variable is set to false automatically.
	588	)))\|(% colspan="1" %)(% colspan="1" %)
	589	(((
	590	output
	591	)))\|(% colspan="1" %)(% colspan="1" %)
	592	(((
	593	bool
	594	)))\|(% colspan="1" %)(% colspan="1" %)
	595	(((
	596	direction has to be one of Up, Down
	597
	598	default volume is 10
34.1	599	)))\|(% colspan="1" %)(% colspan="1" %)
	600	(((
	601	sound.ftl
33.1	602	)))
	603	\|(% colspan="1" %)(% colspan="1" %)
	604	(((
	605	UltrasonicSensor, port
	606	)))\|(% colspan="1" %)(% colspan="1" %)
	607	(((
	608	Reads the distance that an ultrasonic sensor measures.
	609	)))\|(% colspan="1" %)(% colspan="1" %)
	610	(((
	611	input
	612	)))\|(% colspan="1" %)(% colspan="1" %)
	613	(((
	614	int
	615	)))\|(% colspan="1" %)(% colspan="1" %)
	616	(((
39.1	617	\\
34.1	618	)))\|(% colspan="1" %)(% colspan="1" %)
	619	(((
	620	ultrasonic.ftl
33.1	621	)))
	622	\|(% colspan="1" %)(% colspan="1" %)
	623	(((
	624	Gyro, port, mode
	625	)))\|(% colspan="1" %)(% colspan="1" %)
	626	(((
	627	Reads the value of a gyroscope.
	628	)))\|(% colspan="1" %)(% colspan="1" %)
	629	(((
	630	input
	631	)))\|(% colspan="1" %)(% colspan="1" %)
	632	(((
	633	int
	634	)))\|(% colspan="1" %)(% colspan="1" %)
	635	(((
	636	Not available on NXT
	637
	638	mode hat to be one of Angle, Rate
34.1	639	)))\|(% colspan="1" %)(% colspan="1" %)
	640	(((
	641	gyro.ftl
33.1	642	)))
	643	\|(% colspan="1" %)(% colspan="1" %)
	644	(((
	645	CalibrateGyro, port, autoReset
	646	)))\|(% colspan="1" %)(% colspan="1" %)
	647	(((
	648	Resets a gyroscope if the variable is true.
	649
	650	If autoReset is true, the variable is set to false automatically.
	651	)))\|(% colspan="1" %)(% colspan="1" %)
	652	(((
	653	output
	654	)))\|(% colspan="1" %)(% colspan="1" %)
	655	(((
	656	bool
	657	)))\|(% colspan="1" %)(% colspan="1" %)
	658	(((
	659	autoReset is true per default
34.1	660	)))\|(% colspan="1" %)(% colspan="1" %)
	661	(((
	662	gyro.ftl
33.1	663	)))
	664
39.1	665	\\
33.1	666
19.1	667	----
	668
	669	== Using the Remote Console (RConsole) ==
	670
21.1	671	The display of the NXT brick is rather small compared to a Monitor. To ease debugging, one can print to a Remote Console (RConsole), if the USB cable is connected. This enables easier collection for example of sensor data.
19.1	672
21.1	673	To use the RConsole, uncomment the RConsole lines in the wrapper code template Main.ftl. Start the nxjconsoleviewer tool in the bin directory of your leJOS installation. Now, when starting the application, the brick tries to connect with the nxjconsoleviewer. Press the //Connect// button. If connected succesfully, RConsole.println(...) commands will be written to this window.
19.1	674
21.1	675	The EV3 brick has a similar feature. However it does not require any code changes. Just run the ev3console program in the bin directory of your leJOS installation from command line. The output of the brick will be printed to this command line.
23.1	676
	677	----
	678
	679	== Problem Solving ==
	680
	681	The following presents typical issues and how to solve them.
	682
35.1	683	(% class="wrapped" %)
23.1	684	\|=(((
	685	Issue
	686	)))\|=(((
	687	Typical Error Messages
	688	)))\|=(((
	689	Description
	690	)))\|=(((
	691	Solution
	692	)))
	693	\|(((
	694	leJOS EV3 does not support Java 8
	695	)))\|(((
	696	"java.lang.UnsupportedClassVersionError"
	697
	698	"unsupported major.minor version"
	699	)))\|(((
	700	You compile the sources in your project with Java 8 and upload them to the brick. However the lejos EV3 does not support Java 8
	701	)))\|(((
	702	Go to the project properties and switch to Java 7 (Right Click on project > Properties > Java Compiler > Compiler compliance level)
	703	)))
31.1	704	\|(% colspan="1" %)(% colspan="1" %)
	705	(((
	706	Uploading to the brick does not respond
	707	)))\|(% colspan="1" %)(% colspan="1" %)
	708	(((
39.1	709	\\
31.1	710	)))\|(% colspan="1" %)(% colspan="1" %)
	711	(((
	712	You compile a file successfully and when uploading the result, the connected brick is found. Anyway the upload does not terminate and does not react.
	713	)))\|(% colspan="1" %)(% colspan="1" %)
	714	(((
	715	Flash the brick with the current leJOS firmware. If the brick is recognized correctly and the attempt to upload a compiled file fails then the firmware on the brick might be outdated.
	716	)))
	717	\|(% colspan="1" %)(% colspan="1" %)
	718	(((
	719	Compilation and uploading works from command line but not when using KIELER
	720	)))\|(% colspan="1" %)(% colspan="1" %)
	721	(((
	722	This Java instance does not support a 32-bit JVM. Please install the desired version.
	723	)))\|(% colspan="1" %)(% colspan="1" %)
	724	(((
	725	You can compile and upload code to the brick using the command line tools but when using KIELER an error message apprears because Java does not support 32-bit JVM.
	726	)))\|(% colspan="1" %)(% colspan="1" %)
	727	(((
	728	Set the LEJOS_NXT_JAVA_HOME environment variable, such that it points to an 32-bit JDK and is visible for GUI applications (or at least KIELER). The process to do so differs on every OS. As alternative, execute KIELER from terminal.
	729	)))
32.1	730	\|(% colspan="1" %)(% colspan="1" %)
	731	(((
	732	Brick does nothing after program finished and prints "Program exit"
	733	)))\|(% colspan="1" %)(% colspan="1" %)
	734	(((
39.1	735	\\
32.1	736	)))\|(% colspan="1" %)(% colspan="1" %)
	737	(((
	738	A program was uploaded and finished without errors. Afterwards the brick prints "Program exit" but does not open the main menu.
	739	)))\|(% colspan="1" %)(% colspan="1" %)
	740	(((
	741	This is normal behaviour if uploading a program in debug mode instead run mode (//Debug As// instead //Run As// in Eclipse). To get back to the main menu, press the ENTER and ESCAPE button of the brick at the same time.
	742	)))
23.1	743
39.1	744	\\
23.1	745
39.1	746	\\

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