Difference between revisions of "Logo for NXT"

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== Welcome to Logo for NXT ==
== Welcome to Logo for NXT ==
* [[NXT Logo Overview|Overview]]
* [[NXT Logo Overview|Overview]]
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* [[NXT Logo User Guide]]
* [[NXT Logo User Guide]]
[[Eurologo2007 Workshop]]
This page contains information about the project of programming NXT in Logo language.
The project is under intensive development, and there are no releases yet. '''the first preview will come in the very start of September'''
However, the projet is open-source and the latest development version is available in the [http://webcvs.robotika.sk/cgi-bin/cvsweb/robotika/src/imagine/nxt/logo/current/ CVS].
== Features ==
* Implemented in Imagine and [[NBC|Next Byte Codes]] (NBC)
* Three levels of use:
# Interactive Imagine project with direct GUI controls that allow interfacing with NXT robot over Bluetooth
# Loadable imagine library (nxt.imt) that contains set of procedures for direct control of NXT robot over Bluetooth from your Imagine projects
# Interpreter of Logo running on the NXT that can run logo programs (with restricted syntax), which can communicate with Imagine projects and control the robots motors and sensors.
== Motor & Sensor procedures ==
(motor m cmd arg)
  where m is the number of motor(s) as in NBC:
    0 - motor A
    1 - motor B
    2 - motor C
    3 - motors AB
    4 - motors AC
    5 - motors BC
    6 - motors ABC
  and cmd is one of (with the corresponding argument, similar to NBC): 
    onfwd      power
    onrev      power 
    off        (ignored)
    float      (ignored)
    fwdr        [power regmode]
    revr        [power regmode]
    fwds        [power turnpct]
    revs        [power turnpct]
    onrot      [power angle]
    rst        kind  (1-4)   
(readmotor m cmd)
  where cmd is one of:
(sensor N)
(setsensor N type)
    where type is number according to NBC:
      0 - raw
      1 - switch
      2 - temperature
      3 - refl
      4 - angle
      5 - light active
      6 - light inactive
      7 - sound db
      8 - sound dba
      9 - custom
      10 - lowspeed
      11 - lowspeed with 9V
      12 - high speed
    add the following constants for adjusting the output:
      32 - boolean output (0/1)
      64 - transition count
      96 - period counter
      128 - percentage (0-1023 value normalized to 0-100)
      160 - temperature in C
      192 - temperature in F
      224 - angle steps
      31 - slope mask
      224 - mode mask
== Supported primitives ==
NXT Logo supports the following primitive procedures and operations:
# Arithmetic:  ''<tt>add, sub, mul, div, mod, neg</tt>''
# Logic: ''<tt>and, or, xor, not</tt>''
# Bitwise: ''<tt>bitand, bitor, bitxor, bitnot</tt>''
# Lists and words: ''<tt>first, bf, last, bl, item, se, list, word</tt>''
# Maps & co.: ''<tt>map, apply, foreach, run, remote</tt>''
# Loops and conditions: ''<tt>repeat, while, foreach, if, ifelse</tt>''
# Predicates: ''<tt>empty? number? list? word? equal? gt? lt? ge? le? member?</tt>''
# Variables and procedures: ''<tt>make, let, to, op, stop, erase, launch</tt>''
# NXT file handling: ''<tt>load, printto, fopen, fwrite, fread, fclose, fremove</tt>''
# Sounds: ''<tt>tone, sound</tt>''
# Motors, sensors: ''<tt>motor, readmotor, sensor, setsensor, battery</tt>''
# Other: ''<tt>wait, random, print, draw, ascii, char, boot, gc, fm</tt>''
The expressions must be in prefix notation. Variables are used the same way as in Logo - as "name when referring to variable name, and as :name when referring to its value. There are global variables as well as local variables, lexical scoping as usual in Logo.
The <tt>(remote "expression)</tt> operations allow to start evaluating an expression on NXT when started from PC, and vice-versa. This can be used for communication. Of course, one could then easily say, for example:
remote "|[print "hello]|
remote "|[my_program 123]|
or read value of remote variable:
remote "|:var|
However, one has to keep in mind that BlueTooth communication is slow due to switching of the direction of the transceiver and receiver. Therefore, it is preferable to implement higher-level functions and procedures that can run on NXT brick autonomously. Logo programs have about 30kb of memory available - for storing both the logo programs and data, however, programs can load/erase data and code from NXT files that are stored in the large flash.
== Examples ==
Some sample code for Logo for NXT is in the [http://webcvs.robotika.sk/cgi-bin/cvsweb/robotika/src/imagine/nxt/logo/current/examples Examples folder].
== Syntax ==
Detailed syntax is shown in the file [http://webcvs.robotika.sk/cgi-bin/cvsweb/~checkout~/robotika/src/imagine/nxt/logo/current/syntax.txt?content-type=text%2Fplain syntax.txt].
== Reference Guide ==
More detailed description of all commands and the system are located here:
[http://webcvs.robotika.sk/cgi-bin/cvsweb/~checkout~/robotika/src/imagine/nxt/logo/current/reference_guide.html Logo for NXT Reference Guide].
== Internals ==
Short specification of the Logo for NXT internals is in the file
[http://webcvs.robotika.sk/cgi-bin/cvsweb/~checkout~/robotika/src/imagine/nxt/logo/current/specification.txt?content-type=text%2Fplain specification.txt].
== Publications ==
* [[Media:eurologo2007_nxtlogo.pdf|Eurologo 2007 paper]] and [http://webcvs.robotika.sk/cgi-bin/cvsweb/~checkout~/robotika/src/imagine/nxt/logo/doc/nxtlogo.ppt presentation]

Revision as of 21:34, 1 October 2007