nqc - A simple C-like language for Lego's RCX programmable brick
] [ actions
] [ -
NQC stands for Not Quite C, and is a simple language for programming the LEGO
RCX. The preprocessor and control structures of NQC are very similar to C. NQC
is not a general purpose language -- there are many restrictions that stem
from limitations of the standard RCX firmware.
This man page does not attempt to describe the NQC programming language or the
RCX API, merely the options of the nqc command-line program. References to
more complete documentation are given at the end of this man page.
nqc is normally used to process a single source file given as filename
You can also read from stdin by using -
instead. If the filename ends
, it is assumed to be a RCX image file from a previous compile,
and will be used as is (for downloading or listing).
- use NQC 1.x compatibility mode. The RCX API changed significantly with
version 2.0. This flag makes the compiler grok old code.
- generate code and use communications methods for "smart bricks"
other than the RCX. Currently, can be either CM or
- download program to the RCX. When this option is given, code is sent
directly over the serial port to the brick and no output file is generated
- prevent the standard nqc.h file from being automatically
- define macro sym as value.
- write compiler errors to filename (or to stdout, if no name
specified) instead of to stderr.
- search path for include files. Multiple directories should be
seperated as normal for the platform (under Linux / Unix, that'd be "
"). Can also be set with the NQC_INCLUDE environment
- generate a human-readable bytecode listing to filename (or to
stdout) instead of generating a binary file.
- output code to outfile. This option causes a file to be written
even if -d or -L is also given. If no filename is specified,
the output file will have the same basename as the input file but an
extension of .rcx instead of .nqc.
- use serial port portname. Under Linux, /dev/ttyS0 is the
default. (This will differ on other platforms.) The port can also be
specified via the RCX_PORT environment variable, but the command line
option takes precedence.
- undefine macro sym.
Actions look similar to options, but they have some subtle differences. In
general, options set up things (such as a serial port) for later use, while
actions cause something to happen. Actions are executed in the order that they
appear on the command line. In addition, actions appearing before the source
file happen before compilation, while actions after the source file happen
after compilation. For historical reasons, downloading the compiled file (
) works as an option and not an action.
- run the current program. This causes the program selected on the RCX to
- -pgm number
- select program number. This changes the program slot on the RCX.
- get the datalog from the RCX and print it to stdout.
- same as -datalog but with more verbose output.
- set the IR port to short-range mode.
- set the IR port to long-range mode.
- -watch time
- set the RCX's clock to the specified time. If you use now, then the
host's current time is used.
- -firmware filename
- downloads the firmware to the RCX. You'll need the official Lego RCX
firmware from the CD-ROM -- the current (and so far only) file is called
firm0309.lgo. This will probably be necessary the first time you
use your RCX, and whenever it's been without batteries for more than a few
- -firmfast filename
- same as -firmware, but at quad speed. Requires the tower to be in
near mode (see -near). If you have trouble getting the fast
download to work, please revert to the older (and slower) method.
- -sleep timeout
- set RCX auto-shutoff timeout, in minutes.
- -msg number
- send IR message to RCX. The brick will respond to this just as it would a
communication from another RCX.
- -raw data
- send an arbitrary packet to the RCX and print the reply (if any) to
stdout. The data should be a hexadecimal string, with no spaces,
zero-padded so that it is an even number of characters (although it may be
an odd number of bytes). For example, to read the contents of variable 1,
you could use -raw 120001. The bytecodes for raw messages can be
found on web sites that document the RCX protocol.
- -remote value repeat
- send a repeating remote command to the RCX.
- erase all programs and datalog from the RCX.
- sets the default serial port. See the -S option.
- specifies extra options to be inserted into the command line. For example,
setting NQC_OPTIONS to -TScout would cause nqc to target the Scout
- specifies additional paths to search for include files. See also the
To compile foo.nqc
, download the bytecode to program slot three, and make
the RCX start executing it immediately:
nqc -d -pgm 3 foo.nqc -run
To just compile bar.nqc
, resulting in bar.rcx
To download bar.rcx
to the RCX:
nqc -d bar.rcx
To set the IR tower to short-range mode and download the firmware at high speed:
nqc -near -firmfast firm0309.lgo
To compile /usr/doc/nqc-2.1.0/test.nqc
and print the resulting bytecode
listing to the screen in human-readable format:
nqc -L /usr/doc/nqc-2.1.0/test.nqc
(This should result in the following output under nqc 2.1.0:
*** Task 0 = main
000 pwr ABC, 7 13 07 02 07
004 dir ABC, Fwd e1 87
006 InType 0, Switch 32 00 01
009 InMode 0, Boolean 42 00 20
012 out A, On 21 81
014 chkl 1 != Input(0), 14 95 82 09 01 00 00 fa ff
022 plays 0 51 00
024 out A, Off 21 41
Older versions of nqc required a seperate rcx.nqh
file. This is now integrated into the binary and no longer necessary, but for
is included with the package. (If you installed the
RPM, try /usr/doc/nqc-2.1.0/rcx2.nqh
- The main Not Quite C web site. You'll definitely want to look here.
Notably, you'll find the NQC Programmer's Guide, which covers the
NQC language itself.
- A great site for alternative RCX / Mindstorms development.
- Details on the internals of the RCX and the RCX protocol.
- Discussion group for NQC. Also available via NNTP at
- Linux binaries and RPM-format packages for NQC, including source RPMs.
Also has an RPM containing the NQC language documentation from Dave's
site, in case you'd prefer to have it installed locally.
None known. But be aware that Scout support is still preliminary and may change
nqc is Copyright (C) 1998-2000 David Baum and released under the terms of the
Mozilla Public License. See the documentation included with the program for
The Not Quite C programming language and the nqc program were written and are
maintained by Dave Baum. Various contributions have been made by other people
-- a full list of these can be found on Dave's web site.
This man page was written by Matthew Miller (email@example.com), with extremely
large amounts of borrowing from other NQC documentation.