NQC (Not Quite C) is a programming language for several LEGO MINDSTORMS products including the RCX, CyberMaster, and Scout.
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Not Quite C is a simple language with a C-like syntax that can be used to program Lego's RCX programmable brick (from the Mindstorms set). If you are just getting started with programming, then graphical environments such as the Mindstorms RIS software or Robolab are probably better choices. If, however, you're a C programmer and prefer typing a few lines to drag and drop icon programming, then NQC may be perfect for you.

This is my own repo to capture my changes to the 3.1r6 code as found on BricxCC. I've been maintaining this private fork for a few years in order to keep it building and running on OS X and BSD.

The original README from the NQC project follows.

NQC Readme

If you have a problem, PLEASE CHECK THE FAQ: http://bricxcc.sourceforge.net/nqc/doc/faq.html

Send bug reports to bricxcc@comcast.net. Be sure to include details about what platform you are running nqc on and a sample file that demonstrates the bug if possible.

For updates and additional documentation, visit the NQC Web Site: http://bricxcc.sourceforge.net/nqc

Note to Windows Users

NQC is a command line based tool - normally you run it by typing an appropriate command into an MS-DOS window. There is no GUI for it and if you double-click the nqc.exe file an MS-DOS console will be created for you, NQC will run within it, then since NQC finishes almost immediately, the entire window will disappear.

Some people prefer command line based tools because they allow you to use the text editor of your choice, etc. It also makes for identical behavior under Windows, Mac, and Linux. In order to use the command line version of NQC you'll need to do two things:

  1. Use some sort of text editor (such as Notepad) to edit and save a source file for NQC to compile.

  2. From an MS-DOS window type the appropriate NQC command. Its usually best to either put all of your programs and nqc.exe in the same directory, or make sure the directory containing NQC is in your command path.

If any of the above seem either too confusing or too tedious, then you may want to try the BricxCC which provides a familiar Windows style GUI on top of the standard NQC compiler. You can download BricxCC here:


Getting started

Download the appropriate compiler (nqc or nqc.exe) and put it where your shell can find it as a command.

The IR tower should be connected to your modem port (macintosh) or COM1 (Win32/Linux). The IR tower should be set for "near" mode (small triangle). The RCX should also be set for this mode, and firmware must already be downloaded.

Compile and download the test file using the following command line:

nqc -d test.nqc

The test program assumes there's a motor on output A and a touch sensor on input 1. It turns on the motor and waits for the switch to be pressed, then it turns off the motor and plays a sound.

If you are using a USB tower or a different serial port you will need to specify the port either by adding a -Sx option (where x is the name of the port) to the command line or by setting the RCX_PORT environment variable.

Here are some examples:

USB tower (where supported) nqc -Susb -d test.nqc

Win32 COM2 port: set RCX_PORT=COM2

Win32 USB port: set RCX_PORT=usb

Linux: The syntax for setting environment variables is shell specific. By default nqcc uses "/dev/ttyS0" as the device name for the serial port. If you are using the second serial port, then "/dev/ttyS1" should work. Other device drivers may or may not work depending on if they implement the expected ioctl's to setup the baud rate, parity, etc.