The Great Cow Great Cow BASIC
An open-source BASIC compiler for microcontrollers
Great Cow BASIC News Archive:
A German translation of Great Cow BASIC is now available, thanks to Peter Rabiger. It can be downloaded from here, and installed by extracting it to the GCBASIC install directory.

Some false virus detections have occured with GCBIDE. These are due to a virus being written in the same language as GCBIDE (RapidQ Basic), and several antivirus developers using a harmless part of the virus executable to create the virus signature.

While GCBIDE is clean it is no longer hosted on this site. All programs hosted by must be open source and the developer of GCBIDE has decided against releasing the source code for version 2.0. GCBIDE is still available from

Version 2.0 of GCBIDE by Emile Tredoux is available. It can be downloaded from the GCBASIC site here, or from Emile's page here.

Sanyaade has created a version of the SciTE editor with support for GCBASIC syntax highlighting. This is old news now, but if you're not one of the many people who have downloaded it already it's worth a look. Please see this page.

Added some guidelines on how to post to the forum. If people can try to follow them it will make answering forum posts a lot easier for us!

The link to these is on the left, right above the link to the forums.

Still no fix for the issue with the Download page, but those who have trouble downloading GCBASIC can use the standard download page at IE 6 is not to blame as I earlier suspected, users of several other browsers have also had trouble.

Emile Tredoux has created a site for GCBIDE, located at

A new version of GCBIDE, 1.3,  is available from the download page. GCBIDE now includes a feature which displays the chip pinout, assigns a name (such as Pin3) to every I/O pin, and allows the initial direction of the pins to be set. For this to work, a new version of the chip data files must be installed.

Those who have downloaded after October 7 will already have the needed files. Anyone else who wishes to use the tool will need to download the new chip data files from here, and install them by extracting the archive to C:\Program Files\GCBASIC.

The Getting Started page has been updated to cover the installation of GCBIDE, BasicIDE and the WinPic programming software.

Also, some users have reported difficulty with the download links. I've found that for some reason IE 6 often doesn't work properly when the download links are clicked. This problem may also affect other versions of IE, but I haven't tried them. All I can recommend is that anyone who has trouble keeps trying, or uses another browser. I normally use Firefox and haven't had any difficulties with the download links. If anyone can shed some light on what is causing this trouble, please email me (Hugh) using the email address at the bottom of this page.

A few minor changes made to this page and the About GCBASIC page.


Two IDEs for GCBASIC are now available!

Emile Tredoux has developed a simple IDE (GCBIDE) for his own use, and kindly offered to make it available. The latest binary is here. The contents of the zip folder need to be extracted so that the .exe is in the same directory as GCBASIC.

Papadopol Lucian is currently developing an IDE for GCBASIC, BasicIDE, using VB. More information is available here, and the program and source code are available at his download page. BasicIDE is available in both English and Italian. While still heavily under development, this program is quite usable.

Crimson Editor support is still available - see the Getting Started page for information on installing it.

A page has been added to this site to list the changes made to

Also, I have finally added the Spanish translation. Presently this is available as a seperate download, but will be added to the installer for the next version of GCBASIC. Thanks to Pablo Curvelo for the translation, and apologies for taking so long to upload the files.


Great Cow BASIC has been released. The most major new features are support for 18C/18F chips (bringing to total number of supported chips to over 300) and a new system for storing chip data which removes the need for the #mem directive, and allows full use of the available RAM. Some other new features are:
  • SELECT CASE control structure
  • Keypad support
  • Partial bit variables
  • Most error messages include the file and line on which the error occurred
An automated test program has been used to check for any MPASM errors produced by a sample of 186 known good GCBASIC programs. All of those errors found have been fixed, along with most of the bugs mentioned on the forums.

Several pages on this site have also been updated.

A severe bug has been found in the 4 and 8 bit LCD routines in GCBASIC, which prevents any of them from working correctly. A fixed lcd.h file is available here - please locate the existing lcd.h file (usually in C:\Program Files\GCBASIC\include\lowlevel), and replace it with the new file.

A new version of Great Cow BASIC,, has been released. This version contains some minor bugfixes, in addition to Italian and Turkish translations.

A significant change in this version is that it is compiled with FreeBASIC, not QBASIC as previous versions have been. This has resulted in several changes - see the changelog for more details.

Some new features were promised for the next version of GCBASIC in the forums. These have not yet been implemented due to time constraints - they will be in version which will be released within a few weeks.


Version released. Included in this new release are many new features and bugfixes, such as new PWM routines, additional LCD support, and many 16-bit variable bugfixes.


Version released. This is a bugfix release - it improves support for 10/12 series chips, and chips without interrupts. The help section on compiler directives has also been expanded, and is near completion.

Version released. This includes some new features such as data tables and SPI. It also has fixes for several bugs associated with A/D conversion, RS232, and newer PIC chips.

Version released. This includes support for MPASM in addition to gputils, additional assistance for new users (two more demos and several new help articles), and a fix for a bug which caused errors when compiling for chips without a low-voltage programming option.

Removed a bug in the installer which prevented GCBASIC from installing to directories with long names (other than C:\Program Files). This is a minor update, and there is no need to obtain itIt includes several bugfixes, if you already have GCBASIC installed successfully.

The latest installer now includes both the Inno Setup script used to create the installer, and the mkcompil.bas file, which is used to create the compile script.

Great Cow BASIC released. A bug involving chips with less than 256 bytes of RAM has been resolved.

The compiler has been changed from alpha to beta status, as it is now feature complete. Once documentation and error checking have been improved, it will be released as version 1.0. Please do not hesitate to report any bugs that you find!

Great Cow BASIC alpha released. This latest update contains fixes for several bugs, and it is recommended that all users of and upgrade.

Great Cow BASIC alpha made available. This newest version includes support for 16-bit unsigned integers, along with several significant bugfixes.

GCBASIC alpha uploaded. Support page added, with links to bug tracker and forum.

Features and Example Projects pages added.

Site created, and latest GCBASIC alpha ( uploaded.

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