Before You Start

This is a reference manual, it is not intended to teach you BASIC. It gives a summary of the commands and functions plus some hints and tips on their use. It also describes the minor differences between this and other versions of BBC BASIC. A general knowledge of BASIC has been assumed.


BBC BASIC (Z80) for the TI-83+ and TI-84+ is a Flash application. To install it you will need a transfer cable and supporting software (such as TI Connect™). Transfer the BBC BASIC.8xk file to your calculator. Once installed BBCBasic should appear on the Applications menu.

Consult your calculator documentation and file transfer software documentation for further information.

Getting Started

Here follows a quick guide to get you up and running in the BBC BASIC environment. For more detailed information, look up keywords in the dedicated reference or documentation in the overview section. For help on entering text, see the page on Editing.

The BBC BASIC Environment

When you run BBC BASIC from the applications menu, you will be presented with the following screen:

BBC BASIC (Z80) v3.00
(C) R.T.Russell 1987

BBC BASIC takes the form of a command-line interface. BASIC commands or OS ("star") commands are typed into this interface for immediate execution or as part of a program. For example, type in


at BASIC's prompt and press the Enter key. This will exit BBC BASIC and return you to the TI-OS.

Return to BBC BASIC and enter the following line at the prompt:


When you press the Enter key, BBC BASIC evaluates the BASIC program code and displays


which is the value of PI. The PRINT statement outputs the value following it to the display; in this case the value is the result of RAD(180). RAD converts a value in degrees into an value in radians; 180 degrees is, indeed, pi radians.

If you wish to store BASIC code as part of a program, for later execution, you need to prefix it by a line number. If you repeat the previous example, and type in the following,

10 PRINT RAD(180)

BBC BASIC will accept the line as part of a program. It is conventional to give BASIC programs line numbers that are multiples of 10, starting at 10 (10, 20, 30, etc). You can now run the program by entering the RUN command.

You can display the current program's listing with the LIST statement, or search through it using the LIST IF statement. If you type in a new line that starts with a line number that already exists, the existing line is overwritten. If you just type a line number, the corresponding line number is deleted.

One reason for entering line numbers in increments of 10 is that it gives you the ability to insert new lines between two existing ones. For example, if you wanted to insert a line between 10 and 20 you could give it a number of 15. This will ultimately lead to erratic and messy line numbers, which can be tidied up with the RENUMBER command.

Saving and Loading Programs

Start by entering the following program to calculate the area of a circle from its radius:

10 INPUT"Radius=",R
20 PRINT"Area=",PI*R^2

Once you have typed it in, you can verify it works by running it with the RUN command. You will usually want to save programs you have worked on so they can be run again at a later date. To do this you will need to use the SAVE command. Try saving the program you just typed in above by typing in the following command:


This will save the program in memory to a program variable named CIRCAREA. (See the Files section for information about filenames and how files are stored). Now type NEW to remove the loaded program from memory followed by the LIST keyword to verify that it has, in fact, been unloaded. Use the LOAD command to reload the CIRCAREA program into memory:


You can now use the LIST command you can see that the file has been reloaded, or simply RUN run it. You can load and run a program from storage directly by using the CHAIN keyword or RUN followed by a filename.