The Microcontroller Idea Book - Jan Axelson's Lakeview Research

Chapter 15
BASIC compilers
A BASIC compiler offers a middle ground between the BASIC-52 interpreter and assembly-language
programming. With a BASIC compiler, you write your programs using the
familiar keywords and syntax rules of BASIC, but the compiled programs run on their own,
without requiring the BASIC-52 interpreter. Binary Technology, Systronix, and Blue Earth
are three vendors of BASIC compilers for the 8052.
As with assembly language, to use a BASIC compiler, you first write a source file, using
any text editor. But instead of using assembly-language mnemonics, you write the source
file using the BASIC compiler’s keywords and conventions. When the program is complete,
the compiler program translates your program lines into the machine codes required by the
8052 chip. The compilers will create an object file, usually in Intel Hex format, for uploading
or programming into EPROM, plus a listing file for documentation and debugging use.
When the object file is stored in the 8052’s code memory, the 8052 can run the program
directly, without having to use the BASIC-52 interpreter.
Using a compiler has several advantages:
• Unlike with assembly language, the syntax used with BASIC compilers is similar to
BASIC-52. This means that you don’t have to learn a new programming language. In
fact, you can usually use the BASIC-52 interpreter to test your code before you compile
it. You can also use BASIC-52 for loading and debugging your compiled programs, as
described in Chapter 13.
• A compiled BASIC program will run faster than an interpreted BASIC-52 program.
The speed increase depends on the program, but programs that run 20 to 50 percent
faster are typical.
• Because a compiler doesn’t limit you to the 8052-BASIC chip, you can develop
programs for other members of the 8051 family. For example, Systronix’s BASIC
compiler has optional language extensions for Dallas Semiconductor’s DS5000
8051-compatible microcontroller.
A disadvantage to using a compiler rather than an interpreter is that you have the extra steps
of compiling and uploading programs before you can run them. But because the BASIC-52
language is so similar to the compilers, you can do a lot of your testing with the interpreter,
and use the compiled version for final testing only.
There’s also the added expense of buying the compiler. But if you develop many different
projects, or if you need many copies of a single project, the compiler can end up saving you
money, since you can use 8032 chips instead of the more expensive 8052-BASICs.
246 The Microcontroller Idea Book