Atmel CAVR-4 사용자 설명서

CAVR-4

Part 1. Using the compiler

The command line option -

e

 makes the extended keywords available, and reserves them 

so that they cannot be used as variable names. See, -e, page 179 for additional 
information. 

For detailed descriptions of the extended keywords, see the chapter Extended keywords. 
To read about special function types, see Special function types, page 29.

The pragma directives control the behavior of the compiler, for example how it allocates 
memory, whether it allows extended keywords, and whether it issues warning messages. 

The pragma directives are always enabled in the AVR IAR C/C++ Compiler. They are 
consistent with ISO/ANSI C, and are very useful when you want to make sure that the 
source code is portable.

For detailed descriptions of the pragma directives, see the chapter Pragma directives.

With the predefined preprocessor symbols, you can inspect your compile-time 
environment, for example time of compilation, the processor variant, and memory 
model in use.

For detailed descriptions of the predefined symbols, see the chapter The preprocessor.

Standard peripheral units are defined in device-specific I/O header files with the 
filename extension 

h

. The product package supplies I/O files for all devices that are 

available at the time of the product release. You can find these files in the 

avr\inc

 

directory. Make sure to include the appropriate include file in your application source 
files. If you need additional I/O header files, they can easily be created using one of the 
provided ones as a template.

For an example, see Accessing special function registers, page 133.

For hardware-related parts of your application, accessing low-level features is essential. 
The AVR IAR C/C++ Compiler supports several ways of doing this: intrinsic functions, 
mixing C and assembler modules, and inline assembler. For information about the 
different methods, see Mixing C and assembler, page 93.