Specifications

CAVR-4

Part 1. Using the compiler

Getting started

In this example, myfile.r90 and myfile2.r90 are object files, lnkm128s.xcl is the

linker command file, and

cl3s-ec.r90 is the runtime library. The option -s specifies

the label where the application starts. The option -o specifies the name of the output

file, and the option -F can be used for specifying the output format. (The default output

format is

Motorola.)

The IAR XLINK Linker produces output according to your specifications. Choose the

output format that suits your purpose. You might want to load the output to a

debugger—which means that you need output with debug information. Alternatively,

you might want to load the output to a flash loader—in which case you need output

without debug information, such as Intel-hex or Motorola S-records.

Basic settings for project configuration

This section gives an overview of the basic settings for the project setup that are needed

to make the compiler generate the best code for the AVR device you are using. You can

specify the options either from the command line interface or in the IAR Embedded

Workbench IDE. For details about how to set options, see Setting command line options,

page 167, and the AVR® IAR Embedded Workbench™ IDE User Guide, respectively.

The basic settings available for the AVR microcontroller are:

● Processor configuration

● Memory model

● Size of double floating-point type

● Optimization for speed and size

● Runtime environment.

In addition to these settings, there are many other options and settings available for

fine-tuning the result even further. See the chapter Compiler options for a list of all

available options.

PROCESSOR CONFIGURATION

To make the compiler generate optimum code you should configure it for the AVR

microcontroller you are using.

The --cpu option versus the -v option

There are two processor options that can be used for configuring the processor support:

--cpu=derivative and -vn

Your program may use only one processor option at a time, and the same processor

option must be used by all user and library modules in order to maintain consistency.