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ST9 USER GUIDE

file as a higher-level code. This is used to change the hardware configuration (assignments of

the port pins, etc.) by changing only those files that are involved with low-level routines.

Once this layout is established, you can then write the files mentioned below. These files are

used to configure the tools. Since they know the program structure, it can be maintained by

compiling the right portions whenever they change. So you absolutely have to go through the

following steps even though they are not directly related to writing code:

– Writing the makefile

– Writing the linker command file

– Writing the start-up file

These files are specific to each project and must be added to the list of source files. Examples

are given in the applications described in this book and are available in the Companion soft-

ware.

5.4.1 Writing the Makefile

The makefile is the template that puts all the program pieces together. It describes the module

interdependencies that enable the gmake utility to build the program efficiently by processing

only those source files that have been modified since the last invocation of gmake(6).

The Make language is very powerful, for a Make utility can be applied to almost any kind of

processing where several files provide a single result. It is a generic machine that manages

updates smartly. When developing programs for the ST9, the makefile description is similar

from one project to another. Most of the changes relate to the name and the number of the

files involved. Thus, we propose here a skeleton makefile and we explain how you can tailor

it for a specific application, without going into the advanced features gmake offers.

A skeleton makefile is given on the companion software, and a variant is included in the direc-

tory of each application. This will help you understand typical makefile usage, which is not dif-

ficult to learn.

The skeleton makefile reads as follows:

#/*******************************/

#/*

MAKEFILE SKELETON

#/*******************************/

# DEFINES

# *******

(6) See GNU9P Make Utility Manual.

ST9 데이터시트(PDF) 114 Page - STMicroelectronics