Project structure – where things go?

Aery32 Software Framework provides a complete project structure to start AVR32 development right away. You just start coding and adding your files. The default project directory structure looks like this:

projectname/
    aery32/
        ...
    examples/
        ...
    board.c
    board.h
    main.c
    Makefile

It is intended that you work under the root directory most of the time as that is the place where you keep adding your .c source files and .h header files.

main.c

The main.c source file contains the default main function where to start. At the top of the file, couple of header files are also included in advance. For example, you most probably are going to use general peripheral input and output pins so aery32/gpio.h has been included. If you will use most part of the framework, instead of including every part separately you may like to include all the headers at once by including aery32/all.h.

#include <stdbool.h>
#include "board.h"
#include <aery32/gpio.h>

#define LED AVR32_PIN_PC04

int main(void)
{
    /* Put your application initialization sequence here */
    init_board();
    aery_gpio_init_pin(LED, GPIO_OUTPUT);

    /* All done, turn the LED on */
    aery_gpio_set_pin_high(LED);

    for(;;) {
        /* Put your application code here */

    }

    return 0;
}

board.h

This is a place for the board specific function prototypes and supportive #define macros. These macros provide a way to do configuration, for example.

board.c

The default board initialization function, init_board(), can be found here. First it sets all the GPIO pins to inputs. Then it configures the board’s power manager. Basicly the external oscillator OCS0 is started and the master clock frequency is set to 66 MHz. If you like to change the master clock frequency or want to change the way how the board is initialized, this is the place where to do it.

aery32/

This directory contains the source files of Aery32 library. The archive of the library (.a file) appears in this directory after the first compile process. The aery32/ subdirectory contains the header files of the library. Linker scripts, which are essential files to define the MCU memory structure are placed under the ldscripts/ directory. However, you should not need to hassle with those files.

examples/

All the example programs are placed under this directory. Every program is completely independent. To test one you can just replace the main.c with one of the example programs and it works out of box when uploaded into the board. Otherwise if you do not need these files you can remove this folder.

Makefile

Makefile enables the project build process and provides the convenient way to upload the compiled application into the board by using in-system programming bus. To compile the project just command:

make

or:

make all

To clean the project folder from binaries call:

make clean

and to recompile all the files:

make re

When you are ready to upload the program into the board type:

make program

If you also want to start the program immediately type:

make program start

or in shorter format:

make programs

How to introduce new source files in the Makefile

Let’s say I would like to separate my source code into a my/ subdirectory under the project root. After creating the directory, I have to edit the Makefile. So, open the Makefile into your editory and find the line:

SOURCES=$(wildcard *.c)

Edit this line so that it looks like this:

SOURCES=$(wildcard *.c) $(wildcard my/*.c)

You can also add single .c files at the end of this list.

Example programs

Aery32 Framework comes with plenty of example programs, which work out of box. To test, for example, the LED toggling demo do the following:

In Windows

Open Command Prompt and command:

cp examples\toggle_led.c main.c
make programs

The quickest way to access Command Prompt is to press Windows-key and R (Win+R) at the same time, and type cmd.

In Linux

Open terminal and:

cp examples/toggle_led.c main.c
make programs

The following lines of commands overwrite the present main.c with the example and the uploads (or programs) it into the development board. The program starts running immediately.

Note

Every example program consists from a single file and can be found from examples/ directory.

Where is my C++?

To use C++ you have to change the avr32-gcc compiler to avr32-g++. This can be done by editing the Makefile. Find the following line under Standard user variables section:

CC=avr32-gcc

and replace it with:

CC=avr32-g++

Also change the C standard, that’s the line below, to:

CSTANDARD=gnu++98

Or if you feel more experimental, you can chooce one of these: c++0x or gnu++0x.

Now you can use C++ in your project. Remember to use the .hh header files instead of .h files. For example, instead of using

#include <aery32/gpio.h>

use

#include <aery32/gpio.hh>

At the moment Aery32 Software Framework uses only the C++ namespaces. The benefits of using namespace is that you can omit the “aery_” prefix in the function calls. This has been demonstrated below

#include <stdbool.h>
#include <aery32/gpio.hh>
#include "board.h"

#define LED AVR32_PIN_PC04

using namespace aery;   // enable aery namespace

int main(void)
{
    init_board();
    gpio_init_pin(LED, GPIO_OUTPUT|GPIO_HIGH); // yay! no "aery_" prefix

    for(;;) {
        /* Put your application code here */

    }

    return 0;
}