How to write a software application for the Pengwyn board

Hereafter, the operating system that runs the IDE/debugger will be named host machine, and the board being debugged will be named target machine. The host machine could be running as a virtual machine guest operating system, anyway, the documentation for the host machine running as a guest operating system and as host operating system is exactly the same.

Pay attention before to start writing your application you need:

• a filesystem (you can use bitbake/hob to build your preferred filesystem) with develop support (that is, it must include all the necessary header files, the tcf-agent program and gdbserver)
• an SD card already partitioned, with the bootloader in the FAT partition, and
• a network connect between the host machine and the target machine.

Creating the Project

You can create two types of projects: Autotools-based, or Makefile-based. This section describes how to create Autotools-based projects from within the Eclipse IDE. Launch Eclipse using Architech Launcher or use run_eclipse command or just click on the desktop icon.

To create a project based on a Yocto template and then display the source code, follow these steps:

• Select File→New→Project...
• Under C/C++, double click on C Project to create the project.
• Expand Yocto ADT Project.
• Select Hello World ANSI C Autotools Project. This is an Autotools-based project based on a Yocto Project template.

• Put a name in the Project name: field. Do not use hyphens as part of the name.
• Click Next.
• Add information in the Author and Copyright notice fields.
• Be sure the License field is correct.
• Click Finish.

Note: If the “open perspective” prompt appears, click Yes so that you enter in the C/C++ perspective. The left-hand navigation pane shows your project. You can display your source by double clicking the project’s source file.

Building the Project

To build the project, select Project→Build Project. The console should update with messages from the cross-compiler. To add more libraries to compile:

• Click on Project→Properties.
• Expand the box next to Autotools.
• Select Configure Settings.
• In CFLAGS field, you can add the path of includes with -Ipath_include
• In LDFLAGS field, you can specify the libraries you use with -lname_library and you can also specify the path where to look for libraries with -Lpath_library

Note: All libraries are located in ~/yocto/remote/nfs-eclipse-rootfs subdirectories.

Deploying and Debugging the Application

Connect the Pengwyn board to the PC by means of a usb cable to power the board and to have the serial console

Once you built the project and the board is running the image, use minicom (refer to section Usb-Serial to know how to configure minicom) to run tcf-agent program in target board:

Yocto (Built by Poky 7.0.1) 1.2.1
 ttyO0

pengwyn login: root
root@pengwyn:~# /etc/init.d/tcf-agent restart

On the Host machine, follow these steps to let Eclipse deploy and debug your application:

• Select Remote System Explorer perspective.

• In Remote System area right-click TCF icon and select Property.

• In Host tab, insert in Host Name and Connection Name fields the IP address of the target board. (e.g. 192.168.0.101)

• Then press OK.
• Select Run→Debug Configurations...
• In the left area, expand C/C++Remote Application.
• Locate your project and select it to bring up a new tabbed view in the Debug Configurations Dialog.

• Use the drop-down menu now in the Connection field and pick the IP Address you entered earlier.
• Enter the absolute path on the target into which you want to deploy the application. Use the Browse button near Remote Absolute File Path for C/C++Application: field. No password is needed.

• Enter also in the path the name of the application you want to build. (e.g. HelloWorld)

• Click Debug to bring up a login screen and login.
• Accept the debug perspective.

Important

If debug does not works, check if tcf-agent is running on the board and gdbserver is present.