| 2.1.2.8 Thin Client example revisited
In the Thin Client example discussed above a configuration was chosen after carefully studying the hardware characteristics of the Thin Client. Do the following steps after opening the Platform Builder:
1. From the file menu, choose new platform, and new platform wizard will appear.
2. Choose next and select one or more available BSPs.
3. On the BSP page choose next and in the platform configuration dialog box, enter a name for the platform.
4. Select a platform configuration from the available configuration area which in this case will be Windows Thin Client with browser for this particular example.
After these steps are completed platform creation is completed. After that the next step is to build the platform:
The OS image will be built based on the platform that has been configured. To build an Operating System image select retail or debug build configuration, modify the platform settings as needed, such as enabling kernel debugger, and then build the image.
After the platform is configured, the platform can be built using the platform builder integrated development environment (IDE).
Platform builder creates an Operating System image in four stages:
1. Sysgen phase.
2. Feature build phase.
3. Release copy phase.
Build system generates header files, links modules, copies the resulting modules to a release directory, and generates a binary image file.
Static library as well as code supplied by the developer or the third party vendors is combined into a binary file and that is downloaded onto the device.
Sysgen Phase: Each feature selected from catalog has a corresponding sysgen variable. If a feature is included in platform, IDE sets the corresponding sysgen variable during the sysgen phase of the build process.
Build system uses these variables to link the corresponding static libraries into modules.
The system also filters the system header files, creating headers that only contain prototypes for the functions exported by the developer’s platform. Import libraries for the system modules are also created during this phase.
Feature Build Phase: After sysgen phase, feature build phase is run. During this phase, all user features including platform builder project (.pbp) files, source files and makefile (.mak) files are compiled and built.
Release Copy Phase: Build system copies all the files needed to make an OS image to the release directory. The modules and files created during the sysgen phase are copied to the directory first, followed by the files created by the feature build phase.
Make Image Phase: The project specific files which includes
Project.bib
Project.dat
Project.db
Project.reg
are copied into Release directory.
Now information in BIBInfo tab of the platform setting dialog box is then added for each module or file. During this phase, the files in the release directory are combined in binary image file Nk.bin. If some modification is done, then the image should be made again.
Platform Downloading
After the platform is built, the OS image associated with the platform will be downloaded to a target device. The IDE gives a mechanism that allows downloading using a number of types of communication hardware, an OS image to target device.
To download an Os image to a target device, there should be connection from development workstation to target device.
Target menu in the IDE provides functionality that allows the developer to download an OS image to a target device. Before downloading configure a connection to the target device. To download using Ethernet, the development workstation and the target device must be on the same subnet. If the subnets will differ then the target device cannot be connected and debugging the OS image will not be possible.
Transfer the Operating System image thus made to the Thin Client at the startup. To make a connection to the device, go to target menu and configure remote connection. Choose services tab and from the active named box choose a connection. This completes the deployment of the operating system image to the Thin Client. This process is the general way to build Windows CE Operating System image for a given hardware platform. Many a time this whole process is not necessary since there are some hardware platforms like Pocket-PC for whom Windows CE image were already built and tested. Such hardware platforms come preloaded with Windows CE image and as mentioned above they export a software development kit which the developers can use to build software for Pocket-PC. Embedded Shruti is also developed using the Pocket-PC software development kit not by building the Windows CE image from the scratch. But every embedded software developer should have an idea of the whole design process so that the software can be ported to custom platforms if required in the future. The process was explained using the Thin Client example. The Thin Client example was the first work carried out by me in this project.
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