Windows ce oal

Designers interface these RTC chips through a common I2C bus shared by a lot of peripherals and sensors. Therefore a common I2C bus driver is needed to the developers. Since an I2C interface is a shared bus, synchronization is needed between the devices to access the I2C bus. Windows CE supports synchronization objects like critical sections, semaphore and mutex etc..

These functions are called from the windows CE standard time functions. OEM is responsible for filling the stub inside these functions. Windows CE has been designed to directly use built-in devices. These devices are controlled by native drivers, which are intimately linked to Windows CE's core components.

For example, the graphics, windowing, and events subsystem GWES module calls specific functions in the display device driver to render images at runtime. As one might expect, these functions are different from those required in the battery driver.

Hence, each native driver must conform to a specific, well-defined interface called the device driver interface DDI. These interfaces are explained in more detail later. Suffice it to say at this point that none of these interfaces can be changed by OEMs and that native drivers must fully support them. Native drivers are built as dynamic-link libraries, with two exceptions: the battery and the LED drivers are built as static libraries linked with the GWES module when a CE image is built because of their small size.

Native drivers are always loaded at boot time. Stream interface drivers all share a common interface. They are mostly used for controlling installable devices a scanner, for example , but a few are used with built-in devices, such as the serial port device driver, because the stream interface is better suited for those devices.

Stream interface drivers that control installable devices are typically accessed by applications. For instance, upon connecting a GPS device to the platform, the user will start a GPS-enabled application that will access and use the device. Microsoft chose to re-use an existing API specifically, the file API to enable the applications to access those drivers, instead of creating a new one.

Consequently, stream interface drivers have been designed to expose a device's capabilities to the applications by presenting the device as a special file, which can be opened, read from, written, closed, and so on. To be easily identified, stream interface drivers follow a unique file naming convention, which is composed of a three-letter prefix such as CAM for camera or BCR for bar code reader , a digit that identifies a specific device when multiple instances are available, and a colon.

The three-letter prefix can be any combination of uppercase letters, but it must be unique on a given platform. When an application opens a file that follows this convention, the file system module recognizes that a driver is being accessed and re-routes subsequent file system calls to the specific driver.

In contrast to the native drivers, the stream interface drivers all share a common interface composed of 10 functions, or entry points, within each driver. These functions, described in Table 1, closely match those found in the file API that are used by the applications. CreateFile combines the ability to create and open files. There is no OpenFile call. CloseHandle is then called to close the handle.

An independent hardware vendor has the freedom to adapt these functions to the device's capabilities. The driver documentation becomes crucial for enabling developers to understand how to use the driver when writing applications that access the device.

Stream drivers can be loaded at various points in time. For built-in devices, such as an audio card, stream drivers are loaded at boot time via entries in the Registry. For detectable devices a serial port implemented on a PC card for instance , the related driver is loaded at detection time, again using entries in the registry. Finally, applications can specifically request a driver to be loaded at run-time, by calling LoadDriver , for instance.

Stream drivers are loaded, managed, and unloaded by the device manager module. Stream interface drivers typically rely on native drivers to perform their duties. For instance, a bar code reader will rely on the serial port driver to physically access the device. In this instance, the bar code reader is called a client driver, and would use the Win32 file API to access the serial driver, the same way an application would. Client drivers are useful because they encapsulate implementation details, such as processing data into a bitmap image, that applications do not have to be concerned about.

The full USB host-side specification is supported on CE, including the various data transfer methods-control, isochronous, interrupt-driven, and bulk. USB drivers can be implemented using three approaches. First, a USB driver can be implemented as a standard stream-interface driver, allowing applications to use the file API to access the device. NDIS drivers.

Only a subset of the original specification, NDIS 4. As a result, miniport drivers are supported, but monolithic and full drivers are not. Fortunately, miniport drivers are largely source-compatible with those on NT.

Microsoft provides various NDIS driver samples, and recommends porting an existing NT driver, if one is available, rather than creating one from scratch. Device driver implementation. Adapting Windows CE to a specific platform is mostly a matter of developing the drivers for the particular devices the board features. The other aspects are to configure, build, and test the Windows CE image itself. Driver development, as I will explain, consists of implementing interrupt handlers driectly in the kernel and the code that access the devices the drivers themselves.

Interrupts are processed in unique fashion in Windows CE, as shown in Figure 1. The kernel's event handler is the first to catch a raised interrupt.

The interrupt, as well as lower priority interrupts, are disabled, but all other interrupts of higher priority remain enabled provided the underlying architecture supports nesting interrupts based on their priorities. The related interrupt service routine ISR is then called. I am very close to quiting the procedure Hi buddies,.

Thanks for your replies and thanks for share your experiences. Have a great day! The content you requested has been removed. Ask a question. Quick access. Search related threads. Remove From My Forums.

Asked by:. Archived Forums. Microsoft Device Emulator. Sign in to vote. I used platform builder to build an SDK for x86, and I'm using the corresponding emulator.

Wednesday, December 22, PM. After enabling build the OS image and download it. Thursday, December 23, AM. I will check them and report back regards ilias. The options you mentioned are already checked, but still no luck. Let me explain the procedure I am following. After building the OS image i configured the emulator as follows 1. Figure 5 Cool New Emulator Aside from the new, spiffier look see Figure 5 , the most important new feature of this emulator is a greater similarity between the behavior of the PocketPC emulator which was built using the same technology and an actual, shipping device.

An OEM that wants to customize the look of the emulator can create a new UI skin, to make the emulator more closely resemble the actual device being emulated. And while the low-level machine instruction differences—x86 instead of ARM instructions—might mean that you have to rely on device-based testing for issues like misaligned data access, developers will likely find that the new emulation is a very big improvement over what they had to work with in previous SDKs.

Few developers use this resource when it could provide assistance at a low cost. And the scope of available source code has grown. The earlier offering involved about source files, while the new set adds over source files to bring the total to almost Of course, a count of files is a crude way to measure value—like counting lines of code to measure programmer productivity.

So, perhaps you're wondering why this is so valuable. I will take a moment to describe some of the gems you'll find. For starters, the source code includes the Windows CE kernel. Have a question on memory allocation, thread scheduling, DLL loading, or interrupt handling? Are you building a new OAL and wondering just when and why it is called?

Simply search for the OEM prefix, and you'll get a screenful and more to help you understand the intimate relationship between the CE kernel and your OAL.

Building a display driver? To help you make better use of this class library, the Platform Builder source code includes the complete source files to the GPE classes. You'll also find a variation of GPE that supports rotating a CE-based display driver's image by 90, , and degrees. Or perhaps your work takes you to more Internet-centric parts of Windows CE. The source files will help you here as well. Perhaps that's not low-level enough for you? Maybe you prefer to work with MSMQ and are having problems with some unexplained behavior.

I personally expect to spend much time over the next few years digging into this rich mountain of data. An hour spent spelunking into the source files will save at least a day of staring at your own misbehaving code. Just remember, if you read the licensing agreement you'll see that the source code is available to help you learn about Windows CE and to help you debug your systems.

You cannot build and ship any portion of these source files for commercial purposes, but you can build the sources to help you debug your Windows CE-based systems. You can also build the kernel for noncommercial purposes for example, in school to learn about embedded systems or as a hobbyist to create a radio-controlled robot. Another enhancement in the Windows CE.

NET Platform Builder is improved support for debugging over a network. This support was already present in Windows CE 3. With Windows CE. NET, a single network adapter can be used for both purposes. Although you are able to download an image using the parallel port of your development system, doing so will slow the pace of your development project considerably.

If you can participate in the design of your hardware, you ought to suggest—even insist—that it support networking download and debug. The key benefit over the other alternatives is speed. While a parallel port may give you KB throughput, a network adapter will give you at least times that speed. So instead of waiting over 10 minutes to download a 10MB image when using a parallel port download, that same image will download in 15 seconds over a 10MB network.

You probably have better things to do with your life than wait for binary images to download. A long-standing strength of Windows CE has been its connectivity. Windows CE. NET continues to push the envelope, adding new device drivers, support for new protocols, and new APIs. Next, I'll discuss features and protocols available for creating secure wireless connections. NET improves security for network-connected devices. Since version 2. DLL , and X.

This effectively allows you to create a custom security interface. NET is the same as for Windows to provide authentication, data integrity, and data privacy. The support that Windows CE. Kerberos is the newer, more flexible, and more secure package that you will likely use for servers running Windows and Windows XP. An additional advantage of Kerberos is that it is an industry standard, making it a good choice when you plan to connect to servers in a multivendor setting.

Bluetooth is a protocol for wireless device connectivity. The promise of Bluetooth is the emergence of Personal Area Networks PAN in which laptops, desktop computers, cell phones, printers, and so on communicate with one another.

The range of basic Bluetooth devices is 10 meters 30 feet , and eight devices can be strung together to form a single network, referred to as a Piconet. These are the same two mechanisms available for accessing infrared ports. I saw a demonstration in which a Bluetooth-enabled Pocket PC accessed a Bluetooth-enabled cell phone to call out to the Internet.

Bluetooth could be used for wireless access in many situations, including for wireless headsets for phones or stereos, and as a replacement for any application that currently uses infrared. A key advantage of Bluetooth over infrared is that you do not need to align two ports to communicate, which is only partially reliable whether you are talking about communicating between two Pocket PCs to exchange contact or schedule information or between a TV and its remote.

Although the 1MB throughput means that Bluetooth is not likely to replace LAN adapters for point-to-point communication tasks like synchronizing a mobile device or programming a VCR it has plenty of bandwidth.

Since devices based on Microsoft, for example, has A number of airports provide I have tried it out equipped with my laptop and its The 11MB throughput provides more than adequate response time when I am away from the office. It enables roaming between Once a network is configured, the OS remembers the configuration and automatically detects when it needs to switch.

It also simplifies initial configuration by determining most of the required settings automatically and by letting the user know when it has discovered a wireless network that it can use. Windows XP features provide the same experience to laptop users. Another feature relating to The IEEE WEP keys are limited in their ability to provide secure communications.