Windows CE-based remote alarm system design (1)

At present, the general warning issuing system is based upon PC/SCM technology of half-duplex for point to multipoint network of dedicated remote control antenna.

System Control Center by PC/IPC, every Executive Terminal MCU core controller to perform control functions. From the use of management and development perspective, the following deficiencies: PC/IPC based control centre unit volume, the equipment is expensive, and because the task is relatively simple, so use efficiency is not high, but based on microprocessor control perform Terminal better complete decoding of control functions, but cannot meet the alert information dissemination technology improvements and operate interactively oriented management needs, such as the complete high-quality single-chip, high-efficiency audio coding, entry and also the original implementation information interaction of function is a more difficult issue. This design is in the light of the above requirements, the use of hardware and software resources and reduction of data processing power powerful and have general control features of embedded technology, the design of a small size, low cost, features strong, short development cycle of embedded Center controller and terminal controller to the original alert distribution system.

Introduction to the system as a whole

Improved system consists of a control centre and multiple Terminal.

Control Center and terminal between wireless data-transmission module to create wireless data access. Each terminal configuration unique address, when issuing the alert, the control centre can be paid to how Group sending alerts and you can specify the Terminal address to point to point to the specified Terminal host issue the specified alert.

The terminal controller's audio output port and power amplifier.

When the Terminal receiving alerts belonging to native instructions, depending on the alert, call the different audio files, and finally by the audio output unit and power amplifier.

In order to guarantee the reliability, the controller scheduled for testing.

Detection control center to serial named methods on each terminal. Detection of content including Central and terminal wireless data access and dissemination equipment of audio. In order to properly understand the work of the terminal equipment, in Terminal audio input interface is equipped with a microphone, for acquisition of alert sounds, acquisition of sound compression file and then through the wireless network is returned to the main control center, then in the control center for processing and analysis of the terminal's package of equipment is working properly or not.

Generally speaking, the embedded controller is designed for a specific feature to design, it can be considered as a specific function in a dedicated computer.

In this system, the control centre and the terminal controller needs to implement the main task is the data transfer and audio processing, so the choice in hardware resources, the Centre and the terminal can use the same set of hardware devices. In the system, just in the center of the controller and the terminal controller to install different applications to complete system requirements. So in the design and development, once the control center, which is basically completed terminal design tasks.

System hardware and software resources

System selection

In order to facilitate the implementation of audio processing functions, accelerate system development time, select the Windows CE operating system as a controller.

While Windows CE is a soft real-time operating system, but fully meet the requirements of real-time systems team. At the same time, Windows CE has excellent graphical user interface, powerful multimedia features, good communication skills. Friendly interface of embedded platform Tools Platform Builder for Windows CE development. With Visual C + +, and basically the same characteristics of application development tool, Embedded Visual C ++ and are familiar with Windows programming for developers with a shortcut. So use a full-featured API function library for Windows CE operating system, can cause the system to display a lot of superiority.

Hardware structure

There are several types of CPU core support WinCE operating system, such as ARM, MIPS, PowerPC, x86, SH, etc.

The current market with MIPS and ARM architecture CPU occupied a dominant position. This system control center select Intel CPU PXA255 XScale @ microcontroller processor it comply with ARM 5V.TE framework, running at speeds up to 400MHz, Intel ultra line technology and unique dynamic power management technology, making it both high performance and low power consumption characteristics. In order to achieve the embedded Win CE operating system requirements, system configuration 32M 64M SDRAM and Flash. The system also displays system configured LCD and touch screen. Audio controller using TI company TSC2301 Audio Codec chip, the chip supports AC ' 97 standard 20-bit stereo decoding, support, programmable sample rates, input and output gain and digital audio processing functions, while the integrated touch screen control function. It is also an important component of the system hardware. Based on serial port communication for wireless data-transmission module in practice already very mature in the market also has a range of available products. This article on this is described in more detail. The following are the system hardware chart.

　　

Windows CE operating system and applications

System development

Each of the Windows CE operating system is based on a fixed hardware platform to run.

A complete basic Windows CE operating system includes the following aspects:

1.

Bootloader, is used to load the Windows CE operating system;

2.

The initial code for the CPU, on the basis of the specific CPU series;

3. the driver, including keyboard,

Mouse, sound card, COM, etc., different hardware devices may have different settings, drivers from Windows CE and hardware vendors;

5. complete the particular function of the application.

WinCE Platform development is completed, the Builder in this process, you need to select a specific development board support package BSP and the corresponding application and a service component, in the selection process in order to save hardware resources to enable the kernel to be able to reach requirements as far as possible, the need to streamline applications and components.

Themselves to write the application, in order to enable the application to become a part of a mirroring system, you can create your own Platform Builder of CEC files, making it the new features and added to the need for System Properties Directory.

Develop complete systems are compiled to generate a system kernel image, while generating a Eboot files.

First of all download via JTAG Eboot file, and then through Ethernet download system image file, on this basis we can complete the system with debugging and curing.

Application

Should the program primarily draw man-machine interface, serial communication function, and has the sound of the acquisition, encoding and playback capabilities.

The application is in the Embedded Visual C ++ environment editing '.

Win CE and desktop Windows systems is also a graphical interface of the operating system he can help us design a rich graphical interface, Win CE provides a powerful graphics device interface (GDI), using the GDI function can easily draw points, lines, rectangles, polygons, ellipses, bitmap, and text and so on, and the Visual C + +, like embedded Visual C ++ also provides many frequently used controls, thus drawing the human-computer interaction interface work relatively simple.

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