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UML in embedded system design

In Electronic Infomation Category: U | on November 10,2010

Abstract: UML and LM139J datasheet and the UML for embedded system design, the role and LM139J price and significance; analysis application in UML for embedded system design and LM139J suppliers and difficulty of the basic steps; combination of GPS car terminal system design, describes a UML specific application process.

Keywords: UML (Unified Modeling Language) design in-vehicle GPS system embedded systems

embedded system design is a hardware and software co-design combination (Hardware / Software Co-design), require different technical backgrounds to jointly develop. This raises the question of how these different technical backgrounds and expertise of the people of joint development, co-design. In the software and hardware design, the Unified Modeling Language UML (Unified Modeling Language) uses a simple and intuitive way to describe the graphical system design and details the various issues. Just a different technical background to understand the simple UML design notation can easily communicate with each other, the common design. Because of these features in the embedded system design using UML to model and write a document can often play a multiplier effect.

This article will focus on how to use UML for embedded system design techniques, and used-car GPS terminal project as an example to demonstrate the specific use of UML for embedded system design process.

1 and characteristics of the Unified Modeling Language UML

1.1 Unified Modeling Language UML < / P>

Unified Modeling Language UML is a visual modeling language in one. It will use the standard model, the information visually displayed graphic elements, so that users, developers, testers, project managers and other personnel involved in better communication. The most commonly used visual modeling language Booch method, object modeling technique (OMT) and the Unified Modeling Language UML. OMG UML which is the ANSI and the standards adopted by the organization, was accepted by most companies in the world.

UML is Grady Booch, James Rumbaugh and Ivar Jacobson, and many other scientists, the collective wisdom. Can be any static structure and dynamic behavior of the modeling for the different stages of system development. Design using UML has the following advantages:

· different backgrounds developers and designers can exchange;

· visual depiction of a more intuitive;

· easy to learn, easy to use;

* is the industry standard, recognized by most people in the industry;

· favor of the essence to save the system used for the next development (not just a bunch of schematics and code);

· contribute to project back to test.

1.2 UML diagram

as a visual modeling language, UML in morpheme is a block diagram of all. All designers is to use this diagram describes the overall system design. UML diagram of the model are the following:

· Business Use Case Diagram and Use Case diagram, the former describes the function of the body, the latter mainly from the users describe the function of the system point of view. The latter is typically used with the system so the customer communications, extract the users needs.

· Class diagram, this one is a static diagram, describe the system classes. In this diagram can be reflected in the main content and functionality class, class structure and relationships between.

· State Chart diagram provides a modeling objects and their various states of relationships between the conversion. It provides a dynamic modeling system functions. The diagram is widely used to establish the actual system, the system will generate all the code.

· Activity Diagram and State Chart diagram of the dynamic function of the same description, but it focuses on the function display system flow, Use Case diagram shows a case (Case ) flow of events. It defines the work flow from when to start, where to begin, what order occurs, which finally ended.

· Sequence Diagram Use Case diagram shows the specific function of each object in the process. Sequence diagram shows the details of business processes. It should be noted that this diagram shows only the object, does not display category. Sequence diagram that is targeted to a specific situation, a particular object description.

· Collaboration Diagram and Sequence Diagram also describes the relationship between objects. Sequence diagram but it is not as described in chronological order as, but highlighting the interaction between objects and roles. The aim is to make quality assurance engineers and architects of the system objects the distribution process. If the distribution is unreasonable, the system architects might consider re-allocation of processing.

· Component diagram shows the physical view of the model also shows that the system software and hardware components and their mutual relations.

· Deployment diagram shows the physical layout of the system and various components of the location and configuration.

the block diagram for the system analysis, design, modeling provides a variety of graphic forms of expression can be used in different stages of development. Combination of them can build a complete and consistent system. The following in-vehicle GPS terminal for this specific project descriptions in the UML in embedded system design specific applications.

2 UML in the automotive GPS terminal design

2.1 Introduction Car GPS terminal

Car GPS terminal is placed inside the real-time vehicle positioning device shown in Figure 1. Its application is the need to locate the object, dispatching teams, such as: transport fleet and taxis and so on. Vehicle GPS satellites through the terminals and real-time, accurate positioning and wireless communication network through the center of the remote reporting system. Remote monitoring center via the terminal road routing, even in exceptional circumstances control the vehicle through the terminal. At the same time, the terminal can also play a role in car phone, and alarm when the vehicle in distress. In addition, the vehicle through the terminal can also receive a small amount of scheduling information.

2.2 needs analysis

needs analysis in the system, you can use the Use Case diagram Analysis of the functional requirements. Use Case diagram sub-role (Actor) and Case (Case) in two parts. Role is to interact with the system, person or thing, and case is provided by the system function blocks. Use Case Observation System with the ability to separate the target system with the system to help developers understand the most important part, to meet the needs of users, and not immersed in the implementation details.

GPS terminal for the car, there are two main roles: end users and monitoring center-board users. End users can call the police, hit car phone, etc.; the monitoring center can check vehicle location, send scheduling information. The Use Case diagram shown in Figure 2.

2.3 specification

specification more detailed than the requirements analysis, through the UML design can make specification more intuitive and clear. First, use the Class diagram describes the system processing the data structure. For example, in-vehicle GPS terminal design specifications can be described using the Class Diagram needs to receive the GPS satellite signal, shown in Figure 3.

Second, the specification phase, the system also need to identify the object. First of all functional blocks divided broadly identify the main target of the system; and then use the Collaboration diagram describes the relationship between them. Figure 4 describes the main target of car GPS terminal, under the block diagram can be further refined.

Finally, the system specification stage of the business description. Standardized system to complete certain functions that the main process. This can be carried out using Activity diagram. Figure 5 shows the arrival of GPS data, GPS systems for terminal handling process.

2.4 System Design

specification is complete, the need for each module and the module system careful analysis of the relationship between, to determine which parts of the hardware to complete, which some use the software. In this case, the need for hardware implementation of the modules are: GPS receiver module, power module, the user control module, LCD display module and the GSM communication module. All control logic and data in terms of total software by the main controller.

Subsequently, the system is divided into two branches: the hardware design and software design. Collaboration with UML-diagrams and Component diagram of the system hardware and software system design, respectively. Component diagram of Figure 6 describes the use of GPS car terminal system software system architecture.

2.5 Component Design

next to each component of a system for detailed design. For some large projects, or even need to add each component as a project to re-order requirements analysis, specification design cycle components commenced. In the component design, in addition to previously introduced using a variety of UML diagram, but usually need to use the State Chart, Sequence Diagram describes both the details of the specific system processes.

In this case, GSM module there are four states: standby, there are problems, call, short message communication. Describe their use of State Chart diagram of the conversion relationships between, as shown in Figure 7.

Sequence diagram shows the operation of a particular object encountered by a particular process. Figure 8 shows a vehicle in a dangerous end-user pressed the alarm button, the system process.

2.6 integration testing and deployment

in integration tests, can be combined with a careful analysis of all of the UML diagram for each a component of the principle functions of a system for each and every error that may occur during the corresponding test procedures to write, complete and reliable procedure for testing.

system design using UML and the method can make the traditional farewell of embedded system design, "Hand Workshop" development mode, greatly improve the speed of development of embedded systems and products quality, and enhance design reusability.

but the UML is a graphical description language, more suitable for object-oriented programming; the design specifications for the precise language or object-oriented design is to was not satisfactory. In specific applications, the flexible application of annotations to the corresponding block diagram of the specific specifications required in the form of notes written in the diagram, the full use of State Chart, and Sequence Diagram to complete the process-oriented part of the design.

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