[Iot smart gateway-10] Build a stream-driven model on the. net mf Platform

Whether it is a driver development in Linux or a driver development on the Windows CE platform, you must be familiar with the streaming driver model. In this architecture, all hardware devices are regarded as files. The interaction with devices is actually reading and writing files, that is, data flow. This development driver is not only simple and practical, but also allows users to access hardware with consistent interfaces, greatly reducing the learning cost. However. net micro framework platform, but does not provide such a driver development interface, if you want to operate hardware at the application layer, you must do a dedicated interface library (InterOP), if there are n devices, the corresponding driver interface library file must also be N, if an applicationProgramTo communicate with N devices, you must reference n databases. In addition, if the library interface is changed, the upper and lower layersCodeIt must be re-compiled before it can be used.

It is based on some of the advantages of the stream driver and the complexity of InterOP driver interface development, so I have built a streaming driver architecture on the. NET micro framework system. It is particularly worth mentioning that, on the basis of the stream-Driven Architecture, users can use C ++ to develop stream-driven systems in the mdk ide environment (see relatedArticle. Net micro framework dynamically calls C/C ++ underlying code).

The C # interface code of the streaming driver application layer is as follows:

 Public   Sealed   Class  Generalstream {publicgeneralstream ();  Public  Event  Generalstreameventhandlernotice;  Public   Int  Close ();  Public   Int  Iocontrol (intcode );  Public   Int Iocontrol (intcode, Int  Parameter );  Public   Int Iocontrol (intcode, Byte [] Inbuffer, intincount, Byte [] Outbuffer, Int  Outcount );  Public   Int  Open (stringname );  Public   Int Open ( String Name, Int  Config );  Public   Int Open ( String Name,String  Config );  Public   Int Read ( Byte [] Buffer, Int  Offset, intcount );  Public   Int Write ( Byte [] Buffer, Int  Offset, intcount );} 

The above interfaces are actually very similar to the stream interfaces on the wince platform, but they are quite distinctive. They also provide an Event Notification interface, this provides more flexible support for various hardware driver development. With this stream interface, it generally provides proprietary hardware underlying functions for the upper-layer C # language, so you do not need to write interface-related code, directly write the relevant C/C ++ code, and then compile the link.

Currently, we have implemented drivers for 10 devices and functional modules based on the streaming driver interface. The following is a brief introduction and will be detailed in subsequent articles.

Serial number	Name	Description	Remarks
000	Userdriver	User streaming driver development interface	C ++ development under MDK
001	Watchdog	Dog driver
002	Ultrasonic	Ultrasonic module driver	Ranging
003	Dht11	Temperature and humidity module driver
004	Gpio	Gpio special function driver	For example, you can configure the Vulnerability
005	Counter	High-speed counters
006	Adis16227	Adis16227 module driver	Based on special SPI Interfaces
007	Max7219	Max71219 chip driver	Led and lattice Control
008	Pcd8544	Norkia5110 display module driver
009	Lcd1602	Lcd1602 module driver

When developing drivers for the adis16227, norkia5110, and lcd1602 modules, I deeply felt that it is very important to leave a C ++ driver development interface for users because of this type of driver, upper-layer applications do not have ready-made interfaces. Second, they cannot directly use C #. Therefore, they must be transplanted at the underlying layer. If no ready-made user interfaces are available, they must rely on the vendor, this greatly limits the initiative and flexibility of user development, as well as the control of products and projects.

I will introduce this part in detail in the user stream driver development interface (userdriver) article.

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Mf Introduction: http://blog.csdn.net/yefanqiu/article/details/5711770

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