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Portability and the hardware abstraction architecture in .NET Assign Code-128 in .NET Portability and the hardware abstraction architecture




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Portability and the hardware abstraction architecture using barcode development for visual studio .net control to generate, create barcode standards 128 image in visual studio .net applications. Windows Forms TinyOS s main t Code 128 Code Set A for .NET ool to maximize portability while maintaining easy access to platform-speci c features is a multi-level hardware abstraction architecture (HAA), shown in Figure 12.1.

The device driver components that give access to a mote s various hardware resources are divided into three categories:. The hardware interface layer (HIL): a device driver is part of the HIL if it provides access to a dev .NET barcode standards 128 ice (radio, storage, timers, etc.) in a platform-independent way, using only hardware independent interfaces.

The functionality of the HIL is limited by what is available on multiple platforms. For instance, while some ash chips incorporate some form of write protection, this functionality is not common to all ash chips, so not re ected in the storage layer HIL (Section 6.5).

Except for the sensors, all the components (for communication, storage, etc.) we used for the anti-theft demo in 6 are part of the HIL. The hardware adaptation layer (HAL): device drivers in the HAL simplify the use of the often complex underlying hardware, by exposing it via high-level interfaces.

For instance, the HAL for the Atmel AT45DB-family of ash chips provides operations to. 12.1 Portability and the HAA Cross-platform application Platform-specific application Platform-specific application HIL 1 HIL 2 HIL 3 HAL 1 HAL 2 HAL 3 Hardware-independent interface Hardware-specific interface HPL 1 HPL 2 HPL 3 H/W S/W boundary H/W platform 1 H/W platform 2 H/W platform 3 Figure 12.1 TinyOS s three-level hardware abstraction architecture. read and write Code128 for .NET parts of the ash s storage blocks, while automatically managing the ash chip s 2 RAM buffers. HAL components are platform-speci c, but should use hardware independent interfaces when possible.

For instance, the Alarm interface used internally in the micaz s HilTimerMilliC component (Section 9.2.1) is provided by a micaz-speci c AlarmCounterMilliP component, but used by the portable AlarmToTimerC component that implements a Timer interface given an Alarm interface.

The hardware presentation layer (HPL): device drivers in the HPL sit directly above the hardware without abstracting away any of its functionality. The goal of HPL components is to hide irrelevant differences between similar hardware and to present hardware functionality in a nesC-friendly fashion. For instance, on the micaz platform, the HplAtm128GeneralIOC exposes the ATmega128 s 53 digital I/O pins as 53 GeneralIO interfaces, hiding the slightly different instruction sequences needed to perform some operations on some I/O pins (some I/O pins can be set atomically in a single assembly instruction, while others require interrupts to be disabled to guarantee atomicity).

. As shown in Fig ure 12.1, a device s HIL is normally built on top of the device s HAL, which is itself built on top of the HPL. The behaviour, name and speci cations of TinyOS s hardware independent layers are speci ed in TinyOS Enhancement Proposals (TEPs), and the hardware abstraction architecture itself is described in TEP 2 [8].

TEPs do not specify the contents of the HAL or HPL for any hardware, but do sometimes provide guidelines on HAL structure, and on the use of hardware independent interfaces in the HAL and HPL.. Device drivers and the HAA BlockWrite BlockRead LogWrite LogRead LogStorageC ConfigStorage ConfigStorageC BlockWrite BlockRead BlockStorageC LogWrite LogRead LogStorageC ConfigStorage ConfigStorageC BlockStorageC At45dbC At45dbStorageManagerC Stm25pSectorC Stm25pSpiC HplAt45dbC HplS USS Code 128 for .NET tm25pSpiC H/W S/W boundary SPI bus AT45DB041B Hardware-specific interfaces SPI bus ST M25P. Figure 12.2 HPL, HAL, and HIL Storage Components in TinyOS. Examples Figure 12.2 ill ustrates a typical example of the hardware abstraction architecture: the structure of the storage for two different ash chips, Atmel s AT45DB041B serial data ash, and ST s M25P serial NOR ash. Both chips support the three HIL storage abstractions that we saw in Section 6.

5, BlockStorageC, LogStorageC, and Con gStorageC. However, the implementations of these abstractions is different for each chip. The HAL layers for each chip are composed of different numbers of components, and provide different interfaces:.

configuration A VS .NET code128b t45dbC { provides interface At45db ; ..

. } module At45dbStorageManagerC { p r o v i d e s i n t e r f a c e A t 4 5 d b V o l u m e [ v o l u m e _ i d _ t v o l i d ]; } configuration Stm25pSectorC { p r o v i d e s i n t e r f a c e S t m 2 5 p S e c t o r as S e c t o r [ u i n t 8 _ t id ]; ..

. }. The AT45DB041B HAL is provided by two components: At45dbC provides a single interface (At45db) with erase, read, write, and CRC-computation commands, and manages a small on- ash-chip cache. The At45dbStorageManagerC component returns the con guration of a speci c TinyOS storage volume given its id. In contrast, the ST M25P HAL is provided by a single component, Stm25pSectorC, which combines high-level erase, read, write, and CRC computation (in the Stm25pSector interface) with volume management.

Stm25pSectorC provides a parameterized interface where the interface parameter identi es each individual HAL user..
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