Architecture implementation

Automatic synthesis of control units has been dominated by PLA implementations, where boolean functions in the sum-of-product form are mapped onto an array structure, or standard cell implementations, where the optimized logic functions are mapped onto a predefined library of cells. As already mentioned, an alternative to the fixed library is the use of cell compilers, which permit full exploitation of the advantages of the optimized logic. 

Implementing the combinational part of a control architecture using a PLA is very common. The synthesis onto PLAs is efficient and well understood however the PLA structure is not very flexible, usually resulting in fixed speed and an aspect ratio that cannot be varied. Furthermore, a multilevel implementation will in many cases result in smaller and faster circuits. 

The examples of table 1 have been synthesized through the two-level logic optimizer Espresso [6], and implemented using a custom PLA generator built in the GDT environment [9]. The results for the three architectures presented in table 2 include the area for state registers, etc. For the stack and register architectures, only the area relative to the original architecture is presented. 

Using standard cells for implementation of the control architecture allows for the implementation of both combinational and clocked elements. However, the combinational part that is implemented as multilevel logic is separated in the optimization step, and then afterwards merged with the clocked elements before placement and routing. 

Although a cell compiler is in principle capable of realizing an infinite library of cells, it is in practice limited by the technology, i.e., the stack size restric- 

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A design described using connectors doesn t depend on a particular way of implementing each category of connector. What s important is that the designer know what each one achieves. We can distinguish the component architecture model (which connectors can be used) from the component architecture implementation (how they work). 

It s important to remember that an architecture does not necessarily define any code. The type lays down rules for what the connectors achieve, and the architecture implementation defines the collaborations to achieve that. The collaborations tell the designers of the components which messages they must send and in what sequence. 

Architecture implementation This portion of the life cycle is crucial to a correct instruction set. One key issue to be resolved in implementation is whether a feature should be implemented in software or hardware. 

Pipelining This is an architecture implementation technique that allows multiple instmctions to overlap in execution. The processor is organized as a number of stages that allow multiple instmctions to be in various stages of their instmction cycle. The pipeline for instmctions is analogous to an assembly line for automobiles. To implement the pipeline, additional processor resources are required. In order to achieve maximum efficiency, the instmction cycle must be divided so that approximately the same amount of work is done in each of the stages. There are a number of potential hazards that exist ... 

Fig. 10. Architecture implemented in the pilot plant (PROCEL) following CIM Standards.

Lab-on-a-Chip Devices fer Sample Extractiens, Figure 3 An integrated cell lysis and DNA extraction device. Parts (a) to (e) show the sequence of steps involved in introducing the cell sample, lysis buffer and mixing to extract DNA Part (f) shows the parallel architecture implementation of the DNA extraction system. (Reprinted by permission from [5])... 

Another ALMR control system design task is to develop a control and communications architecture simulation capability to provide a software-based approach to test the ALMR control system architecture designs before implementation. The implementation of a plant architecture can be very costly. Therefore, it is important that the architecture implemented will support the plant s needs under all conditions. This simulator will allow potential architecture designs to be modeled. These models can then be tested under a variety of plant and information-flow conditions to assure that a vehicle for testing modifications to the architecture and new systems being implemented. This capability will discover architecture problems and facilitate fixing them before costly implementation expenditures. 

For behavioral synthesis, functionality is described with regard to occurrence of operations with no notion of the actual implementation and without binding operations to specific clock cycles. Architectural implementation decisions are made by the behavioral synthesis tool based on cycle period, latency and throughput goals. The behavioral synthesis tools does however, maintain the implicit dependency of the operations in the HDL code. 

An extensive behavioural verification of the SiLAGE specification is required, either by simulation or by emulation. Our compiled-code simulator S2C efficiently simulates at a high level using floating-point precision, or at the bit-true level where the exact finite word-length specifications are taken into account. The Silage description may contain high-level functions such as an FFT, an absolute value, a mean calculation or a division. For these functions, bit-true behavioural simulation models have to be fetched from the framework LIB to ensure consistency with the architectural implementation models. 

The fourth chapter gives an educational approach regarding advanced computer architectures. Implemented Cray-1 architecture on the unified learning platform allows students to learn, through exercises, the historical development of multicore systems and supercomputers. 

Figure 2.5 shows the architecture of ground equipment. This hardware architecture implements four types of safety dual redundancy with dial indicator, controlled safety (in case of detection of a defect, stopping can be commanded), safety by output reread, and intrinsic safety (dynamic dial indicator for example). 

This chapter has provided an opportunity to present the first architecture implemented in the context of railway systems the coded safe processor. Several systems have been constructed based on this system (SACEM, TVM, MAGGALY, SAET-METEOR, etc.). Since then, industries have implemented 2oo3-type architectures in addition to the SCP. Chapters 3,4 and 5 will present some examples of this evolution. 

The object-oriented emphasis on the separation of the interface of an object from its operation is mirrored dosely in VHDL. In this case the entity provides the interface specification to the circuit and die architecture (implementation) of the drcuit provides the functionality. Moreover, the same entity can have multiple architectural representations, thus providing a range of descriptions for die same component. T3rpically, this is of use in top-down design, in which a behavioural description can be modelled first and die design incrementally refined towards a more detailed structural description. Where logic synthesis tools are involved it is possible to have multiple descriptions of the same circuit and it is easy to experiment with die s)mthesis tool to find out which instantiation of die circuit iimction is the most suitable. 

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