15.01.2013 Views

U. Glaeser

U. Glaeser

U. Glaeser

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

FIGURE 36.2<br />

Presently, a context-specific architecture is painstakingly developed by hand. The SPS explores an automated<br />

framework, where a systematic method generates context-specific programmable architectures.<br />

The basic building blocks of the SPS architecture are parameterized functional blocks called VPBs. They<br />

are preplaced within a fully reconfigurable fabric. When implementing an application, operations can be<br />

performed on the VPBs or mapped onto the fully reconfigurable portion of the chip. An instance of our<br />

SPS architecture is generated for a given set of applications (specified by C or Fortran code). The functionality<br />

of the VPBs is tailored towards implementing those applications efficiently. The VPBs are customized<br />

and fixed on the chip; they do not require configuration, hence there are considerably less configuration<br />

bits to program as compared to the implementation of the same design on a traditional FPGA.<br />

The motivation is to automate the process of developing hybrid reconfigurable architectures that target<br />

a set of applications. These architectures would contain VPBs that specially suit the needs of the particular<br />

family of applications. Yet, the adaptable nature of our architecture should not be severely restricted. The<br />

SPS remains flexible enough to implement a very broad range of applications due to the reconfigurable<br />

resources. These powerful features help the architecture maintain its tight relation to its predecessors,<br />

traditional FPGAs. At the same time the SPS is forming one of the first efforts in the direction of contextspecific<br />

programmable devices.<br />

In general, two aspects are part of the SPS system. The first area involves generating a context-specific<br />

architecture given a set of target applications. Once there is a context-specific architecture, one must also<br />

be able to map any application to the architecture.<br />

36.4 Overview of SPS<br />

Versatile Parameterizable Blocks (VPBs)<br />

The main components of SPS are the VPBs. The VPBs are embedded in a sea of fine-grain programmable<br />

logic blocks. Consider a lookup table (LUT) based logic blocks commonly referred to as combinatorial<br />

logic blocks (CLBs), though it is possible to envision other types of fine-grain logic blocks, e.g., PLAbased<br />

blocks.<br />

Essentially, VPBs are hard-wired ASIC blocks that perform a complex function. Because the VPB is<br />

fixed resource, it requires little reconfiguration time when switching the functionality of the chip. *<br />

Therefore, SPS is not limited by large reconfiguration times like current FPGAs. But, the system must<br />

strike a balance between flexibility and reconfiguration time. The system should not consist mainly of<br />

VPBs, as it will not be able to handle a wide range of functionality.<br />

* By functionally, we mean the application of the chip can change entirely, e.g., from image detection to image<br />

restoration, or part of the application can change, e.g., a different image detection algorithm.<br />

© 2002 by CRC Press LLC

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!