Reconfigurable pipelined 2-D convolvers for fast digital signal processing

In order to make software applications simpler to write and easier to maintain, a software digital signal-processing library that performs essential signal- and image-processing functions is an important part of every digital signal processor (DSP) developer´s toolset. In general, such a library provides high-level interface and mechanisms, therefore, developers only need to know how to use algorithms, not the details of how they work. Complex signal transformations then become function calls, e.g., C-callable functions. Considering the two-dimensional (2-D) convolver function as an example of great significance for DSP´s, this paper proposes to replace this software function by an emulation on a field-programmable gate array (FPGA) initially configured by software programming. Therefore, the exploration of the 2-D convolver´s design space will provide guidelines for the development of a library of DSP-oriented hardware configurations intended to significantly speed up the performance of general DSP processors. Based on the specific convolver, and considering operators supported in the library as hardware accelerators, a series of tradeoffs for efficiently exploiting the bandwidth between the general-purpose DSP and accelerators are proposed. In terms of implementation, this paper explores the performance and architectural tradeoffs involved in the design of an FPGA-based 2-D convolution coprocessor for the TMS320C40 DSP microprocessor available from Texas Instruments Incorporated. However, the proposed concept is not limited to a particular processor.