Custom Processors in FPGAs

Processor cores, systems, and designs are gaining ground in the field programmable gate array (FPGA) solution portfolio. Xilinx MicroBlaze and PicoBlaze processors, along with the EDK development tool, have paved the way to processor-based systems on a single chip. Designers are not, however, limited to these solutions only—one can always implement a soft processor with specific desired features. This article, which is devoted to soft processors in general, attempts to determine when it is preferable to implement custom soft-core processors instead of proven Xilinx solutions.