Rapid prototyping of signal processors in an educational environment

A programmable control-path allows designers to build and evaluate many different instruction sets in a short period of time. For this approach to be practical, the effort and time needed to modify the control-path to reflect the changes in the instruction set must be minimized. We describe a flexible and efficient method for generating control logic information given an instruction set. All the information regarding the instruction set, namely, the mnemonics, the opcodes and the values of the control lines for the data path, are stored in a single file. This information is used by the assembler to assemble programs as well as to generate control-path programming information, which in turn is used to set up the new control-path. A way of searching the design space to iteratively modify an instruction set is also presented. Using this method we have successfully built a prototype of the Micro Grain Array Processor. We were able to submit the board for fabrication before finalizing an instruction set hence overlapping the design phase of the control-path with the board fabrication.