Emulating peripheral chips using a RISC core

As a first step in reducing the design time of peripheral chips and, ultimately, reducing controller boards to a single chip, a new reduced-instruction-set-computer (RISC) technology is proposed. In this technology, hardware task switching support that allows peripheral functions to be realized in firmware on a RISC core processor is provided. Whereas standard microprocessors require many clock cycles for a task switch, this approach reduces the task switching latency to one clock cycle. Such task switching can be controlled both internally from and externally to the core processor. Special instructions can also be used to effect the task scheduling process. Core processors with data and control path sizes of 8 b, 16 b and 32 b can be generated. The architecture permits several instruction formats. A prototype 25-50-MIPS are processor containing instances of many of the possible core components has been fabricated.<>