ASYNMPU: a fully asynchronous CISC microprocessor

In this paper, the design and implementation of an asynchronous 8/16 bit microprocessor (ASYNMPU) are described. The objective of this work is to investigate the potential of asynchronous computer architecture in small scale low power applications. ASYNMPU is one of the first CISC type microprocessors that is designed with asynchronous technique. Some features have been incorporated in ASYNMPU to handle the complicated structure of a CISC type processor, such as variable instruction length and microprogramming. Furthermore, a new external synchronism is built to provide compatibility to external circuit. ASYNMPU is pin-to-pin compatible with Intel 8/16-bit microprocessor. It can be used to directly replace the Intel 8/16-bit microprocessor in any existing system. It will then be modified to become a Intel 8/16-bit microprocessor based microcontroller for low power process control applications. As a distinct feature of an asynchronous processor, the functionality of ASYNMPU is independent of external system clock frequency. The power dissipation is reduced in idle state which is an inherent benefit of asynchronous design approach.