Implementation of a simple 8-bit microprocessor with reversible energy recovery logic

Abstract

We describe a simple 8-bit adiabatic microprocessor implemented with nMOS reversible energy recovery logic (nRERL) [1]. The implemented adiabatic microprocessor supports only a subset of the DLX instruction set architecture [15] in order to be fitted into a limited silicon area, and is integrated with an energy-efficient 6- phase clocked power generator (CPG). Phase scheduling was employed to reduce the number of the buffers required in the adiabatic microprocessor. Furthermore, reversibility breaking with self-energy recovery circuits (SERCs) was also employed to reduce energy consumption as well as circuit complexity by. The 8-bit microprocessor core and its on-chip 6-phase CPG were implemented in 0.18-μm CMOS technology. The former and the latter occupied 2.62 x 2.03 mm2 and 1.0 x 0.6 mm2, respectively. From the measurements, we have found that its minimum power consumption is 7.5μW at Vdd =1.8V and f=880kHz.