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IEEE International Superconductive Electronics Conference (ISEC)

Logic Design of an 8-bit RSFQ Microprocessor

Jia-Hong Yang, Guang-Ming Tang, Pei-Yao Qu, Xiaochun Ye, Dongrui Fan, Zhimin Zhang, Ninghui Sun

Published Jul 1, 2019• 2 citations
Publisher

Abstract

An 8-bit bit-parallel RSFQ microprocessor, named HUTU, is proposed. It can execute 28 different instructions. Each instruction consists of eight bits. Harvard-type architecture is adopted for parallel processing between the control unit and the datapath. The control unit uses an asynchronous timing method to avoid pipeline flushing and to reduce the area. Concurrent-flow clocking is adopted in the datapath for high performance. The simulation result shows that the elements of HUTU run correctly.

DOI
10.1109/isec46533.2019.8990959

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With Moore's law approaching its physical limits, low-temperature computing technology is ushering in unprecedented development opportunities. Rapid single-flux-quantum (RSFQ) circuit technology is currently the most mature superconducting integrated circuit technology. Based on the current fabrication process, we propose an 8-bit bit-parallel RSFQ microprocessor. The proposed microprocessor processes 8-bit data each clock cycle. Ten different instructions are executed. The microprocessor mainly consists of an on-chip instruction memory, two data registers, an instruction decoder, an 8-bit bit-parallel arithmetic logic unit, and a program counter. The microprocessor contains 7702 JJs (based on the Open Dataset of CONNECT Cell Library for AIST ADP2) without considering splitters, Josephson transmission lines, and passive transmission lines. We perform a logic-level simulation of the proposed microprocessor. The simulation results show correct operation with a target frequency of 16.7 GHz.
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