Design of Datapath Circuits for a Bit-Parallel 8-bit RSFQ Microprocessor

Rapid single-flux-quantum (RSFQ) is expected to be the next generation integrated circuit technology because of its ultra-high-speed with ultra-low-power consumption. We propose datapath circuits for an 8-bit bit-parallel RSFQ microprocessor. The proposed datapath circuits process 8-bit data each clock cycle. Seven instructions are executed in the datapath, including ADD, ADDI, IN, OUT, LOADI, SRL and MOV. The datapath circuits consist of eight input ports, eight output ports, five multiplexers (MUXs), two 8-bit data registers and one 8-bit bit-parallel arithmetic logic unit (ALU). The datapath circuits contain 12 pipeline stages and 2993 JJs based on the Open Dataset of CONNECT Cell Library for AIST ADP2 without considering wiring cells. We perform digital simulation of the proposed datapath circuits. The simulation results show correct operation with the assumed frequency of 20 GHz.