Low-power fault-tolerant interconnect method based on LCDMA and duplication

High computing capabilities and limited number of input/output pins of modern integrated circuits require an efficient and reliable interconnection architecture. The proposed communication scheme allows a large number of IP cores to send data over a single wire using logic code division multiple access (LCDMA) technique. Reliability is increased by using hardware redundancy, and three LCDMA-based fault tolerant designs are proposed: (a) duplication with logic comparison (DLC), (b) conventional triple modular redundancy (TMR), and (c) triple modular redundancy with sign voter (TSV). With aim to detect a received bit from chip sequence, LCDMA-DLC and LCDMA-TSV designs compare absolute values of the sums, while LCDMA-TMR compares only sign bits of the sums generated at the outputs of decoders. All proposed designs are implemented in FPGA and ASIC technologies. MATLAB simulation results show that increasing the length of spreading codes affects to an increase in reliability. A comparative analysis of the proposed fault tolerant designs in terms of hardware complexity, latency, power consumption and error detecting and correcting capability is conducted. It is shown that LCDMA-DLC design has lower hardware overhead and power consumption, with satisfactory better bit error rate (BER) performance, in comparison to LCDMA-TMR and LCDMA-TSV approach.