An efficient and low power one-lambda crosstalk avoidance code design for network on chips

Crosstalk faults occurring in wires of Networks on Chip (NoCs) can seriously threaten the reliability of data transfer. One efficient way to tackle crosstalk faults is numeral-based Crosstalk Avoidance Codes (CACs). Numeral-based CACs reduce crosstalk faults by preventing specific transition patterns to occur. One-Lambda Codes (OLCs) are the most efficient types of CACs. However, the codec of OLCs imposes overheads including power consumption, critical path and area occupation to the routers of NoCs. To find overhead-efficient OLCs, this paper proposes an Algorithm for Generating OLC Numeral systems (AGON). AGON provides a tradeoff for designers in selecting overhead-efficient OLCs. Using AGON, an efficient numeral-based OLC called Subtraction-based-Numeral (Sub-Num) is proposed that benefits the Numeral system that can omit OLC-induced transition patterns completely. In addition, the mapping algorithm of Sub-Num can reduce the overheads of codec more efficiently than the other state-of-the art OLCs. Evaluation results using SPICE and VHDL simulations show that Sub-Num reduces power consumption and average delay of wires by 10% and 9%, and also overheads of codecs including dynamic power consumption, critical path and area occupation by 52%, 51% and 21%, respectively as compared to the state-of-the-art numeral-based OLC.