Abstract
Asynchronous logic is a promising technology for building the chip-level interconnect of multi-core systems. However, asynchronous circuits are vulnerable to faults. This paper presents a novel scheme to improve the robustness of asynchronous systems. Our first contribution is a fault tolerant delay-insensitive redundant check coding scheme named DIRC. Using DIRC in 4-phase 1-of-n quasi-delay-insensitive (QDI) interconnects, all 1-bit and some multi-bit transient faults can be tolerated. The DIRC and the basic 4-phase 1-of-n pipeline stages are mutually exchangeable so that arbitrary basic stages can be replaced by DIRC stages to strengthen the fault-tolerance of long wires. Our second contribution, RPA, is a redundant technique to protect the acknowledge wires from transient faults - an issue that has long been disregarded by the community. The DIRC pipelines (using DIRC plus RPA) were simulated using the UMC 0.13 mu m standard cell library and compared with the basic pipelines. Detailed experimental results show that the 128-bit DIRC 1-of-4 pipeline is only 13% slower than the basic one but increases fault-tolerance hundred-folds when multi-bit transient faults are considered.