LinkBo: An Adaptive Single-Wire, Low-Latency, and Fault-Tolerant Communications Interface for Variable-Distance Chip-to-Chip Systems

Abstract

Cost-effective embedded systems necessitate utilizing the single-wire communication protocol for inter-chip communication, thanks to its reduced pin count in comparison to the multi-wire I2C or SPI protocols. However, current single-wire protocols suffer from increased latency, restricted throughput, and lack of robustness. This paper presents LinkBo, an innovative single-wire protocol that offers reduced latency, enhanced throughput, and greater robustness with hardware-interrupt for variable-distance inter-chip communication. The LinkBo protocol-level guarantees that high-priority messages are delivered with an error detection feature in just 50.4 $\mu$s, surpassing current commercial options, 1-wire and UNI/O by at least 20X and 6.3X, respectively. In addition, we present the hardware architecture for this new protocol and its performance evaluation on a hardware platform consisting of two FPGAs. Our findings demonstrate that the protocol reliably supports wire lengths up to 15 meters with a data rate of 300 kbps, while reaching a maximum data rate of 7.5 Mbps over an 11 cm wire, providing reliable performance for varying inter-chip communication distances.