1 Introduction

As modern systems become increasingly data-intensive and computationally heavy, there is a growing need for faster speed communication. SPI has become a popular protocol across many industries due to its ability to provide continuous streams of data, supporting faster data-rates, and allowing full duplex communication between peripheral ICs and a controller. While standard SPI typically uses two data lines, Quad-SPI (QSPI) and Octo-SPI (OSPI) use four and eight lines respectively, significantly increasing data throughput. SPI has many market applications in data centers, automotive, and industrial systems. To support high-density and multi-peripheral SPI systems, multiplexers can overcome GPIO pin and ADC limitations by switching SPI buses, signals, or control pins to reduce complexity, cost, and board size.