FPGA implementation of I2C & SPI protocols: A comparative study

IC and SPI are the most commonly used serial protocols for both inter-chip and intra-chip low/medium bandwidth data-transfers. This paper contrasts and compares physical implementation aspects of the two protocols through a number of recent Xilinx’s FPGA families, showing up which protocol features are responsible of substantial area overhead. This valuable information helps designers to make careful and tightly tailored architecture decisions. For a comprehensive comparative study, both protocols are implemented as general purpose IP solutions, incorporating all necessary features required by modern ASIC/SoC applications according to a recent market investigation of an important number of commercial IC and SPI devices. The RTL code is technology independent, inducing around 25% area overhead for IC over SPI, and almost the same delays for both designs. Keywords— Inter Integrated Circuit (IC), Serial Peripheral Interface (SPI), Intellectual Property (IP), System-on-Chip (SoC).