Design and Implementation of a Protocol Conversion Unit for SPI to I2C Communication

One of the most popular ways to connect microcontrollers to a variety of peripherals, including sensors, shift registers, SRAM, Analog-to-Digital converters (ADC), and Digital-to-Analog converters (DAC), is through Serial Peripheral Interface (SPI). On the other hand, the InterIntegrated Circuit (I2C) offers a two-wire bus solution that enables many system devices to communicate with one another. Synchronous serial communication, or SPI, is widely used in embedded systems, where microprocessors and microcontrollers communicate with peripherals, enabling shortrange data transmission. In the meantime, I2C which has a reputation for having a slower communication speed works best in promoting communication between integrated circuits. In order to provide smooth communication between SPI and I2C, two commonly used serial communication protocols, this work aims to construct and simulate a Protocol Conversion Unit (PCU). This kind of architecture makes it possible for the SPI protocol to work with a receiver device that uses the I2C protocol, which would not be possible otherwise. I2C only supports half-duplex communication; in contrast, SPI supports full-duplex communication and runs at a quicker speed. I2C just needs two wires since it doesn’t require a separate slave select line as SPI requires. The address and acknowledgment protocol is used in I2C instead of other protocols for communication with the slave.