UART, I2C, and SPI are standard communication protocols used to connect microchips within devices like smartphones, laptops, and appliances. These protocols define the rules for data exchange between components, such as processors and sensors, which otherwise operate independently.
UART is an asynchronous protocol connecting two devices directly via TX and RX lines. It requires both sides to be pre-configured to the same baud rate, such as 9600 or 115200 bits per second. Optional RTS and CTS wires can be added for flow control to prevent data loss.
I2C is a bus-based protocol using two wires, SDA for data and SCL for clock signals, allowing multiple chips to share the same connection. Each device has a unique 7-bit address. I2C typically operates at 100 or 400 kilobits per second, with newer I3C standards offering higher speeds.
SPI is designed for high-speed data transfer, utilizing a shared clock and data lines alongside a dedicated chip select (CS or SS) wire for each device. Unlike I2C, SPI does not use addresses and can reach speeds of tens of megabits per second, making it suitable for components like fingerprint scanners.
