An introduction to I2C and SPI protocols

Today, at the low end of the communication protocols we find the inter-integrated circuit (I
²
C) and the serial peripheral interface (SPI) protocols. Both protocols are well suited for communications between integrated circuits for slow communication with on-board peripherals. The two protocols coexist in modern digital electronics systems, and they probably will continue to compete in the future, as both I
²
C and SPI are actually quite complementary for this kind of communication.