SPI bus - Computer Definition
(Serial Peripheral Interface bus) A four-line, synchronous, serial bus from Motorola that is widely used to connect a microcontroller to peripheral chips on a circuit board. Each device has one input line and one output line, and data are exchanged in full-duplex mode. SPI operates in a master-slave topology where the microcontroller is the master and clock controller, and the peripheral chips respond as slaves. SPI is typically faster than the I2C bus. See I2C bus.