SPI bus
(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.
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| SPI on a Microcontroller |
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| This Ramtron microcontroller (MCU) includes controllers for both SPI and I2C buses for peripheral data transfer (note upper right of diagram). (Image courtesy of Ramtron International Corporation, www.ramtron.com) |