ABSTRACT
The serial peripheral interface (SPI) communication protocol was developed by the Motorola in 1972. SPI interface can be done on popular communication controllers such as 8051, PIC, AVR, ARM controller, etc. It has synchronous serial communication data link that operates in full duplex, which means the data signals carry on both the directions simultaneously. SPI protocol consists of four wires such as MISO, MOSI, CLK, and SS used for master/slave communication. The master is a microcontroller, and the slaves are other peripherals like sensors, GSM modem, GPS modem, etc. The multiple slaves are interfaced to the master through a SPI serial bus. The SPI protocol does not support the Multi-master communication and it is used for a short distance within a circuit board.
