On AVR based boards, the dividers available are 2, 4, 8, 16, 32, 64 or 128. SPI.setClockDivider(divider) − To set the SPI clock divider relative to the system clock. SPI.begin() − Initializes the SPI bus by setting SCK, MOSI, and SS to outputs, pulling SCK and MOSI low, and SS high. MISO − This is the master input / slave output driven by the master.
MOSI − This is the master output / slave input driven by the master. SCK − This is the serial clock driven by the master. The maximum baud rate is higher than that in the I2C communication system. It is a full duplex connection, which means that the data is sent and received simultaneously.
One conductor is used for data receiving, one for data sending, one for synchronization and one alternatively for selecting a device to communicate with. A Serial Peripheral Interface (SPI) bus is a system for serial communication, which uses up to four conductors, commonly three.
