Introduction to SPI
Ameba provides SPI pin to connect to high speed SPI devices, such as LCD and camera. These devices would be very slow through other connection interface (e.g., UART, I2C).
SPI devices communicate using a master-slave architecture with a single master.
The SPI interface is consist of four pins:
MOSI: Master Output, Slave Input (output from master).
MISO: Master Input, Slave Output (output from slave).
SCK: Serial Clock, output from master.
CS: Chip Select, also called SS (Slave Select), a SPI Master can be connected to many Slaves. To communicate with a specific Slave, the Master pull the CS pin connected to the Slave to LOW.