A Serial Peripheral Bus (SPI) is a synchronous serial bus. It’s used for fast interconnection of the peripherals inside the device. TOWER uses SPI for example in the LCD Module.
The SPI uses these signals:
- SCK - Serial Clock (P14 Core Module) - SPI transfers are synchronous and need the clock signal
- MOSI - Master Out, Slave In (P13 Core Module) - This is serial output from MCU to the peripheral
- MISO - Master In, Slave Out (P12 Core Module) - This is serial input for data from peripheral to MCU
- NSS - Negative Slave Select (P15 Core Module) - This signal activates the slave device. It’s active low, that’s why the word negative. If you have multiple slave devices you have multiple NSS signals. It’s sometimes also called the Chip Select CS.
You can read more information about SPI.
To see how the TOWER uses SPI, you can read the How To: SPI Bus.