SPI - Serial Peripheral Interface

• SPI0 pins are GPIO 7, GPIO 8, GPIO 9, GPIO 10, GPIO 11
• SPI1 pins are GPIO 16, GPIO 17, GPIO 18, GPIO 19, GPIO 20, GPIO 21

Known as the four-wire serial bus, SPI lets you attach multiple compatible devices to a single set of pins by assigning them different chip-select pins.

To talk to an SPI device, you assert its corresponding chip-select pin.

By default the Pi allows you to use SPI0 with chip select pins on CE0 on GPIO 8 and CE1 on GPIO 7.

Enable via config.txt

You can enable SPI1 with a dtoverlay configured in "/boot/firmware/config.txt", for example:

dtoverlay=spi1-3cs

For full details of the SPI dtoverlays (and others) see the Raspberry Pi dtoverlay README