begin(SPI_Mode, uint16_t)

SPI

Since 0.5.0:

Initializes the device SPI peripheral in master or slave mode.

Note: MISO, MOSI and SCK idle in high-impedance state when SPI peripheral is configured in slave mode and the device is not selected.

Parameters:

mode: SPI_MODE_MASTER or SPI_MODE_SLAVE
ss_pin: slave-select pin to initialize. The default SS pin varies by port and device, see above.

// Example using SPI in master mode, with the default SS pin:
SPI.begin(SPI_MODE_MASTER);

// Example using SPI1 in slave mode, with D5 as the SS pin
SPI1.begin(SPI_MODE_SLAVE, D5);

// Example using SPI2 in slave mode, with C0 as the SS pin
// (Electron and E-Series only)
SPI2.begin(SPI_MODE_SLAVE, C0);

On Gen 3 devices (Argon, Boron, and Xenon), SPI slave can only be used on SPI1. It is not supported on SPI. The maximum speed is 8 MHz on SPI1.