SPI

setClockDivider()

Sets the SPI clock divider relative to the selected clock reference. The available dividers are 2, 4, 8, 16, 32, 64, 128 or 256. The default setting is SPI_CLOCK_DIV4, which sets the SPI clock to one-quarter the frequency of the system clock.

// SYNTAX
SPI.setClockDivider(divider);

Where the parameter, divider can be:

• SPI_CLOCK_DIV2
• SPI_CLOCK_DIV4
• SPI_CLOCK_DIV8
• SPI_CLOCK_DIV16
• SPI_CLOCK_DIV32
• SPI_CLOCK_DIV64
• SPI_CLOCK_DIV128
• SPI_CLOCK_DIV256

The clock reference varies depending on the device.

• On Gen 3 devices (Argon, Boron, B-Series SoM, Tracker SoM), the clock reference is 64 MHz.
• On Gen 2 devices (Photon, P1, Electron, E-Series), the clock reference is 120 MHz.

Note that you must use the same SPI object as used with SPI.begin() so if you used SPI1.begin() also use SPI1.setClockDivider().