SPI (Serial Peripheral Interface)ΒΆ

The RP2040 has two hardware SPI interfaces, spi0 (SPI) and spi1 (SPI1). These interfaces are supported by the SPI library in master mode.

SPI pinouts can be set before SPI.begin() using the following calls:

bool setRX(pin_size_t pin);
bool setCS(pin_size_t pin);
bool setSCK(pin_size_t pin);
bool setTX(pin_size_t pin);

Note that the CS pin can be hardware or software controlled by the sketch. When software controlled, the setCS() call is ignored.

The Arduino SPI documentation gives a detailed overview of the library, except for the following RP2040-specific changes:

  • SPI.begin(bool hwCS) can take an options hwCS parameter. By passing in true for hwCS the sketch does not need to worry about asserting and deasserting the CS pin between transactions. The default is false and requires the sketch to handle the CS pin itself, as is the standard way in Arduino.

  • The interrupt calls (usingInterrupt, notUsingInterrupt, attachInterrupt, and detachInterrpt) are not implemented.