Cette page est inspirée de penguintutor.com Using Raspberry Pi and Arduino together through SPI serial communications

# include SPI.h
 
void setup() 
{
  // Set the Main in Secondary Out as an output
  pinMode(MISO, OUTPUT);
  // turn on SPI as a secondary
  // Set appropriate bit in SPI Control Register
  SPCR |= _BV(SPE);
}
 
// The following code is then used to receive a byte and then set the data register to return a byte to the master controller device.
void loop () 
{
  byte in_byte;
  // SPIF indicates transmission complete (byte received)
  if ((SPSR & (1 << SPIF)) != 0)
  {
    in_byte = SPDR;
    // Handle the input code here
    // Set return_val to the value you want to return
    SPDR = return_val;
  }