void SPIClass::begin() {

  // Set SS to high so a connected chip will be "deselected" by default

  digitalWrite(SS, HIGH);

  // When the SS pin is set as OUTPUT, it can be used as
  // a general purpose output port (it doesn't influence
  // SPI operations).

  pinMode(SS, OUTPUT);

  // Warning: if the SS pin ever becomes a LOW INPUT then SPI
  // automatically switches to Slave, so the data direction of
  // the SS pin MUST be kept as OUTPUT.