teensy-sdfat/SdFat/examples/SoftwareSpi/SoftwareSpi.ino

// An example of the SdFatSoftSpi template class.
// This example is for an Adafruit Data Logging Shield on a Mega.
// Software SPI is required on Mega since this shield connects to pins 10-13.
// This example will also run on an Uno and other boards using software SPI.
//
#include <SPI.h>
#include <SdFat.h>
#if USE_MULTIPLE_SPI_TYPES  // Must be nonzero in SdFat/SdFatConfig.h
//
// Pin numbers in templates must be constants.
const uint8_t SOFT_MISO_PIN = 12;
const uint8_t SOFT_MOSI_PIN = 11;
const uint8_t SOFT_SCK_PIN  = 13;
//
// Chip select may be constant or RAM variable.
const uint8_t SD_CHIP_SELECT_PIN = 10;

// SdFat software SPI template
SdFatSoftSpi<SOFT_MISO_PIN, SOFT_MOSI_PIN, SOFT_SCK_PIN> sd;

// Test file.
SdFile file;

void setup() {
  Serial.begin(9600);
  while (!Serial) {}  // Wait for Leonardo 
  
  Serial.println("Type any character to start");
  while (Serial.read() <= 0) {}
  
  if (!sd.begin(SD_CHIP_SELECT_PIN)) sd.initErrorHalt();
  
  if (!file.open("SOFT_SPI.TXT", O_CREAT | O_RDWR)) {
    sd.errorHalt(F("open failed"));
  }
  file.println(F("This line was printed using software SPI."));
  
  file.close();
  
  Serial.println(F("Done."));
}
//------------------------------------------------------------------------------
void loop() {}
#else  // USE_MULTIPLE_SPI_TYPES
#error USE_MULTIPLE_SPI_TYPES must be set nonzero in SdFat/SdFatConfig.h
#endif  //USE_MULTIPLE_SPI_TYPES