SW_SPI.cpp

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#include "SW_SPI.h"
 
SW_SPIClass::SW_SPIClass(uint16_t mosi, uint16_t miso, uint16_t sck) :
  mosi_pin(mosi),
  miso_pin(miso),
  sck_pin(sck)
  {}
 
void SW_SPIClass::init() {
  pinMode(mosi_pin, OUTPUT);
  pinMode(sck_pin, OUTPUT);
  pinMode(miso_pin, INPUT_PULLUP);
  #ifdef ARDUINO_ARCH_AVR
    mosi_register = portOutputRegister(getPort(mosi_pin));
    miso_register = portInputRegister(getPort(miso_pin));
    sck_register = portOutputRegister(getPort(sck_pin));
    mosi_bm = digitalPinToBitMask(mosi_pin);
    miso_bm = digitalPinToBitMask(miso_pin);
    sck_bm = digitalPinToBitMask(sck_pin);
  #endif
  writeSCK_H;
}
 
uint8_t SW_SPIClass::transfer(uint8_t ulVal) {
  uint8_t value = 0;
  writeSCK_L;
 
  for (uint8_t i=7 ; i>=1 ; i--) {
    // Write bit
    !!(ulVal & (1 << i)) ? writeMOSI_H : writeMOSI_L;
    // Start clock pulse
    writeSCK_H;
    // Read bit
    value |= ( readMISO ? 1 : 0) << i;
    // Stop clock pulse
    writeSCK_L;
  }
 
  !!(ulVal & (1 << 0)) ? writeMOSI_H : writeMOSI_L;
  writeSCK_H;
  value |= ( readMISO ? 1 : 0) << 0;
 
  return value;
}
 
uint16_t SW_SPIClass::transfer16(uint16_t data) {
  uint16_t returnVal = 0x0000;
  returnVal |= transfer((data>>8)&0xFF) << 8;
  returnVal |= transfer(data&0xFF) & 0xFF;
  return returnVal;
}