/*
   * Copyright (c) 2010 by Cristian Maglie <c.maglie@bug.st>
   * SPI Master library for arduino.
   *
   * This file is free software; you can redistribute it and/or modify
   * it under the terms of either the GNU General Public License version 2
   * or the GNU Lesser General Public License version 2.1, both as
   * published by the Free Software Foundation.
   */
  
  #include "pins_arduino.h"
  #include "SPI.h"
  
  SPIClass SPI;
  
  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.
    SPCR |= _BV(MSTR);
    SPCR |= _BV(SPE);
  
    // Set direction register for SCK and MOSI pin.
    // MISO pin automatically overrides to INPUT.
    // By doing this AFTER enabling SPI, we avoid accidentally
    // clocking in a single bit since the lines go directly
    // from "input" to SPI control.  
    // http://code.google.com/p/arduino/issues/detail?id=888
    pinMode(SCK, OUTPUT);
    pinMode(MOSI, OUTPUT);
  }
  
  
  void SPIClass::end() {
    SPCR &= ~_BV(SPE);
  }
  
  void SPIClass::setBitOrder(uint8_t bitOrder)
  {
    if(bitOrder == LSBFIRST) {
      SPCR |= _BV(DORD);
    } else {
      SPCR &= ~(_BV(DORD));
    }
  }
  
  void SPIClass::setDataMode(uint8_t mode)
  {
    SPCR = (SPCR & ~SPI_MODE_MASK) | mode;
  }
  
  void SPIClass::setClockDivider(uint8_t rate)
  {
    SPCR = (SPCR & ~SPI_CLOCK_MASK) | (rate & SPI_CLOCK_MASK);
    SPSR = (SPSR & ~SPI_2XCLOCK_MASK) | ((rate >> 2) & SPI_2XCLOCK_MASK);
  }