Spi.cpp

/*
  Spi.cpp - SPI library
  Copyright (c) 2008 Cam Thompson.
  Author: Cam Thompson, Micromega Corporation, <www.micromegacorp.com>
  Version: December 15, 2008

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "Spi.h"

//---------- constructor ----------------------------------------------------

SPI::SPI()
{
   // initialize the SPI pins
   pinMode(SCK_PIN, OUTPUT);
   pinMode(MOSI_PIN, OUTPUT);
   pinMode(MISO_PIN, INPUT);
   pinMode(SS_PIN, OUTPUT);

   // enable SPI Master, MSB, SPI mode 0, FOSC/4
   mode(0);

   digitalWrite(SS_PIN,HIGH);
   digitalWrite(MOSI_PIN,LOW);
   digitalWrite(SCK_PIN,HIGH);

}

//------------------ mode ---------------------------------------------------

void SPI::mode(byte config)
{
   byte tmp;

   // enable SPI master with configuration byte specified
   SPCR = 0;
   SPCR = (config & 0x7F) | (1<<SPE) | (1<<MSTR);
   tmp = SPSR;
   tmp = SPDR;
}

//------------------ transfer -----------------------------------------------

byte SPI::transfer(byte value)
{
   byte x;
   SPDR = value;
   while (!(SPSR & (1<<SPIF))) ;
   x  = SPDR;
   return x;
}


//------------------ slave Select ---------------------------------------------
byte SPI::slaveSelect(byte value)
{
   digitalWrite(SS_PIN,value);
}

//---------- preinstantiate SPI object --------------------------------------

SPI Spi = SPI();