avr/spi.c

   1 /*
   2  Copyright (C) 2012 jaseg <s@jaseg.de>
   3
   4  This program is free software; you can redistribute it and/or
   5  modify it under the terms of the GNU General Public License
   6  version 3 as published by the Free Software Foundation.
   7  */
   8
   9 #include "spi.h"
  10
  11 void spi_begin(){
  12     SPI_MOSI_DDR |= _BV(SPI_MOSI_PIN);
  13     SPI_SCK_DDR |= _BV(SPI_SCK_PIN);
  14 }
  15
  16 //The following function is never called.
  17 void spi_end(){
  18     //FIXME what should I do here?
  19 }
  20
  21 void spi_setup(uint8_t config){
  22     SPCR = config | _BV(SPE) | _BV(MSTR);
  23     if(config & _BV(SPE)){
  24         SPSR = _BV(SPE);
  25     }else{
  26         SPSR = 0;
  27     }
  28 }
  29
  30 uint8_t spi_transfer(uint8_t data){
  31     SPDR = data;
  32     while(!(SPSR & _BV(SPIF))){
  33         //She waves and opens a door back onto the piazza where her robot cat – the alien's nightmare intruder in the DMZ – sleeps, chasing superintelligent dream mice through multidimensional realities.
  34     }
  35     return SPDR;
  36 }
  37