Subversion Repositories igor

#include "spi.h"

#include <avr/io.h>

//Configure the SPI interface for use with SD/MMC and Ethernet

void configure_spi(void)

{

        //Set pins as output

        SPI_DDR |= (1<<SPI_SCK) | (1<<SPI_MOSI) | (1<<SPI_SS_MMC) | (1<<SPI_SS_ETHERNET);

        //Set pins as input

        SPI_DDR &= ~(1<<SPI_MISO);

        //Activate pull-up on MISO and set both SS lines high (deasserted)

        SPI_PORT |= (1<<SPI_MISO) | (1<<SPI_SS_MMC) | (1<<SPI_SS_ETHERNET);

        //Drive SCK and MOSI low

        SPI_PORT &= ~((1<<SPI_SCK) | (1<<SPI_MOSI));

        // Disable SPI powersaving

        PRR0 &= ~(1<<PRSPI);

        /*Configure SPI interface:

        * Disable SPI interrupts

        * Enable SPI

        * Set data order MSB first

        * Set SPI master mode

        * Set clock polarity idle low

        * Set clock phase to sample on rising edge

        * Set SPI speed to freq_cpu/4

        */

        SPCR = (0<<SPIE)|(1<<SPE)|(0<<DORD)|(1<<MSTR)|(0<<CPOL)|(0<<CPHA)|(0<<SPR1)|(0<<SPR0);

        //Activate SPI2X, doubling the speed set in the previous register

        SPSR = (1<<SPI2X);

}