ATmega88 @ 8MHz SPI-Slave - Daten am MOSI empfangen und am PORTD ausgeben

spi-receive-01.c

/* * spi_receive_01.c
* SPI-Slave - Daten am MOSI empfangen und am PORTD ausgeben
* Controller: ATmega88 @ 8MHz
*/
#include <avr/io.h>
#include <util/delay.h>
 
void SPI_Slave_Init(void)
{
    SPCR &= ~(1<<MSTR);       // Controller = Slave
    SPCR &= ~(1<<CPOL);       // CLK positiv phase
    SPCR |= (1<<CPHA);        // Sampling data @ rising edge
    DDRB |= (1<<PB4);     // Set MISO output
    DDRB &= ~(1<<PB3);        // Set MOSI input
    DDRB &= ~(1<<PB5);        // Set SCK input
    DDRB &= ~(1<<PB2);        // Set SS input
    SPCR |= (1<<SPE);     // SPI enable
}
 
uint8_t SPI_Slave_Receive(void)
{
    while (!(SPSR & (1<<SPIF)));  // Wait for transmission complete
    return SPDR;                    // return spi data register
}
 
int main(void)
{
    DDRD = 0xFF;
    SPI_Slave_Init();               // Init SPI Interface as Slave
     
    while(1)
    {
        PORTD = SPI_Slave_Receive();
    }
}