void board_setFS(uint8_t fs)
{
    //cli();
    uint16_t ratio = 0;

    RST_CS_PORT &= ~(1<<RST_CS_PIN); //CS8416 power down
    AD_RST_PORT &= ~(1<<AD_RST_PIN); //reset AD
    _delay_ms(50);
    switch(fs)
    {
        case 0b010: //44.1
            set_mck(0);
            set_pdur(1);
            ratio = 0;
        break;

        case 0b000:
            set_mck(1);
            set_pdur(1);
            ratio = 0;
        break;

        case 0b110:
            set_mck(0);
            set_pdur(1);
            ratio = 1;
        break;

        case 0b100:
            set_mck(1);
            set_pdur(1);
            ratio = 1;
        break;

        case 0b011:
            set_mck(0);
            set_pdur(0);
            ratio = 2;
        break;

        case 0b001: //192
            set_mck(1);
            set_pdur(0);
            ratio = 2;
        break;
    }

    _delay_ms(50);
    RST_CS_PORT |= (1<<RST_CS_PIN); //CS8416 power up
    AD_RST_PORT |= (1<<AD_RST_PIN);

    //nastavení AD1955 přes SPI

    ratio = (ratio << 8);

    spi_send(0x201, RIGHT);
    _delay_ms(1);
    spi_send((ratio | 0xC00), RIGHT);
    _delay_ms(1);
    spi_send(0x201, LEFT); //see datasheet of the AD1955
    _delay_ms(1);
    spi_send((ratio | 0x800), LEFT);

    _delay_ms(50);
    RE_MUTE_PORT |= (1<<RE_MUTE_PIN);
    _delay_ms(10);
    //sei();
}