30 01 20 23

7f fb 58 00
fb ff ff ff
00 00 00 00
ff ff ff ff
ab ab ab ab
e7 e7 e7 e7

//Эти значения идут в init_usart_spi
#define BRREG 128
#define SPIMODE 1

void init_usart_spi( unsigned char spimode, unsigned int brreg )
{
         // Baud rate must be set to 0 prior to enabling the USART as SPI
        // master, to ensure proper initialization of the XCK line.
        UBRR0H = 0x00;
        UBRR0L = 0x00;

        // Set XCK line to output, ie. set USART in master mode.
        USARTDDR |= (1<<XCKPIN);

        // Set USART to Master SPI mode.
        UCSR0C = (1<<UMSEL01) | (1<<UMSEL00);

        // Set clock polarity and phase to correct SPI mode.
        if( spimode & 0x01 ) UCSR0C |= (1<<UCPOL0);
        if( spimode & 0x02 ) UCSR0C |= (1<<UCPHA0);

        // Enable RX and TX.
        UCSR0B = (1<<RXEN0) | (1<<TXEN0);

        // Set baud rate. Must be set _after_ enabling the transmitter.
        UBRR0H = (uint8_t) (brreg>>8);
        UBRR0L = (uint8_t) brreg;

}


uint8_t spi_shift_byte(uint8_t value )
{
        // Wait for empty transmit buffer.
        do {} while( (UCSR0A & (1<<UDRE0)) == 0 );

        // Send data.
        UDR0 = value;

        // Wait for transfer to complete and return received value.
        do {} while( (UCSR0A & (1<<RXC0)) == 0 );

        return UDR0;
}

//Read 4 registers from ADC

uint8_t SPI_buf[4];
spi_shift_byte(RREG | 0x00);    //Read from register with starting at address 0x00
_delay_us(5);
spi_shift_byte(0x03);       //Read 4 register
_delay_us(50);             //*ADS1256 t6 VERY IMPORTANT* min_us=t6/F_ADS1256=50/7.68MHz=7us
SPI_buf[0]=spi_shift_byte(0xAB);
_delay_us(5);
SPI_buf[1]=spi_shift_byte(0xAB);
_delay_us(5);
SPI_buf[2]=spi_shift_byte(0xAB);
_delay_us(5);
SPI_buf[3]=spi_shift_byte(0xAB);
_delay_us(5);