/*slave*/
#include <asf.h>
#include "main.h"
#include "SPI.h"
#include "uart.h"
#include "modbus_func.h"

void Timer_ini() // T=2мс
{
	TCNT2 = 0;
	OCR2A = 248;
	TCCR2A = 0b00000010;
	TCCR2B = 0b00000011;
	TIMSK2 = (1<<OCIE2A);
}

ISR(SPI_STC_vect)
{
	Massiv_input[len] = SPDR;
	len++;
	global_time = 0;
}

ISR(TIMER2_COMPA_vect)
{
	if (global_time != 0xFFFF)  global_time++;
}

int main (void)
{
	SPI_SlaveInit();
	Timer_ini();
	sei();
	adress = 0x04;

	while(1)
	{
		if (global_time != 0xFFFF)
		{
			if (global_time > 10)
			{
				global_time = 0xFFFF;
//----------------------------------------------------------------------
				last_mas = 0;
				//Проверка адреса устройства
				if (Massiv_input[0] == adress)
				{
					Massiv_output[0] = Massiv_input[0];
					last_mas++;
				}
				else
				{
					//Massiv_output[0] = MB_exception_rsp[0];
					//break;
				}

				//Проверка функции
				if (Massiv_input[1] == 0x03)
				{
					Massiv_output[1] = Massiv_input[1];
					last_mas++;
					//чтение
					Read_Holding_Reg();
				}
				else if (Massiv_input[1] == 0x04)
				{
					Massiv_input[1] = Massiv_output[1];
					last_mas++;
					Read_Input_Registers();
				}
				else if (Massiv_input[1] == 0x06)
				{
					Massiv_output[1] = Massiv_input[1];
					last_mas++;
					//запись
					Write_single_register();
				}
				else if (Massiv_input[1] == 0x10)
				{
					Massiv_output[1] = Massiv_input[1];
					last_mas++;
					Write_Multiple_Registers();
				}

				else
				{
					Massiv_output[1] = 0x83;
					last_mas++;
				}
//------------------------------------------------------------------------
				SPI_Write_Array((void *) last_mas, &Massiv_output);
			}
		}
	}
}

_______________________________________________
SPI инициализация
#ifndef SPI_H_
#define SPI_H_

#define SPI_PORTX PORTB
#define SPI_DDRX DDRB

#define DDR_SPI DDRB
#define DD_SCK 5
#define DD_MISO 4
#define DD_MOSI 3
#define SPI_SS 2

void SPI_SlaveInit(void)
{
	DDR_SPI = (1<<DD_MISO);
	SPCR = (1<<SPIE)|(1<<SPE)|(0 << DORD)|(0 << MSTR);
	SPSR = (0 << SPI2X);
}

void SPI_Write_Array(uint8_t num, uint8_t *data)
{
	PORTB &= ~(1<<SPI_SS);
	while(num--)
	{
		SPDR = *data++;
		while(!(SPSR & (1<<SPIF)));
	}
	PORTB |= (1<<SPI_SS);
}

#endif /* SPI_H_ */
______________________________________
уарт инициализация
#define UART_TO_TRANSMIT UCSR0B = (0<<RXEN0)|(1<<TXEN0)|(0 << RXCIE0)|(0 << TXCIE0);
#define UART_TO_RECEIVE  UCSR0B = (1<<RXEN0)|(0<<TXEN0)|(1 << RXCIE0)|(0 << TXCIE0);

void USART_ini( unsigned int speed) //инициализация USART
{
	UBRR0H = (unsigned char) (speed>>8);
	UBRR0L = (unsigned char) speed;
	UCSR0B = (0<<RXEN0)|(1<<TXEN0)|(0 << RXCIE0)|(0 << TXCIE0);
	UCSR0A = (0 << U2X0);
	UCSR0C = (1<<USBS0)|(3<<UCSZ00);
}

void USART_Transmit(unsigned char data)  //передача по USART из мк в пк
{
	while (!(UCSR0A&(1<<UDRE0)));
	UDR0 = data;
}

unsigned char USART_Receive() //передача по USART из пк в мк
{
	while (!(UCSR0A&(1<<RXC0)));
	return UDR0;
}

void USART_Transmit_data(unsigned char *data, unsigned char loc_len)   //передача с мк на пк. data - массив с байтами, len - длина массива
{
	while (loc_len--)
	{
		while (!(UCSR0A&(1<<UDRE0)));
		UDR0 = *data;
		data++;
	}
}