diff --git a/spi_master.c b/spi_master.c
new file mode 100644
index 0000000..ea220b7
--- /dev/null
+++ b/spi_master.c
@@ -0,0 +1,285 @@
+#include <avr/interrupt.h>
+#include <avr/io.h>
+#include <string.h>
+#include <util/delay.h>
+#include "spi_master.h"
+#include "func.h"
+
+#define MAX_DIGITS 11
+#define F_CPU 16000000UL
+#define DELAY_MS 3000
+
+void output_on_display(struct calculator *calc)
+{
+	char buffer[8];
+	switch (calc->state)
+	{
+		case NUMBER_FIRST:
+		{
+			size_t b_size = display_all_clear(0, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			b_size = display_set_page(0x01, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			int size = count_digits(calc->num1);
+			char mapped_digits[size];
+			prepare_data(mapped_digits, calc->num1, size);
+			b_size = display_add_simbol(mapped_digits, size, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			break;
+		}
+		case NUMBER_SECOND:
+		{
+			size_t b_size = display_all_clear(0, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			b_size = display_set_page(0x01, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			int size = count_digits(calc->num1);
+			char mapped_digits[size];
+			prepare_data(mapped_digits, calc->num1, size);
+			b_size = display_add_simbol(mapped_digits, size, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			char symbol[] = {0x01};
+			// операция
+			switch (calc->operation)
+			{
+				case NO_OP:
+				break;
+				case ADD:
+				symbol[0] = 0x04;
+				break;
+				case SUB:
+				symbol[0] = 0x06;
+				break;
+				case DIV:
+				symbol[0] = 0x08;
+				break;
+				case MUL:
+				symbol[0] = 0x03;
+				break;
+			}
+			
+			b_size = display_add_simbol(symbol, 1, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			b_size = display_set_page(0x02, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			size = count_digits(calc->num2);
+			char mapped_digits1[size];
+			prepare_data(mapped_digits1, calc->num2, size);
+			b_size = display_add_simbol(mapped_digits1, size, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			break;
+		}
+		case RESULT:
+		{
+			size_t b_size = display_all_clear(0, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			b_size = display_set_page(0x01, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			int size = count_digits(calc->num1);
+			char mapped_digits[size];
+			prepare_data(mapped_digits, calc->num1, size);
+			b_size = display_add_simbol(mapped_digits, size, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			char symbol[] = {0x01};
+			// операция
+			switch (calc->operation)
+			{
+				case NO_OP:
+				break;
+				case ADD:
+				symbol[0] = 0x04;
+				break;
+				case SUB:
+				symbol[0] = 0x06;
+				break;
+				case DIV:
+				symbol[0] = 0x08;
+				break;
+				case MUL:
+				symbol[0] = 0x03;
+				break;
+			}
+			
+			b_size = display_add_simbol(symbol, 1, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			b_size = display_set_page(0x02, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			size = count_digits(calc->num2);
+			char mapped_digits1[size];
+			prepare_data(mapped_digits1, calc->num2, size);
+			b_size = display_add_simbol(mapped_digits1, size, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+
+			// линия
+			
+			
+			// результат
+			b_size = display_set_page(0x03, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			symbol[0] = 0x15;
+			b_size = display_add_simbol(symbol, 1, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			size = count_digits(calc->result);
+			char mapped_digits2[size];
+			prepare_data(mapped_digits2, calc->result, size);
+			b_size = display_add_simbol(mapped_digits2, size, buffer);
+			SPI_MasterTransmit(buffer, b_size);
+			
+			break;
+		}
+		default:
+		display_all_clear(0, buffer);
+	}
+}
+
+void SPI_MasterInit(void)
+{
+	/* Настройка MOSI и SCK как выход,
+	все остальные сигналы как вход: */
+	SPI_DDRX = (1 << SPI_MOSI) | (1 << SPI_SCK) | (1 << SPI_SS) | (0 << SPI_MISO);
+
+	/* Разрешить работу SPI, режим Master,
+	установить скорость тактов fck/16: */
+	SPCR = (1 << SPE) | (1 << MSTR) | (0 << CPOL) | (0 << CPHA) | (1 << SPR1);
+
+	SPI_PORTX |= (1 << SPI_SS);
+}
+
+void SPI_MasterTransmit(char *buffer, size_t length)
+{
+	SPI_PORTX &= ~(1 << SPI_SS);
+	for (int i = 0; i < length; i++)
+	{
+		SPDR = buffer[i];
+		while (!(SPSR & (1 << SPIF)))
+		{
+			// ожидание завершения передачи
+		}
+	}
+	SPI_PORTX |= (1 << SPI_SS);
+	_delay_ms(DELAY_MS);
+}
+
+char crc8(char *data, int len) {
+	char crc = 0x00;
+	while (len--) {
+		crc ^= *data++;
+		for (int i = 0; i < 8; i++) {
+			if (crc & 0x80) {
+				crc = (crc << 1) ^ 0x07;
+				} else {
+				crc <<= 1;
+			}
+		}
+	}
+	return crc;
+}
+
+//очищение экранa
+size_t display_all_clear(char color, char *buffer)
+{
+	buffer[0] = 0x01;
+	buffer[1] = color;
+	buffer[2] = crc8(buffer, 2);
+	return 3;
+}
+
+//выбор точки
+size_t display_set_page(char point, char *buffer)
+{
+	buffer[0] = 0x02;
+	buffer[1] = point;
+	buffer[2] = crc8(buffer, 2);
+	return 3;
+}
+
+//добавление нового символа и его параметров
+size_t display_add_simbol(char *str, size_t str_len, char *buffer)
+{
+	size_t idx = 0;
+	buffer[idx] = 0x03;
+	idx++;
+	for (int i = 0; i < str_len; i++)
+	{
+		buffer[idx] = str[i];
+		idx++;
+	}
+	buffer[idx] = crc8(buffer, idx);
+	idx++;
+	return idx;
+}
+
+//удаление символа и его параметров
+size_t display_del_simbol(char number, char *buffer)
+{
+	buffer[0] = 0x04;
+	buffer[1] = number;
+	buffer[2] = crc8(buffer, 2);
+	return 3;
+}
+
+//закрашивание пикселя
+size_t display_draw_pixel(char x, char y, char color, uint8_t *buffer)
+{
+	buffer[0] = 0x05;
+	buffer[1] = x;
+	buffer[2] = y;
+	buffer[3] = color;
+	buffer[4] = crc8(buffer, 4);
+	return 5;
+}
+
+//рисует линию
+size_t display_draw_line(char x1, char y1, char x2, char y2, char color, char *buffer)
+{
+	buffer[0] = 0x06;
+	buffer[1] = x1;
+	buffer[2] = y1;
+	buffer[3] = x2;
+	buffer[4] = y2;
+	buffer[5] = color;
+	buffer[6] = crc8(buffer, 6);
+	return 7;
+}
+
+//рисует круг
+size_t display_draw_circle(char x, char y, char r, char color, uint8_t *buffer)
+{
+	buffer[0] = 0x07;
+	buffer[1] = x;
+	buffer[2] = y;
+	buffer[3] = r;
+	buffer[4] = color;
+	buffer[5] = crc8(buffer, 5);
+	return 6;
+}
+
+//рисует прямоугольник
+size_t display_draw_rectangle(char x, char y, char height, char width, char color, uint8_t *buffer)
+{
+	buffer[0] = 0x08;
+	buffer[1] = x;
+	buffer[2] = y;
+	buffer[3] = height;
+	buffer[4] = width;
+	buffer[5] = color;
+	buffer[6] = crc8(buffer, 6);
+	return 7;
+}
+
+
diff --git a/spi_master.h b/spi_master.h
new file mode 100644
index 0000000..3826c9b
--- /dev/null
+++ b/spi_master.h
@@ -0,0 +1,20 @@
+#define SPI_PORTX PORTB
+#define SPI_DDRX DDRB
+#define SPI_MISO 4
+#define SPI_MOSI 3
+#define SPI_SCK 5
+#define SPI_SS 2
+
+#include "calculator.h"
+
+void output_on_display(struct calculator *calc);
+void SPI_MasterInit(void);
+void SPI_MasterTransmit(char *buffer, size_t length);
+void transmit_first_num(struct calculator *calc, char *buffer);
+void transmit_second_num(struct calculator *calc, char *buffer);
+void transmit_result(struct calculator *calc, char *buffer, char *symblo);
+size_t display_all_clear(char color, char *buffer);
+size_t display_add_simbol(char *str, size_t str_len, char *buffer);
+size_t display_draw_line(char x1, char y1, char x2, char y2, char color, char *buffer);
+size_t display_del_simbol(char number, char *buffer);
+size_t display_set_page(char point, char *buffer);