diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..13566b8
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 0000000..639da93
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/Display_Avr_3.iml" filepath="$PROJECT_DIR$/.idea/Display_Avr_3.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/client.c b/client.c
new file mode 100644
index 0000000..a456c45
--- /dev/null
+++ b/client.c
@@ -0,0 +1,125 @@
+#include "client.h"
+
+#include <stdio.h>
+#include <fcntl.h>
+
+#define START_FLAG 0x7E
+#define END_FLAG 0x7E
+
+void init_Client(Client* client, bool test_is_valid, uint8_t address) {
+    client->TEST_IS_VALID = test_is_valid;
+    client->address = address;
+    client->_send_sequence_number = 0;
+    client->poll_final = 1;
+    client->_receive_sequence_number = 0;
+}
+
+
+void connect(Client* client) {
+    UFrame u_frame;
+    init_UFrame(&u_frame, client->address, client->poll_final, "BP", NULL, 0);
+
+    uint8_t result[256];
+    create_frame(&u_frame.base, result);
+
+
+    // Wait for acknowledgment frame
+    bool flag = true;
+    uint8_t data;
+    while(flag){
+        data = uart_read();
+        if (data > 0){
+            flag = false;
+        }
+    }
+
+    HDLCFrame frame;
+    init_HDLCFrame(&frame, 0, 0, &data + 3, 256 - 6);
+    if (validate(&data, 256)) {
+        return;
+    } else {
+        // Connection failed
+    }
+}
+
+void send(Client* client, uint8_t* data, size_t data_length) {
+    connect(client);
+
+    IFrame i_frame;
+    init_IFrame(&i_frame, client->address, client->_receive_sequence_number, client->poll_final, client->_send_sequence_number, data, data_length);
+
+    uint8_t result[256];
+    create_frame(&i_frame.base, result);
+
+    uart_send_byte(*i_frame.base.data);
+
+    client->_send_sequence_number++;
+}
+
+void receive_data(uint8_t* recivedData) {
+    bool flag = true;
+    while(flag){
+        *recivedData = uart_read();
+        if (recivedData > 0){
+            flag = false;
+        }
+    }
+}
+
+#include <stdbool.h>
+
+bool validate(const uint8_t* frame, size_t length) {
+    if (length < 4 || frame[0] != START_FLAG || frame[length - 1] != END_FLAG) {
+        // Invalid frame length or missing start/end flag
+        return false;
+    }
+
+    uint16_t received_fcs = (frame[length - 3] << 8) | frame[length - 2];
+    uint16_t calculated_fcs = 0xFFFF;
+
+    for (size_t i = 1; i < length - 3; i++) {
+        uint8_t byte = frame[i];
+        calculated_fcs = (calculated_fcs >> 8) ^ (calculated_fcs << 8) ^ byte;
+        calculated_fcs &= 0xFFFF;
+    }
+
+    return received_fcs == calculated_fcs;
+}
+
+int sendSerialData(const char* port, uint8_t* data, size_t length) {
+    int serial_port = open(port, O_RDWR);
+
+    if (serial_port < 0) {
+        perror("Error opening the serial port");
+        return -1;
+    }
+
+    ssize_t bytes_written = write(serial_port, data, length);
+
+    if (bytes_written < 0) {
+        perror("Error writing to the serial port");
+        return -1;
+    }
+
+    close(serial_port);
+    return bytes_written;
+}
+
+int receiveSerialData(const char* port, uint8_t* data, int length) {
+    int serial_port = open(port, O_RDWR); // Replace "port" with your serial port device
+
+    if (serial_port < 0) {
+        perror("Error opening the serial port");
+        return -1;
+    }
+
+    ssize_t bytes_read = read(serial_port, data, length);
+
+    if (bytes_read < 0) {
+        perror("Error reading from the serial port");
+        return -1;
+    }
+
+    close(serial_port);
+    return bytes_read;
+}
\ No newline at end of file
diff --git a/client.h b/client.h
new file mode 100644
index 0000000..0a19d58
--- /dev/null
+++ b/client.h
@@ -0,0 +1,24 @@
+#ifndef CLIENT_H
+#define CLIENT_H
+
+#include "hdlc_frame.h"
+#include "uart_module.h"
+#include <stdbool.h>
+#include <stddef.h> // Для использования size_t
+#include <stdint.h>
+
+typedef struct {
+    bool TEST_IS_VALID;
+    uint8_t address;
+    uint8_t _send_sequence_number;
+    uint8_t poll_final;
+    uint8_t _receive_sequence_number;
+} Client;
+
+void init_Client(Client* client, bool test_is_valid, uint8_t address);
+void connect(Client* client);
+void send(Client* client, uint8_t* data, size_t data_length);
+void receive_data(uint8_t* recivedData);
+bool validate(const uint8_t* frame, size_t length);
+
+#endif
diff --git a/hdlc_frame.c b/hdlc_frame.c
new file mode 100644
index 0000000..e7965c6
--- /dev/null
+++ b/hdlc_frame.c
@@ -0,0 +1,108 @@
+#include "hdlc_frame.h"
+
+#include <string.h>
+
+#define START_FLAG 0x7E
+#define END_FLAG 0x7E
+#define ESCAPE_FLAG 0x7D
+#define ESCAPE_XOR 0x20
+
+void init_HDLCFrame(HDLCFrame* frame, uint8_t address, uint8_t control, uint8_t* data, size_t data_length) {
+    frame->address = address;
+    frame->control = control;
+    frame->data = data;
+    frame->data_length = data_length;
+}
+
+uint16_t calculate_fcs(const HDLCFrame *frame, size_t i) {
+    uint16_t fcs = 0xFFFF;
+
+    uint8_t data_bytes[2 + frame->data_length];
+    data_bytes[0] = frame->address;
+    data_bytes[1] = frame->control;
+    memcpy(data_bytes + 2, frame->data, frame->data_length);
+
+    for (size_t i = 0; i < frame->data_length + 2; i++) {
+        uint8_t byte = data_bytes[i];
+        fcs = (fcs >> 8) ^ (fcs << 8) ^ byte;
+        fcs &= 0xFFFF;
+    }
+
+    return fcs;
+}
+
+void create_frame(const HDLCFrame* frame, uint8_t* result) {
+    size_t index = 0;
+
+    result[index++] = START_FLAG;
+    result[index++] = frame->address;
+    result[index++] = frame->control;
+
+    if (frame->data != NULL) {
+        for (size_t i = 0; i < frame->data_length; i++) {
+            uint8_t byte = frame->data[i];
+            if (byte == START_FLAG || byte == END_FLAG || byte == ESCAPE_FLAG) {
+                result[index++] = ESCAPE_FLAG;
+                result[index++] = byte ^ ESCAPE_XOR;
+            } else {
+                result[index++] = byte;
+            }
+        }
+    }
+
+    uint16_t fcs = calculate_fcs(frame, 0);
+    result[index++] = fcs & 0xFF;
+    result[index++] = (fcs >> 8) & 0xFF;
+    result[index++] = END_FLAG;
+}
+
+void init_IFrame(IFrame* frame, uint8_t address, uint8_t receive_sequence_number, uint8_t poll_final,
+                 uint8_t send_sequence_number, uint8_t* data, size_t data_length) {
+    init_HDLCFrame(&frame->base, address,
+                   ((receive_sequence_number & 0b111) << 6) | ((poll_final & 0b1) << 4) |
+                   ((send_sequence_number & 0b111) << 1) | 0,
+                   data, data_length);
+    frame->receive_sequence_number = receive_sequence_number;
+    frame->poll_final = poll_final;
+    frame->send_sequence_number = send_sequence_number;
+}
+
+void init_SFrame(SFrame* frame, uint8_t address, uint8_t receive_sequence_number, uint8_t poll_final,
+                 const char* frame_type) {
+    uint8_t frame_type_value;
+    if (strcmp(frame_type, "RR") == 0) {
+        frame_type_value = 0;
+    } else if (strcmp(frame_type, "RNR") == 0) {
+        frame_type_value = 1;
+    } else if (strcmp(frame_type, "REJ") == 0) {
+        frame_type_value = 2;
+    } else if (strcmp(frame_type, "SREJ") == 0) {
+        frame_type_value = 3;
+    } else {
+        // Handle error
+        return;
+    }
+
+    init_HDLCFrame(&frame->base, address,
+                   ((receive_sequence_number & 0b111) << 6) | ((poll_final & 0b1) << 5) |
+                   ((frame_type_value & 0b111) << 2) | 1,
+                   NULL, 0);
+    frame->receive_sequence_number = receive_sequence_number;
+    frame->poll_final = poll_final;
+    frame->frame_type = frame_type;
+}
+
+void init_UFrame(UFrame* frame, uint8_t address, uint8_t poll_final, const char* frame_type,
+                 uint8_t* data, size_t data_length) {
+    uint8_t frame_type_value;
+    if (strcmp(frame_type, "BP") == 0) {
+        frame_type_value = 63;
+    } else {
+        // Handle error
+        return;
+    }
+
+    init_HDLCFrame(&frame->base, address, (frame_type_value << 2) | 3, data, data_length);
+    frame->poll_final = poll_final;
+    frame->frame_type = frame_type;
+}
diff --git a/hdlc_frame.h b/hdlc_frame.h
new file mode 100644
index 0000000..c12eaf5
--- /dev/null
+++ b/hdlc_frame.h
@@ -0,0 +1,45 @@
+#ifndef HDLC_FRAME_H
+#define HDLC_FRAME_H
+
+#include <stdint.h>
+
+typedef struct {
+    uint8_t address;
+    uint8_t control;
+    uint8_t* data;
+    size_t data_length;
+} HDLCFrame;
+
+void init_HDLCFrame(HDLCFrame* frame, uint8_t address, uint8_t control, uint8_t* data, size_t data_length);
+uint16_t calculate_fcs(const HDLCFrame *frame, size_t i);
+void create_frame(const HDLCFrame* frame, uint8_t* result);
+
+typedef struct {
+    HDLCFrame base;
+    uint8_t receive_sequence_number;
+    uint8_t poll_final;
+    uint8_t send_sequence_number;
+} IFrame;
+
+void init_IFrame(IFrame* frame, uint8_t address, uint8_t receive_sequence_number, uint8_t poll_final,
+                 uint8_t send_sequence_number, uint8_t* data, size_t data_length);
+
+typedef struct {
+    HDLCFrame base;
+    uint8_t receive_sequence_number;
+    uint8_t poll_final;
+    const char* frame_type;
+} SFrame;
+
+void init_SFrame(SFrame* frame, uint8_t address, uint8_t receive_sequence_number, uint8_t poll_final,
+                 const char* frame_type);
+
+typedef struct {
+    HDLCFrame base;
+    uint8_t poll_final;
+    const char* frame_type;
+} UFrame;
+
+void init_UFrame(UFrame* frame, uint8_t address, uint8_t poll_final, const char* frame_type, uint8_t* data, size_t data_length);
+
+#endif
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..93e2b83
--- /dev/null
+++ b/main.c
@@ -0,0 +1,25 @@
+#include <stdint.h>
+#include "config.h"
+#include <avr/io.h>
+#include <util/delay.h>
+#include <avr/interrupt.h>
+#include "uart_hal.h"
+
+
+int main(void)
+{
+	//example
+	uint8_t data = 'A';
+
+	uart_init(9600,0);
+    uart_send_byte(data);
+	sei();
+    while (1) 
+    {
+		if(uart_read_count() > 0){
+			data = uart_read();
+			uart_send_byte(data);
+		}
+
+    }
+}
\ No newline at end of file
diff --git a/uart_module.c b/uart_module.c
new file mode 100644
index 0000000..c4cbc2a
--- /dev/null
+++ b/uart_module.c
@@ -0,0 +1,82 @@
+#include "uart_hal.h"
+
+volatile static uint8_t rx_buffer[RX_BUFFER_SIZE] = {0};
+volatile static uint16_t rx_count = 0;
+volatile static uint8_t uart_tx_busy = 1;
+// кольцевой буффер
+ISR(USART_RX_vect){
+	
+	volatile static uint16_t rx_write_pos = 0;
+	
+	rx_buffer[rx_write_pos] = UDR0;
+	rx_count++;
+	rx_write_pos++;
+	if(rx_write_pos >= RX_BUFFER_SIZE){
+		rx_write_pos = 0;
+	}
+	
+}
+
+
+ISR(USART_TX_vect){
+	uart_tx_busy = 1;
+}
+
+
+void uart_init(uint32_t baud,uint8_t high_speed){
+	
+	uint8_t speed = 16;
+	
+	if(high_speed != 0){
+		speed = 8;
+		UCSR0A |= 1 << U2X0;
+	}
+	
+	baud = (F_CPU/(speed*baud)) - 1;
+	
+	UBRR0H = (baud & 0x0F00) >> 8;
+	UBRR0L = (baud & 0x00FF);
+	
+	UCSR0B |= (1 << TXEN0) | (1 << RXEN0) | (1 << TXCIE0) | (1 << RXCIE0);
+	
+}
+
+
+void uart_send_byte(uint8_t c){
+	while(uart_tx_busy == 0);
+	uart_tx_busy = 0;
+	UDR0 = c;
+}
+
+void uart_send_array(uint8_t *c,uint16_t len){
+	for(uint16_t i = 0; i < len;i++){
+		uart_send_byte(c[i]);
+	}
+}
+
+void uart_send_string(uint8_t *c){
+	uint16_t i = 0;
+	do{
+		uart_send_byte(c[i]);
+		i++;
+		
+	}while(c[i] != '\0');
+	uart_send_byte(c[i]);
+}
+
+uint16_t uart_read_count(void){
+	return rx_count;
+}
+
+uint8_t uart_read(void){
+	static uint16_t rx_read_pos = 0;
+	uint8_t data = 0;
+	
+	data = rx_buffer[rx_read_pos];
+	rx_read_pos++;
+	rx_count--;
+	if(rx_read_pos >= RX_BUFFER_SIZE){
+		rx_read_pos = 0;
+	}
+	return data;
+}
\ No newline at end of file
diff --git a/uart_module.h b/uart_module.h
new file mode 100644
index 0000000..284a941
--- /dev/null
+++ b/uart_module.h
@@ -0,0 +1,20 @@
+#ifndef UART_HAL_H_
+#define UART_HAL_H_
+
+
+#include <stdint.h>
+#include "config.h"
+#include <avr/io.h>
+#include <util/delay.h>
+#include <avr/interrupt.h>
+
+#define RX_BUFFER_SIZE 128
+
+void uart_init(uint32_t baud,uint8_t high_speed);
+void uart_send_byte(uint8_t c);
+void uart_send_array(uint8_t *c,uint16_t len);
+void uart_send_string(uint8_t *c);
+uint16_t uart_read_count(void);
+uint8_t uart_read(void);
+
+#endif /* UART_HAL_H_ */
\ No newline at end of file