UART Driver Implementation (Embedded C)

🔹 Overview

This project implements a UART (Universal Asynchronous Receiver Transmitter) driver using register-level programming in Embedded C.

The driver enables reliable serial communication between microcontroller and external devices by handling both transmission (TX) and reception (RX) operations.

This project focuses on low-level peripheral control, without using any external libraries or HAL.

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🔹 Features

• UART Initialization (Baud rate configuration)
• Data Transmission (TX)
• Data Reception (RX)
• Polling-based communication
• Register-level programming
• Lightweight and efficient implementation

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🔹 Technologies Used

• Embedded C
• STM32 / Generic Microcontroller
• UART Protocol
• Register-Level Programming

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🔹 Project Structure

uart-driver/
│
├── inc/
│   ├── uart.h        // Function declarations
│   └── uart_reg.h    // Register definitions
│
├── src/
│   ├── uart.c        // UART logic implementation
│   └── uart_reg.c    // Register configuration
│
├── main.c            // Example usage
└── README.md

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🔹 UART Working Principle

UART is an asynchronous serial communication protocol, meaning no clock signal is shared between devices.

🔸 Communication Flow:

1. Data is loaded into the transmit register
2. Converted into serial bits (start + data + stop bits)
3. Sent over communication line
4. Receiver reconstructs data from incoming bits

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🔹 How It Works

1. Initialization

• Configure baud rate
• Enable UART peripheral
• Enable TX and RX

2. Transmission

• Load data into transmit register
• Wait until transmission is complete

3. Reception

• Wait for data availability
• Read data from receive register

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🔹 API Functions

🔸 Initialize UART

void UART_Init(void);

🔸 Send Single Character

void UART_SendChar(char data);

🔸 Receive Single Character

char UART_ReceiveChar(void);

🔸 Send String

void UART_SendString(char *str);

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🔹 Example Usage

#include "uart.h"

int main()
{
    UART_Init();

    UART_SendChar('H');
    UART_SendChar('i');

    UART_SendString(" UART Working\n");

    char data = UART_ReceiveChar();

    while(1);
}

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🔹 Output

• Characters successfully transmitted via UART
• Data received correctly from serial terminal
• Verified communication between devices

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🔹 Applications

• Serial communication between microcontrollers
• Debugging using serial monitor
• Sensor data transmission
• Communication with modules (GPS, Bluetooth, etc.)

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🔹 Key Learnings

• Register-level programming
• UART protocol implementation
• Embedded system communication
• Peripheral interfacing

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🔹 Future Improvements

• Interrupt-based UART
• DMA-based communication
• Error handling (parity, framing errors)
• Integration with RTOS (FreeRTOS)

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🔹 Author

Naga Rohit Anudeep N Embedded Systems Engineer

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🔹 Tags

Embedded C, UART Driver, STM32, Firmware Development, Register-Level Programming