Communication Protocols

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UART Communication

Universal Asynchronous Receiver/Transmitter (UART) is a simple yet powerful serial communication protocol widely used in embedded systems.

UART Basics

1. UART Configuration

// Initialize UART
void initUART(uint32_t baudRate) {
    // Calculate baud rate register value
    uint16_t ubrr = F_CPU/16/baudRate - 1;
    
    // Set baud rate
    UBRR0H = (uint8_t)(ubrr>>8);
    UBRR0L = (uint8_t)ubrr;
    
    // Enable receiver and transmitter
    UCSR0B = (1<<RXEN0)|(1<<TXEN0);
    
    // Set frame format: 8data, 1stop bit
    UCSR0C = (1<<UCSZ01)|(1<<UCSZ00);
}

2. Sending/Receiving Data

// Send a byte
void UARTsendByte(uint8_t data) {
    // Wait for empty transmit buffer
    while (!(UCSR0A & (1<<UDRE0)));
    UDR0 = data;
}

// Receive a byte
uint8_t UARTreceiveByte() {
    // Wait for data
    while (!(UCSR0A & (1<<RXC0)));
    return UDR0;
}