Arduino Serial Input/Output Test.c

#include <avr\io.h>
#include <util\delay.h>
#include <stdio.h>

#include "moreTypes.h"
#define true -1
#define false 0

#define F_CPU 16000000UL // Frequency of processor
#define BAUD  9600       // Baud rate of serial connections

void initUART() {
    #include <util\setbaud.h>
    UBRR0H = UBRRH_VALUE;
    UBRR0L = UBRRL_VALUE;

    #if USE_2X
        UCSR0A |=  _BV(U2X0);
    #else
        UCSR0A &= ~_BV(U2X0);
    #endif

    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); // Use 8-bit data
    UCSR0B = _BV(RXEN0) | _BV(TXEN0);   // Enable RX/TX
}

// Read a byte from the UART
ubyte getByte(int iWaitData) {
    // If wait flag set, loop until data is ready on RX
    if (iWaitData)
       loop_until_bit_is_set(UCSR0A, RXC0);

    // Return byte from serial UART
    return UDR0;
}

int readString(char* str, int iMaxLength) {
    ubyte tmpByte;
    int iDataRead = 0;

    while (1) {
        tmpByte = getByte(true);

        switch(tmpByte) {
            // If we read a newline the string parsing is done
            case '\r': case '\n':
                str[iDataRead] = '\0'; // Set last char to null-terminator
                return iDataRead;      // Return length of string read

            case 0x7F: // Backspace
                str[iDataRead] = '\0'
                if (iDataRead > 0)
                    iDataRead--;
                break;

            case else:
                str[iDataRead++] = tmpByte;
                if (iDataRead >= iMaxLength)
                    return iDataRead;
        }

    }
}

// Send a byte to the UART
void sendByte(ubyte data) {
    loop_until_bit_is_set(UCSR0A, UDRE0); // Wait until data register empty
    UDR0 = data;
}

// Send raw data of specified size over serial
void sendData(ubyte* data, int dataLen) {
    for (int i = 0; i < dataLen; i++)
        sendByte(data[i]);
}

// Send a null-terminated string over serial
void sendString(char* str) {
    int i = 0;
    while (str[i] != 0) {
        sendByte(str[i++]);
    }
}

char* sBuff = "Read byte: 0xFF\r\n\0";
void main() {
    initUART();
    while (1) {
        sprintf(sBuff, "Read byte: 0x%02X\r\n\0", getByte(true));
        sendString(sBuff);
    }
}