#include <avr/io.h>
#include <avr/interrupt.h>

#define F_CPU 16000000UL
#define BAUD 9600
#define MYUBRR F_CPU/16/BAUD-1

void USART_Init(unsigned int ubrr) {
    UBRR0H = (unsigned char)(ubrr>>8);
    UBRR0L = (unsigned char)ubrr;
    UCSR0B = (1<<RXEN0)|(1<<TXEN0)|(1<<RXCIE0);
    UCSR0C = (1<<USBS0)|(3<<UCSZ00);
}

void USART_Transmit(unsigned char data) {
    while (!(UCSR0A & (1<<UDRE0)));
    UDR0 = data;
}

char USART_Receive() {
    while (!(UCSR0A & (1<<RXC0)));
    return UDR0;
}

void ADC_Init() {
    ADMUX = (1<<REFS0);
    ADCSRA = (1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);
}

int ADC_Read(unsigned char channel) {
    ADMUX = (ADMUX & 0xF0) | (channel & 0x0F);
    ADCSRA |= (1<<ADSC);
    while (ADCSRA & (1<<ADSC));
    return ADC;
}

int main() {
    char s[] = "Comunicacao SERIAL\n";
    char bt_press[] = "pressionado\n";
    char bt_solto[] = "solto\n";
    char buffer[5];
    volatile char ch;
    volatile char flag_com = 0;
    int valor_adc = 0;

    DDRC = 0b00000000;
    PORTC = 0b00001100;
    DDRD = 0b11111111;
    PORTD = 0b00000000;

    USART_Init(MYUBRR);
    ADC_Init();

    sei();

    while(1) {
        if (flag_com == 1) {
            switch (ch) {
                case 'A':
                    PORTD |= (1<<PD6); // Liga LED
                    break;

                case 'B':
                    PORTD &= ~(1<<PD6); // Desliga LED
                    break;

                case 'C':
                    if (!(PINC & (1<<PINC2)))
                        USART_TransmitString(bt_press);
                    else
                        USART_TransmitString(bt_solto);
                    break;

                case 'D':
                    valor_adc = ADC_Read(0);
                    sprintf(buffer, "%4d\n", valor_adc);
                    USART_TransmitString(buffer);
                    break;
            }
            flag_com = 0;
        }
    }
}

void USART_TransmitString(char *str) {
    while (*str) {
        USART_Transmit(*str);
        str++;
    }
}