#include <avr/io.h>

#include <avr/interrupt.h>

#include "uart.h"

// UART buffers

volatile char rxbuf[64];

volatile uint8_t rdptr = 0;

volatile uint8_t wrptr = 0;

/**

 * Set up the UART

 */

void uart_setup(void) {

    DDRD |= (1<<TXD_PIN);

        UBRR0H = 0;

        UBRR0L = 25;

        UCSR0A |= (0<<U2X0);

        UCSR0B |= (1<<RXEN0) | (1<<TXEN0) | (1<<RXCIE0);

}

void uart_putchar(uint8_t c) {

        while( ! (UCSR0A & (1<<UDRE0)) );

        UDR0 = c;

}

int uart_putchar_f(char c, FILE *stream) {

    if(c == '\n') uart_putchar_f('\r', stream);

        while( ! (UCSR0A & (1<<UDRE0)) );

        UDR0 = c;

    return 0;

}

void uart_putdata(uint8_t *data, uint8_t count) {

        int i;

        for(i=0; i<count; i++) uart_putchar(data[i]);

}

uint8_t uart_data_available() {

    return !(rdptr == wrptr);

}

int16_t uart_getchar(uint8_t blocking) {

        char c;

    if(blocking)

        while(rdptr == wrptr);

    else

        if(rdptr == wrptr) return -1;

        c = rxbuf[rdptr];

        rdptr = (rdptr + 1) & 63;

        return c;

}

int uart_getchar_f(FILE *stream) {

    char c;

    while(rdptr == wrptr);

    c = rxbuf[rdptr];

    rdptr = (rdptr + 1) & 63;

    return c;

}

/**

 * UART Receive ISR

 */

ISR(USART_RX_vect) {

        rxbuf[wrptr] = UDR0;

    //uart_putchar(rxbuf[wrptr]);

        wrptr = (wrptr + 1) & 63;

        if(wrptr == rdptr) rdptr = (rdptr + 1) & 63;

}