/*
    File:       main.c
    Version:    1.0.0
    Date:       May. 11, 2006

    GP2D120 Distance Measurement Demo #1 on an ATMega8 AVR.

    ****************************************************************************
    Copyright (C) 2006 Micah Carrick   <email@micahcarrick.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    ****************************************************************************
*/

#define F_CPU 8000000UL         /* 8 MHz crystal clock */
#define UART_BAUD_RATE 9600     /* UART Baud Rate */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <util/delay.h>

#include "gp2d120.h"
#include "uart.h"

/* initializes the ADC */
void adc_init(void)
{
        ADMUX = 0 | _BV(ADLAR); // channel 0, left-justified result
        ADCSRA = _BV(ADEN) | _BV(ADPS2);
}

/* starts an ADC conversion */
void adc_start_conversion(void)
{
    ADCSRA |= _BV(ADSC);
}

/* returns boolean value indicating if the ADC conversion is still in prgress */
int adc_conversion_in_progress(void)
{
    return !(ADCSRA & _BV(ADIF));
}

/* clears the ADC interrupt flag */
void adc_clear_interrupt_flag(void)
{
    ADCSRA |= _BV(ADIF);
}

int
main (void)
{
        uint8_t adc_value;      /* gp2d120 ADC value */
        uint8_t distance;       /* gp2d120 distance in cm */
        char buffer[4];         /* max '255\0' */
        uint8_t i;              /* loop counter */

        /* initialize */
        uart_init( UART_BAUD_SELECT(UART_BAUD_RATE,F_CPU) );
	sei();
	uart_puts_P("*** GP2D120 Test Application ***\n\r");
        adc_init();

        while (1)
        {

                /* get ADC value */
                adc_start_conversion();
                while (adc_conversion_in_progress());
                adc_value = ADCH;
                adc_clear_interrupt_flag();

                /* calculate the distance */
                distance = gp2d120_adc8_to_cm(adc_value);

                /* convert ADC value to ascii for UART */
                itoa (adc_value, buffer, 10);
                uart_putc('\t');
                uart_puts(buffer);

                /* convert distance to ascii for UART */
                itoa (distance, buffer, 10);
                uart_putc('\t');
                uart_puts(buffer);
                uart_puts_P("cm\n\r");

                /* long delay */
                for (i=0; i<20; i++) { _delay_ms(250); }
        }
        return (0);
}