/*
	Analog2.C  ->  Data Collection / Monitor
	
	Written by Jeffrey J. Richardson	September 7, 2002
	
	Uses the MegaAVR-DEVelopment Board available from PRLLC
		with an ATmega163 controller operating at 6MHz.
		
	Second Analog to Digital program.
		This program will setup the ADC...
		Reads the value every 60 seconds and sends it out the serial port (CSV)
*/

#include<mega163.h>
#include<stdio.h>

#define XTAL 	6000000L
#define BAUD 	9600
#define OCF2 	0x80

void init_serial(void);
void init_ports(void);
void init_delay2(void);
void init_ADC(void);
unsigned char read_ADC(void);

void main(void)
	{
	unsigned char temp, seconds;
	unsigned int time;
	
	init_ports();					// setup the ports
	init_serial();					// setup the serial port
	init_ADC();					// setup the Analog Converter
	init_delay2();					// setup the timer
		
	printf("Analog to Digital Converter 2.\n\r");
	printf("Time, Temp\n");
	
	seconds = 0;
	time = 0;
	
	while(1)					// do forever...
		{
		if(seconds == 0)
			{
			temp = read_ADC();
			PORTC = ~temp;			// monitor the ADC input and display it on the LEDs
			printf("%i,%d\n", time, temp);
			}
			
                while( (TIFR & OCF2) == 0)		// wait for second to be up...
			{
			}
		TIFR = (TIFR | OCF2);			// clear flag for next time

		seconds++;				// increment the seconds
		if(seconds > 59)
			{
			seconds = 0;
			time++;
			}
	        }
	}

unsigned char read_ADC(void)
	{
	unsigned char value;
	
	ADCSR = ADCSR | 0x40;			// start a conversion
	
	while( (ADCSR & 0x10) == 0 );		// wait for conversion to be completed
	
	value = ADCH;				// get the upper 8-bits
	ADCSR = ADCSR | 0x10;			// clear the flag
	
	return value;
	}
	
void init_serial(void)
	{
	unsigned int UBR;				// 16 bit variable to hold serial port calculations

	UBR = XTAL / 16 / BAUD - 1;			// calculate the load values
	UBRR = (unsigned char)(UBR & 0xFF);		// load the lower 8 bits
	UBRRHI = (unsigned char)(UBR >> 8);		// load the upper bits
	UCSRB = 0x18;					// enable transmit and receive
	}
	
void init_ports(void)
	{
	DDRC = 0xFF;					// setup PortC for output
	PORTC = 0x00; 
	}

void init_ADC(void)
	{
	ADMUX = 0x00;			// start by selecting channel 0
	ADMUX = ADMUX | 0x40;		// select the voltage reference
	ADMUX = ADMUX | 0x20;		// set for Left Justified
	
	ADCSR = 0x07;			// select the ADC clock frequency
	ADCSR = ADCSR | 0x80;		// enable the ADC
	}

void init_delay2(void)                       		// variable 1 second based delay using Timer2
	{						// will flash the LED on PortB during operation!!
	ASSR = 0x08;					// set for asynchronous clock
	TCCR2 = 0x0F;					// set prescale for 1024 & clear counter on compare match
	TIFR = (TIFR | 0xC0);				// clear any previous timer flags
	OCR2 = 32;					// additional prescale for 1 second timer
	while(ASSR & 0x02);				// wait for info to be transfered to OCR2
	}