/*
 * geigerzaehler.c
 *
 * Created			:	28.02.2019 09:07:22
 * Author			:	John Ditgens, Alexander Brandscheidt
 * Git-Repository	:	https://gitea.Railduction.eu/JohnD/Geigerzaehler.git
 *
 * MController		:	AtMega328P
 * Board			:	Arduino Nano
 */ 
#define F_CPU 16000000UL 				// Clock speed: 16 MHz	- Speed from onboard oscillator

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

// Global variable declaration
uint16_t boost_frequency = 2000;		// 2kHz frequency

uint8_t boost_enable	=	0;
uint8_t boost_highVoltage_nextHigh	=	1;
clock_t boost_highVoltage_nextTick	=	0;

// Todo [CRITICAL]: Clock does not exist! Use timer.

uint8_t signalOutput_enable	=	0;
uint8_t signalOutput_nextHigh	=	1;
clock_t signalOutput_nextTick	=	0;


int main()
{
	// Inputs
    DDRD &= (0 << PORTD2);					// Activate input PD2
    DDRD &= (0 << PORTD3);					// Activate input PD3						
	//PORTD |= (1 << PORTD2);					// Enable pull-up-resistor D2
	//PORTD |= (1 << PORTD3);					// Enable pull-up-resistor D3
	// Todo [CRITICAL]: External pull-down resistors	10kOhm
	
	// Outputs
	DDRD |= (1 << PORTD4);
	DDRD |= (1 << PORTD5);
	DDRD |= (1 << PORTD6);
	
	// Interrupt for INT0	Pin-D2	High-voltage check
    EICRA |= (0 << ISC01)|(1 << ISC00); // On at any edge		[Code: 01]
    EIMSK |= (1 << INT0);				// Activate Interrupt INT0
    
	// Interrupt for INT1	Pin-D3	Counter-click
    EICRA |= (1 << ISC11)|(1 << ISC10);	// On rising edge		[Code: 11]
    EIMSK |= (1 <<INT1);				// Activate Interrupt INT1
	
    sei();		// Activate global interrupts
	
	// Endless loop
    while (1) 
    {
		// HighVoltage boosting
		if(boost_enable == 1)
		{
			if(clock() >= boost_highVoltage_nextTick)	// If we are on or after the tick it should be executed
			{
				// Set pin according to next exec
				if(boost_highVoltage_nextHigh == 1)		// Set it high
				{
					PORTD |= (1 << PORTD4);
					boost_highVoltage_nextHigh = 0;	// Next is low
				}
				else  								// Set it low
				{
					PORTD |= (0 << PORTD4);
					boost_highVoltage_nextHigh = 1;	// Next is high
				}
				
				// Calculate when next high/low should be set
				boost_highVoltage_nextTick = clock() + F_CPU * 1/(boost_frequency/2);		// Half of time it should be high/low
			}
		}else
		{
			if(boost_highVoltage_nextTick > 0)		// If boosting is deactivated, but the nextTick was not reset yet
			{
				// Reset boost-state
				PORTD |= (0 << PORTD4);
				boost_highVoltage_nextHigh = 1;
				boost_highVoltage_nextTick = 0;
			}
		}
		
		
		// Signal output
		if(signalOutput_enable)
		{
			if(clock() >= signalOutput_nextTick)	// If we are on or after the tick it should be executed
			{
				// Set pin according to next exec
				if(signalOutput_nextHigh == 1)		// Set it high
				{
					PORTD |= (1 << PORTD5);
					PORTD |= (1 << PORTD6);
					signalOutput_nextHigh = 0;	// Next is low
				}
				else  								// Set it low
				{
					PORTD |= (0 << PORTD5);
					PORTD |= (0 << PORTD6);
					signalOutput_nextHigh = 1;	// Next is high
					
					signalOutput_enable = 0;	// Disable signalOutput
				}
				
				// When the signal should stop
				signalOutput_nextTick = clock() + F_CPU * 0.2; 		// nextTick is in 0.2s
			}
		}
    }
}

/*
 * Interrupt-handler
 * ISR - Interrupt service routine
 */
// Address: 0x001	INT0	-	On any edge		[Code: 01]
// Handles:	Over/Below working voltage
ISR(INT0_vect)
{
	if(!(PIND & (1 << PORTD2)))	// Falling edge
	{	
		// Below ~400V, activate booster
		boost_enable = 1;
	}
	else					// Rising edge
	{
		// Reached ~400V, deactivate booster
		boost_enable = 0;
	}
	
	reti();		// Exit interrupt-handler
}

// Address: 0x002	INT1	-	On rising edge	[Code: 11]
// Handles:	Counter tube "tick"
ISR(INT1_vect)
{
	// Tick detected, signalOutput
	signalOutput_enable = 1;
	// Execute immediately
	signalOutput_nextTick = 0;
	
	reti();		// Exit interrupt-handler
}